Fiber break detection method and apparatus, fiber optic communication system

Abstract

The application discloses a fiber breakage detection method and device and an optical fiber communication system, and belongs to the technical field of optical communication. In the method, a first device collects an optical signal based on the fact that the received optical power of the optical signal received through an optical fiber link is less than a first power threshold and greater than a second power threshold. The first device determines the position of a breakage point of the optical fiber link according to the collected signal. The hardware implementation of the application is simple, and the detection cost is low.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a fiber breakage detection method and device, and an optical fiber communication system. Background Technology

[0002] Fiber optic communication systems typically include transmitting equipment, receiving equipment, and fiber optic links. The transmitting and receiving equipment are connected via fiber optic links. The transmitting equipment modulates the information to be transmitted onto an optical signal and then transmits this optical signal to the receiving equipment via the fiber optic link. The receiving equipment receives the optical signal via the fiber optic link and demodulates the information carried by the optical signal. In practical applications, most fiber optic links are located in buried optical cables or laid in building utility tunnels. Fiber optic links can break due to human damage, natural disasters, animal damage, power outages, cable aging, and other reasons. Therefore, it is necessary to inspect fiber optic links to determine the location of the breakage point.

[0003] Currently, optical time domain reflectometers (OTDRs) are commonly used to detect fiber optic links. For example, an OTDR is deployed in a fiber optic link, controlling it to transmit optical signals through the link and detect the reflected optical signals. Based on the reflected optical signals detected by the OTDR, the location of the fault point (e.g., break point) in the fiber optic link is determined.

[0004] However, currently, testing fiber optic links requires an additional OTDR, which complicates the hardware implementation for testing fiber optic links. Summary of the Invention

[0005] This application provides a fiber breakage detection method and apparatus, and an optical fiber communication system. The technical solution of this application is as follows.

[0006] In a first aspect, a fiber breakage detection method is provided, applied to a first device. The method includes: receiving a first optical signal through an optical fiber link deployed between the first device and a second device; the first optical signal including a second optical signal and a reflected optical signal; the second optical signal being an optical signal generated by the second device; and the reflected optical signal being an optical signal reflected during the transmission of the second optical signal through the optical fiber link; acquiring the first optical signal based on the received optical power being less than a first power threshold and greater than a second power threshold to obtain an acquired signal; and determining the location of the fiber breakage point based on the acquired signal.

[0007] The first and second power thresholds are both preset empirical values. Research has found that when the received optical power of the optical signal received through the fiber optic link reaches (e.g., decreases to) the first power threshold, it is highly likely that the fiber optic link is beginning to break; when the received optical power of the optical signal received through the fiber optic link reaches (e.g., decreases to) the second power threshold, it is highly likely that the fiber optic link has already broken. Therefore, if the received optical power of the optical signal received through the fiber optic link is less than the first power threshold but greater than the second power threshold, it is highly likely that the fiber optic link is breaking.

[0008] The technical solution provided in this application involves a first device acquiring the first optical signal based on the received optical power being less than a first power threshold and greater than a second power threshold. This can be considered as the first device acquiring the first optical signal received through the optical fiber link during a break in the fiber optic link. The first device determines the location of the break point in the optical fiber link based on the acquired signal, thus achieving fiber break detection. The technical solution provided in this application is a transmission-type detection scheme, where existing equipment in the optical fiber communication system (i.e., the first and second devices) performs fiber break detection on the optical fiber link. Fiber break detection can be achieved without deploying additional hardware in the optical fiber link, resulting in simple hardware implementation and low detection cost.

[0009] Secondly, a fiber breakage detection method is provided, applied to a first device. The method includes: receiving a first optical signal through an optical fiber link deployed between the first device and a second device; the first optical signal including a second optical signal and a reflected optical signal; the second optical signal being an optical signal generated by the second device based on a notification message sent by the first device; the notification message being sent by the first device when the received optical power of the optical signal received through the optical fiber link is less than a first power threshold and greater than a second power threshold; and the reflected optical signal being an optical signal reflected during the transmission of the second optical signal through the optical fiber link; acquiring the first optical signal to obtain an acquired signal; and determining the location of the break point of the optical fiber link based on the acquired signal.

[0010] The technical solution provided in this application involves a first device sending a notification message to a second device when the received optical power of the optical signal received through the fiber optic link is less than a first power threshold but greater than a second power threshold. This can be considered as the first device sending a notification message to the second device during the fiber optic link breakage process. During the fiber optic link breakage process, the second device, based on the notification message, sends a second optical signal to the first device through the fiber optic link. The second optical signal is transmitted through the fiber optic link and becomes a first optical signal. The first device collects the first optical signal to obtain a collected signal and determines the location of the fiber optic link breakage point based on the collected signal, thus realizing fiber optic link breakage detection. The technical solution provided in this application is a transmission-type detection scheme, which uses existing equipment in the fiber optic communication system (i.e., the first and second devices) to perform fiber optic link breakage detection. Fiber optic link breakage detection can be achieved without deploying additional hardware in the fiber optic link, resulting in simple hardware implementation and low detection cost.

[0011] Optionally, in the second aspect, the method further includes: stopping the acquisition of the first optical signal based on the fact that the received optical power of the first optical signal received through the optical fiber link is less than a second power threshold. If the received optical power of the first optical signal received through the optical fiber link is less than the second power threshold, it is highly likely that the optical fiber link has broken; therefore, the first device stops acquiring the first optical signal.

[0012] Optionally, in the first and second aspects described above, the second optical signal carries a detection signal, which is used by the first device to determine the location of the fiber optic link break point. Furthermore, the second optical signal may also carry a service signal (or service information or data signal). With the second optical signal carrying both the detection signal and the service signal, this application can achieve in-line fiber optic link break detection. The detection signal can be a detection sequence or a continuous wave (CW) optical signal. A CW optical signal is a continuous, stable, single-frequency signal that does not involve modulation; the amplitude and frequency of the CW optical signal are constant.

[0013] Optionally, in the first case of the first aspect and the second aspect described above, the second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point of the optical fiber link. Determining the location of the break point of the optical fiber link based on the acquired signal includes: demodulating the acquired signal to obtain the detection sequence; and determining the location of the break point of the optical fiber link based on the demodulated detection sequence.

[0014] Since the second optical signal carries a detection sequence, and the first optical signal includes the second optical signal, the first optical signal also carries a detection sequence. The acquired signal obtained by acquiring the first optical signal also carries a detection sequence. In this way, the first device can obtain the detection sequence by demodulating the acquired signal, and can determine the location of the fiber optic link break point based on the demodulated detection sequence. The technical solution provided in this application, by carrying a detection sequence in the second optical signal, allows the first device to perform fiber break detection on the fiber optic link to determine the location of the break point. Fiber break detection can be achieved without deploying additional hardware in the fiber optic link, resulting in simple hardware implementation and low detection cost.

[0015] In the optional implementation of the first case, the autocorrelation curve corresponding to the detection sequence carried by the second optical signal has a single characteristic peak. For example, the autocorrelation curve corresponding to the detection sequence carried by the second optical signal has only one characteristic peak.

[0016] The technical solution provided in this application has a characteristic peak in the autocorrelation curve corresponding to the detection sequence carried by the second optical signal, and the first optical signal includes the second optical signal. Therefore, the autocorrelation curve corresponding to the detection sequence carried by the first optical signal has a characteristic peak, and the autocorrelation curve corresponding to the detection sequence carried by the acquisition signal obtained by acquiring the first optical signal has a characteristic peak. In this way, the first device can easily determine the location of the fiber optic link break point based on the characteristic peak of the autocorrelation curve corresponding to the detection sequence demodulated from the acquisition signal.

[0017] In the optional implementation of the first case, the detection sequence carried by the second optical signal includes multiple sub-detection sequences. The autocorrelation curve corresponding to the detection sequence is determined based on the autocorrelation curves of the multiple sub-detection sequences. The autocorrelation value at each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation values ​​at each position point on the autocorrelation curves of the multiple sub-detection sequences.

[0018] In an optional implementation of the first case, the second optical signal carries multiple detection sequences that are periodically distributed; there are boundary markers between adjacent detection sequences; or, adjacent detection sequences are consecutive.

[0019] The technical solution provided in this application carries multiple detection sequences in the second optical signal, which reduces the difficulty for the first device to demodulate the detection sequences from the acquired signal. Specifically, if the second optical signal carries only one detection sequence, then the first optical signal also carries only one detection sequence, and the acquired signal obtained from the first optical signal also carries only one detection sequence. The first device needs to accurately demodulate this detection sequence from the acquired signal in order to determine the location of the fiber optic link breakpoint based on the demodulated detection sequence. However, if the second optical signal carries multiple detection sequences, then the first optical signal also carries multiple detection sequences, and the acquired signal obtained from the first optical signal also carries multiple detection sequences. The first device only needs to demodulate one of these multiple detection sequences from the acquired signal to determine the location of the fiber optic link breakpoint based on the demodulated detection sequence, thereby reducing the difficulty for the first device to demodulate the detection sequences from the acquired signal.

[0020] In an optional implementation of the first case, the second optical signal carries multiple detection sequences, which are periodically distributed and have boundary markers between adjacent detection sequences. Demodulating the acquired signal to obtain the detection sequences includes: determining the multiple detection sequences carried by the acquired signal based on the boundary markers carried by the acquired signal.

[0021] The technical solution provided in this application allows the first device to determine the detection sequence carried by the acquired signal based on the boundary marker during the demodulation process of the acquired signal, thereby reducing the difficulty for the first device to demodulate the detection sequence from the acquired signal.

[0022] In the optional implementation of the first case, the second optical signal carries multiple detection sequences, which are periodically distributed and adjacent detection sequences are continuous. Demodulating the acquired signal to obtain the detection sequences includes: determining the multiple detection sequences carried by the acquired signal based on the characteristics of the detection sequences.

[0023] In the technical solution provided in this application, during the demodulation of the acquired signal by the first device, the first device determines the detection sequence carried by the acquired signal based on the characteristics of the detection sequence, so that the first device can determine the location of the fiber optic link break point based on the demodulated detection sequence.

[0024] In the optional implementation of the first case, determining the location of the fiber optic link breakpoint based on the demodulated detection sequence includes: obtaining the correlation curve corresponding to the demodulated detection sequence, which is an autocorrelation curve or a cross-correlation curve, and the cross-correlation curve is determined based on the demodulated detection sequence and the detection sequence known by the first device; and determining the location of the fiber optic link breakpoint based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence.

[0025] The technical solution provided in this application allows the cross-correlation curve determined based on the demodulated detection sequence and the known detection sequence of the first device to be considered as the autocorrelation curve of the detection sequence. Since the autocorrelation curve corresponding to the detection sequence carried by the second optical signal has a characteristic peak, the first device can determine the location of the fiber optic link breakpoint based on the characteristic peak of the autocorrelation curve corresponding to the demodulated detection sequence.

[0026] In the optional implementation of the first case, the reflected optical signal includes a first sub-reflected optical signal, which is the optical signal reflected from the second optical signal between the break point of the optical fiber link and the reflective end face of the second device. The location of the break point of the optical fiber link is determined based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence, including: determining the delay of the first sub-reflected optical signal compared to the second optical signal based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence; and determining the distance between the break point of the optical fiber link and the reflective end face of the second device based on the delay of the first sub-reflected optical signal compared to the second optical signal.

[0027] The technical solution provided in this application includes a first sub-reflected optical signal in the reflected optical signal. Therefore, the correlation curve corresponding to the demodulated detection sequence includes a characteristic peak corresponding to the first sub-reflected optical signal. The characteristic peak corresponding to the first sub-reflected optical signal is caused by the first sub-reflected optical signal. The first sub-reflected optical signal has a certain delay compared to the second optical signal. The magnitude of the delay depends on the distance between the break point of the optical fiber link and the reflective end face of the second device (that is, the length of the optical fiber located between the break point and the reflective end face of the second device in the optical fiber link). Therefore, the first device can determine the delay of the first sub-reflected optical signal compared to the second optical signal based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence, and then determine the distance between the break point of the optical fiber link and the reflective end face of the second device based on the delay of the first sub-reflected optical signal compared to the second optical signal.

[0028] In the optional implementation of the first case, the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks. Determining the delay of the first sub-reflected optical signal relative to the second optical signal based on these characteristic peaks includes: determining the delay of the first sub-reflected optical signal relative to the second optical signal based on the main peak and the first peak among the multiple characteristic peaks. Here, the first peak corresponds to the first sub-reflected optical signal, and the first peak is caused by the first sub-reflected optical signal.

[0029] In the alternative implementation of the first scenario, the second optical signal also carries a service signal. The detection sequence can be modulated onto the service signal. That is, by carrying the service signal and the detection sequence in the same optical signal, it is possible to perform fiber optic link breakage detection along the path.

[0030] In the alternative implementation of the first scenario, the second optical signal also carries a service signal, and the detection sequence is modulated onto the service signal. In the second optical signal, the modulation depth of the detection sequence is less than the modulation depth of the service signal, and the baud rate of the detection sequence is less than the baud rate of the service signal.

[0031] The technical solution provided in this application sets the modulation depth of the detection sequence to be less than the modulation depth of the service signal, and the baud rate of the detection sequence to be less than the baud rate of the service signal. This can achieve fiber breakage detection along the fiber link while avoiding the detection sequence from affecting the service signal.

[0032] In the optional implementation of the first case, in the second optical signal, the ratio of the modulation depth of the detection sequence to the modulation depth of the service signal is less than a preset ratio; the difference between the baud rate of the service signal and the baud rate of the detection sequence is within a preset range.

[0033] The technical solution provided in this application ensures that the difference between the baud rate of the service signal and the baud rate of the detection sequence is within a preset range. Therefore, the baud rate of the detection sequence is less than the baud rate of the service signal, but the baud rate of the detection sequence is not very small. In this way, the detection sequence can avoid affecting the service signal while avoiding the detection sequence baud rate being too small, which would make it difficult to detect fiber optic link breaks.

[0034] In the optional implementation of the first scenario, the second optical signal also carries a service signal (i.e., the second optical signal carries both a detection sequence and a service signal), with the detection sequence modulated onto the service signal. Demodulation of the acquired signal includes filtering the acquired signal.

[0035] The technical solution provided in this application, since the second optical signal carries the detection sequence and the service signal, the first optical signal carries the detection sequence and the service signal, and the collected signal obtained by collecting the first optical signal carries the detection sequence and the service signal, the first device filters the collected signal, which can reduce the influence of the service signal on the detection sequence, thereby reducing the influence of the service signal on the detection result.

[0036] Optionally, in the second case of the first and second aspects described above, the second optical signal carries a CW optical signal, which is used by the first device to determine the location of the break point of the optical fiber link. The reflected optical signal includes a CW reflected optical signal, which is an optical signal reflected during the transmission of the CW optical signal through the optical fiber link. Determining the location of the break point of the optical fiber link based on the acquired signal includes: determining the target spectrum of the CW reflected optical signal based on the acquired signal; and determining the location of the break point of the optical fiber link based on the target spectrum.

[0037] The technical solution provided in this application involves a first device receiving a first optical signal via an optical fiber link. The first optical signal includes a second optical signal and a reflected optical signal. The second optical signal carries a CW (Continuous Wave) optical signal, and the reflected optical signal includes a CW reflected optical signal. Therefore, the acquired signal obtained by acquiring the first optical signal includes signal components corresponding to the CW reflected optical signal. In this way, the first device can determine the target spectrum of the CW reflected optical signal based on the acquired signal, and then determine the location of the fiber optic link break point based on the target spectrum, thus achieving fiber break detection. The technical solution provided in this application utilizes existing equipment in the optical fiber communication system (i.e., the first and second devices) to perform fiber break detection on the optical fiber link. It achieves fiber break detection without deploying additional hardware in the optical fiber link, simplifying hardware implementation and reducing detection costs.

[0038] In the optional implementation of the second case, the target spectrum includes a first spectral curve, which is the spectral curve of the first CW sub-reflected optical signal. The first CW sub-reflected optical signal is the optical signal reflected by the CW optical signal carried by the second optical signal between the break point of the optical fiber link and the reflective end face of the second device. The aforementioned CW reflected optical signal includes the first CW sub-reflected optical signal. Determining the location of the break point of the optical fiber link based on the target spectrum includes: determining the distance between the break point of the optical fiber link and the reflective end face of the second device based on the frequency corresponding to the characteristic peak of the first spectral curve.

[0039] In the alternative implementation of the second scenario, the second optical signal also carries a service signal. That is, the second optical signal carries both a CW optical signal and a service signal. Since the service optical signal is used to carry service signals (or service information), and the service optical signal typically carries the CW optical signal naturally, in the case where the second optical signal carries both the CW optical signal and the service signal, the second optical signal can be the service optical signal.

[0040] The technical solution provided in this application carries CW optical signals and service signals in the second optical signal, which can realize fiber optic link breakage detection along the path.

[0041] In the alternative implementation of the second case, the second optical signal is a CW optical signal.

[0042] In the second scenario of the first and second aspects described above, the target spectrum of the CW reflected optical signal can be determined by a single Fourier transform or by two Fourier transforms. Determining the target spectrum by two Fourier transforms makes the characteristic peaks of the spectral curve more prominent, thus facilitating the determination of the frequencies corresponding to these characteristic peaks. This allows for the identification of the fiber optic link breakpoint based on the frequencies corresponding to the characteristic peaks. The Fourier transform can be a Fast Fourier Transform (FFT), thereby reducing the computational complexity of determining the target spectrum.

[0043] Optionally, in the second case described above, determining the target spectrum of the CW reflected light signal based on the acquired signal includes the following seven implementation methods.

[0044] The first implementation method, which determines the target spectrum of the CW reflected light signal based on the acquired signal, includes performing a Fourier transform on the acquired signal to obtain the target spectrum of the CW reflected light signal. For example, when the second light signal only carries a CW light signal, such as when the second light signal is a CW light signal, this first implementation method is used to determine the target spectrum of the CW reflected light signal.

[0045] In the second implementation, the second optical signal also carries a service signal; that is, the second optical signal carries both a CW optical signal and a service signal. For example, the second optical signal is a service optical signal. Determining the target spectrum of the CW reflected optical signal based on the acquired signal includes: filtering the acquired signal to obtain a filtered signal; and performing a Fourier transform on the filtered signal to obtain the target spectrum of the CW reflected optical signal.

[0046] In the third implementation, the second optical signal also carries a service signal; that is, the second optical signal carries both the CW optical signal and the service signal. For example, the second optical signal is a service optical signal. Determining the target spectrum of the CW reflected optical signal based on the acquired signal includes: performing a Fourier transform on the acquired signal to obtain a first spectrum; and filtering the first spectrum to obtain the target spectrum of the CW reflected optical signal.

[0047] The fourth implementation method determines the target spectrum of the CW reflected light signal based on the acquired signal, including: performing a Fourier transform on the acquired signal to obtain a first spectrum; and performing a Fourier transform on the first spectrum to obtain the target spectrum of the CW reflected light signal. For example, this fourth implementation method is used to determine the target spectrum of the CW reflected light signal when the second light signal only carries the CW light signal.

[0048] In the fifth implementation, the second optical signal also carries a service signal; that is, the second optical signal carries both a CW optical signal and a service signal. For example, the second optical signal is a service optical signal. Determining the target spectrum of the CW reflected optical signal based on the acquired signal includes: filtering the acquired signal to obtain a filtered signal; performing a Fourier transform on the filtered signal to obtain a first spectrum; and performing a Fourier transform on the first spectrum to obtain the target spectrum of the CW reflected optical signal.

[0049] In the sixth implementation, the second optical signal also carries a service signal; that is, the second optical signal carries both the CW optical signal and the service signal. For example, the second optical signal is a service optical signal. Determining the target spectrum of the CW reflected optical signal based on the acquired signal includes: performing a Fourier transform on the acquired signal to obtain a first spectrum; performing a Fourier transform on the first spectrum to obtain a second spectrum; and filtering the second spectrum to obtain the target spectrum of the CW reflected optical signal.

[0050] In the seventh implementation, the second optical signal also carries a service signal; that is, the second optical signal carries both the CW optical signal and the service signal. For example, the second optical signal is a service optical signal. Determining the target spectrum of the CW reflected optical signal based on the acquired signal includes: performing a Fourier transform on the acquired signal to obtain a first spectrum; filtering the first spectrum to obtain a second spectrum; and performing a Fourier transform on the second spectrum to obtain the target spectrum of the CW reflected optical signal.

[0051] The first to third implementations described above determine the target spectrum of the CW reflected optical signal through a single Fourier transform, while the fourth to seventh implementations determine the target spectrum of the CW reflected optical signal through two Fourier transforms. When the second optical signal carries only the CW optical signal, either the first or fourth implementation can be used to determine the target spectrum of the CW reflected optical signal.

[0052] In the optional implementation of the second scenario described above, the target spectrum of the CW reflected optical signal is determined by a single Fourier transform. The frequency corresponding to the characteristic peak of the first spectrum curve and the distance between the fiber optic link break point and the reflecting end face of the second device satisfy f. N =c / n / (2×L)×N, f N The frequency corresponding to the characteristic peak of the first spectral curve is represented by c, the transmission rate of the optical signal in a vacuum is represented by n, the refractive index of the optical fiber link is represented by L, the distance between the break point of the optical fiber link and the reflective end face of the second device is represented by N, and the symbol " / " represents the division sign.

[0053] In the optional implementation of the second scenario described above, the target spectrum of the CW reflected optical signal is determined by two Fourier transforms. The frequency corresponding to the characteristic peak of the first spectrum curve and the distance between the fiber optic link break point and the reflecting end face of the second device satisfy f. N =1 / (c / n / (2×L)×N), f N The frequency corresponding to the characteristic peak of the first spectral curve is represented by c, the transmission rate of the optical signal in a vacuum is represented by n, the refractive index of the optical fiber link is represented by L, the distance between the break point of the optical fiber link and the reflective end face of the second device is represented by N, and the symbol " / " represents the division sign.

[0054] Optionally, in the third case of the first and second aspects above, determining the location of the fiber optic link break point based on the acquired signal includes: determining the cepstral of the acquired signal based on the acquired signal; and determining the location of the fiber optic link break point based on the cepstral of the acquired signal.

[0055] In the third optional implementation, the reflected optical signal includes a first sub-reflected optical signal, which is the optical signal reflected from the second optical signal between the break point of the optical fiber link and the reflective end face of the second device. Determining the location of the break point of the optical fiber link based on the cepstrum of the acquired signal includes: determining the delay of the first sub-reflected optical signal relative to the second optical signal based on the cepstrum of the acquired signal; and determining the distance between the break point of the optical fiber link and the reflective end face of the second device based on the delay of the first sub-reflected optical signal relative to the second optical signal.

[0056] In the third alternative implementation, the second optical signal carries the service signal. For example, the second optical signal is a service optical signal. This enables in-line fiber optic link breakage detection.

[0057] In the third alternative implementation, the second optical signal carries a CW optical signal. For example, the second optical signal is a CW optical signal.

[0058] Optionally, the fiber breakage detection method provided by the first aspect and its optional implementations, as well as the fiber breakage detection method provided by the second aspect and its optional implementations, can be executed by the first device, the optical module in the first device, or the optical fiber card in the first device.

[0059] Thirdly, a fiber breakage detection method is provided, applied to a second device. The method includes: receiving a notification message sent by a first device to the second device when the received optical power of an optical signal received via an optical fiber link is less than a first power threshold but greater than a second power threshold, wherein the optical fiber link is deployed between the first and second devices; generating a second optical signal based on the notification message; and transmitting the second optical signal to the first device via the optical fiber link, wherein the second optical signal, after transmission via the optical fiber link, becomes a first optical signal, the first optical signal including the second optical signal and a reflected optical signal, the reflected optical signal being the optical signal reflected during the transmission of the second optical signal via the optical fiber link. The first device is used to determine the location of the fiber breakage point based on the first optical signal. For example, the first device is used to collect the first optical signal to obtain a collected signal, and to determine the location of the fiber breakage point based on the collected signal.

[0060] The first and second power thresholds are both preset empirical values. Research has found that when the received optical power of the optical signal received through the fiber optic link reaches (e.g., decreases to) the first power threshold, it is highly likely that the fiber optic link is beginning to break; when the received optical power of the optical signal received through the fiber optic link reaches (e.g., decreases to) the second power threshold, it is highly likely that the fiber optic link has already broken. Therefore, if the received optical power of the optical signal received through the fiber optic link is less than the first power threshold but greater than the second power threshold, it is highly likely that the fiber optic link is breaking.

[0061] The technical solution provided in this application involves a first device sending a notification message to a second device when the received optical power of the optical signal received through the fiber optic link is less than a first power threshold but greater than a second power threshold. This can be considered as the first device sending a notification message to the second device during the fiber optic link breakage process. During the fiber optic link breakage process, the second device, based on the notification message, sends a second optical signal to the first device through the fiber optic link. The second optical signal is transmitted through the fiber optic link and becomes a first optical signal. The first device collects the first optical signal to obtain a collected signal and determines the location of the fiber optic link breakage point based on the collected signal, thus realizing fiber optic link breakage detection. The technical solution provided in this application is a transmission-type detection scheme, which uses existing equipment in the fiber optic communication system (i.e., the first and second devices) to perform fiber optic link breakage detection. Fiber optic link breakage detection can be achieved without deploying additional hardware in the fiber optic link, resulting in simple hardware implementation and low detection cost.

[0062] In the third aspect, the second optical signal carries a detection signal, which is used by the first device to determine the location of the fiber optic link break point. Furthermore, the second optical signal may also carry a service signal. With the second optical signal carrying both the detection signal and the service signal, this application can achieve in-line fiber optic link break detection. The detection signal can be a detection sequence or a CW optical signal.

[0063] In the first case of the third aspect, the second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point in the optical fiber link.

[0064] Since the second optical signal carries a detection sequence, and the first optical signal includes the second optical signal, the first optical signal also carries a detection sequence. The acquired signal obtained by acquiring the first optical signal also carries a detection sequence. In this way, the first device can obtain the detection sequence by demodulating the acquired signal, and can determine the location of the fiber optic link break point based on the demodulated detection sequence. The technical solution provided in this application, by carrying a detection sequence in the second optical signal, allows the first device to perform fiber break detection on the fiber optic link to determine the location of the break point. Fiber break detection can be achieved without deploying additional hardware in the fiber optic link, resulting in simple hardware implementation and low detection cost.

[0065] In the optional implementation of the first case, the autocorrelation curve corresponding to the detection sequence carried by the second optical signal has a single characteristic peak. For example, the autocorrelation curve corresponding to the detection sequence carried by the second optical signal has only one characteristic peak.

[0066] The technical solution provided in this application has a characteristic peak in the autocorrelation curve corresponding to the detection sequence carried by the second optical signal, and the first optical signal includes the second optical signal. Therefore, the autocorrelation curve corresponding to the detection sequence carried by the first optical signal has a characteristic peak, and the autocorrelation curve corresponding to the detection sequence carried by the acquisition signal obtained by acquiring the first optical signal has a characteristic peak. In this way, the first device can easily determine the location of the fiber optic link break point based on the characteristic peak of the autocorrelation curve corresponding to the detection sequence demodulated from the acquisition signal.

[0067] In the optional implementation of the first case, the detection sequence carried by the second optical signal includes multiple sub-detection sequences. The autocorrelation curve corresponding to the detection sequence is determined based on the autocorrelation curves of the multiple sub-detection sequences. The autocorrelation value at each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation values ​​at each position point on the autocorrelation curves of the multiple sub-detection sequences.

[0068] In an optional implementation of the first case, the second optical signal carries multiple detection sequences that are periodically distributed; there are boundary markers between adjacent detection sequences; or, adjacent detection sequences are consecutive.

[0069] The technical solution provided in this application carries multiple detection sequences in the second optical signal, which reduces the difficulty for the first device to demodulate the detection sequences from the acquired signal. Specifically, if the second optical signal carries only one detection sequence, then the first optical signal also carries only one detection sequence, and the acquired signal obtained from the first optical signal also carries only one detection sequence. The first device needs to accurately demodulate this detection sequence from the acquired signal in order to determine the location of the fiber optic link breakpoint based on the demodulated detection sequence. However, if the second optical signal carries multiple detection sequences, then the first optical signal also carries multiple detection sequences, and the acquired signal obtained from the first optical signal also carries multiple detection sequences. The first device only needs to demodulate one of these multiple detection sequences from the acquired signal to determine the location of the fiber optic link breakpoint based on the demodulated detection sequence, thereby reducing the difficulty for the first device to demodulate the detection sequences from the acquired signal.

[0070] In the alternative implementation of the first scenario, the second optical signal also carries a service signal. The detection sequence can be modulated onto the service signal. That is, by carrying the service signal and the detection sequence in the same optical signal, it is possible to perform fiber optic link breakage detection along the path.

[0071] In the alternative implementation of the first scenario, the second optical signal also carries a service signal, and the detection sequence is modulated onto the service signal. In the second optical signal, the modulation depth of the detection sequence is less than the modulation depth of the service signal, and the baud rate of the detection sequence is less than the baud rate of the service signal.

[0072] The technical solution provided in this application sets the modulation depth of the detection sequence to be less than the modulation depth of the service signal, and the baud rate of the detection sequence to be less than the baud rate of the service signal. This can achieve fiber breakage detection along the fiber link while avoiding the detection sequence from affecting the service signal.

[0073] In the optional implementation of the first case, in the second optical signal, the ratio of the modulation depth of the detection sequence to the modulation depth of the service signal is less than a preset ratio; the difference between the baud rate of the service signal and the baud rate of the detection sequence is within a preset range.

[0074] The technical solution provided in this application ensures that the difference between the baud rate of the service signal and the baud rate of the detection sequence is within a preset range. Therefore, the baud rate of the detection sequence is less than the baud rate of the service signal, but the baud rate of the detection sequence is not very small. In this way, the detection sequence can avoid affecting the service signal while avoiding the detection sequence baud rate being too small, which would make it difficult to detect fiber optic link breaks.

[0075] In the second case of the third aspect, the second optical signal carries a CW optical signal, which is used by the first device to determine the location of the break point of the optical fiber link.

[0076] In the alternative implementation of the second scenario, the second optical signal also carries a service signal. That is, the second optical signal carries both a CW optical signal and a service signal. Since the service optical signal is used to carry service signals (or service information), and the service optical signal typically carries the CW optical signal naturally, in the case where the second optical signal carries both the CW optical signal and the service signal, the second optical signal can be the service optical signal.

[0077] The technical solution provided in this application carries CW optical signals and service signals in the second optical signal, which can realize fiber optic link breakage detection along the path.

[0078] In the alternative implementation of the second case, the second optical signal is a CW optical signal.

[0079] Fourthly, a fiber breakage detection device is provided, applied to a first device, the fiber breakage detection device comprising at least one functional module. The at least one functional module is used to perform the fiber breakage detection method provided by the first aspect or any optional method of the first aspect described above. Alternatively, the at least one functional module is used to perform the fiber breakage detection method provided by the second aspect or any optional method of the second aspect described above. The at least one functional module can be implemented based on software, hardware, or a combination of software and hardware, and the at least one functional module can be arbitrarily combined or divided based on a specific implementation. Optionally, the fiber breakage detection device is the first device, an optical module in the first device, or a fiber optic card in the first device; or, the fiber breakage detection device is integrated into the first device, integrated into an optical module in the first device, or integrated into a fiber optic card in the first device.

[0080] Fifthly, a fiber breakage detection device is provided, applied to a second device. The fiber breakage detection device includes at least one functional module for performing the fiber breakage detection method provided by the third aspect or any optional method of the third aspect. The at least one functional module can be implemented based on software, hardware, or a combination of both, and can be arbitrarily combined or divided based on a specific implementation. Optionally, the fiber breakage detection device is the second device, an optical module in the second device, or a fiber optic card in the second device; alternatively, the fiber breakage detection device is integrated into the second device, an optical module integrated into the second device, or a fiber optic card integrated into the second device.

[0081] Sixthly, a fiber breakage detection device is provided, comprising a memory and a processor; the memory stores a computer program; the processor executes the computer program stored in the memory to cause the fiber breakage detection device to perform a fiber breakage detection method as provided in the first aspect or any optional method of the first aspect, or to cause the fiber breakage detection device to perform a fiber breakage detection method as provided in the second aspect or any optional method of the second aspect. Optionally, the fiber breakage detection device is a first device, an optical module in the first device, or a fiber optic card in the first device; or, the fiber breakage detection device is integrated into the first device, an optical module integrated into the first device, or a fiber optic card integrated into the first device.

[0082] In a seventh aspect, a fiber breakage detection device is provided, comprising a memory and a processor; the memory stores a computer program; the processor executes the computer program stored in the memory to cause the fiber breakage detection device to perform the fiber breakage detection method provided in the third aspect or any optional embodiment of the third aspect. Optionally, the fiber breakage detection device is a second device, an optical module in the second device, or a fiber optic card in the second device; or, the fiber breakage detection device is integrated into the second device, an optical module integrated into the second device, or a fiber optic card integrated into the second device.

[0083] Eighthly, a fiber breakage detection device is provided, comprising a main control board and an interface board. The main control board and the interface board are used to implement the fiber breakage detection method provided by the first aspect or any optional embodiment of the first aspect described above. Alternatively, the main control board and the interface board are used to implement the fiber breakage detection method provided by the second aspect or any optional embodiment of the second aspect described above.

[0084] In a ninth aspect, a fiber breakage detection device is provided, comprising a main control board and an interface board. The main control board and the interface board are used to implement the fiber breakage detection method provided in the third aspect or any alternative embodiment of the third aspect described above.

[0085] A tenth aspect provides a fiber breakage detection device, comprising a processor and an optical device. The optical device is used to perform transmit / receive operations in the fiber breakage detection method provided by the first aspect or any optional embodiment thereof; the processor is used to perform operations other than transmit / receive operations in the fiber breakage detection method provided by the first aspect or any optional embodiment thereof. Alternatively, the optical device is used to perform transmit / receive operations in the fiber breakage detection method provided by the second aspect or any optional embodiment thereof; the processor is used to perform operations other than transmit / receive operations in the fiber breakage detection method provided by the second aspect or any optional embodiment thereof.

[0086] Eleventhly, a fiber breakage detection device is provided, comprising a processor and an optical device. The optical device is used to perform transmit / receive operations in the fiber breakage detection method provided by the third aspect or any optional embodiment of the third aspect; the processor is used to perform operations other than transmit / receive operations in the fiber breakage detection method provided by the third aspect or any optional embodiment of the third aspect.

[0087] In an optional implementation, in the tenth and eleventh aspects above, the processor includes an optical digital signal processor (ODSP); the optical device includes at least one of an optical transmitter or an optical receiver.

[0088] In the optional implementation, in the tenth and eleventh aspects mentioned above, the fiber breakage detection device is an optical module or a fiber optic card.

[0089] In a twelfth aspect, an optical fiber communication system is provided, including a first device, a second device, and an optical fiber link; the first device and the second device are connected via the optical fiber link. The first device includes a fiber breakage detection device as provided in the fourth, sixth, eighth, or tenth aspects above. The second device includes a fiber breakage detection device as provided in the fifth, seventh, ninth, or eleventh aspects above.

[0090] In a thirteenth aspect, a computer-readable storage medium is provided, wherein a computer program is stored thereon. When executed, the computer program implements at least some steps of the fiber breakage detection method provided by the first aspect or any alternative embodiment of the first aspect. Alternatively, when executed, the computer program implements at least some steps of the fiber breakage detection method provided by the second aspect or any alternative embodiment of the second aspect. Alternatively, when executed, the computer program implements at least some steps of the fiber breakage detection method provided by the third aspect or any alternative embodiment of the third aspect.

[0091] In a fourteenth aspect, a computer program product is provided, comprising a program or code. When executed, the program or code implements at least some steps of the fiber breakage detection method provided by the first aspect or any optional embodiment of the first aspect. Alternatively, when executed, the program or code implements at least some steps of the fiber breakage detection method provided by the second aspect or any optional embodiment of the second aspect. Alternatively, when executed, the program or code implements at least some steps of the fiber breakage detection method provided by the third aspect or any optional embodiment of the third aspect.

[0092] In a fifteenth aspect, a chip is provided, comprising programmable logic circuitry and / or program instructions. The chip, when operated, is configured to implement at least some steps of the fiber breakage detection method provided by the first aspect or any optional embodiment of the first aspect. Alternatively, the chip, when operated, is configured to implement at least some steps of the fiber breakage detection method provided by the second aspect or any optional embodiment of the second aspect. Alternatively, the chip, when operated, is configured to implement at least some steps of the fiber breakage detection method provided by the third aspect or any optional embodiment of the third aspect.

[0093] The beneficial effects achieved by aspects four through fifteen and their corresponding optional implementations can be referenced to the beneficial effects achieved by aspects one through three and their corresponding optional implementations, and will not be elaborated upon here. In aspects one through fifteen, both the first device and the second device can be network devices, terminal devices, or servers. Network devices can be optical transmission network equipment, switches, or routers, etc. Terminal devices can be personal computers (PCs), desktop computers, printers, or cameras, etc. Attached Figure Description

[0094] Figure 1 This is a schematic diagram illustrating an application scenario provided in an embodiment of this application;

[0095] Figure 2 This is a schematic diagram illustrating another application scenario provided by an embodiment of this application;

[0096] Figure 3 This is a schematic diagram illustrating the transmission of an optical signal in an optical fiber link according to an embodiment of this application;

[0097] Figure 4 This is a flowchart of a fiber breakage detection method provided in an embodiment of this application;

[0098] Figure 5 This is a schematic diagram of a sub-detection sequence X1 provided in an embodiment of this application;

[0099] Figure 6This is a schematic diagram of a sub-detection sequence X2 provided in an embodiment of this application;

[0100] Figure 7 This is a schematic diagram of the autocorrelation curves of a sub-detection sequence X1 and a sub-detection sequence X2 provided in an embodiment of this application;

[0101] Figure 8 This is a schematic diagram of the autocorrelation curve corresponding to a detection sequence X provided in an embodiment of this application;

[0102] Figure 9 This is a schematic diagram of the correlation curve corresponding to a detection sequence X provided in an embodiment of this application;

[0103] Figure 10 This is a schematic diagram of a first spectrum curve provided in an embodiment of this application;

[0104] Figure 11 This is a flowchart of another fiber breakage detection method provided in the embodiments of this application;

[0105] Figure 12 This is a schematic diagram of a fiber breakage detection device provided in an embodiment of this application;

[0106] Figure 13 This is a schematic diagram of another fiber breakage detection device provided in the embodiments of this application;

[0107] Figure 14 This is a schematic diagram of another fiber breakage detection device provided in the embodiments of this application;

[0108] Figure 15 This is a schematic diagram of another fiber breakage detection device provided in the embodiments of this application. Detailed Implementation

[0109] The embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0110] An optical fiber communication system is a communication system that uses optical fiber as the transmission medium. By modulating information onto optical signals and transmitting them through optical fibers, an optical fiber communication system can achieve high-speed, long-distance, and high-capacity communication transmission.

[0111] Fiber optic communication systems typically include transmitting equipment, receiving equipment, and fiber optic links. The transmitting and receiving equipment are connected via a fiber optic link. The transmitting equipment modulates the information to be transmitted onto an optical signal and then transmits this optical signal to the receiving equipment via the fiber optic link. The receiving equipment receives the optical signal via the fiber optic link and demodulates the information carried by the optical signal. Both the transmitting and receiving equipment are optical communication devices; however, the terms "transmitting device" and "receiving device" are relative, and any optical communication device in a fiber optic communication system can function as either a transmitting or receiving device.

[0112] In practical applications, most fiber optic links are located within buried cables, submarine cables, or in building utility tunnels. These links can break due to human damage, natural disasters, animal damage, power outages, and cable aging. For example, buried and submarine cables may break due to construction work, excavation, or intentional damage. Cables may also break due to natural disasters such as earthquakes, floods, and typhoons; animal damage; power outages such as lightning strikes and electric arcs; aging; wear; or corrosion. A broken fiber optic link affects communication between transmitting and receiving equipment; therefore, it is necessary to inspect the fiber optic link to determine the location of the break and subsequently repair it.

[0113] Currently, optical time domain reflectometers (OTDRs) are commonly used to inspect fiber optic links. OTDRs detect the loss, attenuation, reflection, and location of faults (e.g., breaks) in fiber optic links based on time-domain reflectometry. For example, an OTDR is deployed in a fiber optic link, controlling it to transmit an optical signal through the link and detect the reflected optical signal. Based on the time, intensity, and waveform of the reflected optical signal detected by the OTDR, the loss, attenuation, reflection, and location of faults (e.g., breaks) in the fiber optic link are determined. Specifically, an OTDR consists of a laser and a detector, deployed at the same end of the fiber optic link. The laser transmits the optical signal through the link, and the detector detects the reflected optical signal after the laser has transmitted the signal. To allow the reflected optical signal to reach the detector, a circulator or power divider is deployed in the fiber optic link, and the detector is connected to the link through the circulator or power divider. The reflected optical signal is coupled to the detector through the power divider or circulator for detection. However, using an OTDR to test fiber optic links requires additional hardware such as the OTDR and circulator (or power divider) to be deployed within the fiber optic link, and fiber plugging and unplugging is also necessary. This makes the hardware implementation for testing fiber optic links complex and the testing cost high. Integrating the OTDR into the optical module would increase both the cost and size of the optical module.

[0114] In addition to using OTDR to test fiber optic links, staff can also carry instruments to the site to locate faults in fiber optic links. However, this method is cumbersome to operate, complicated to implement, and has high labor costs.

[0115] This application provides a fiber breakage detection method and apparatus, as well as an optical fiber communication system. It utilizes existing equipment (such as transmitting and receiving equipment) within the optical fiber communication system to detect fiber breakages and determine the location of the break point. This eliminates the need for additional hardware such as OTDRs, circulators (or power dividers) in the fiber optic link, fiber plugging and unplugging, integrating OTDRs into optical modules, and requiring personnel to carry instruments to the site for testing. Therefore, the hardware implementation for fiber breakage detection is simple, the detection cost is low, and it enables in-line fiber breakage detection without increasing the cost and size of optical modules, resulting in low labor costs.

[0116] The technical solutions of the embodiments of this application are described below. First, the application scenarios of the embodiments of this application are introduced.

[0117] This application provides an optical fiber communication system, which includes a first device, a second device, and at least one optical fiber link deployed between the first device and the second device. The at least one optical fiber link is used for communication between the first device and the second device. Either the first device or the second device can act as a transmitting device to send an optical signal to the other device, whereby the other device acts as a receiving device. For example, if the first device sends an optical signal to the second device via the optical fiber link, then the first device is the transmitting device and the second device is the receiving device. As another example, if the second device sends an optical signal to the first device via the optical fiber link, then the second device is the transmitting device and the first device is the receiving device.

[0118] In this embodiment, both the first and second devices are optical communication devices. The optical communication device includes an optical module and / or a fiber optic card, which performs operations related to optical signal processing. In an optional embodiment, the optical module and / or fiber optic card are pluggable in the optical communication device. For example, the optical communication device includes a slot into which the optical module and / or fiber optic card are inserted to be disposed. In this embodiment, the optical communication device can be a network device, a terminal device, or a server. The network device can be an optical transport network device, a switch, or a router, etc. The terminal device can be a personal computer (PC), a desktop computer, a printer, or a camera, etc. For example, the optical module is pluggable in the optical transport network device, switch, router, or terminal device, and the fiber optic card is pluggable in the optical transport network device or data communication device.

[0119] In the embodiments of this application, the first device includes any one of a network device, a terminal device, or a server, and the second device includes any one of a network device, a terminal device, or a server. Furthermore, the first device and the second device can be the same type of optical communication device, or they can be different types of optical communication devices. In one example, both the first device and the second device are network devices; for example, both the first device and the second device are switches or both are routers. In another example, both the first device and the second device are terminal devices; for example, both the first device and the second device are PCs or both are desktop computers. In yet another example, both the first device and the second device are servers. In yet another example, the first device is a network device, and the second device is a terminal device or a server. In yet another example, the first device is a terminal device, and the second device is a network device or a server. In yet another example, the first device is a server, and the second device is a network device or a terminal device.

[0120] The aforementioned at least one optical fiber link may include a unidirectional optical fiber link or a bidirectional optical fiber link. A unidirectional optical fiber link is used for one of the first and second devices to transmit optical signals to the other device, but not for the other device to transmit optical signals to the first device. A bidirectional optical fiber link is used for both the first device to transmit optical signals to the second device and the second device to transmit optical signals to the first device.

[0121] As an example, please refer to Figure 1 This illustration shows a schematic diagram of an optical fiber communication system provided in an embodiment of this application. The optical fiber communication system includes a first device 110, a second device 120, and an optical fiber link 130 deployed between the first device 110 and the second device 120. The optical fiber link 130 is a bidirectional optical fiber link between the first device 110 and the second device 120, used for both the first device 110 and the second device 120 to transmit optical signals. Alternatively, the optical fiber link 130 can be a unidirectional optical fiber link between the first device 110 and the second device 120, used for one device to transmit optical signals to the other, but not for the other device to transmit optical signals to the first device; for example, the optical fiber link 130 can be used for the second device 120 to transmit optical signals to the first device 110, but not for the first device 110 to transmit optical signals to the second device 120.

[0122] In a specific embodiment, the first device 110 includes an optical transmitter and an optical receiver. Figure 1 (Not shown in the image), the second device 120 includes an optical transmitter and an optical receiver. Figure 1 (Not shown in the image). For example, the first device 110 includes an optical module and / or a fiber optic card (not shown in the image). Figure 1(Not shown in the image), the optical module and / or the optical fiber card includes an optical transmitter and an optical receiver; the second device 120 includes an optical module and / or an optical fiber card (…). Figure 1 (Not shown in the image), the optical module and / or the optical fiber card includes an optical transmitter and an optical receiver. When the optical fiber link 130 is a bidirectional optical fiber link between the first device 110 and the second device 120, the optical fiber link 130 is connected to both the optical transmitter and the optical receiver in the first device 110, and also to both the optical transmitter and the optical receiver in the second device 120. When the optical fiber link 130 is a unidirectional optical fiber link between the first device 110 and the second device 120, and the optical fiber link 130 is used for the second device 120 to transmit optical signals to the first device 110, but not for the first device 110 to transmit optical signals to the second device 120, the optical fiber link 130 is connected to the optical receiver in the first device 110, and also to the optical transmitter in the second device 120.

[0123] As another example, please refer to Figure 2 This illustration shows a schematic diagram of another optical fiber communication system provided in an embodiment of this application. The optical fiber communication system includes a first device 210, a second device 220, and optical fiber links 230 and 240 deployed between the first device 210 and the second device 220. Both optical fiber links 230 and 240 can be unidirectional optical fiber links between the first device 210 and the second device 220. For example, optical fiber link 230 is used for the second device 220 to send optical signals to the first device 210, but not for the first device 210 to send optical signals to the second device 220; optical fiber link 240 is used for the first device 210 to send optical signals to the second device 220, but not for the second device 220 to send optical signals to the first device 210. In a specific embodiment, the first device 210 includes an optical receiver 211 and an optical transmitter 212, and the second device 220 includes an optical transmitter 221 and an optical receiver 222. For example, the first device 210 includes an optical module and / or an optical fiber card (…). Figure 2 (Not shown in the image), the optical module and / or the optical fiber card includes an optical receiver 211 and an optical transmitter 212; the second device 220 includes an optical module and / or an optical fiber card (…). Figure 2 (Not shown in the image), the optical module and / or the optical card includes an optical transmitter 221 and an optical receiver 222. An optical fiber link 230 is connected to the optical transmitter 221 and the optical receiver 211, respectively. An optical fiber link 240 is connected to the optical transmitter 212 and the optical receiver 222, respectively.

[0124] A break in the fiber optic link between the first and second devices will affect communication between them. Therefore, it is necessary to perform fiber break detection on the fiber optic link between the first and second devices to determine the location of the break point and then repair it. Typically, a fiber optic link breakage lasts for a period of time (e.g., referred to as the fiber optic link breakage process). In this embodiment, for any fiber optic link between the first and second devices, the first and second devices cooperate to perform fiber break detection during the breakage process. This embodiment eliminates the need for additional hardware such as OTDRs, circulators (or power dividers) in the fiber optic link, eliminates the need for fiber plugging and unplugging, and eliminates the need to integrate OTDRs into the optical module. Therefore, the hardware implementation is simple, the detection cost is low, and it can perform fiber break detection along the fiber optic link without increasing the cost and size of the optical module.

[0125] Specifically, the duration of a fiber optic link break is typically from a few milliseconds to hundreds of milliseconds. From a microscopic perspective, the fiber optic link breakage process is essentially the gradual increase in distance between the two end faces (these two end faces are formed due to the fiber optic link breakage; in the absence of a break, these two end faces are hypothetical) starting from zero. During the breakage, the intensity of the optical signal transmitted from the transmitting device to the receiving device through the break point gradually decreases until it reaches zero. Similarly, the received optical power of the optical signal received by the receiving device gradually decreases until it reaches zero. The receiving device experiences a transition from being able to receive optical signals through the fiber optic link to being unable to receive them (or in other words, receiving very little optical power). For the receiving device, the fiber optic link breakage process is essentially a fading process of the received optical power of the optical signal received through the fiber optic link.

[0126] by Figure 1Taking the fiber optic link 130 as an example, the second device 120 sends an optical signal to the first device 110 through the fiber optic link 130, and the first device 110 receives the optical signal sent by the second device 120 through the fiber optic link 130. When the fiber optic link 130 is intact, the optical signal sent by the second device 120 to the first device 110 through the fiber optic link 130 can be almost entirely transmitted to the first device 110 (for example, without considering other losses in the fiber optic link 130, the optical signal sent by the second device 120 to the first device 110 through the fiber optic link 130 can be entirely transmitted to the first device 110). The intensity of the optical signal received by the first device 110 through the fiber optic link 130 is the highest, and the received optical power of the optical signal received by the first device 110 through the fiber optic link 130 is the highest. In the event of a break in the fiber optic link 130, such as... Figure 3 As shown, in the optical signal sent from the second device 120 to the first device 110 via the fiber optic link 130: a portion of the optical signal (e.g.) Figure 3 The optical signal S0 shown continues to be transmitted to the first device 110 through the break point; another part of the optical signal (e.g.) Figure 3 The optical signal S1 shown is reflected back to the second device 120 from the break point, and after being reflected at the reflective end face (e.g., the end face of the laser) of the second device 120, it continues to be transmitted to the first device 110 through the break point. For an optical fiber link with a length of tens of kilometers, the duration of the optical fiber link break is much longer than the time required for the optical signal to be transmitted in the optical fiber link. Therefore, the optical signal S1 can eventually be transmitted to the first device 110; and a portion of the optical signal ( Figure 3 (Not shown) The light will leak out from the break point. The reflection and leakage of the optical signal caused by the break point will reduce the strength of the optical signal that can continue to be transmitted to the first device 110 through the break point, thereby reducing the received optical power of the optical signal received by the first device 110 through the optical fiber link 130. It is evident that the optical signal will attenuate due to the break in the optical fiber link 130 during transmission. Furthermore, as the distance between the two end faces corresponding to the break point gradually increases, the attenuation of the optical signal transmitted in the optical fiber link 130 gradually increases, the strength of the optical signal that can continue to be transmitted to the first device 110 through the break point gradually decreases, and the received optical power of the optical signal received by the first device 110 through the optical fiber link 130 gradually decreases. For the first device 110, the breakage process of the optical fiber link 130 is the process of attenuation of the received optical power of the optical signal received through the optical fiber link 130. Figure 3In the example shown, the optical signal received by the first device 110 includes optical signal S0 and optical signal S1. Optical signal S1 is multipath interference (MPI) noise. Optical signal S1 has a certain delay compared to optical signal S0. The magnitude of the delay depends on the length of the optical fiber on the optical fiber link 130 located between the reflection end face of the second device 120 and the break point. For example, let "S2" represent the optical signal received by the first device 110. P0 represents the intensity of the optical signal S0 when it reaches the first device 110, d(t) represents the optical signal S0, and ω0 represents the frequency of the optical signal S0. Let d(t-τ) represent the phase of optical signal S0, d(t-τ) represent optical signal S1, and τ represent the delay of optical signal S1 relative to optical signal S0. denoted by , where 'a' represents the phase of the optical signal S1, and 'a' represents the loss factor due to reflection.

[0127] In this embodiment, a first device and a second device cooperate to perform fiber breakage detection on the fiber optic link deployed between the first device and the second device, based on the characteristics of the fiber optic link breakage process, to determine the location of the fiber optic link breakage point. In one embodiment, a certain fiber optic link deployed between the first device and the second device (e.g., Figure 1 The fiber optic link 130 shown is or Figure 2 The fiber optic link 230 shown is used by the second device to send optical signals to the first device. The second device sends optical signals to the first device through this fiber optic link. The first device receives the optical signals sent by the second device through this fiber optic link and monitors the received optical power of the received optical signals through this fiber optic link. Based on the fact that the received optical power of the optical signals received through this fiber optic link is less than a first power threshold and greater than a second power threshold, the first device collects the collected optical signals to obtain a collected signal. The first device determines the location of the break point of the fiber optic link based on the collected signal.

[0128] The first and second power thresholds are preset empirical values, which can be flexibly set according to actual conditions. As mentioned earlier, for the receiving device, the fiber optic link breakage process is the fading process of the received optical power of the optical signal received through the fiber optic link. Research has found that when the received optical power of the optical signal received by the receiving device through the fiber optic link reaches (e.g., decreases to) the first power threshold, it is very likely that the fiber optic link has begun to break, that is, the breakage process of the fiber optic link has begun; when the received optical power of the optical signal received by the receiving device through the fiber optic link reaches (e.g., decreases to) the second power threshold, it is very likely that the fiber optic link has completed the breakage, that is, the breakage process of the fiber optic link has ended. Therefore, when the received optical power of the optical signal received by the receiving device through the fiber optic link is less than the first power threshold but greater than the second power threshold, it is very likely that the fiber optic link is breaking. The first device collects the optical signal received through the fiber optic link based on the fact that the received optical power of the optical signal received through the fiber optic link is less than the first power threshold but greater than the second power threshold, which can be considered as the first device collecting the optical signal received through the fiber optic link during the breakage process of the fiber optic link. For example, when the first device determines that the received optical power of the optical signal received through the optical fiber link reaches a first power threshold, it starts to collect the optical signal received through the optical fiber link; when the first device determines that the received optical power of the optical signal received through the optical fiber link reaches a second power threshold, it stops collecting the optical signal received through the optical fiber link. This enables the collection of the optical signal received through the optical fiber link during the breakage process of the optical fiber link, and then determines the location of the breakage point of the optical fiber link based on the collected signal.

[0129] It should be noted that, Figure 1 and Figure 2 The application scenarios illustrated are for illustrative purposes only and are not intended to limit the technical solutions of this application. The structure of the optical fiber communication system can be adjusted according to actual needs. For example, an optical fiber link may include multiple optical fiber segments and optical fiber connectors, with adjacent optical fiber segments connected by optical fiber connectors. The length of the optical fiber link, the number of optical fiber connectors included in the optical fiber link, etc., can be adjusted according to actual needs. As another example, the application scenarios in this application embodiment may also include control devices or network management devices, which can be connected to the first device and the second device respectively, and can control the first device and the second device. This application embodiment does not limit this aspect.

[0130] The above describes the application scenarios of the embodiments of this application. The method embodiments of this application are described below.

[0131] Please refer to Figure 4The diagram illustrates a flowchart of a fiber breakage detection method provided in an embodiment of this application. This fiber breakage detection method is applied to an optical fiber communication system including a first device and a second device, and the method is executed in cooperation between the first device and the second device. For example, the optical fiber communication system is as follows... Figure 1 or Figure 2 As shown. In Figure 4 In the illustrated embodiment, the second device can be a transmitting device, and the first device can be a receiving device.

[0132] See Figure 4 The fiber breakage detection method includes the following steps S401 to S405.

[0133] S401. The second device generates a second optical signal.

[0134] The second optical signal carries a detection signal, which is used by the first device to detect fiber optic link Z as a break to determine the location of the break point. Fiber optic link Z is deployed between the first and second devices. Fiber optic link Z is used by the second device to send optical signals to the first device, and can also be used by the first device to send optical signals to the second device. For example, fiber optic link Z is... Figure 1 Fiber optic link 130 or Figure 2 Fiber optic link 230 in the middle.

[0135] In an optional embodiment, the second optical signal also carries a service signal (or service information or data signal), thereby enabling fiber optic link Z to be detected along the path.

[0136] The detection signal can be a detection sequence or a continuous wave (CW) optical signal. A CW optical signal is a continuous, stable, single-frequency signal that does not involve modulation; the amplitude and frequency of a CW optical signal are constant.

[0137] The implementation process of S401 is described below in two scenarios.

[0138] In the first scenario, the second optical signal carries a detection sequence X, which is used by the first device to determine the location of the break point in the fiber optic link Z. In other words, the detection sequence X is used by the first device to detect fiber breakage in the fiber optic link Z.

[0139] In this embodiment, the autocorrelation curve corresponding to the detection sequence X has a single characteristic peak. Specifically, the autocorrelation curve corresponding to the detection sequence X has only one characteristic peak, and the autocorrelation values ​​at all points on the autocorrelation curve other than this characteristic peak are less than a threshold. That is, the autocorrelation values ​​at all points on the autocorrelation curve corresponding to the detection sequence X, excluding this characteristic peak, are all small (e.g., very small). For example, the autocorrelation curve corresponding to the detection sequence X has only one characteristic peak, and the autocorrelation values ​​at all points on the autocorrelation curve corresponding to the detection sequence X, excluding this characteristic peak, are all 0. For example, the detection sequence X is a pseudo-random binary sequence (PRBS) or a complementary sequence. Furthermore, this complementary sequence can be a periodic complementary sequence or an aperiodic complementary sequence. For example, the detection sequence X is a Gray complementary sequence. A Gray complementary sequence is a pulse-coded sequence, and a Gray complementary sequence is an aperiodic complementary sequence.

[0140] In an optional embodiment, the detection sequence X includes multiple sub-detection sequences, and the autocorrelation curve corresponding to the detection sequence X is determined based on the autocorrelation curves of the multiple sub-detection sequences. The autocorrelation curve corresponding to the detection sequence X can be a superimposed curve of the autocorrelation curves of the multiple sub-detection sequences. There is a one-to-one correspondence between the position points on the autocorrelation curve corresponding to the detection sequence X and the position points on the autocorrelation curves of the multiple sub-detection sequences. The autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence X is equal to the sum of the autocorrelation values ​​of that position point on the autocorrelation curves of the multiple sub-detection sequences. For example, if there are k sub-detection sequences, where k is an integer greater than 1, the autocorrelation value of each position point on the autocorrelation curve corresponding to the k sub-detection sequences (each of the k autocorrelation curves corresponds one-to-one with the k sub-detection sequences, and each of the k position points is located on one of the k autocorrelation curves) is equal to the sum of the autocorrelation values ​​of the k position points on the k autocorrelation curves of the k sub-detection sequences. The autocorrelation curve of each of the multiple sub-detection sequences has at least one peak, including a primary peak and potentially a secondary peak. The peak value of the primary peak (i.e., the autocorrelation value of the primary peak) is greater than a first threshold, and the peak value of the secondary peak (i.e., the autocorrelation value of the secondary peak) is less than a second threshold. The first threshold is greater than the second threshold, and the difference between the first threshold and the second threshold is greater than a preset difference. The first threshold, the second threshold, and the preset difference can all be set according to actual conditions. That is, on the autocorrelation curve of each sub-detection sequence, the peak value of the primary peak is relatively large (e.g., very large), and the peak value of the secondary peak is relatively small (e.g., very small). In the detection sequence X, the multiple sub-detection sequences are arranged sequentially and are adjacent to each other. The length of each of the multiple sub-detection sequences is a fixed length, and the lengths of the multiple sub-detection sequences can be equal or unequal.

[0141] As an example, the detection sequence X includes two sub-detection sequences, X1 and X2. Sub-detection sequence X2 follows sub-detection sequence X1 and is adjacent to it. The lengths of both sub-detection sequences X1 and X2 are 8. Sub-detection sequence X1 is 1,1,1,-1,1,1,-1,1, and sub-detection sequence X2 is 1,1,1,-1,-1,-1,1,-1. Detection sequence X is 1,1,1,-1,1,1,-1,1,1,1,1,-1,-1,-1,-1,1,-1. Sub-detection sequence X1 is as follows: Figure 5 As shown (the horizontal axis represents the number of symbols included in sub-detection sequence X1, and the vertical axis represents the amplitude of the symbols included in sub-detection sequence X1), sub-detection sequence X2 is as follows: Figure 6 As shown (the horizontal axis represents the number of symbols included in sub-detection sequence X2, and the vertical axis represents the amplitude of the symbols included in sub-detection sequence X2). The autocorrelation curves of sub-detection sequence X1 and sub-detection sequence X2 are shown below. Figure 7 As shown. See also Figure 7 The autocorrelation curve of sub-detection sequence X1 has a large peak value, and the autocorrelation values ​​at all other points on the autocorrelation curve of sub-detection sequence X1 are relatively small. Similarly, the autocorrelation curve of sub-detection sequence X2 also has a large peak value, and the autocorrelation values ​​at all other points on the autocorrelation curve of sub-detection sequence X2 are relatively small. Furthermore, the autocorrelation values ​​at all other points on the autocorrelation curves of sub-detection sequences X1 and X2 are opposite. The autocorrelation curve corresponding to detection sequence X is a superposition curve of the autocorrelation curves of sub-detection sequences X1 and X2. Figure 7 The superimposed curve of the two curves in the image), the autocorrelation curve corresponding to the detection sequence X is as follows: Figure 8 As shown. See also Figure 8 The autocorrelation curve corresponding to the detection sequence X has only one characteristic peak, and the autocorrelation value at all points on the autocorrelation curve other than this characteristic peak is 0. It should be noted that when obtaining the autocorrelation curve of a sub-detection sequence, one of the two sub-detection sequences needs to be shifted relative to the other by sign; the number of signs shifted is also called the time-shift sign number. For example, when obtaining the autocorrelation curve of the sub-detection sequence X1, one of the two sub-detection sequences X1 needs to be shifted relative to the other by sign. Figure 7 and Figure 8In the diagram, the horizontal axis represents the sign of time shift, and the vertical axis represents the autocorrelation value (i.e., correlation). Negative and positive signs of time shift indicate different directions of shift. For example, a negative sign of time shift indicates a shift to the left, while a positive sign of time shift indicates a shift to the right.

[0142] In an optional embodiment, the second optical signal carries multiple detection sequences X, which are periodically distributed. There are boundary markers between adjacent detection sequences X; or, adjacent detection sequences X are consecutive. The boundary markers can be idle sequences (e.g., sequences of all zeros) or sequences with amplitudes smaller than the amplitude of the detection sequence X, for example, the amplitude of the boundary marker is half the amplitude of the detection sequence X. When there are boundary markers between adjacent detection sequences X, they are separated by the boundary markers, and there are gaps between them. When adjacent detection sequences X are consecutive, there are no gaps between them. All of the multiple detection sequences X carried by the second optical signal can be used by the first device to determine the location of the break point in the optical fiber link Z. In this embodiment, the second optical signal is transformed into a first optical signal after transmission via the optical fiber link Z. The first optical signal includes the second optical signal and a reflected optical signal R, which is the optical signal reflected during the transmission of the second optical signal via the optical fiber link Z. After receiving the first optical signal, the first device collects the first optical signal to obtain a collected signal. The first device demodulates the detection sequence X from the collected signal and then determines the location of the break point in the fiber optic link Z based on the demodulated detection sequence X. When the second optical signal carries multiple detection sequences X, the first optical signal also carries multiple detection sequences X, and the collected signal obtained from the first optical signal also carries multiple detection sequences X. This facilitates the first device's demodulation of the detection sequences X from the collected signal. For example, if the second optical signal carries only one detection sequence X, then the first optical signal also carries only one detection sequence X, and the collected signal obtained by the first device also carries only one detection sequence X. The first device needs to accurately demodulate this detection sequence X from the collected signal to determine the location of the break point in the fiber optic link Z based on this detection sequence X. However, if the second optical signal carries multiple detection sequences X, the first device only needs to accurately demodulate any one of these multiple detection sequences X from the collected signal to determine the location of the break point in the fiber optic link Z based on the demodulated detection sequence X. It is evident that carrying multiple detection sequences X in the second optical signal can reduce the difficulty for the first device to demodulate the detection sequences X from the acquired signal.

[0143] In an optional embodiment, in this first case, the second optical signal also carries a service signal, and the detection sequence is modulated onto the service signal. That is, the second optical signal carries both the detection sequence X and the service signal, thereby enabling fiber optic link Z to be detected along the path. Since the detection sequence X is considered noise for the service signal, the modulation depth of the detection sequence X in the second optical signal is less than the modulation depth of the service signal, and the baud rate of the detection sequence X is less than the baud rate of the service signal. In this way, fiber optic link Z can be detected along the path without the detection sequence X affecting the service signal. In one embodiment, the ratio of the modulation depth of the detection sequence X to the modulation depth of the service signal in the second optical signal is less than a preset ratio, and the difference between the baud rate of the service signal and the baud rate of the detection sequence X is within a preset range. Both the preset ratio and the preset range can be set according to actual conditions. For example, the preset ratio is 0.1, and the preset range is from several MHz (megahertz) to several GHz (gigahertz). Since the ratio of the modulation depth of the detection sequence X to the modulation depth of the service signal is less than a preset ratio, the baud rate of the detection sequence X is less than the baud rate of the service signal, and the difference between the baud rate of the service signal and the baud rate of the detection sequence X is within a preset range, it is possible to avoid the detection sequence X from affecting the service signal while avoiding the detection sequence X from having too small a baud rate, which would make it difficult to detect fiber breakage in the fiber link Z.

[0144] In this first scenario, the second device can generate the second optical signal using direct modulation and / or external modulation. Direct modulation refers to modulation within the light source, specifically controlling the light source (e.g., directly controlling the pump source of a laser) to make it emit the desired optical signal. Direct modulation is also called internal modulation. External modulation refers to modulating the optical signal emitted by the light source using a modulator outside the light source. The light source can be a laser or a laser diode (LD). The laser can include any one of a vertical cavity surface emitting laser (VCSEL), an electro-absorption modulated laser (EML), or a directly modulated laser (DML). The modulator can be a Mach-Zehnder modulator (MZM) or an electrically variable optical attenuator (EVOA). This application does not limit the light source or modulator.

[0145] In this first case, the second device can generate the second optical signal using any of the following five implementation methods.

[0146] The first implementation involves a second optical signal carrying a detection sequence X but not a service signal. The second device generates the second optical signal using direct modulation. In a specific embodiment, the optical transmitter of the second device includes a light source. The second device modulates the driving signal (e.g., driving current) of the light source using the detection sequence X, so that the light source emits a second optical signal carrying the detection sequence X.

[0147] The second implementation involves a second optical signal carrying a detection sequence X but not a service signal. The second device generates the second optical signal using external modulation. In a specific embodiment, the optical transmitter of the second device includes a light source and a modulator. The second device controls the modulator to modulate the optical signal emitted by the light source using the detection sequence X, thereby obtaining a second optical signal carrying the detection sequence X.

[0148] The third implementation: The second optical signal carries a detection sequence X and a service signal, and the second device generates the second optical signal using a direct modulation method. In a specific embodiment, the optical transmitter of the second device includes a light source, and the second device modulates the driving signal of the light source using the detection sequence X and the service signal, so that the light source emits a second optical signal carrying the detection sequence X and the service signal.

[0149] In one example, the second device first modulates the drive signal of the light source with the detection sequence X, and then modulates the drive signal of the light source with the detection sequence X with the service signal, so that the light source emits a second optical signal carrying the detection sequence X and the service signal.

[0150] In another example, the second device first modulates the drive signal of the light source with the service signal, and then modulates the drive signal of the light source with the service signal using the detection sequence X, so that the light source emits a second optical signal carrying the detection sequence X and the service signal.

[0151] In another example, the second device modulates the detection sequence X onto the service signal, and then uses the service signal modulated with the detection sequence X to modulate the drive signal of the light source, so that the light source emits a second optical signal carrying the detection sequence X and the service signal.

[0152] The fourth implementation method: The second optical signal carries the detection sequence X and the service signal, and the second device generates the second optical signal using an external modulation method. In a specific embodiment, the optical transmitter of the second device includes a light source and a modulator. The second device controls the modulator to modulate the optical signal emitted by the light source using the detection sequence X and the service signal to obtain the second optical signal carrying the detection sequence X and the service signal.

[0153] In one example, the optical transmitter of the second device includes a light source, a first modulator, and a second modulator. The second device controls the first modulator to modulate the optical signal emitted by the light source using a detection sequence X, obtaining an optical signal carrying the detection sequence X. The second device controls the second modulator to modulate the optical signal carrying the detection sequence X obtained by the first modulator using a service signal, obtaining a second optical signal carrying both the detection sequence X and the service signal. That is, the second device sequentially modulates the optical signal emitted by the light source using the detection sequence X and the service signal.

[0154] In another example, the optical transmitter of the second device includes a light source, a first modulator, and a second modulator. The second device controls the first modulator to modulate the optical signal emitted by the light source using a service signal, obtaining an optical signal carrying the service signal. The second device controls the second modulator to modulate the optical signal carrying the service signal obtained by the first modulator using a detection sequence X, obtaining a second optical signal carrying both the detection sequence X and the service signal. That is, the second device sequentially modulates the optical signal emitted by the light source using the service signal and the detection sequence X.

[0155] In another example, the optical transmitter of the second device includes a light source and a modulator. The second device modulates the detection sequence X onto the service signal. The second device controls the modulator to modulate the optical signal emitted by the light source with the service signal modulated with the detection sequence X, thereby obtaining a second optical signal carrying the detection sequence X and the service signal.

[0156] The fifth implementation method: The second optical signal carries the detection sequence X and the service signal, and the second device generates the second optical signal using direct modulation and external modulation methods.

[0157] In one example, the optical transmitter of the second device includes a light source and a modulator; the second device modulates the drive signal of the light source with a detection sequence X so that the light source emits an optical signal carrying the detection sequence X; the second device controls the modulator to modulate the optical signal carrying the detection sequence X emitted by the light source with a service signal to obtain a second optical signal carrying the detection sequence X and the service signal.

[0158] In another example, the optical transmitter of the second device includes a light source and a modulator; the second device modulates the drive signal of the light source with a service signal so that the light source emits an optical signal carrying the service signal; the second device controls the modulator to modulate the optical signal carrying the service signal emitted by the light source with a detection sequence X to obtain a second optical signal carrying the detection sequence X and the service signal.

[0159] In the second scenario: the second optical signal carries CW optical signal A, which is used by the first device to determine the location of the break point in the fiber optic link Z. That is, CW optical signal A is used by the first device to detect fiber breakage in fiber optic link Z.

[0160] In an optional embodiment, the second optical signal also carries a service signal. That is, the second optical signal carries both the CW optical signal A and the service signal, thereby enabling fiber breakage detection along the fiber link Z. It should be noted that since the service optical signal is used to carry service signals (or service information or data signals), and service optical signals typically inherently carry the CW optical signal, when the second optical signal carries both the CW optical signal A and the service signal, the second optical signal can be the service optical signal. It can be understood that carrying the CW optical signal A in the second optical signal includes two implementation methods. In one implementation, the second optical signal only carries the CW optical signal A; for example, the second optical signal is the CW optical signal A. In another implementation, the second optical signal is the service optical signal, carrying both the CW optical signal A and the service signal.

[0161] In this second scenario, the second device can generate the second optical signal using any of the following three implementation methods.

[0162] The first implementation involves a second optical signal carrying a CW optical signal A but not a service signal. The optical transmitter of the second device includes a light source, and the second device controls this light source to emit the second optical signal carrying the CW optical signal A. For example, the second optical signal is CW optical signal A, and the second device controls the light source to emit CW optical signal A.

[0163] The second implementation involves a second optical signal carrying a CW optical signal A and a service signal. The second device generates the second optical signal using direct modulation. In a specific embodiment, the optical transmitter of the second device includes a light source. The second device modulates the driving signal (e.g., driving current) of the light source using the service signal, causing the light source to emit a second optical signal carrying the CW optical signal A and the service signal. For example, if the second optical signal is a service optical signal, the second device modulates the driving signal of the light source using the service signal, causing the light source to emit the service optical signal.

[0164] The third implementation method: The second optical signal carries the CW optical signal A and the service signal. The optical transmitter of the second device includes a light source and a modulator. The second device controls the light source to emit the CW optical signal A. The second device controls the modulator to modulate the CW optical signal A emitted by the light source using the service signal to obtain the second optical signal carrying the CW optical signal A and the service signal. The second optical signal is the service optical signal.

[0165] S402. The second device sends a second optical signal to the first device through the fiber optic link Z.

[0166] The second device includes an interface corresponding to fiber optic link Z, through which it transmits a second optical signal to the first device via fiber optic link Z. This interface is a physical (PHY) interface. For example, it is a gigabit Ethernet (GE) interface (e.g., a 400GE interface) or a terabit Ethernet (TE) interface.

[0167] S403. The first device receives a first optical signal through the optical fiber link Z. The first optical signal includes a second optical signal and a reflected optical signal R.

[0168] The second device sends a second optical signal to the first device via fiber optic link Z. The second optical signal is then transmitted via fiber optic link Z and becomes a first optical signal. The first device receives the first optical signal via fiber optic link Z. In a specific embodiment, the first device includes an interface corresponding to fiber optic link Z, through which it receives the first optical signal. This interface is a PHY interface. For example, this interface is a GE interface or a TE interface.

[0169] The first optical signal includes a second optical signal and a reflected optical signal R. The reflected optical signal R is the optical signal reflected during the transmission of the second optical signal through the fiber optic link Z. For example, the reflected optical signal R is the optical signal obtained by reflection (e.g., an even number of reflections) between reflection points on the fiber optic link Z during its transmission. Reflection points on the fiber optic link Z include break points of the fiber optic link Z and the reflective end face of the second device, and may also include other reflection points. The reflective end face of the second device may be the end face of the laser in the second device. Other reflection points on the fiber optic link Z may be, for example, connectors with poor contact (e.g., loose connectors causing poor contact).

[0170] A reflecting cavity can be formed between any two reflection points on the optical fiber link Z. The reflecting cavity formed between any two reflection points is a cavity created between those two reflection points. The two reflection points forming any reflecting cavity may include a break point in the optical fiber link Z, and may also include the reflecting end face of a second device. The reflected optical signal R may include at least one sub-reflected optical signal, which corresponds one-to-one with at least one reflecting cavity on the optical fiber link Z. Each sub-reflected optical signal is an optical signal obtained by reflecting a second optical signal within the corresponding reflecting cavity (i.e., reflecting between the two reflection points constituting the corresponding reflecting cavity). Each sub-reflected optical signal has a certain delay compared to the second optical signal. The magnitude of the delay depends on the length of the corresponding reflecting cavity (i.e., the length of the optical fiber on the optical fiber link Z located between the two reflection points constituting the corresponding reflecting cavity, also called the distance between the two reflection points). The intensity of each sub-reflected optical signal depends on the reflection intensity of the two reflection points constituting the corresponding reflecting cavity. For example, the at least one reflecting cavity includes a reflecting cavity formed between the break point of the optical fiber link Z and the reflecting end face of the second device. For ease of description, the reflecting cavity formed between the break point of the optical fiber link Z and the reflecting end face of the second device is referred to as the first reflecting cavity, and the optical signal obtained by reflecting the second optical signal in the first reflecting cavity is referred to as the first sub-reflected optical signal. Therefore, the at least one sub-reflected optical signal includes the first sub-reflected optical signal. That is, the reflected optical signal R includes the first sub-reflected optical signal.

[0171] The second optical signal can resonate within some reflecting cavities on the optical fiber link Z. A reflecting cavity capable of resonating is called a resonant cavity, and the optical signal reflected within a resonant cavity is called a resonant signal. For example, the second optical signal resonates within the first reflecting cavity; the first reflecting cavity is the resonant cavity, and the first sub-reflected optical signal is the resonant signal. It is easy to understand that the optical fiber link Z includes at least one reflecting cavity, which includes at least one resonant cavity. The reflected optical signal R includes at least one sub-reflected optical signal corresponding to each of the at least one reflecting cavity, and each sub-reflected optical signal includes at least one resonant signal corresponding to each of the at least one resonant cavity. It can be understood that if the optical fiber link Z does not include any reflecting points other than the break point and the reflecting end face of the second device, the optical fiber link Z does not include any reflecting cavities other than the first reflecting cavity, and the reflected optical signal R only includes the first sub-reflected optical signal. The reflected optical signal R can be the first sub-reflected optical signal. For example, the first reflecting cavity is the resonant cavity, and the reflected optical signal R is the resonant signal. For example... Figure 3The optical signal S1 shown is a resonant signal obtained by reflection within a resonant cavity formed between the break point of the optical fiber link 130 and the reflecting end face of the second device 120, where the optical signal sent from the second device 120 to the first device 110 is reflected. Typically, when the frequency of the optical signal satisfies the resonance condition of the optical cavity (e.g., the aforementioned reflecting cavity), the optical signal will be amplified within the optical cavity to form a resonance. The frequency at which the optical signal resonates within the optical cavity to form a stable standing wave is the resonant frequency of that optical cavity (i.e., the resonant cavity).

[0172] In an optional embodiment, for the second case in S401 (i.e., the case where the second optical signal carries the CW optical signal A), the reflected optical signal R includes a CW reflected optical signal R1, which is the optical signal reflected during the transmission of the CW optical signal A carried by the second optical signal via the optical fiber link Z. The CW reflected optical signal R1 may include at least one CW sub-reflected optical signal, which corresponds one-to-one with the at least one reflecting cavity on the optical fiber link Z. Each CW sub-reflected optical signal is the optical signal reflected by the CW optical signal A within the corresponding reflecting cavity. For ease of description, the optical signal reflected by the CW optical signal A within the first reflecting cavity is referred to as the first CW sub-reflected optical signal; therefore, the at least one CW sub-reflected optical signal includes the first CW sub-reflected optical signal. That is, the CW reflected optical signal R1 includes the first CW sub-reflected optical signal. In this embodiment, the at least one CW sub-reflected optical signal may include at least one resonant signal, which corresponds one-to-one with the at least one resonant cavity on the optical fiber link Z. Each resonant signal is the optical signal obtained by reflecting the CW optical signal A within the corresponding resonant cavity. For example, the first reflecting cavity is a resonant cavity, and the first CW sub-reflected optical signal is a resonant signal. It can be understood that if the optical fiber link Z does not include any reflection points other than the break point and the reflecting end face of the second device, the optical fiber link Z does not include any reflecting cavities other than the first reflecting cavity, and the CW reflected optical signal R1 only includes the first CW sub-reflected optical signal.

[0173] It is easy to understand that, for the second case in S401, the second optical signal carries the CW optical signal A but does not carry the service signal (for example, the second optical signal only carries the CW optical signal A, or more specifically, the second optical signal is the CW optical signal A), or the second optical signal carries both the CW optical signal A and the service signal. When the second optical signal only carries the CW optical signal A, the reflected optical signal R only includes the CW reflected optical signal R1; for example, the second optical signal is the CW optical signal A, and the reflected optical signal R is the CW reflected optical signal R1. When the second optical signal carries both the CW optical signal A and the service signal, the reflected optical signal R includes the CW reflected optical signal R1 and the reflected optical signal corresponding to the service signal.

[0174] S404. The first device collects the first optical signal based on the fact that the received optical power of the first optical signal is less than a first power threshold and greater than a second power threshold, and obtains the collected signal G.

[0175] During the process of receiving a first optical signal through fiber optic link Z, the first device monitors the received optical power of the first optical signal. If the first device determines that the received optical power of the first optical signal is less than a first power threshold and greater than a second power threshold, the first device collects the first optical signal to obtain a collected signal G. The collection duration of the collected signal G is greater than twice the transmission duration of the optical signal in fiber optic link Z. The transmission duration of the optical signal in fiber optic link Z is equal to the length of fiber optic link Z divided by the transmission rate of the optical signal in fiber optic link Z. The transmission rate of the optical signal in fiber optic link Z is equal to the transmission rate of the optical signal in vacuum divided by the refractive index of fiber optic link Z. The collection duration of the collected signal G is a preset duration set according to the length of fiber optic link Z. For example, the length of the collected signal G is predetermined based on the length of fiber optic link Z, and then the collection duration of the collected signal G is determined based on the collection frequency (also called sampling frequency) and the length of the collected signal G. The length of the collected signal G is the number of collection points (also called sampling points) included in the collected signal G, and the collection duration of the collected signal G is equal to the length of the collected signal G divided by the collection frequency. The first device collects the first optical signal based on the collection duration and the collection frequency to obtain the collected signal G.

[0176] In an optional embodiment, the first device acquires at least one acquisition signal G from the first optical signal, wherein the acquisition duration of each acquisition signal G is greater than twice the transmission duration of the optical signal in the optical fiber link Z. In a specific embodiment, the first device begins acquiring the first optical signal when the received optical power of the first optical signal reaches a first power threshold; during the acquisition process, the first device continuously monitors the received optical power of the first optical signal; the first device stops acquiring the first optical signal when the received optical power of the first optical signal reaches a second power threshold; the first device can acquire at least one acquisition signal G. That is, the first device acquires the first optical signal as the received optical power of the first optical signal decreases from the first power threshold to the second power threshold, obtaining at least one acquisition signal G.

[0177] In a specific embodiment, when the first device determines that the received optical power of the first optical signal is less than a first power threshold and greater than a second power threshold, the first device performs photoelectric conversion on the first optical signal to obtain an analog baseband signal (i.e., an analog electrical signal). The first device then acquires the analog baseband signal to obtain an acquisition signal G, which is a digital baseband signal (i.e., a digital electrical signal). The first optical signal includes a second optical signal and a reflected optical signal R. The analog baseband signal includes an analog DC component and an analog AC component. The analog DC component includes an analog DC component corresponding to the second optical signal, and may also include an analog DC component corresponding to the reflected optical signal R. The analog AC component includes an AC reflected signal, which corresponds to the reflected optical signal R; for example, the analog AC component is an AC reflected signal corresponding to the reflected optical signal R. The acquisition signal G obtained by acquiring the analog baseband signal includes a digital DC component and a digital AC component. The digital DC component corresponds to the analog DC component of the analog baseband signal, and the digital AC component corresponds to the analog AC component of the analog baseband signal. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital AC component includes an AC reflected signal, which corresponds to the reflected optical signal R. For example, the digital AC component is the AC reflected signal corresponding to the reflected optical signal R. It should be noted that, in the first case of S401, the second optical signal carries the detection sequence X, therefore, the first optical signal also carries the detection sequence X, the analog baseband signal obtained by photoelectric conversion of the first optical signal also carries the detection sequence X, and the acquisition signal G also carries the detection sequence X. In the second case of S401, the analog DC component in the analog baseband signal corresponding to the second optical signal may be the analog DC component corresponding to the CW optical signal A carried by the second optical signal, and the digital DC component in the acquisition signal G corresponding to the second optical signal may be the digital DC component corresponding to the CW optical signal A carried by the second optical signal. This application embodiment does not limit this.

[0178] In an optional embodiment, the first device includes a power monitoring unit and a data acquisition unit. The power monitoring unit monitors the received optical power of the first optical signal received through the optical fiber link Z. The data acquisition unit acquires the first optical signal to obtain a data acquisition signal G when the power monitoring unit determines that the received optical power of the first optical signal is less than a first power threshold and greater than a second power threshold. For example, when the power monitoring unit determines that the received optical power of the first optical signal reaches the first power threshold, it triggers the data acquisition unit to start acquiring the first optical signal. During the acquisition process, the power monitoring unit continuously monitors the received optical power of the first optical signal. When the power monitoring unit determines that the received optical power of the first optical signal reaches the second power threshold, it triggers the data acquisition unit to stop acquiring the first optical signal. In an optional embodiment, the data acquisition unit includes an optical receiver and an analog-to-digital converter (ADC). The optical receiver performs photoelectric conversion on the first optical signal to obtain an analog baseband signal, and the ADC acquires the analog baseband signal to obtain the data acquisition signal G. The ADC is also called a sampling quantizer, sampling quantization unit, or analog-to-digital conversion unit, and this embodiment does not limit the terminology.

[0179] It should be noted that the above explanation uses the example of the first device stopping the acquisition of the first optical signal when it determines that the received optical power of the first optical signal has reached the second power threshold. The acquisition signal G includes multiple acquisition points (here, acquisition points refer to the acquired data). During the acquisition of the first optical signal, the first device stores each acquisition point in its storage space. The first device can also stop acquiring the first optical signal when the storage space overflows (i.e., the storage space is full). For example, if the first device determines that the storage space has overflowed before the received optical power of the first optical signal reaches the second power threshold, the first device stops acquiring the first optical signal. Furthermore, in this embodiment, the acquisition duration of the acquisition signal G is set to be more than twice the transmission duration of the optical signal in the optical fiber link Z, taking into account that the optical signal will undergo at least two reflections (including one reflection at the break point of the optical fiber link Z and one reflection at the reflection end face of the second device). The acquisition duration of the acquisition signal G can also be other durations, and can be flexibly adjusted according to the actual situation.

[0180] S405. The first device determines the location of the break point in the optical fiber link Z based on the acquired signal G.

[0181] The first device analyzes the acquired signal G, and determines the location of the break point in the optical fiber link Z based on the analysis results.

[0182] In this embodiment of the application, the first device determines the location of the break point of the optical fiber link Z based on the acquired signal G in the following three ways.

[0183] The first scenario (corresponding to the first scenario in S401): The second optical signal carries the detection sequence X. The first optical signal includes the second optical signal and the reflected optical signal R. Therefore, the first optical signal also carries the detection sequence X, and the acquisition signal G also carries the detection sequence X. The first device demodulates the acquisition signal G to obtain the detection sequence X; the first device determines the location of the break point in the optical fiber link Z based on the demodulated detection sequence X.

[0184] In an optional embodiment, the second optical signal carries multiple periodically distributed detection sequences X, and correspondingly, the first optical signal carries multiple periodically distributed detection sequences X, and the acquisition signal G carries multiple periodically distributed detection sequences X. The first device can obtain multiple detection sequences X by demodulating the acquisition signal G.

[0185] In one embodiment, in the second optical signal, there are boundary markers between adjacent detection sequences X among the plurality of detection sequences X. Therefore, in the first optical signal, there are boundary markers between adjacent detection sequences X among the plurality of detection sequences X. In the acquisition signal G, there are boundary markers between adjacent detection sequences X among the plurality of detection sequences X. The first device determines the detection sequence X carried by the acquisition signal G based on the boundary markers carried by the acquisition signal G. In a specific embodiment, the first device searches for boundary markers in the acquisition signal G; the first device determines (i.e., identifies) the start position and / or end position of the detection sequence X carried by the acquisition signal G based on the boundary markers found in the acquisition signal G; the first device determines the detection sequence X carried by the acquisition signal G based on the identified start position and / or end position. For example, the first device identifies the start position and end position of the detection sequence X carried by the acquisition signal G based on the boundary markers found in the acquisition signal G, and the first device defines the portion between the identified start position and end position as a detection sequence X. For example, the first device identifies the starting position of the detection sequence X carried by the acquisition signal G based on the boundary markers found in the acquisition signal G, and the first device determines the portion between adjacent starting positions as a detection sequence X. As another example, the first device identifies the ending position of the detection sequence X carried by the acquisition signal G based on the boundary markers found in the acquisition signal G, and the first device determines the portion between adjacent ending positions as a detection sequence X. Since the multiple detection sequences X are periodically distributed in the acquisition signal G, after the first device determines one detection sequence X carried by the acquisition signal G based on the found boundary markers, the first device determines other detection sequences X carried by the acquisition signal G based on the distribution period of the multiple detection sequences X. This embodiment of the application does not limit this process.

[0186] In another embodiment, in the second optical signal, adjacent detection sequences X among the plurality of detection sequences X are continuous, and there are no boundary markers between adjacent detection sequences X among the plurality of detection sequences X. Therefore, in the first optical signal, adjacent detection sequences X among the plurality of detection sequences X are continuous. In the acquisition signal G, adjacent detection sequences X among the plurality of detection sequences X are continuous. The first device determines the detection sequence X carried by the acquisition signal G based on the characteristics of the detection sequence X. The characteristics of the detection sequence X may be the distribution characteristics or correlation characteristics (e.g., autocorrelation characteristics) of the detection sequence X. In an optional implementation, the first device extracts a sequence from the acquisition signal G based on the length of the detection sequence X known to the first device, for example, by randomly extracting the sequence. For ease of description, the sequence extracted by the first device from the acquisition signal G is called the test sequence, and the length of the test sequence is equal to the length of the detection sequence X known to the first device. The first device verifies whether the test sequence is a detection sequence X based on the detection sequence X known to the first device. If the test sequence is determined to be a detection sequence X through verification, the first device determines that a detection sequence X has been found in the acquisition signal G, and the first device determines other detection sequences X carried by the acquisition signal G based on the distribution period of the plurality of detection sequences X. If verification determines that the sequence to be tested is not the detection sequence X, the first device re-extracts the sequence to be tested from the acquired signal G and verifies whether the re-extracted sequence to be tested is the detection sequence X, until the first device finds a detection sequence X in the acquired signal G. In one example, the first device performs cross-correlation calculation on the sequence to be tested and the detection sequence X known to the first device, and determines whether the sequence to be tested is the detection sequence X based on the cross-correlation calculation result. In a specific embodiment, the first device performs cross-correlation calculation on the sequence to be tested and the detection sequence X known to the first device to obtain the cross-correlation curve between the sequence to be tested and the detection sequence X known to the first device; the first device compares the cross-correlation curve with the autocorrelation curve of the detection sequence X known to the first device to determine whether the cross-correlation curve and the autocorrelation curve match; if the comparison determines that the cross-correlation curve and the autocorrelation curve match, the first device determines that the sequence to be tested is the detection sequence X; if the comparison determines that the cross-correlation curve and the autocorrelation curve do not match, the first device determines that the sequence to be tested is not the detection sequence X. In another example, the first device compares the sequence to be tested with a known detection sequence X to determine whether the sequence to be tested matches the known detection sequence X. If the comparison determines that the sequence to be tested matches the known detection sequence X, the first device determines that the sequence to be tested is the detection sequence X; if the comparison determines that the sequence to be tested does not match the known detection sequence X, the first device determines that the sequence to be tested is not the detection sequence X. It should be noted that the matching described in this paragraph includes, but is not limited to, being substantially the same or completely identical. "Substantially the same" means essentially identical but may have minor differences.For example, for ease of description, the cross-correlation curve between the sequence to be tested and the known detection sequence X of the first device is called the cross-correlation curve Q1, and the autocorrelation curve of the known detection sequence X of the first device is called the autocorrelation curve Q2. The cross-correlation curve Q1 and the autocorrelation curve Q2 are approximately the same in the following aspects: the number of time-shifted signs at each position point on the cross-correlation curve Q1 is the same as the number of time-shifted signs at the corresponding position point on the autocorrelation curve Q2, and the correlation value at each position point on the cross-correlation curve Q1 is approximately the same as the correlation value at the corresponding position point on the autocorrelation curve Q2 (for example, the correlation values ​​are equal or the difference in correlation values ​​is less than a threshold). For example, the cross-correlation curve Q1 and the autocorrelation curve Q2 each include position points -w to w. The correlation value of position point -w on the cross-correlation curve Q1 is approximately the same as the correlation value of position point -w on the autocorrelation curve Q2. The correlation value of position point -w+1 on the cross-correlation curve Q1 is approximately the same as the correlation value of position point -w+1 on the autocorrelation curve Q2. The correlation value of position point -w+2 on the cross-correlation curve Q1 is approximately the same as the correlation value of position point -w+2 on the autocorrelation curve Q2, and so on. Matching the sequence to be tested with the known detection sequence X of the first device includes: multiple symbols of the sequence to be tested correspond one-to-one with multiple symbols of the known detection sequence X of the first device; the amplitude of the symbol of the sequence to be tested is approximately the same as the amplitude of the corresponding symbol of the known detection sequence X of the first device (e.g., the amplitudes are equal or the difference in amplitude is less than a threshold). For example, if the known detection sequence X of the first device is 1,1,1,-1,1,1,-1,1,1,1,1,-1,-1,-1,-1,-1,1,-1, and the sequence to be verified is 1,1,1,-1.2,1,1,-1,1,1.3,1,1,-1,-1,-1,1,1, then the sequence to be verified matches the pre-acquired detection sequence X. It should be noted that the known detection sequence X of the first device is a detection sequence X obtained by the first device in any possible way. For example, the known detection sequence X of the first device is a detection sequence X pre-negotiated by the first device and the second device, or a detection sequence X pre-configured in the first device. In some embodiments, the first device and the second device may pre-negotiate the length of the detection sequence X, or the length of the detection sequence X may be pre-configured in the first device; for example, the length of the detection sequence X is referred to as the target length. The first device extracts the sequence to be verified from the acquired signal G according to the target length, and the length of the sequence to be verified is equal to the target length. The first device performs a hard decision on the sequence to be verified to obtain a hard decision sequence. The first device uses the hard decision sequence as the detection sequence X known to the first device, and then verifies whether the sequence to be verified is the detection sequence X based on the detection sequence X known to the first device (i.e., the hard decision sequence). This application embodiment does not limit this.

[0187] Since the acquired signal G typically contains noise, before determining the detection sequence X from the acquired signal G, the first device performs noise reduction and equalization processing on the acquired signal G to reduce the impact of noise on the acquired signal G. The first device then determines the detection sequence X from the noise-reduced and equalized acquired signal G, thereby avoiding the influence of noise on the first device's determination of the detection sequence X from the acquired signal G. In this embodiment, the process by which the first device determines the detection sequence X from the acquired signal G can be called a synchronization process. For example, the first device includes a synchronization unit, which determines the detection sequence X from the acquired signal G; this embodiment does not limit this aspect.

[0188] In optional embodiments, the second optical signal also carries a service signal. For example, the second optical signal carries a service signal and multiple periodically distributed detection sequences X. Correspondingly, the first optical signal also carries a service signal, and the acquisition signal G also carries a service signal. Before the first device determines the detection sequence X from the acquisition signal G, the first device filters the acquisition signal G, and the filtered acquisition signal G carries the detection sequence X. Here, we take the filtering of the acquisition signal G by the first device as an example. In other embodiments, after the first device converts the first optical signal into an analog baseband signal, the first device filters the analog baseband signal to obtain a filtered analog baseband signal; the first device acquires the filtered analog baseband signal to obtain the acquisition signal G. This application embodiment does not limit this. Wherein, the first device uses an analog filter to filter the analog baseband signal, and the first device uses a digital filter to filter the acquisition signal G. For example, in the second optical signal, the modulation depth of the detection sequence X is less than the modulation depth of the service signal, and the baud rate of the detection sequence X is less than the baud rate of the service signal. The filter is a low-pass filter.

[0189] After demodulating the acquisition signal G to obtain the detection sequence X, the first device determines whether the fiber optic link Z has broken based on the demodulated detection sequence X. If the first device determines that the fiber optic link Z has broken, it determines the location of the break point of the fiber optic link Z based on the demodulated detection sequence X. When the second optical signal carries multiple detection sequences X, the first optical signal also carries multiple detection sequences X, and the acquisition signal G also carries multiple detection sequences X, the first device can demodulate at least one detection sequence X from the acquisition signal G. The first device can perform fiber break detection on the fiber optic link Z based on one or more of these at least one detection sequence X (e.g., determining whether the fiber optic link Z has broken, and if so, determining the location of the break point). For example, to ensure the reliability of the detection results, the first device performs fiber break detection on the fiber optic link Z based on multiple detection sequences X demodulated from the acquisition signal G. The implementation process of the first device performing fiber break detection on the fiber optic link Z based on any two detection sequences X demodulated from the acquisition signal G is the same. The following describes the first device performing fiber break detection on the fiber optic link Z based on one detection sequence X demodulated from the acquisition signal G as an example.

[0190] In this embodiment, the autocorrelation curve corresponding to the detection sequence X carried by the second optical signal has a characteristic peak. The first device acquires the correlation curve corresponding to the detection sequence X demodulated from the acquisition signal G. The first device determines whether the optical fiber link Z has broken based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence X. If the first device determines that the optical fiber link Z has broken, the first device determines the location of the break point of the optical fiber link Z based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence X. The correlation curve corresponding to the demodulated detection sequence X can be an autocorrelation curve or a cross-correlation curve. The autocorrelation curve corresponding to the demodulated detection sequence X is determined based on the demodulated detection sequence X. The cross-correlation curve corresponding to the demodulated detection sequence X is determined based on the demodulated detection sequence X and the detection sequence X known to the first device. The cross-correlation curve determined based on the demodulated detection sequence X and the detection sequence X known to the first device can also be considered as the autocorrelation curve of the detection sequence X.

[0191] In an optional embodiment, the autocorrelation curve corresponding to the detection sequence X carried by the second optical signal has only one characteristic peak, and the autocorrelation values ​​at all points on the autocorrelation curve other than the characteristic peak are less than a threshold, for example, the autocorrelation values ​​at all points on the autocorrelation curve other than the characteristic peak are all 0. The first device determines the number of characteristic peaks in the correlation curve corresponding to the detection sequence X demodulated from the acquisition signal G. If the correlation curve corresponding to the demodulated detection sequence X has only one characteristic peak, the first device determines that the optical fiber link Z has not been broken. If the correlation curve corresponding to the demodulated detection sequence X has multiple characteristic peaks, the first device determines that the optical fiber link Z may be broken. It should be noted that if the correlation curve corresponding to the detection sequence X demodulated from the acquisition signal G has only one characteristic peak, the first device can also determine that the optical fiber link Z does not have poorly contacted connectors or other reflection points. If the correlation curve corresponding to the detection sequence X demodulated from the acquisition signal G has multiple characteristic peaks, the multiple characteristic peaks include one main peak and at least one secondary peak. The primary peak is an inherent characteristic peak of the autocorrelation curve corresponding to the detection sequence X, and this inherent characteristic peak is independent of the presence or absence of reflection. The at least one secondary peak is a characteristic peak caused by reflection, and its peak value is smaller than that of the primary peak. Each of the at least one secondary peak corresponds one-to-one with at least one sub-reflected optical signal included in the reflected optical signal R. Based on the description in S403, it is easy to understand that the at least one sub-reflected optical signal may or may not include the first sub-reflected optical signal. For example, in the case of a break in the optical fiber link Z, the optical fiber link Z includes a first reflecting cavity (i.e., a reflecting cavity formed between the break point of the optical fiber link Z and the reflecting end face of the second device), and the at least one sub-reflected optical signal includes the first sub-reflected optical signal (i.e., the optical signal obtained by reflecting the second optical signal within the first reflecting cavity); in the case of no break in the optical fiber link Z, the optical fiber link Z does not include the first reflecting cavity, and the at least one sub-reflected optical signal does not include the first sub-reflected optical signal. Therefore, when the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G has multiple characteristic peaks, there may be a secondary peak corresponding to the first sub-reflected light signal among these multiple characteristic peaks, or there may be no secondary peak corresponding to the first sub-reflected light signal. That is, there may be a secondary peak related to the breakage of the optical fiber link Z among these multiple characteristic peaks, or there may be no secondary peak related to the breakage of the optical fiber link Z. Therefore, when the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G has multiple characteristic peaks, the first device determines that the optical fiber link Z may have broken.

[0192] In an optional embodiment, when the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G has multiple characteristic peaks, the first device determines whether the optical fiber link Z has broken based on first prior knowledge and the characteristic peaks of the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G. The first prior knowledge may be obtained by detecting the optical fiber link Z using an optical signal carrying the detection sequence X, for example, when the received optical power of the optical signal received through the optical fiber link Z is greater than a first power threshold, provided that the optical fiber link Z has not broken. The first prior knowledge may include the correlation curve corresponding to the detection sequence X demodulated from the optical signal received through the optical fiber link Z. For ease of description, the correlation curve of the detection sequence X included in the first prior knowledge is referred to as the prior correlation curve, and the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G is referred to as the first correlation curve. This prior correlation curve includes at least one characteristic peak. When the at least one characteristic peak is multiple characteristic peaks, the multiple characteristic peaks include a main peak and at least one secondary peak. The main peak is an inherent characteristic peak of the autocorrelation curve corresponding to the detection sequence X, and the at least one secondary peak is a secondary peak caused by reflection unrelated to the breakage of the optical fiber link Z. The first device compares the first correlation curve with the prior correlation curve to determine whether the fiber optic link Z has broken. If the number of characteristic peaks in the first correlation curve is the same as the number of characteristic peaks in the prior correlation curve, and the positions of each characteristic peak in the first correlation curve correspond one-to-one with the positions of each characteristic peak in the prior correlation curve, the first device determines that the fiber optic link Z has not broken. If the number of characteristic peaks in the first correlation curve is greater than the number of characteristic peaks in the prior correlation curve, the positions of some characteristic peaks in the first correlation curve correspond one-to-one with the positions of each characteristic peak in the prior correlation curve, and there are no characteristic peaks in the prior correlation curve that correspond to other characteristic peaks in the first correlation curve, it indicates that these other characteristic peaks in the first correlation curve are due to the breakage of the fiber optic link Z, and the first device determines that the fiber optic link Z has broken. Here, the horizontal axis of the correlation curve represents the number of time shift signs. The position of each characteristic peak in the correlation curve can be the number of time shift signs corresponding to the peak value of each characteristic peak. If the number of time shift signs corresponding to the peak values ​​of two characteristic peaks is the same, then the positions of the two characteristic peaks are the same. For example, the first correlation curve has three characteristic peaks, 11 to 13, and the prior correlation curve has two characteristic peaks, 21 and 22. The position of characteristic peak 11 is the same as the position of characteristic peak 21, and the position of characteristic peak 12 is the same as the position of characteristic peak 22. The prior correlation curve does not have a characteristic peak corresponding to characteristic peak 13. Therefore, the first device determines that the optical fiber link Z has broken, and determines that characteristic peak 13 is caused by the breakage of the optical fiber link Z.

[0193] When the first device determines that the optical fiber link Z has broken, it determines the location of the break point of the optical fiber link Z based on the characteristic peak of the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G. In a specific embodiment, the first optical signal includes a second optical signal and a reflected optical signal R. The reflected optical signal R includes at least one sub-reflected optical signal, which includes the first sub-reflected optical signal. The first sub-reflected optical signal is the optical signal obtained by reflecting the second optical signal between the break point of the optical fiber link Z and the reflecting end face of the second device (that is, the first sub-reflected optical signal is the optical signal obtained by reflecting the second optical signal within the first reflecting cavity). The first sub-reflected optical signal has a certain delay compared to the second optical signal. The magnitude of the delay depends on the length of the optical fiber on the optical fiber link Z located between the break point and the reflecting end face of the second device (that is, the distance between the break point and the reflecting end face of the second device). The first device determines the delay of the first sub-reflected optical signal compared to the second optical signal based on the characteristic peak of the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G. Based on this delay, the first device determines the distance between the break point of the optical fiber link Z and the reflecting end face of the second device. Once the first device determines the distance between the break point of the optical fiber link Z and the reflecting end face of the second device, it also determines the location of the break point of the optical fiber link Z.

[0194] In a specific embodiment, the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G includes multiple characteristic peaks, including a main peak and at least one secondary peak. Each secondary peak corresponds one-to-one with at least one sub-reflected light signal included in the reflected light signal R, and each sub-reflected light signal includes a first sub-reflected light signal. The first device determines the secondary peak corresponding to the first sub-reflected light signal from among the at least one secondary peak. For example, the first device determines the secondary peak corresponding to the first sub-reflected light signal from among the at least one secondary peak based on first prior knowledge. For example, characteristic peak 13 is the secondary peak corresponding to the first sub-reflected light signal. For ease of description, the secondary peak corresponding to the first sub-reflected light signal is referred to as the first peak. The first device determines the delay of the first sub-reflected light signal compared to the second light signal based on the main peak and the first peak. In a specific embodiment, the first device determines the difference between the number of time-shifted symbols corresponding to the first peak and the number of time-shifted symbols corresponding to the main peak (for example, this difference is referred to as the time-shifted symbol difference corresponding to the first peak); the first device determines the delay of the first sub-reflected optical signal relative to the second optical signal based on the time-shifted symbol difference corresponding to the first peak and the baud rate of the detection sequence X carried by the second optical signal. The delay of the first sub-reflected optical signal relative to the second optical signal is the transmission time of the first sub-reflected optical signal between the break point of the optical fiber link Z and the reflection end face of the second device. The delay of the first sub-reflected optical signal relative to the second optical signal includes the time it takes for the first sub-reflected optical signal to reflect from the break point of the optical fiber link Z to the reflection end face of the second device, and the time it takes for the first sub-reflected optical signal to reflect from the reflection end face of the second device to the break point. The time-shifted symbol difference corresponding to the first peak may be positive or negative. A positive value indicates that the first sub-reflected optical signal is the optical signal obtained by reflecting the second optical signal carrying the detection sequence X within the current period from the reflection point corresponding to the first peak (i.e., the reflection end face of the second device and the break point of the fiber optic link Z). A negative value indicates that the first sub-reflected optical signal is the optical signal delayed to the current period from the optical signal obtained by reflecting the second optical signal carrying the detection sequence X within the previous period from the reflection point corresponding to the first peak. When the time shift symbol difference corresponding to the first peak is positive, the first device determines the delay of the first sub-reflected optical signal compared to the second optical signal by multiplying the time shift symbol difference corresponding to the first peak by the symbol period (i.e., the reciprocal of the baud rate) of the detection sequence X carried by the second optical signal. When the time-shift symbol difference corresponding to the first peak is negative, the first device determines the sum of the time-shift symbol difference corresponding to the first peak and the length of the target sequence. The first device determines the sum of the time-shift symbol difference corresponding to the first peak and the length of the target sequence as the number of delayed symbols corresponding to the first peak. The first device determines the delay of the first sub-reflected light signal compared to the second light signal by multiplying the number of delayed symbols corresponding to the first peak with the symbol period of the detection sequence X carried by the second optical signal.The target sequence is the sequence used in the process of obtaining the correlation curve corresponding to the demodulated detection sequence X. The target sequence can be the detection sequence X or any sub-detection sequence included in the detection sequence X.

[0195] After determining the delay of the first sub-reflected optical signal compared to the second optical signal, the first device uses a distance-time formula to determine the distance between the break point of the optical fiber link Z and the reflecting end face of the second device (i.e., the length of the optical fiber between the reflecting end face of the second device and the optical fiber link Z). For example, this distance-time formula is L = (c × τ) / (2 × n), where L represents the distance between the break point of the optical fiber link Z and the reflecting end face of the second device, c represents the transmission rate of the optical signal in vacuum, n represents the refractive index of the optical fiber link Z (c / n represents the transmission rate of the optical signal in the optical fiber link Z), τ represents the delay of the first sub-reflected optical signal compared to the second optical signal, and the symbol " / " represents division. The first device substitutes the delay of the first sub-reflected optical signal compared to the second optical signal into this distance-time formula to calculate the distance between the break point of the optical fiber link Z and the reflecting end face of the second device.

[0196] As an example, please refer to Figure 9 This illustration shows a schematic diagram of the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G, provided in an embodiment of this application. The correlation curve can be an autocorrelation curve or a cross-correlation curve. The correlation curve has two characteristic peaks, and the correlation value at all points on the correlation curve other than these two characteristic peaks is 0. Figure 9 As an example only, in practical applications, due to the influence of random noise, the autocorrelation values ​​at all points on the correlation curve other than the characteristic peak are all very low noise floors; that is, the correlation values ​​at all points on the correlation curve other than the characteristic peak are very small but may not be zero. Assume the prior correlation curve is as follows... Figure 8 The correlation curve shown is based on the first device according to... Figure 8 The correlation curve shown and as Figure 9 The correlation curve shown confirms that fiber optic link Z has broken. Furthermore, in... Figure 9 In the correlation curve shown, the two characteristic peaks include one main peak and one secondary peak. The first device, according to... Figure 8 The correlation curve shown and as Figure 9The correlation curve shown indicates that the secondary peak corresponds to the first sub-reflected optical signal. Since the number of time-shifted symbols corresponding to the primary peak is 0, and the number of time-shifted symbols corresponding to the secondary peak is 2, the first device determines the time-shifted symbol difference corresponding to the secondary peak to be 2 (2-0=2). The first device determines the delay of the first sub-reflected optical signal compared to the second optical signal by multiplying the time-shifted symbol difference corresponding to the secondary peak by the symbol period of the detection sequence X carried by the second optical signal. Based on the delay of the first sub-reflected optical signal compared to the second optical signal, the first device uses the aforementioned distance-time formula to determine the distance between the break point of the fiber optic link Z and the reflection end face of the second device.

[0197] As mentioned earlier, the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G can be an autocorrelation curve or a cross-correlation curve. The autocorrelation curve corresponding to the detection sequence X demodulated from the acquired signal G is determined based on the demodulated detection sequence X. The cross-correlation curve corresponding to the detection sequence X demodulated from the acquired signal G is determined based on the demodulated detection sequence and the detection sequence X known to the first device. The following describes the implementation process of the first device acquiring the correlation curve corresponding to the demodulated detection sequence X.

[0198] In one embodiment, the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G is an autocorrelation curve. The first device determines the autocorrelation curve corresponding to the demodulated detection sequence X based on the demodulated detection sequence X. In a specific embodiment, the detection sequence X carried by the second optical signal includes multiple sub-detection sequences. The first device determines the multiple sub-detection sequences from the demodulated detection sequence X, and determines the autocorrelation curve corresponding to the demodulated detection sequence X based on the multiple sub-detection sequences determined from the demodulated detection sequence X. Taking the example that the multiple sub-detection sequences are k sub-detection sequences, and the k sub-detection sequences are sub-detection sequences X1 to Xk. For ease of description, the sub-detection sequences determined from the demodulated detection sequence X are referred to as demodulated sub-detection sequences. For each of the demodulated sub-detection sequences X1 to Xk: the first device performs autocorrelation calculation on the demodulated sub-detection sequence to obtain the autocorrelation curve of the sub-detection sequence. The first device obtains multiple autocorrelation curves corresponding one-to-one with the demodulated sub-detection sequences X1 to Xk. For example, these multiple autocorrelation curves are referred to as autocorrelation curves 1 to k, and each autocorrelation curve 1 to k corresponds one-to-one with the demodulated sub-detection sequences X1 to Xk. Autocorrelation curve 1 is the autocorrelation curve of the demodulated sub-detection sequence X1. Autocorrelation curve 2 is the autocorrelation curve of the demodulated sub-detection sequence X2, and so on. Autocorrelation curve k is the autocorrelation curve of the demodulated sub-detection sequence Xk. The first device determines the autocorrelation curve corresponding to the demodulated detection sequence X based on autocorrelation curves 1 to k. The autocorrelation curve corresponding to the demodulated detection sequence X can be a superposition curve of autocorrelation curves 1 to k. In a specific embodiment, the position points on autocorrelation curves 1 to k (that is, the position points corresponding to the time shift sign number) correspond one-to-one. The first device adds the amplitudes (i.e., autocorrelation values) on autocorrelation curves 1 to k according to the corresponding position points. The first device plots a curve based on the added amplitudes (i.e., autocorrelation values) to obtain the autocorrelation curve corresponding to the demodulated detection sequence X. In one example, the autocorrelation curves 1 to k all include position points -w to w, each position point -w to w corresponding to a time shift symbol number, where w is a positive integer. Position points -w to w on the autocorrelation curves 1 to k are one-to-one correspondents. The first device adds the k amplitudes (i.e., k autocorrelation values) corresponding to the k position points -w (each of which is located on the autocorrelation curves 1 to k) to obtain the superimposed amplitude corresponding to position point -w. The first device also adds the k amplitudes (i.e., k autocorrelation values) corresponding to the k position points -w+1 (each of which is located on the autocorrelation curves 1 to k) to obtain the superimposed amplitude corresponding to position point -w+1.The first device adds up the k amplitudes (i.e., k autocorrelation values) corresponding to k position points -w+2 (each of which corresponds to a position on the autocorrelation curve 1 to k) to obtain the superimposed amplitude corresponding to position point -w+2. Similarly, the first device adds up the k amplitudes (i.e., k autocorrelation values) corresponding to k position points w (each of which corresponds to a position on the autocorrelation curve 1 to k) to obtain the superimposed amplitude corresponding to position point w. The first device can determine the superimposed amplitudes corresponding to position points -w to w. The first device then plots a curve based on the position points -w to w and their corresponding superimposed amplitudes. The curve plotted by the first device is the autocorrelation curve corresponding to the demodulated detection sequence X. In this embodiment, the aforementioned target sequence can be any one of the demodulated sub-detection sequences X1 to Xk.

[0199] In another embodiment, the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G is a cross-correlation curve. The first device determines the cross-correlation curve corresponding to the demodulated detection sequence X based on the demodulated detection sequence X and the detection sequence X known to the first device. In a specific embodiment, the detection sequence X carried by the second optical signal includes multiple sub-detection sequences. The first device determines the multiple sub-detection sequences from the demodulated detection sequence X, and also determines the multiple sub-detection sequences from the detection sequence X known to the first device. The first device determines the cross-correlation curve corresponding to the demodulated detection sequence X based on the multiple sub-detection sequences determined from the demodulated detection sequence X and the multiple sub-detection sequences determined from the detection sequence X known to the first device. Taking k sub-detection sequences as an example, for ease of description, the k sub-detection sequences determined from the demodulated detection sequence X are referred to as sub-detection sequences X1 to Xk, and the k sub-detection sequences determined from the detection sequence X known to the first device are referred to as sub-detection sequences X1' to Xk'. The first device performs cross-correlation calculations on sub-detection sequences X1 and X1' to obtain the cross-correlation curve of sub-detection sequence X1; the first device performs cross-correlation calculations on sub-detection sequences X2 and X2' to obtain the cross-correlation curve of sub-detection sequence X2; and so on; the first device performs cross-correlation calculations on sub-detection sequences Xk and Xk' to obtain the cross-correlation curve of sub-detection sequence Xk. The first device obtains multiple cross-correlation curves corresponding one-to-one with sub-detection sequences X1 to Xk. For example, these multiple cross-correlation curves are called cross-correlation curves 1 to k, and cross-correlation curves 1 to k correspond one-to-one with sub-detection sequences X1 to Xk. Cross-correlation curve 1 is the cross-correlation curve of sub-detection sequence X1. Cross-correlation curve 2 is the cross-correlation curve of sub-detection sequence X2. And so on. Cross-correlation curve k is the cross-correlation curve of sub-detection sequence Xk. The first device determines the cross-correlation curve corresponding to the demodulated detection sequence X based on cross-correlation curves 1 to k. This cross-correlation curve can be a superposition of cross-correlation curves 1 to k. In a specific embodiment, the position points on cross-correlation curves 1 to k (also the position points corresponding to the time-shift symbol numbers) correspond one-to-one. The first device adds the amplitudes (i.e., cross-correlation values) on cross-correlation curves 1 to k according to the corresponding position points. The first device then plots a curve based on the added amplitudes (i.e., cross-correlation values) to obtain the cross-correlation curve corresponding to the demodulated detection sequence X. In one example, cross-correlation curves 1 to k all include position points -w to w, where each position point corresponds to a time-shift symbol number, and w is a positive integer. The position points -w to w on cross-correlation curves 1 to k correspond one-to-one. The first device adds up the k amplitudes (i.e. k cross-correlation values) corresponding to the k position points -w on the cross-correlation curve 1 to k.The first device adds up the k amplitude values ​​(i.e., k cross-correlation values) corresponding to k position points -w+1 (each of these k position points -w+1 corresponds to a position on the cross-correlation curve 1 to k) to obtain the superimposed amplitude value corresponding to position point -w+1. The first device adds up the k amplitude values ​​(i.e., k cross-correlation values) corresponding to k position points -w+2 (each of these k position points -w+2 corresponds to a position on the cross-correlation curve 1 to k) to obtain the superimposed amplitude value corresponding to position point -w+2. Similarly, the first device adds up the k amplitude values ​​(i.e., k cross-correlation values) corresponding to k position points w (each of these k position points w corresponds to a position on the cross-correlation curve 1 to k) to obtain the superimposed amplitude value corresponding to position point w. The first device can determine the superposition amplitude corresponding to each position point -w to w. The first device then plots a curve based on the position points -w to w and their corresponding superposition amplitudes. This curve is the cross-correlation curve corresponding to the demodulated detection sequence X. In this embodiment, the aforementioned target sequence can be any one of the sub-detection sequences X1 to Xk determined by the first device from the demodulated detection sequence X, or any one of the sub-detection sequences X1' to Xk' determined by the first device from the known detection sequence X.

[0200] In another embodiment, the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G is the autocorrelation curve of the demodulated detection sequence X, and the detection sequence X can be a pseudo-random code sequence. The first device performs autocorrelation calculation on the demodulated detection sequence X to obtain the autocorrelation curve of the demodulated detection sequence X. In this embodiment, the aforementioned target sequence can be the demodulated detection sequence X.

[0201] In another embodiment, the correlation curve corresponding to the detection sequence X demodulated from the acquired signal G is the cross-correlation curve between the demodulated detection sequence X and the detection sequence X known to the first device. The detection sequence X can be a pseudo-random code sequence. The first device performs cross-correlation calculation on the demodulated detection sequence X and the detection sequence X known to the first device to obtain the cross-correlation curve between the demodulated detection sequence X and the detection sequence X known to the first device. In this embodiment, the aforementioned target sequence can be either the demodulated detection sequence X or the detection sequence X known to the first device.

[0202] In an optional embodiment, the detection sequence X includes sub-detection sequences X1 to Xk. In the detection sequence X, sub-detection sequences X1 to Xk are arranged sequentially, and any two adjacent sub-detection sequences X1 to Xk are consecutive. The length of each sub-detection sequence X1 to Xk is a fixed length. The first device determines the sub-detection sequences X1 to Xk from the demodulated detection sequence X based on their arrangement order and length. For example, sub-detection sequences X1 to Xk are sub-detection sequences X1 and X2. In the detection sequence X, sub-detection sequences X1 and X2 are arranged sequentially and are consecutive. The length of sub-detection sequence X1 is a first length, and the length of sub-detection sequence X2 is a second length. The first device determines the sequence with the first length, starting from the beginning position of the demodulated detection sequence X, as sub-detection sequence X1. The first device determines the sequences in the demodulated detection sequence X other than sub-detection sequence X1 as sub-detection sequence X2. The first device can use a similar method to determine the sub-detection sequences X1' to Xk' from the detection sequence X known to the first device.

[0203] The second scenario (corresponding to the second scenario in S401): The second optical signal carries the CW optical signal A, and the first optical signal includes the second optical signal and the reflected optical signal R, where the reflected optical signal R includes the CW reflected optical signal R1. Therefore, the acquired signal G obtained by acquiring the first optical signal includes the signal component corresponding to the CW reflected optical signal R1. The first device determines the target spectrum of the CW reflected optical signal R1 based on the acquired signal G, and the first device determines the location of the break point in the fiber optic link Z based on the target spectrum of the CW reflected optical signal R1.

[0204] The first device processes the acquired signal G to obtain the target spectrum of the CW reflected light signal R1. In this embodiment, the first device can determine the target spectrum of the CW reflected light signal R1 using any one of the following seven implementation methods.

[0205] The first implementation: The second optical signal carries the CW optical signal A but does not carry any service signal. The first optical signal includes the second optical signal and the reflected optical signal R, where the reflected optical signal R includes the CW reflected optical signal R1. For example, the second optical signal only carries the CW optical signal A, and the reflected optical signal R only includes the CW reflected optical signal R1. For instance, the second optical signal is the CW optical signal A, and the reflected optical signal R is the CW reflected optical signal R1. The first device acquires the first optical signal, resulting in an acquisition signal G that includes a digital DC component and a digital AC component. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital DC component corresponding to the second optical signal can be the digital DC component corresponding to the CW optical signal A carried by the second optical signal. The digital AC component includes an AC reflected signal that corresponds to the reflected optical signal R; for example, the digital AC component is the AC reflected signal corresponding to the reflected optical signal R. The first device performs a Fourier transform on the acquisition signal G to obtain the spectrum of the acquisition signal G. The spectrum of the acquired signal G includes the spectrum of the digital DC component and the spectrum of the digital AC component. Within the spectrum of the acquired signal G, the spectrum of the digital DC component and the spectrum of the digital AC component are separate (i.e., independent of each other). The first device determines the target spectrum of the CW reflected light signal R1 based on the spectrum of the acquired signal G. For example, the first device determines the spectrum of the digital AC component in the spectrum of the acquired signal G as the target spectrum of the CW reflected light signal R1.

[0206] It should be noted that in the first implementation, the first device performs a Fourier transform on the acquired signal G, which not only obtains the spectrum of the digital DC component and the spectrum of the digital AC component of the acquired signal G, but also separates the spectrum of the digital DC component and the spectrum of the digital AC component. For example, the digital DC component is the digital DC component corresponding to the CW optical signal A carried by the second optical signal, and the digital AC component is the AC reflected signal corresponding to the reflected optical signal R. Furthermore, the reflected optical signal R only includes the CW reflected optical signal R1. The spectrum of the digital DC component is the spectrum of the CW optical signal A, and the spectrum of the digital AC component is the spectrum of the CW reflected optical signal R1. Therefore, in this embodiment, by performing a Fourier transform on the acquired signal G, not only can the spectrum of the CW optical signal A and the spectrum of the CW reflected optical signal R1 be obtained, but the spectrum of the CW optical signal A and the spectrum of the CW reflected optical signal R1 can also be separated (i.e., they are independent of each other).

[0207] The second implementation: The second optical signal carries a CW optical signal A and a service signal (e.g., the second optical signal is a service optical signal). The first optical signal includes the second optical signal and a reflected optical signal R, where the reflected optical signal R includes the CW reflected optical signal R1. The first device acquires the first optical signal to obtain an acquisition signal G, which includes a digital DC component and a digital AC component. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital DC component corresponding to the second optical signal can be the digital DC component corresponding to the CW optical signal A carried by the second optical signal. The digital AC component includes the service signal and an AC reflected signal, which corresponds to the reflected optical signal R. The first device filters the acquisition signal G to obtain a filtered signal, which includes the AC reflected signal. The first device performs a Fourier transform on the filtered signal to obtain its spectrum, which includes the spectrum of the AC reflected signal. The first device determines the target spectrum of the CW reflected optical signal R1 based on the spectrum of the filtered signal. For example, the first device determines the spectrum of the AC reflected signal in the spectrum of the filtered signal as the target spectrum of the CW reflected light signal R1.

[0208] It should be noted that filtering the acquired signal G by the first device can reduce the influence of the service signal on the AC reflected signal included in the acquired signal G. For example, filtering the acquired signal G to remove the service signal eliminates its influence on the AC reflected signal. Furthermore, filtering the acquired signal G can also reduce the influence of the digital DC component of the acquired signal G on the AC reflected signal. For example, filtering the acquired signal G to remove the digital DC component eliminates its influence on the AC reflected signal. Since the service signal is typically a high-frequency signal, the first device can use a low-pass filter to filter the acquired signal G to reduce (e.g., eliminate) the influence of the service signal on the AC reflected signal included in the acquired signal G. Alternatively, the first device can use a band-pass filter to filter the acquired signal G to reduce (e.g., eliminate) the influence of the digital DC component of the acquired signal G on the AC reflected signal.

[0209] In one embodiment, the acquired signal G includes a digital DC component and a digital AC component, the digital AC component including a service signal and an AC reflected signal. A first device uses a low-pass filter to filter the acquired signal G to obtain a filtered signal, which includes the digital DC component and the AC reflected signal. The first device performs a Fourier transform on the filtered signal to obtain its spectrum, which includes the spectrum of the digital DC component and the spectrum of the AC reflected signal. Furthermore, in the spectrum of the filtered signal, the spectrum of the digital DC component and the spectrum of the AC reflected signal are separate (i.e., independent). For example, the digital DC component corresponds to the CW optical signal A carried by the second optical signal, the AC reflected signal corresponds to the reflected optical signal R, and the reflected optical signal R only includes the CW reflected optical signal R1. The spectrum of the digital DC component is the spectrum of the CW optical signal A, and the spectrum of the AC reflected signal is the spectrum of the CW reflected optical signal R1. Therefore, by performing a Fourier transform on the filtered signal, this embodiment of the application can not only obtain the spectrum of the CW optical signal A and the spectrum of the CW reflected optical signal R1, but also separate the spectrum of the CW optical signal A and the spectrum of the CW reflected optical signal R1 (that is, the two are independent).

[0210] In another embodiment, the acquired signal G includes a digital DC component and a digital AC component, the digital AC component including a service signal and an AC reflected signal. A first device filters the acquired signal G using a low-pass filter and a band-pass filter to obtain a filtered signal, which includes the AC reflected signal. The first device performs a Fourier transform on the filtered signal to obtain its spectrum, which includes the spectrum of the AC reflected signal. For example, if the filtered signal is the AC reflected signal and its spectrum is the same as the AC reflected signal's spectrum, the first device determines the spectrum of the AC reflected signal (i.e., the spectrum of the filtered signal) as the target spectrum of the CW reflected light signal R1.

[0211] The third implementation: The second optical signal carries a CW optical signal A and a service signal (e.g., the second optical signal is a service optical signal). The first optical signal includes the second optical signal and a reflected optical signal R, where the reflected optical signal R includes the CW reflected optical signal R1. The first device acquires the first optical signal to obtain an acquisition signal G, which includes a digital DC component and a digital AC component. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital DC component corresponding to the second optical signal may be the digital DC component corresponding to the CW optical signal A carried by the second optical signal. The digital AC component includes the service signal and an AC reflected signal, which corresponds to the reflected optical signal R. The first device performs a Fourier transform on the acquisition signal G to obtain a first spectrum, which is the spectrum of the acquisition signal G. The first spectrum includes the spectrum of the digital DC component of the acquisition signal G and the spectrum of the digital AC component of the acquisition signal G. Furthermore, in the first spectrum, the spectrum of the digital DC component and the spectrum of the digital AC component are separated (i.e., they are independent of each other). The spectrum of the digital AC component includes the spectrum of the service signal and the spectrum of the AC reflected signal. The first device filters the first spectrum to obtain a second spectrum, which includes the spectrum of the AC reflected signal. The first device determines the target spectrum of the CW reflected optical signal R1 based on the second spectrum. For example, the first device determines the spectrum of the AC reflected signal in the second spectrum as the target spectrum of the CW reflected optical signal R1.

[0212] It should be noted that filtering the first spectrum by the first device can reduce the influence of the service signal's spectrum on the AC reflected signal's spectrum. For example, filtering the first spectrum by the first device to remove the service signal's spectrum eliminates its influence on the AC reflected signal's spectrum. Furthermore, filtering the first spectrum by the first device can also remove the spectrum of the digital DC component. Since service signals are typically high-frequency signals, the first device can use a low-pass filter to filter the first spectrum to reduce (e.g., eliminate) the influence of the service signal's spectrum on the AC reflected signal's spectrum. The first device can also use a band-pass filter to filter the first spectrum to remove the spectrum of the digital DC component.

[0213] In one embodiment, the first spectrum includes the spectrum of the digital DC component of the acquired signal G and the spectrum of the digital AC component of the acquired signal G. Furthermore, in the first spectrum, the spectrum of the digital DC component and the spectrum of the digital AC component are separated (i.e., they are independent of each other). The spectrum of the digital AC component includes the spectrum of the service signal and the spectrum of the AC reflected signal. The first device uses a low-pass filter to filter the first spectrum to obtain a second spectrum. The second spectrum includes the spectrum of the AC reflected signal and the spectrum of the digital DC component. In the second spectrum, the spectrum of the AC reflected signal and the spectrum of the digital DC component are separated (i.e., they are independent of each other).

[0214] In another embodiment, the first spectrum includes the spectrum of the digital DC component of the acquired signal G and the spectrum of the digital AC component of the acquired signal G. Furthermore, in the first spectrum, the spectrum of the digital DC component is separated from the spectrum of the digital AC component, which includes the spectrum of the traffic signal and the spectrum of the AC reflected signal. The first device filters the first spectrum using a low-pass filter and a band-pass filter to obtain a second spectrum, which includes the spectrum of the AC reflected signal. For example, the second spectrum is the spectrum of the AC reflected signal.

[0215] The fourth implementation: The second optical signal carries the CW optical signal A but does not carry any service signal. The first optical signal includes the second optical signal and the reflected optical signal R, where the reflected optical signal R includes the CW reflected optical signal R1. For example, the second optical signal only carries the CW optical signal A, and the reflected optical signal R only includes the CW reflected optical signal R1. For instance, the second optical signal is the CW optical signal A, and the reflected optical signal R is the CW reflected optical signal R1. The acquisition signal G obtained by the first device from the first optical signal includes a digital DC component and a digital AC component. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital DC component corresponding to the second optical signal may be the digital DC component corresponding to the CW optical signal A carried by the second optical signal. The digital AC component includes an AC reflected signal, which corresponds to the reflected optical signal R. For example, the digital AC component is the AC reflected signal corresponding to the reflected optical signal R. The first device performs a Fourier transform on the acquired signal G to obtain a first spectrum. The first spectrum is the spectrum of the acquired signal G, and it includes the spectrum of the digital DC component and the spectrum of the digital AC component. Furthermore, in the first spectrum, the spectrum of the digital DC component and the spectrum of the digital AC component are separated (i.e., they are independent). The first spectrum has a periodic distribution characteristic. For example, the spectrum of the digital AC component in the first spectrum has a periodic distribution characteristic. The first device performs a Fourier transform on the first spectrum to obtain a second spectrum. The second spectrum includes the spectrum corresponding to the spectrum of the digital AC component in the first spectrum (for example, the spectrum corresponding to the spectrum of the digital AC component in the first spectrum is called spectrum C). For example, the second spectrum is spectrum C. The first device determines the target spectrum of the CW reflected light signal R1 based on the second spectrum. For example, the first device determines spectrum C in the second spectrum as the target spectrum of the CW reflected light signal R1.

[0216] The fifth implementation: The second optical signal carries a CW optical signal A and a service signal (e.g., the second optical signal is a service optical signal). The first optical signal includes the second optical signal and a reflected optical signal R, where the reflected optical signal R includes the CW reflected optical signal R1. The first device acquires the first optical signal to obtain an acquisition signal G, which includes a digital DC component and a digital AC component. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital DC component corresponding to the second optical signal may be the digital DC component corresponding to the CW optical signal A carried by the second optical signal. The digital AC component includes the service signal and an AC reflected signal, which corresponds to the reflected optical signal R. The first device filters the acquisition signal G to obtain a filtered signal, which includes the AC reflected signal. The first device performs a Fourier transform on the filtered signal to obtain a first spectrum, which is the spectrum of the filtered signal and includes the spectrum of the AC reflected signal. The first spectrum has a periodic distribution characteristic. For example, the spectrum of the AC reflected signal in the first spectrum has a periodic distribution characteristic. The first device performs a Fourier transform on the first spectrum to obtain a second spectrum, which includes the spectrum corresponding to the spectrum of the AC reflected signal in the first spectrum (for example, the spectrum corresponding to the spectrum of the AC reflected signal in the first spectrum is called spectrum D). For example, the second spectrum is spectrum D. The first device determines the target spectrum of the CW reflected optical signal R1 based on the second spectrum. For example, the first device determines spectrum D in the second spectrum as the target spectrum of the CW reflected optical signal R1.

[0217] It should be noted that, in the fifth implementation, the relevant description of the first device filtering the acquired signal G can be referred to in the second implementation above, which describes the first device filtering the acquired signal G. The embodiments of this application will not be repeated here.

[0218] The sixth implementation: The second optical signal carries a CW optical signal A and a service signal (e.g., the second optical signal is a service optical signal). The first optical signal includes the second optical signal and a reflected optical signal R, where the reflected optical signal R includes the CW reflected optical signal R1. The first device acquires the first optical signal to obtain an acquisition signal G, which includes a digital DC component and a digital AC component. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital DC component corresponding to the second optical signal may be the digital DC component corresponding to the CW optical signal A carried by the second optical signal. The digital AC component includes the service signal and an AC reflected signal, which corresponds to the reflected optical signal R. The first device performs a Fourier transform on the acquisition signal G to obtain a first spectrum, which is the spectrum of the acquisition signal G. The first spectrum includes the spectrum of the digital DC component of the acquisition signal G and the spectrum of the digital AC component of the acquisition signal G. Furthermore, in the first spectrum, the spectrum of the digital DC component and the spectrum of the digital AC component are separated (i.e., they are independent of each other). The spectrum of the digital AC component includes the spectrum of the service signal and the spectrum of the AC reflected signal. The first spectrum has a periodic distribution characteristic. For example, the spectrum of the AC reflected signal in the first spectrum has a periodic distribution characteristic. The first device performs a Fourier transform on the first spectrum to obtain a second spectrum, which includes the spectrum corresponding to the spectrum of the digital AC component in the first spectrum (for example, the spectrum corresponding to the spectrum of the digital AC component in the first spectrum is called spectrum E). For example, the second spectrum is spectrum E. Spectrum E includes the spectrum of the service signal and the spectrum of the AC reflected signal. The first device filters the second spectrum to obtain a third spectrum, which includes the spectrum of the AC reflected signal. For example, the third spectrum is the spectrum of the AC reflected signal. The first device determines the target spectrum of the CW reflected optical signal R1 based on the third spectrum. For example, the first device determines the spectrum of the AC reflected signal in the third spectrum as the target spectrum of the CW reflected optical signal R1.

[0219] It should be noted that filtering the second spectrum by the first device can reduce the influence of the traffic signal's spectrum on the AC reflected signal's spectrum. For example, filtering the second spectrum by the first device to remove the traffic signal's spectrum can eliminate the influence of the traffic signal's spectrum on the AC reflected signal's spectrum. Since the traffic signal is typically a high-frequency signal, the first device can use a low-pass filter to filter the second spectrum to reduce (e.g., eliminate) the influence of the traffic signal's spectrum on the AC reflected signal's spectrum.

[0220] The seventh implementation: The second optical signal carries a CW optical signal A and a service signal (e.g., the second optical signal is a service optical signal). The first optical signal includes the second optical signal and a reflected optical signal R, where the reflected optical signal R includes a CW reflected optical signal R1. The first device acquires the first optical signal to obtain an acquisition signal G, which includes a digital DC component and a digital AC component. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital DC component corresponding to the second optical signal may be the digital DC component corresponding to the CW optical signal A carried by the second optical signal. The digital AC component includes the service signal and an AC reflected signal, which corresponds to the reflected optical signal R. The first device performs a Fourier transform on the acquisition signal G to obtain a first spectrum, which is the spectrum of the acquisition signal G. The first spectrum includes the spectrum of the digital DC component of the acquisition signal G and the spectrum of the digital AC component of the acquisition signal G. Furthermore, in the first spectrum, the spectrum of the digital DC component and the spectrum of the digital AC component are separated (i.e., they are independent of each other). The spectrum of the digital AC component includes the spectrum of the service signal and the spectrum of the AC reflected signal. The first device filters the first spectrum to obtain a second spectrum, which includes the spectrum of the AC reflected signal. The second spectrum has a periodic distribution characteristic. For example, the spectrum of the AC reflected signal in the second spectrum has a periodic distribution characteristic. The first device performs a Fourier transform on the second spectrum to obtain a third spectrum, which includes the spectrum corresponding to the spectrum of the AC reflected signal in the second spectrum (for example, the spectrum corresponding to the spectrum of the AC reflected signal in the second spectrum is called spectrum F). For example, the third spectrum is spectrum F. The first device determines the target spectrum of the CW reflected optical signal R1 based on the third spectrum. For example, the first device determines spectrum F in the third spectrum as the target spectrum of the CW reflected optical signal R1.

[0221] It should be noted that, in the seventh implementation, the relevant description of the first device filtering the first spectrum can be referred to in the third implementation above, and the relevant description of the first device filtering the first spectrum will not be repeated here in this application embodiment.

[0222] It should also be noted that the second and fifth implementation methods described above are illustrated using signal filtering in the time domain as an example, while the third, sixth, and seventh implementation methods are illustrated using signal filtering in the frequency domain as an example. In the second and fifth implementation methods, when the first device uses a low-pass filter and a band-pass filter to filter the acquired signal G, the first device can first use a low-pass filter to filter the acquired signal G, and then use a band-pass filter to filter the signal filtered by the low-pass filter; alternatively, it can first use a band-pass filter to filter the acquired signal G, and then use a low-pass filter to filter the signal filtered by the band-pass filter. The embodiments of this application do not limit the order in which the acquired signal G is filtered. In the third, sixth, and seventh implementations described above, when the first device uses a low-pass filter and a band-pass filter to filter the spectrum, the first device can first use a low-pass filter to filter the spectrum, and then use a band-pass filter to filter the spectrum filtered by the low-pass filter; alternatively, it can first use a band-pass filter to filter the spectrum, and then use a low-pass filter to filter the spectrum filtered by the band-pass filter. This application does not limit the order in which the spectrum is filtered. Furthermore, the first device can also use other methods (such as averaging or equalization) to replace the above filtering methods to achieve a similar effect to the filtering described above, and this application does not limit this approach.

[0223] The Fourier transform described in the seven implementation methods above can be the Fast Fourier Transform (FFT). FFT is a fast algorithm for the Discrete Fourier Transform (DFT), obtained by improving the DFT algorithm based on the odd, even, imaginary, and real characteristics of the DFT, thus reducing computational complexity. The embodiments in this application use FFT to determine the spectrum, resulting in lower computational complexity.

[0224] After determining the target spectrum of the CW reflected optical signal R1, the first device determines whether the optical fiber link Z has broken based on the target spectrum. If the first device determines that the optical fiber link Z has broken, it determines the location of the break point of the optical fiber link Z based on the target spectrum.

[0225] In a specific embodiment, the CW reflected optical signal R1 includes at least one CW sub-reflected optical signal, which corresponds one-to-one with at least one reflecting cavity on the optical fiber link Z. Each of the at least one CW sub-reflected optical signals is an optical signal obtained by reflecting the CW optical signal A carried by the second optical signal in the corresponding reflecting cavity. The target spectrum includes at least one spectral curve, which corresponds one-to-one with the at least one CW sub-reflected optical signal, and thus corresponds one-to-one with the at least one reflecting cavity. Each of the at least one spectral curves is the spectral curve of the corresponding CW sub-reflected optical signal. Based on the description of S403, it is easy to understand that the at least one CW sub-reflected optical signal may or may not include the first CW sub-reflected optical signal. For example, in the case of a break in fiber optic link Z, fiber optic link Z includes a first reflecting cavity (i.e., a reflecting cavity formed between the break point of fiber optic link Z and the reflecting end face of the second device), and the at least one CW sub-reflected optical signal includes a first CW sub-reflected optical signal (i.e., the optical signal obtained by reflecting the CW optical signal A carried by the second optical signal within the first reflecting cavity); in the case of no break in fiber optic link Z, fiber optic link Z does not include the first reflecting cavity, and the at least one CW sub-reflected optical signal does not include the first CW sub-reflected optical signal. The first device can determine whether fiber optic link Z has broken based on second prior knowledge and the target spectrum. The second prior knowledge can be obtained by detecting fiber optic link Z using CW optical signals when fiber optic link Z has not broken, for example, when the received optical power of the optical signal received through fiber optic link Z is greater than a first power threshold. The second prior knowledge can include the spectrum of the CW reflected optical signal in the optical signal received through fiber optic link Z. For ease of description, the spectrum of the CW reflected optical signal included in the second prior knowledge is called the prior spectrum, which can be the spectrum obtained by one Fourier transform or the spectrum obtained by two Fourier transforms. The prior spectrum includes at least one spectral curve, each corresponding to at least one CW sub-reflected optical signal, all of which are reflections unrelated to the breakage of fiber link Z. The first device compares the target spectrum with the prior spectrum to determine whether fiber link Z has broken. If the number of spectral curves in the target spectrum is the same as the number of spectral curves in the prior spectrum, and the spectral curves in the target spectrum correspond one-to-one with those in the prior spectrum, the first device determines that fiber link Z has not broken.If the number of spectral curves included in the target spectrum is greater than the number of spectral curves included in the prior spectrum, some spectral curves included in the target spectrum correspond one-to-one with the spectral curves included in the prior spectrum, and the prior spectrum does not include characteristic peaks corresponding to other spectral curves included in the target spectrum, it indicates that the other spectral curves included in the target spectrum are caused by the breakage of fiber optic link Z, and the first device determines that fiber optic link Z has broken. In the embodiments of this application, two identical spectral curves can be completely identical or approximately identical. For example, if the positions of the characteristic peaks of two spectral curves correspond one-to-one, and the peak values ​​of the characteristic peaks of the two spectral curves correspond one-to-one, then the two spectral curves are identical. For example, the target spectrum includes three spectral curves, spectral curves 11 to 13, and the prior spectrum includes two spectral curves, spectral curves 21 and 22. Spectral curve 11 is identical to spectral curve 21, and spectral curve 12 is identical to spectral curve 22. The prior spectrum does not include the characteristic peak corresponding to spectral curve 13. Therefore, the first device determines that fiber optic link Z has broken, and determines that spectral curve 13 is caused by the breakage of fiber optic link Z.

[0226] When the first device determines that fiber optic link Z has broken, it determines the location of the break point of fiber optic link Z based on the target spectrum. In a specific embodiment, when fiber optic link Z breaks, the CW reflected optical signal R1 includes at least one CW sub-reflected optical signal. This at least one CW sub-reflected optical signal includes a first CW sub-reflected optical signal, which is the optical signal reflected from the CW optical signal A carried by the second optical signal between the break point of fiber optic link Z and the reflecting end face of the second device. The target spectrum includes a first spectrum curve, which is the spectrum curve of the first CW sub-reflected optical signal. The first device determines the distance between the break point of fiber optic link Z and the reflecting end face of the second device based on the first spectrum curve. For example, the first device determines the distance between the break point of fiber optic link Z and the reflecting end face of the second device based on the frequency corresponding to the characteristic peak of the first spectrum curve. After the first device determines the distance between the break point of fiber optic link Z and the reflecting end face of the second device, it also determines the location of the break point of fiber optic link Z.

[0227] In this embodiment, the first CW sub-reflected light signal may or may not be a resonant signal. The spectral curve of a resonant signal is also called a resonant spectrum curve. The resonant spectrum curve has multiple periodically distributed characteristic peaks, including a primary peak and at least one secondary peak. The at least one secondary peak is a resonant peak, and the peak value of each secondary peak is smaller than the peak value of the primary peak. The frequency corresponding to each secondary peak is greater than the frequency corresponding to the primary peak, and the frequency corresponding to each secondary peak is an integer multiple of the frequency corresponding to the primary peak. For example, the at least one secondary peak may be multiple secondary peaks, with the frequencies corresponding to these multiple secondary peaks increasing sequentially, and the frequency corresponding to each secondary peak being an integer multiple of the frequency corresponding to the primary peak. The frequency corresponding to each of these multiple characteristic peaks is the frequency corresponding to the peak value of each characteristic peak. The following explanation uses the example of the first CW sub-reflected optical signal being a resonant signal. The first reflecting cavity (i.e., the reflecting cavity formed between the break point of the optical fiber link Z and the reflecting end face of the second device) is the resonant cavity, and the first spectrum curve is the resonant spectrum curve. The first spectrum curve has multiple characteristic peaks with periodic distribution. The frequency corresponding to the main peak among these multiple characteristic peaks and the frequency corresponding to each secondary peak among these multiple characteristic peaks are the resonant frequencies of the first reflecting cavity (i.e., the resonant cavity).

[0228] The first device can determine a first spectral curve from the target spectrum based on second prior knowledge; for example, spectral curve 13 mentioned above is the first spectral curve. The first device extracts the first spectral curve from the target spectrum. The first device determines the distance between the break point of the fiber optic link Z and the reflecting end face of the second device based on the frequency corresponding to any characteristic peak of the first spectral curve. For example, the first device determines the distance between the break point of the fiber optic link Z and the reflecting end face of the second device based on the frequency corresponding to the main peak of the first spectral curve. As an example, Figure 10 This is a schematic diagram of a first spectral curve provided in an embodiment of this application. The first spectral curve includes three periodically distributed characteristic peaks, including one main peak and two secondary peaks. The two secondary peaks are resonant peaks, and the peak values ​​of the two secondary peaks are both smaller than the peak value of the main peak. The frequency corresponding to each secondary peak is greater than the frequency corresponding to the main peak, and the frequency corresponding to each secondary peak is an integer multiple of the frequency corresponding to the main peak. The two secondary peaks are secondary peak 1 and secondary peak 2. Secondary peak 1 is the resonant peak of the first harmonic, and secondary peak 2 is the resonant peak of the second harmonic. The frequency corresponding to secondary peak 1 is twice the frequency corresponding to the main peak, and the frequency corresponding to secondary peak 3 is three times the frequency corresponding to the main peak. The first device can determine the distance between the break point of the optical fiber link Z and the reflective end face of the second device based on the frequency corresponding to any one of the main peak, secondary peak 1, and secondary peak 2. For example, the first device can determine the distance between the break point of the optical fiber link Z and the reflective end face of the second device based on the frequency f1 corresponding to the main peak.

[0229] In one embodiment, in the second case of S405, the first device determines the target spectrum of the CW reflected optical signal R1 using any one of the first to third implementation methods. That is, the first device determines the target spectrum of the CW reflected optical signal R1 through a single Fourier transform. In this case, the frequency corresponding to the characteristic peak of the first spectrum curve and the distance between the break point of the fiber optic link Z and the reflection end face of the second device satisfy f N = c / n / (2×L)×N. f N Let N represent the frequency corresponding to the characteristic peak of the first spectral curve, c represent the transmission rate of the optical signal in vacuum, n represent the refractive index of the optical fiber link Z, L represent the distance between the break point of the optical fiber link Z and the reflecting end face of the second device, and N be a positive integer. The symbol " / " represents division. As mentioned earlier, the first device can determine the distance between the break point of the optical fiber link Z and the reflecting end face of the second device based on the frequency corresponding to any characteristic peak of the first spectral curve. N is a multiple of the frequency corresponding to that characteristic peak and the frequency corresponding to the main peak of the target spectrum. When the first device determines the distance between the break point of the optical fiber link Z and the reflecting end face of the second device based on the frequency corresponding to the main peak of the first spectral curve, N is 1. See also Figure 10 In one example, the first device determines the distance between the break point of the fiber optic link Z and the reflecting end face of the second device based on the frequency f1 corresponding to the main peak of the first spectrum curve, where N is 1. In another example, the first device determines the distance between the break point of the fiber optic link Z and the reflecting end face of the second device based on the frequency f2 corresponding to the secondary peak 1 of the first spectrum curve, where N is 2. In yet another example, the first device determines the distance between the break point of the fiber optic link Z and the reflecting end face of the second device based on the frequency f3 corresponding to the secondary peak 2 of the first spectrum curve, where N is 3. In a specific embodiment, the first device determines the frequency corresponding to any characteristic peak of the first spectrum curve, and substitutes the frequency corresponding to any characteristic peak into the relation "f N The distance between the break point of the fiber optic link Z and the reflective end face of the second device is obtained by calculating = c / n / (2×L)×N”.

[0230] In another embodiment, in the second case of S405, the first device determines the target spectrum of the CW reflected optical signal R1 using any one of the fourth to seventh implementation methods. That is, the first device determines the target spectrum of the CW reflected optical signal R1 through two Fourier transforms. In this case, the frequency corresponding to the characteristic peak of the first spectrum curve and the distance between the break point of the fiber optic link Z and the reflection end face of the second device satisfy f N = 1 / (c / n / (2×L)×N). f NLet N represent the frequency corresponding to the characteristic peak of the first spectral curve, c represent the transmission rate of the optical signal in vacuum, n represent the refractive index of the optical fiber link Z, L represent the distance between the break point of the optical fiber link Z and the reflecting end face of the second device, and N be a positive integer. The symbol " / " represents division. As mentioned earlier, the first device determines the distance between the break point of the optical fiber link Z and the reflecting end face of the second device based on the frequency corresponding to any characteristic peak of the first spectral curve. N is a multiple of the frequency corresponding to that characteristic peak and the frequency corresponding to the main peak of the target spectrum. When the first device determines the distance between the break point of the optical fiber link Z and the reflecting end face of the second device based on the frequency corresponding to the main peak of the first spectral curve, N is 1. See also... Figure 10 In one example, the first device determines the distance between the break point of the fiber optic link Z and the reflecting end face of the second device based on the frequency f1 corresponding to the main peak of the first spectrum curve, where N is 1. In another example, the first device determines the distance between the break point of the fiber optic link Z and the reflecting end face of the second device based on the frequency f2 corresponding to the secondary peak 1 of the first spectrum curve, where N is 2. In yet another example, the first device determines the distance between the break point of the fiber optic link Z and the reflecting end face of the second device based on the frequency f3 corresponding to the secondary peak 2 of the first spectrum curve, where N is 3. In a specific embodiment, the first device determines the frequency corresponding to any characteristic peak of the first spectrum curve, and substitutes the frequency corresponding to any characteristic peak into the relation "f N The distance between the break point of the fiber optic link Z and the reflective end face of the second device is obtained by calculating =1 / (c / n / (2×L)×N).

[0231] The third scenario: The first device determines the cepstral of the acquired signal G based on the acquired signal G, and then determines whether the fiber optic link Z has broken based on the cepstral of the acquired signal G. If the first device determines that the fiber optic link Z has broken, it determines the location of the break point of the fiber optic link Z based on the cepstral of the acquired signal G. This third scenario can correspond to the first or second scenario in S401, or any other possible scenario besides the first and second scenarios. That is, when the second optical signal carries the detection sequence X, the first device can perform fiber break detection on the fiber optic link Z based on this third scenario (e.g., determine whether the fiber optic link Z has broken, and if the fiber optic link Z has broken, determine the location of the break point); when the second optical signal carries the CW optical signal A, the first device can also perform fiber break detection on the fiber optic link Z based on this third scenario; when the second optical signal carries any information other than the detection sequence X and the CW optical signal A, the first device can also perform fiber break detection on the fiber optic link Z based on this third scenario.

[0232] The first optical signal includes a second optical signal and a reflected optical signal R. The reflected optical signal R includes at least one sub-reflected optical signal. The acquisition signal G obtained by the first device from acquiring the first optical signal includes signal components corresponding to the reflected optical signal R, thereby including signal components that correspond one-to-one with the at least one sub-reflected optical signal. The cepstrum of the acquisition signal G includes characteristic peaks that correspond one-to-one with the at least one sub-reflected optical signal, and each characteristic peak corresponds to a time-shifted symbol number. Based on the description of S403, it is easy to understand that the at least one sub-reflected optical signal may or may not include the first sub-reflected optical signal. For example, if the optical fiber link Z is broken, the optical fiber link Z includes a first reflecting cavity (i.e., a reflecting cavity formed between the break point of the optical fiber link Z and the reflecting end face of the second device), and the at least one sub-reflected optical signal includes the first sub-reflected optical signal (i.e., the optical signal obtained by reflecting the second optical signal within the first reflecting cavity); if the optical fiber link Z is not broken, the optical fiber link Z does not include the first reflecting cavity, and the at least one sub-reflected optical signal does not include the first sub-reflected optical signal. The first device can determine whether the optical fiber link Z is broken based on the third prior knowledge and the cepstrum of the acquisition signal G. The third prior knowledge can be determined by collecting the optical signal received through optical fiber link Z, assuming the optical fiber link Z is not broken, for example, when the received optical power of the optical signal received through optical fiber link Z is greater than a first power threshold. The third prior knowledge may include the cepstrum of the collected signal.

[0233] For ease of description, the cepstrum of the acquired signal included in the third prior knowledge is referred to as the prior cepstrum. This prior cepstrum includes at least one characteristic peak, which is a secondary peak unrelated to the breakage of the fiber optic link Z. The first device compares the cepstrum of the acquired signal G with the prior cepstrum to determine whether the fiber optic link Z has broken.

[0234] When the first device determines that fiber optic link Z has broken, it determines that the reflected optical signal R includes a first sub-reflected optical signal. This first sub-reflected optical signal has a certain delay compared to the second optical signal. The magnitude of this delay depends on the length of the optical fiber in fiber optic link Z located between the break point and the reflecting end face of the second device (also known as the distance between the break point and the reflecting end face of the second device). The first device acquires a sampled signal G from the first optical signal, which includes signal components corresponding to the first sub-reflected optical signal. The first device determines the delay of the first sub-reflected optical signal compared to the second optical signal based on the cepstral spectrum of the sampled signal G. Based on this delay, the first device determines the distance between the break point of fiber optic link Z and the reflecting end face of the second device. After determining the distance between the break point of fiber optic link Z and the reflecting end face of the second device, the location of the break point of fiber optic link Z is determined. In a specific embodiment, the cepstral spectrum of the acquired signal G includes a characteristic peak corresponding to the first sub-reflected optical signal. The first device determines the delay of the first sub-reflected optical signal compared to the second optical signal based on the number of time-shifted symbols corresponding to the characteristic peak of the first sub-reflected optical signal and the sampling interval of the acquired signal G (the interval between two adjacent acquisition points). For example, the first device determines the delay of the first sub-reflected optical signal compared to the second optical signal as the product of the number of time-shifted symbols corresponding to the characteristic peak of the first sub-reflected optical signal and the sampling interval of the acquired signal G. Based on the delay of the first sub-reflected optical signal compared to the second optical signal, the first device uses the distance-time formula "L=(c×τ) / (2×n)" to determine the distance between the break point of the optical fiber link Z and the reflection end face of the second device.

[0235] In a specific embodiment, the acquired signal G includes a digital DC component and a digital AC component. The digital DC component includes the digital DC component corresponding to the second optical signal, and may also include the digital DC component corresponding to the reflected optical signal R. The digital AC component includes an AC reflected signal, which corresponds to the reflected optical signal R. The first device performs a Fourier transform on the acquired signal G to obtain the spectrum of the acquired signal G. The spectrum of the acquired signal G includes the spectrum of the digital DC component and the spectrum of the digital AC component. The first device squares the spectrum of the acquired signal G, then takes the logarithm of the squared result, and finally performs an inverse Fourier transform on the obtained logarithm to obtain the cepstrum of the acquired signal G. The cepstrum of the acquired signal G is the digital baseband signal.

[0236] It should be noted that since the modulated optical signal (e.g., the second optical signal carrying the detection sequence X) typically carries a CW optical signal naturally, in the first case described above, the second optical signal also carries a CW optical signal. However, in this first case, the detection sequence X carried by the second optical signal is used by the first device to determine the location of the break point in the fiber optic link Z, while the CW optical signal carried by the second optical signal is not used by the first device to determine the location of the break point in the fiber optic link Z. In other embodiments, for the first case described above, the CW optical signal carried by the second optical signal can also be used by the first device to determine the location of the break point in the fiber optic link Z, and this application does not limit this.

[0237] Furthermore, based on the description of step S404, the first device can obtain at least one acquisition signal G by acquiring the first optical signal. In S405, the first device can determine the location of the break point of the optical fiber link Z based on one or more of the at least one acquisition signal G. The implementation process of the first device determining the location of the break point of the optical fiber link Z based on any one of the at least one acquisition signal G can refer to the above description in S405. The first device can ensure the accuracy of the determined break point location by determining the location of the optical fiber link Z based on multiple acquisition signals G. In addition, after determining the location of the break point of the optical fiber link Z, the first device can also provide fault warning. For example, the first device can control the indicator light of the first device to flash or light up to provide fault warning. As another example, the first device can output warning information to a device with a display component and / or a voice broadcast component to provide fault warning. The device with a display component and / or a voice broadcast component can present the warning information through display or voice broadcast to provide fault warning, and this application embodiment does not limit this.

[0238] In summary, the technical solution provided in this application involves a second device sending a second optical signal to the first device via an optical fiber link deployed between the first and second devices. The second optical signal is then transmitted through this optical fiber link and becomes a first optical signal. The first device collects the first optical signal based on the received optical power being less than a first power threshold and greater than a second power threshold. The first device then determines the location of the fiber optic link break point based on the collected signal, thus achieving fiber break detection. Therefore, this application provides a transmission-type detection scheme where existing equipment in the optical fiber communication system (i.e., the first and second devices) cooperate to detect fiber break points and determine their location. This eliminates the need for additional hardware such as OTDRs, circulators (or power dividers) in the fiber optic link, avoids fiber plugging and unplugging, eliminates the need to integrate OTDRs into optical modules, and eliminates the need for personnel to carry instruments to the site for testing. Therefore, the hardware implementation is simple, the detection cost is low, and on-the-path detection is possible without increasing the cost and size of the optical module, resulting in low labor costs for detection.

[0239] Please refer to Figure 11 The diagram illustrates a flowchart of another fiber breakage detection method provided in an embodiment of this application. This fiber breakage detection method is applied to an optical fiber communication system including a first device and a second device, and the method is performed in cooperation between the first device and the second device. For example, the optical fiber communication system is as follows... Figure 1 or Figure 2 As shown. See also Figure 11 The method includes the following steps S1101 to S1107.

[0240] S1101. The first device sends a notification message B to the second device based on the fact that the received optical power of the optical signal received through the optical fiber link Z is less than a first power threshold and greater than a second power threshold. The optical fiber link Z is deployed between the first device and the second device.

[0241] The first device and the second device communicate via fiber optic link Z. The second device sends an optical signal to the first device via fiber optic link Z, and the first device receives the optical signal via fiber optic link Z. The first device also monitors the received optical power of the received optical signal via fiber optic link Z. For example, the second device sends a service optical signal (i.e., an optical signal carrying a service signal) to the first device via fiber optic link Z, and the first device receives the service optical signal via fiber optic link Z. The first device monitors the received optical power of the service optical signal received via fiber optic link Z. If the first device determines that the received optical power of the optical signal received via fiber optic link Z is less than a first power threshold but greater than a second power threshold, the first device generates a notification message B and sends notification message B to the second device. For example, the first device generates notification message B and sends notification message B to the second device when it determines that the received optical power of the optical signal received via fiber optic link Z reaches (e.g., drops to) the first power threshold.

[0242] The format of notification message B is agreed upon by the first and second devices. Notification message B is used to instruct fiber optic link Z to undergo fiber breakage detection. For example, notification message B includes the identifier of fiber optic link Z and detection indication information, which instructs the fiber optic link Z to undergo fiber breakage detection. Notification message B may also include detection strategy indication information to indicate the detection strategy for fiber optic link Z. The detection strategy may be to use detection sequence X to detect fiber breakage in fiber optic link Z, or it may be to use CW optical signals to detect fiber breakage in fiber optic link Z.

[0243] In a specific embodiment, the first device sends an optical signal carrying notification message B to the second device. In one embodiment, the fiber optic link Z is used for the second device to send an optical signal to the first device, and can also be used for the first device to send an optical signal to the second device. The first device sends the optical signal carrying notification message B to the second device via the fiber optic link Z. For example, the fiber optic link Z is... Figure 1 In one embodiment, fiber optic link 130 is used for the second device 120 to send an optical signal to the first device 110, and also for the first device 110 to send an optical signal to the second device 120. The first device 110 sends an optical signal carrying a notification message B to the second device 120 via fiber optic link 130. In another embodiment, fiber optic link Z is used for the second device to send an optical signal to the first device, but not for the first device to send an optical signal to the second device. The first device sends an optical signal carrying a notification message B to the second device via the fiber optic link used for sending an optical signal from the first device to the second device. For example, fiber optic link Z is... Figure 2The fiber optic link 230 is used for the second device 220 to send an optical signal to the first device 210, but is not used for the first device 210 to send an optical signal to the second device 220. The fiber optic link 240 is used for the first device 210 to send an optical signal to the second device 220. The first device 210 sends an optical signal carrying a notification message B to the second device 220 through the fiber optic link 240.

[0244] In this embodiment, the first device can send the notification message B and the service signal to the second device in the same optical signal (i.e., send the notification message B to the second device along with the path), or it can send the notification message B and the service signal to the second device in different optical signals. When sending the notification message B and the service signal to the second device in the same optical signal, the first device can modulate the notification message B onto the service signal and send it to the second device, or it can send the notification message B and the service signal to the second device in a time-division multiplexing manner in the same optical signal (for example, the first device sends an optical signal carrying the notification message B to the second device during a first time period, and the first device sends the optical signal carrying the service signal to the second device during a second time period). This embodiment does not limit the scope of this embodiment.

[0245] S1102. The second device receives notification message B.

[0246] Corresponding to the first device sending notification message B to the second device, the second device receives notification message B sent by the first device. In a specific embodiment, the second device receives an optical signal carrying notification message B through an optical fiber link, and the second device obtains notification message B from the optical signal.

[0247] S1103. The second device generates a second optical signal based on notification message B.

[0248] Based on notification message B, the second device determines that fiber optic link Z needs to be detected for fiber breakage, and then generates a second optical signal.

[0249] In this embodiment, the second optical signal carries a detection signal, which is used by the first device to detect fiber optic link Z as a break to determine the location of the break point. Furthermore, the second optical signal may also carry a service signal. With both the detection signal and the service signal carried by the second optical signal, this embodiment can perform fiber optic link Z break detection along the path. The detection signal can be a detection sequence X or a CW optical signal.

[0250] In an optional embodiment, notification message B includes detection strategy indication information, which indicates a detection strategy for detecting fiber optic link Z to be disconnected. The detection strategy can be to use detection sequence X to detect fiber optic link Z to be disconnected, or it can be to use a CW optical signal to detect fiber optic link Z to be disconnected. The second device determines the detection strategy for detecting fiber optic link Z to be disconnected based on the detection strategy indication information, and generates a second optical signal according to the detection strategy. For example, if the detection strategy is to use detection sequence X to detect fiber optic link Z to be disconnected, the second device generates a second optical signal carrying detection sequence X; if the detection strategy is to use a CW optical signal to detect fiber optic link Z to be disconnected, the second device generates a second optical signal carrying CW optical signal A.

[0251] The implementation process of S1101 is described below in two scenarios.

[0252] In the first scenario, the second optical signal carries a detection sequence X, which is used by the first device to determine the location of the break point in the fiber optic link Z. In other words, the detection sequence X is used by the first device to detect fiber breakage in the fiber optic link Z.

[0253] The autocorrelation curve corresponding to the detection sequence X has a single characteristic peak. For example, the autocorrelation curve corresponding to the detection sequence X may have only one characteristic peak, and the autocorrelation values ​​at all points on the autocorrelation curve other than this characteristic peak are less than a threshold. The detection sequence X may include multiple sub-detection sequences, and the autocorrelation curve corresponding to the detection sequence X is determined based on the autocorrelation curves of these multiple sub-detection sequences. The autocorrelation curve corresponding to the detection sequence X may be a superposition curve of the autocorrelation curves of these multiple sub-detection sequences, with a one-to-one correspondence between the points on the autocorrelation curve of the detection sequence X and the points on the autocorrelation curves of these multiple sub-detection sequences. The autocorrelation value at each point on the autocorrelation curve of the detection sequence X is equal to the sum of the autocorrelation values ​​at that point on the autocorrelation curves of these multiple sub-detection sequences.

[0254] In an optional embodiment, the second optical signal carries multiple detection sequences X, which are periodically distributed. There are boundary markers between adjacent detection sequences X; or, adjacent detection sequences X are consecutive.

[0255] In an optional embodiment, the second optical signal also carries a service signal, with the detection sequence modulated onto the service signal. That is, the second optical signal carries both the detection sequence X and the service signal. In the second optical signal, the modulation depth of the detection sequence X is less than the modulation depth of the service signal, and the baud rate of the detection sequence X is less than the baud rate of the service signal. This allows for simultaneous fiber breakage detection along the fiber link Z without the detection sequence X affecting the service signal.

[0256] In the second scenario: the second optical signal carries CW optical signal A, which is used by the first device to determine the location of the break point in the fiber optic link Z. That is, CW optical signal A is used by the first device to detect fiber breakage in fiber optic link Z.

[0257] In an optional embodiment, the second optical signal also carries a service signal. That is, the second optical signal carries both the CW optical signal A and the service signal, thereby enabling fiber breakage detection along the fiber link Z.

[0258] S1104. The second device sends a second optical signal to the first device through the optical fiber link Z.

[0259] S1105. The first device receives a first optical signal through the optical fiber link Z. The first optical signal includes a second optical signal and a reflected optical signal R.

[0260] The second device sends a second optical signal to the first device via fiber optic link Z. After being transmitted via fiber optic link Z, the second optical signal becomes the first optical signal. Therefore, the first device receives the first optical signal via fiber optic link Z. The first optical signal includes the second optical signal and a reflected optical signal R, which is the optical signal reflected during the transmission of the second optical signal via fiber optic link Z.

[0261] S1106. The first device collects the first optical signal and obtains the collected signal G.

[0262] S1107. The first device determines the location of the break point in the optical fiber link Z based on the acquired signal G.

[0263] The first device analyzes the acquired signal G, and determines the location of the break point in the optical fiber link Z based on the analysis results.

[0264] In this embodiment of the application, the first device determines the location of the break point of the optical fiber link Z based on the acquired signal G in the following three ways.

[0265] The first scenario (corresponding to the first scenario in S1101): The second optical signal carries the detection sequence X. The first optical signal includes the second optical signal and the reflected optical signal R. Therefore, the first optical signal also carries the detection sequence X, and the acquisition signal G also carries the detection sequence X. The first device demodulates the acquisition signal G to obtain the detection sequence X; the first device determines the location of the break point of the optical fiber link Z based on the demodulated detection sequence X.

[0266] In optional embodiments, the second optical signal carries a plurality of periodically distributed detection sequences X, wherein adjacent detection sequences X are marked by boundary markers, or adjacent detection sequences X are consecutive. In one embodiment, adjacent detection sequences X are marked by boundary markers, and the first device determines the detection sequence X carried by the acquisition signal G based on the boundary markers carried by the acquisition signal G. In another embodiment, adjacent detection sequences X are consecutive, and the first device determines the detection sequence X carried by the acquisition signal G based on the characteristics of the detection sequences X. When the second optical signal carries a service signal, the acquisition signal G also carries a service signal. The first device can filter the acquisition signal G and determine the detection sequence X from the filtered acquisition signal G.

[0267] In an optional embodiment, the first device acquires the correlation curve corresponding to the demodulated detection sequence X. This correlation curve is either an autocorrelation curve or a cross-correlation curve, and the cross-correlation curve is determined based on the demodulated detection sequence X and the detection sequence X known to the first device. The first device determines the location of the break point in the optical fiber link Z based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence X. In this embodiment, the autocorrelation curve corresponding to the detection sequence X carried by the second optical signal has one characteristic peak. For example, the autocorrelation curve corresponding to the detection sequence X carried by the second optical signal has only one characteristic peak, and the autocorrelation values ​​at all points on the autocorrelation curve other than the characteristic peak are less than a threshold. If the correlation curve corresponding to the demodulated detection sequence X has only one characteristic peak, the first device determines that the optical fiber link Z has not broken. If the correlation curve corresponding to the demodulated detection sequence X has multiple characteristic peaks, the first device determines that the optical fiber link Z may have broken. If the first device determines that the optical fiber link Z has broken, the first device determines the location of the break point in the optical fiber link Z based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence X. In a specific embodiment, the first optical signal includes a second optical signal and a reflected optical signal R. The reflected optical signal R includes at least one sub-reflected optical signal, which includes a first sub-reflected optical signal. The first sub-reflected optical signal is the optical signal reflected from the second optical signal between the break point of the optical fiber link Z and the reflective end face of the second device. The first sub-reflected optical signal has a certain delay compared to the second optical signal. The first device determines the delay of the first sub-reflected optical signal compared to the second optical signal based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence X. The first device determines the distance between the break point of the optical fiber link Z and the reflective end face of the second device based on the delay of the first sub-reflected optical signal compared to the second optical signal. For example, the first device determines the delay of the first sub-reflected optical signal compared to the second optical signal based on the main peak and the first peak of the correlation curve corresponding to the demodulated detection sequence X. The first peak is the secondary peak in the correlation curve corresponding to the first sub-reflected optical signal.

[0268] The second scenario (corresponding to the second scenario in S1101): The second optical signal carries a CW optical signal A, and the first optical signal includes the second optical signal and a reflected optical signal R. The reflected optical signal R includes a CW reflected optical signal R1. Therefore, the acquisition signal G obtained by acquiring the first optical signal includes the signal component corresponding to the CW reflected optical signal R1. The first device determines the target spectrum of the CW reflected optical signal R1 based on the acquisition signal G; the first device determines the location of the break point of the fiber optic link Z based on the target spectrum of the CW reflected optical signal R1. For example, the CW reflected optical signal R1 includes a first CW sub-reflected optical signal, which is the optical signal reflected by the CW optical signal A carried by the second optical signal between the break point of the fiber optic link Z and the reflection end face of the second device (that is, the first CW sub-reflected optical signal is the optical signal reflected by the CW optical signal A carried by the second optical signal within the first reflection cavity). The target spectrum includes a first spectral curve, which is the spectral curve of the first CW sub-reflected optical signal. The first device determines the distance between the break point of the fiber optic link Z and the reflection end face of the second device based on the first spectral curve.

[0269] The first device can determine the target spectrum of the CW reflected optical signal R1 through one Fourier transform or through two Fourier transforms. When the first device determines the target spectrum of the CW reflected optical signal R1 through one Fourier transform, the frequency corresponding to the characteristic peak of the first spectrum curve and the distance between the reflection endface of the second device and the break point of the fiber link Z satisfy f. N =c / n / (2×L)×N; When the first device determines the target spectrum of the CW reflected optical signal R1 through two Fourier transforms, the frequency corresponding to the characteristic peak of the first spectrum curve and the distance between the reflection end face of the second device and the break point of the optical fiber link Z satisfy f N = 1 / (c / n / (2×L)×N). f N The frequency corresponding to the characteristic peak of the first spectral curve is represented by c, the transmission rate of the optical signal in vacuum is represented by n, the refractive index of the optical fiber link Z is represented by L, the distance between the break point of the optical fiber link Z and the reflective end face of the second device is represented by N, and the symbol " / " represents the division sign.

[0270] The third scenario: The first device determines the cepstral of the acquired signal G based on the acquired signal G; the first device determines the location of the break point in the fiber optic link Z based on the cepstral of the acquired signal G. In a specific embodiment, the first optical signal includes a second optical signal and a reflected optical signal R. The reflected optical signal R includes at least one sub-reflected optical signal, which includes the first sub-reflected optical signal. The acquired signal G includes signal components corresponding to the reflected optical signal R, thereby including signal components that correspond one-to-one with the at least one sub-reflected optical signal. The cepstral of the acquired signal G includes characteristic peaks that correspond one-to-one with the at least one sub-reflected optical signal, and each characteristic peak corresponds to a time-shift symbol number. The first device determines the delay of the first sub-reflected optical signal compared to the second optical signal based on the cepstral of the acquired signal G. Based on the delay of the first sub-reflected optical signal compared to the second optical signal, the first device determines the distance between the break point in the fiber optic link Z and the reflecting end face of the second device.

[0271] The above is only a brief introduction to S1003 to S1107. The implementation process of S1003 to S1107 can be referred to the implementation process of S401 to S405 above. The embodiments of this application will not be described in detail here.

[0272] In summary, the technical solution provided in this application involves a first device sending a notification message to a second device when the received optical power of the optical signal received through the fiber optic link is less than a first power threshold but greater than a second power threshold. Based on this notification message, the second device sends a second optical signal to the first device through the fiber optic link. The second optical signal is then transmitted through the fiber optic link and becomes a first optical signal. The first device collects the first optical signal to obtain a collected signal and determines the location of the fiber optic link break point based on the collected signal, thus achieving fiber break detection. Therefore, this application provides a transmission-type detection scheme that uses existing equipment in the fiber optic communication system to detect fiber break points and determine their location. It eliminates the need for additional hardware such as OTDRs, circulators (or power dividers) in the fiber optic link, fiber plugging and unplugging, integrating an OTDR into the optical module, and requiring personnel to carry instruments to the site for testing. The hardware implementation is simple, the detection cost is low, and on-the-path detection is possible without increasing the cost and size of the optical module, resulting in low labor costs.

[0273] The above is a description of the method embodiments of this application. The following describes the apparatus embodiments of this application, which are used to execute the method of this application. For details not disclosed in the apparatus embodiments, please refer to the method embodiments.

[0274] This application provides a fiber breakage detection device, applied to the first device described above. The fiber breakage detection device includes at least one functional module, which is used to perform actions such as... Figure 4 or Figure 11 The fiber breakage detection method provided in the illustrated embodiment is an operation performed by the first device. The at least one functional module can be implemented based on software, hardware, or a combination of both, and the at least one functional module can be arbitrarily combined or divided based on the specific implementation. The fiber breakage detection device can be the first device or a functional component within the first device. For example, the fiber breakage detection device is the first device, an optical module within the first device, or a fiber optic card within the first device; alternatively, the fiber breakage detection device is integrated into the first device, an optical module within the first device, or a fiber optic card within the first device.

[0275] Please refer to Figure 12 This illustration shows a schematic diagram of a fiber breakage detection device 1200 provided in an embodiment of this application. The fiber breakage detection device 1200 is applied to a first device. The fiber breakage detection device 1200 is used to perform actions such as... Figure 4 or Figure 11 The fiber breakage detection method provided in the illustrated embodiment is performed by the first device. The fiber breakage detection device 1200 includes a receiving module 1210, an acquisition module 1220, and a determination module 1230.

[0276] In one embodiment, the fiber breakage detection device 1200 is applied to, for example... Figure 4 The illustrated embodiment provides a first device in the fiber breakage detection method. The fiber breakage detection device 1200 is used to perform, as shown in the example... Figure 4 The operation performed by the first device in the fiber breakage detection method provided in the illustrated embodiment.

[0277] The receiving module 1210 is used to receive a first optical signal through an optical fiber link deployed between the first device and the second device. The first optical signal includes a second optical signal and a reflected optical signal. The second optical signal is an optical signal generated by the second device, and the reflected optical signal is an optical signal reflected during the transmission of the second optical signal through the optical fiber link.

[0278] The acquisition module 1220 is used to acquire the first optical signal based on the fact that the received optical power of the first optical signal is less than a first power threshold and greater than a second power threshold, and to obtain the acquired signal.

[0279] The determination module 1230 is used to determine the location of the break point of the optical fiber link based on the acquired signal.

[0280] In this embodiment, the functionality of the receiving module 1210 can be referred to the relevant description in S403. The functionality of the acquisition module 1220 can be referred to the relevant description in S404. The functionality of the determining module 1230 can be referred to the relevant description in S405.

[0281] In another embodiment, the fiber breakage detection device 1200 is applied to, for example... Figure 11 The illustrated embodiment provides a first device in the fiber breakage detection method. The fiber breakage detection device 1200 is used to perform, as shown in the example... Figure 11 The operation performed by the first device in the fiber breakage detection method provided in the illustrated embodiment.

[0282] The receiving module 1210 is used to receive a first optical signal through an optical fiber link deployed between a first device and a second device. The first optical signal includes a second optical signal and a reflected optical signal. The second optical signal is an optical signal generated by the second device based on a notification message sent by the first device. The notification message is sent by the first device to the second device when the received optical power of the optical signal received through the optical fiber link is less than a first power threshold and greater than a second power threshold. The reflected optical signal is an optical signal reflected during the transmission of the second optical signal through the optical fiber link.

[0283] The acquisition module 1220 is used to acquire the first optical signal to obtain the acquired signal;

[0284] The determination module 1230 is used to determine the location of the break point of the optical fiber link based on the acquired signal.

[0285] In an alternative implementation of this other embodiment, the acquisition module 1220 is further configured to stop acquiring the first optical signal based on the fact that the received optical power of the first optical signal received through the optical fiber link is less than a second power threshold.

[0286] In this other embodiment, the functionality of the receiving module 1210 can be referred to the relevant description in S1105. The functionality of the acquisition module 1220 can be referred to the relevant description in S1106. The functionality of the determining module 1230 can be referred to the relevant description in S1107.

[0287] In the first case of the two embodiments described above, the second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point of the optical fiber link. The determination module 1230 is used to: demodulate the acquired signal to obtain the detection sequence; and determine the location of the break point of the optical fiber link based on the demodulated detection sequence.

[0288] In the optional implementation of the first case, the autocorrelation curve corresponding to the detection sequence carried by the second optical signal has a characteristic peak.

[0289] In the optional implementation of the first case, the detection sequence carried by the second optical signal includes multiple sub-detection sequences. The autocorrelation curve corresponding to the detection sequence is determined based on the autocorrelation curves of the multiple sub-detection sequences. The autocorrelation value at each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation values ​​at each position point on the autocorrelation curves of the multiple sub-detection sequences.

[0290] In the optional implementation of the first case, the second optical signal carries multiple detection sequences, which are periodically distributed and have boundary markers between adjacent detection sequences. The determining module 1230 is used to determine the multiple detection sequences carried by the acquisition signal based on the boundary markers carried by the acquisition signal.

[0291] In the optional implementation of the first case, the second optical signal carries multiple detection sequences, which are periodically distributed and adjacent detection sequences are continuous. The determining module 1230 is used to determine the multiple detection sequences carried by the acquisition signal based on the characteristics of the detection sequences.

[0292] In the optional implementation of the first case, the determining module 1230 is used to: obtain the correlation curve corresponding to the demodulated detection sequence, the correlation curve being an autocorrelation curve or a cross-correlation curve, the cross-correlation curve being determined based on the demodulated detection sequence and the detection sequence known by the first device; and determine the location of the fiber optic link breakpoint based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence.

[0293] In the optional implementation of the first case, the reflected optical signal includes a first sub-reflected optical signal, which is the optical signal reflected from the second optical signal between the break point of the optical fiber link and the reflective end face of the second device. The determining module 1230 is used to: determine the delay of the first sub-reflected optical signal compared to the second optical signal based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence; and determine the distance between the break point of the optical fiber link and the reflective end face of the second device based on the delay of the first sub-reflected optical signal compared to the second optical signal.

[0294] In the optional implementation of the first case, the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks. The determining module 1230 is used to determine the delay of the first sub-reflected light signal compared to the second light signal based on the main peak among the multiple characteristic peaks and the first peak among the multiple characteristic peaks. The first peak corresponds to the first sub-reflected light signal, and the first peak is caused by the first sub-reflected light signal.

[0295] In the optional implementation of the first case, the second optical signal also carries a service signal, the detection sequence is modulated on the service signal, and the determination module 1230 is used to filter the acquired signal.

[0296] In the optional implementation of the first case, the second optical signal also carries a service signal, and the detection sequence is modulated onto the service signal. In the second optical signal, the modulation depth of the detection sequence is less than the modulation depth of the service signal, and the baud rate of the detection sequence is less than the baud rate of the service signal.

[0297] In the second case of the two embodiments described above, the second optical signal carries a CW optical signal, which is used by the first device to determine the location of the break point of the optical fiber link. The reflected optical signal includes a CW reflected optical signal, which is an optical signal reflected during the transmission of the CW optical signal through the optical fiber link. The determining module 1230 is used to: determine the target spectrum of the CW reflected optical signal based on the acquired signal; and determine the location of the break point of the optical fiber link based on the target spectrum.

[0298] In the optional implementation of the second case, the target spectrum includes a first spectrum curve, which is the spectrum curve of the first CW sub-reflected optical signal. The first CW sub-reflected optical signal is the optical signal reflected by the CW optical signal carried by the second optical signal between the break point of the optical fiber link and the reflective end face of the second device. The CW reflected optical signal includes the first CW sub-reflected optical signal. The determining module 1230 is used to determine the distance between the break point of the optical fiber link and the reflective end face of the second device based on the frequency corresponding to the characteristic peak of the first spectrum curve.

[0299] In the alternative implementation of the second scenario, the second optical signal also carries a service signal. For example, the second optical signal is a service optical signal.

[0300] In the alternative implementation of the second case, the second optical signal is a CW optical signal.

[0301] In the second scenario, the target spectrum of the CW reflected optical signal can be determined by either a single Fourier transform or two Fourier transforms. Determining the target spectrum of the CW reflected optical signal using two Fourier transforms makes the characteristic peaks of the first spectral curve of the CW reflected optical signal more prominent, thus facilitating the determination of the frequencies corresponding to these characteristic peaks. This allows for the location of the fiber optic link breakpoint based on the frequencies corresponding to the characteristic peaks of the first spectral curve. The Fourier transform can be an FFT.

[0302] The determination module 1230 can determine the target spectrum of the CW reflected light signal using any of the following seven implementation methods.

[0303] In the first implementation, the second optical signal carries the CW optical signal but does not carry the service signal. The determination module 1230 is used to perform Fourier transform on the acquired signal to obtain the target spectrum of the CW reflected optical signal.

[0304] In the second implementation, the second optical signal also carries a service signal, that is, the second optical signal carries both a CW optical signal and a service signal. The determining module 1230 is used to: filter the acquired signal to obtain a filtered signal; and perform a Fourier transform on the filtered signal to obtain the target spectrum of the CW reflected optical signal.

[0305] In the third implementation, the second optical signal also carries a service signal, that is, the second optical signal carries both the CW optical signal and the service signal. The determination module 1230 is used to: perform a Fourier transform on the acquired signal to obtain a first spectrum; and filter the first spectrum to obtain the target spectrum of the CW reflected optical signal.

[0306] In the fourth implementation, the second optical signal carries the CW optical signal but does not carry the service signal. The determination module 1230 is used to: perform Fourier transform on the acquired signal to obtain the first spectrum; and perform Fourier transform on the first spectrum to obtain the target spectrum of the CW reflected optical signal.

[0307] In the fifth implementation, the second optical signal also carries a service signal, that is, the second optical signal carries both the CW optical signal and the service signal. The determining module 1230 is used to: filter the acquired signal to obtain a filtered signal; perform a Fourier transform on the filtered signal to obtain a first spectrum; and perform a Fourier transform on the first spectrum to obtain the target spectrum of the CW reflected optical signal.

[0308] In the sixth implementation, the second optical signal also carries a service signal, that is, the second optical signal carries both a CW optical signal and a service signal. The determining module 1230 is used to: perform a Fourier transform on the acquired signal to obtain a first spectrum; perform a Fourier transform on the first spectrum to obtain a second spectrum; and filter the second spectrum to obtain the target spectrum of the CW reflected optical signal.

[0309] In the seventh implementation, the second optical signal also carries a service signal, that is, the second optical signal carries both the CW optical signal and the service signal. The determining module 1230 is used to: perform a Fourier transform on the acquired signal to obtain a first spectrum; filter the first spectrum to obtain a second spectrum; and perform a Fourier transform on the second spectrum to obtain the target spectrum of the CW reflected optical signal.

[0310] In the alternative implementation of the second case, the target spectrum of the CW reflected optical signal is determined by a single Fourier transform. The frequency corresponding to the characteristic peak of the first spectrum curve and the distance between the fiber optic link break point and the reflecting end face of the second device satisfy f. N=c / n / (2×L)×N, f N The frequency corresponding to the characteristic peak of the first spectral curve is represented by c, the transmission rate of the optical signal in a vacuum is represented by n, the refractive index of the optical fiber link is represented by L, the distance between the break point of the optical fiber link and the reflective end face of the second device is represented by N, and the symbol " / " represents the division sign.

[0311] In the alternative implementation of the second case, the target spectrum of the CW reflected optical signal is determined by two Fourier transforms. The frequency corresponding to the characteristic peak of the first spectrum curve and the distance between the fiber optic link break point and the reflecting end face of the second device satisfy f. N =1 / (c / n / (2×L)×N), f N The frequency corresponding to the characteristic peak of the first spectral curve is represented by c, the transmission rate of the optical signal in a vacuum is represented by n, the refractive index of the optical fiber link is represented by L, the distance between the break point of the optical fiber link and the reflective end face of the second device is represented by N, and the symbol " / " represents the division sign.

[0312] In the third case of the above two embodiments, the determining module 1230 is used to: determine the cepstral of the acquired signal based on the acquired signal; and determine the location of the break point of the optical fiber link based on the cepstral of the acquired signal.

[0313] In the optional implementation of the third case, the reflected optical signal includes a first sub-reflected optical signal, which is the optical signal reflected from the second optical signal between the break point of the optical fiber link and the reflective end face of the second device. The determining module 1230 is used to: determine the delay of the first sub-reflected optical signal compared to the second optical signal based on the cepstral spectrum of the acquired signal; and determine the distance between the break point of the optical fiber link and the reflective end face of the second device based on the delay of the first sub-reflected optical signal compared to the second optical signal.

[0314] In the third alternative implementation, the second optical signal carries a service signal. For example, the second optical signal is a service optical signal.

[0315] In the third alternative implementation, the second optical signal carries a CW optical signal. For example, the second optical signal is a CW optical signal.

[0316] In summary, the technical solution provided in this application involves a first device receiving a first optical signal via an optical fiber link deployed between the first and second devices. The first optical signal includes a second optical signal and a reflected optical signal obtained during the transmission of the second optical signal through the optical fiber link. The first device collects the first optical signal based on the received optical power being less than a first power threshold and greater than a second power threshold to obtain a collected signal. The first device determines the location of the fiber optic link break point based on the collected signal, thus achieving fiber break detection. Therefore, this application provides a transmission-type detection scheme that uses existing equipment in the optical fiber communication system to detect fiber break points and determine their location. It eliminates the need for additional hardware such as OTDRs, circulators (or power dividers) in the fiber optic link, fiber plugging and unplugging, integrating OTDRs into optical modules, and requiring personnel to carry instruments to the site for testing. Therefore, the hardware implementation is simple, the detection cost is low, and on-the-path detection is possible without increasing the cost and size of the optical module, resulting in low manpower costs.

[0317] This application provides another fiber breakage detection device, applied to the second device described above. The fiber breakage detection device includes at least one functional module, which is used to perform actions such as... Figure 4 or Figure 11 The fiber breakage detection method provided in the illustrated embodiment is an operation performed by a second device. The at least one functional module can be implemented based on software, hardware, or a combination of both, and can be arbitrarily combined or divided based on specific implementations. The fiber breakage detection device can be the second device or a functional component within the second device. For example, the fiber breakage detection device is the second device, an optical module within the second device, or a fiber optic card within the second device; alternatively, the fiber breakage detection device is integrated into the second device, an optical module within the second device, or a fiber optic card within the second device.

[0318] Please refer to Figure 13 This illustration shows a schematic diagram of another fiber breakage detection device 1300 provided in an embodiment of this application. The fiber breakage detection device 1300 is applied to a second device. The fiber breakage detection device 1300 is used to perform... Figure 11 The operation performed by the second device in the fiber breakage detection method provided in the illustrated embodiment. For example... Figure 13 As shown, the fiber breakage detection device 1300 includes a receiving module 1310, a generating module 1320, and a transmitting module 1130.

[0319] The receiving module 1310 is used to receive a notification message, which is sent by the first device to the second device when the received optical power of the optical signal received through the optical fiber link is less than a first power threshold and greater than a second power threshold. The optical fiber link is deployed between the first device and the second device.

[0320] Generation module 1320 is used to generate a second optical signal based on the notification message;

[0321] The transmitting module 1330 is used to transmit a second optical signal to the first device via the optical fiber link. The second optical signal is converted into a first optical signal after transmission via the optical fiber link. The first optical signal includes the second optical signal and a reflected optical signal, which is the optical signal reflected during the transmission of the second optical signal via the optical fiber link. The first device is used to determine the location of the break point in the optical fiber link based on the first optical signal. For example, the first device is used to: acquire the first optical signal to obtain an acquired signal; and determine the location of the break point in the optical fiber link based on the acquired signal.

[0322] The functionality of the receiving module 1310 can be found in the description in S1102. The functionality of the generating module 1320 can be found in the description in S1103. The functionality of the transmitting module 1330 can be found in the description in S1104.

[0323] In this embodiment, the second optical signal carries a detection signal, which is used by the first device to determine the location of the break point in the optical fiber link. The detection signal can be a detection sequence or a CW optical signal. Two scenarios are described below.

[0324] In the first scenario, the second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point in the fiber optic link.

[0325] In the optional implementation of the first case, the autocorrelation curve corresponding to the detection sequence carried by the second optical signal has a characteristic peak.

[0326] In the optional implementation of the first case, the detection sequence carried by the second optical signal includes multiple sub-detection sequences. The autocorrelation curve corresponding to the detection sequence is determined based on the autocorrelation curves of the multiple sub-detection sequences. The autocorrelation value at each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation values ​​at each position point on the autocorrelation curves of the multiple sub-detection sequences.

[0327] In an optional implementation of the first case, the second optical signal carries multiple detection sequences that are periodically distributed; there are boundary markers between adjacent detection sequences; or, adjacent detection sequences are consecutive.

[0328] In the optional implementation of the first case, the second optical signal also carries a service signal. In the second optical signal, the modulation depth of the detection sequence is less than the modulation depth of the service signal, and the baud rate of the detection sequence is less than the baud rate of the service signal.

[0329] In the second scenario, the second optical signal carries a CW optical signal, which is used by the first device to determine the location of the break point in the fiber optic link.

[0330] In the alternative implementation of the second scenario, the second optical signal also carries a service signal. For example, the second optical signal is a service optical signal.

[0331] In the alternative implementation of the second case, the second optical signal is a CW optical signal.

[0332] In summary, the technical solution provided in this application involves a first device sending a notification message to a second device when the received optical power of the optical signal received through the fiber optic link is less than a first power threshold but greater than a second power threshold. Based on this notification message, the second device sends a second optical signal to the first device through the fiber optic link. The second optical signal is then transmitted through the fiber optic link and becomes a first optical signal. The first device collects the first optical signal to obtain a collected signal and determines the location of the fiber optic link break point based on the collected signal, thus achieving fiber break detection. Therefore, this application provides a transmission-type detection scheme that uses existing equipment in the fiber optic communication system to detect fiber break points and determine their location. It eliminates the need for additional hardware such as OTDRs, circulators (or power dividers) in the fiber optic link, fiber plugging and unplugging, integrating an OTDR into the optical module, and requiring personnel to carry instruments to the site for testing. The hardware implementation is simple, the detection cost is low, and on-the-path detection is possible without increasing the cost and size of the optical module, resulting in low labor costs.

[0333] It should be understood that the fiber breakage detection device provided in this application embodiment can also be implemented using an application-specific integrated circuit (ASIC) or a programmable logic device (PLD). The PLD can be a complex programmable logical device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof. The fiber breakage detection method provided in the above method embodiment can also be implemented in software. When the fiber breakage detection method provided in the above method embodiment is implemented in software, each module in the above fiber breakage detection device can also be a software module.

[0334] This application provides a fiber breakage detection device, which includes a memory and a processor. The memory stores a computer program. The processor executes the computer program stored in the memory to cause the fiber breakage detection device to perform actions such as... Figure 4 or Figure 11 The illustrated embodiment provides all or part of the steps of the fiber breakage detection method. The fiber breakage detection device can be a first device, an optical module within the first device, a fiber optic card within the first device, a second device, an optical module within the second device, a fiber optic card within the second device, etc. Both the first device and the second device can be network devices, terminal devices, or servers.

[0335] In one embodiment, please refer to Figure 14 This illustration shows a schematic diagram of another fiber breakage detection device 1400 provided in an embodiment of this application. The fiber breakage detection device 1400 can be a network device, a terminal device, or a server. The fiber breakage detection device 1400 is used to perform actions such as... Figure 4 or Figure 11 The illustrated embodiments provide all or part of the steps of the fiber breakage detection method. For example... Figure 14 As shown, the fiber breakage detection device 1400 includes at least one processor 1401. Figure 14 (Taking two processors 1401 as an example), a communication bus 1402, a memory 1403, and a communication interface 1404 are connected via the communication bus 1402. The at least one processor 1401, memory 1403, and communication interface 1404 can also be connected using a connection method other than the communication bus 1402.

[0336] The memory 1403 is used to store computer programs that execute the technical solutions of this application and is controlled by the processor 1401 to execute them. The computer programs stored in the memory 1403 include, but are not limited to, program code, program instructions, and data. The memory 1403 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or it may be a non-volatile random access memory (NVRAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. The memory 1403 can exist independently and be connected to the processor 1401 via the communication bus 1402. The memory 1403 can also be integrated with the processor 1401, and this embodiment of the application does not limit this.

[0337] Processor 1401 can be a general-purpose processor or a special-purpose processor. A general-purpose processor is a processor that performs specific steps and / or operations by reading and executing a computer program stored in memory (e.g., memory 1403). In performing the aforementioned steps and / or operations, the general-purpose processor may use the computer program stored in memory (e.g., memory 1403), which can be executed to implement the relevant functions of the aforementioned acquisition module 1220, determination module 1230, and generation module 1320. General-purpose processors include, but are not limited to, central processing units (CPUs). A special-purpose processor is a processor specifically designed to perform specific steps and / or operations. Special-purpose processors include, but are not limited to, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. Processor 1401 can implement or execute various logic blocks, modules, and circuits described in conjunction with the disclosure of embodiments of this application. The processor 1401 can also be a combination of processing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc. The processor can be used to acquire the received first optical signal to obtain an acquired signal, and determine the location of the fiber optic link break point based on the acquired signal.

[0338] The communication bus 1402 is used to transfer information between the processor 1401, the communication interface 1404, and the memory 1403. The communication bus 1402 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The communication bus 1402 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 14 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0339] The communication interface 1404 includes input / output (I / O) interfaces, physical interfaces, and logical interfaces for interconnecting devices within the fiber breakage detection device 1400, as well as interfaces for interconnecting the fiber breakage detection device 1400 with other devices. The physical interfaces can be Ethernet interfaces, Fast Ethernet (FE) interfaces, Gigabit Ethernet (GE) interfaces, Terabit Ethernet (TbE) interfaces, 400GE interfaces, asynchronous transfer mode (ATM) interfaces, etc., used for interconnecting the fiber breakage detection device 1400 with other devices. The logical interfaces are internal interfaces of the fiber breakage detection device 1400, used for interconnecting devices within the fiber breakage detection device 1400. It is easy to understand that the communication interface 1404 is used for communication between the fiber breakage detection device 1400 and other devices or networks; for example, the communication interface 1404 is used for the transmission and reception of optical signals between the fiber breakage detection device 1400 and other devices or networks. The communication interface 1404 can be any transceiver (such as an optical transmitter, optical receiver, or other optical device), and the network can be Ethernet, optical transport network (OTN), secret private network (SPN), fiber channel, infinite bandwidth, etc.

[0340] In a specific implementation, as one embodiment, the fiber breakage detection device 1400 includes a plurality of processors 1401, each of which can be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. Here, a processor can refer to one or more devices, circuits, and / or processing cores used to process data (e.g., computer program instructions).

[0341] In a specific embodiment, when the fiber breakage detection device 1400 is the second device in the aforementioned embodiment, the communication interface 1404 in the fiber breakage detection device 1400 is used to send a second optical signal through the optical fiber link. For the specific implementation process, please refer to the relevant descriptions in S402 and S1104 above. When the fiber breakage detection device 1400 is the first device in the aforementioned embodiment, the communication interface 1404 in the fiber breakage detection device 1400 is used to receive a first optical signal including the second optical signal through the optical fiber link. The processor 1401 in the fiber breakage detection device 1400 is used to acquire the first optical signal to obtain an acquisition signal, and determine the location of the fiber breakage point based on the acquisition signal. For the specific implementation process, please refer to the relevant descriptions in S403 to S405 and S1105 to S1107 above, which will not be repeated here.

[0342] In another embodiment, please refer to Figure 15 This illustration shows a schematic diagram of another fiber breakage detection device 1500 provided in an embodiment of this application. The fiber breakage detection device 1500 can be a network device, such as a switch or router, or other data communication device. The fiber breakage detection device 1500 is used to perform actions such as... Figure 4 or Figure 11 The illustrated embodiments provide all or part of the steps of the fiber breakage detection method. For example... Figure 15As shown, the fiber breakage detection device 1500 includes a main control board and one or more interface boards, which are communicatively connected. The main control board, also called a main processing unit (MPU) or route processor card, is responsible for controlling and managing the various components in the fiber breakage detection device 1500, including route calculation, device management, and maintenance functions. The interface boards, also called line processing units (LPUs) or line cards, are used for forwarding data. In some embodiments, the fiber breakage detection device 1500 may also include a switching fabric unit (SFU), which is communicatively connected to the main control board and the interface boards. The switching fabric unit is used for forwarding data between the interface boards. The switching fabric unit may also be called a switch fabric unit (SFU). The interface board includes a central processing unit (CPU), a memory, a forwarding chip, and a physical interface card (PIC). The CPU is communicatively connected to the memory, the forwarding chip, and the PIC, respectively. The memory is used to store the forwarding table. The forwarding chip forwards received data frames based on a forwarding table stored in memory. If the destination address of the data frame is the address of the fiber breakage detection device 1500, the data frame is sent to the CPU for processing. If the destination address of the data frame is not the address of the fiber breakage detection device 1500, the next hop and outgoing interface corresponding to the destination address are found in the forwarding table, and the data frame is forwarded to the outgoing interface corresponding to the destination address. The forwarding chip can be a network processor (NP) chip. The PIC, also known as a daughter card, can be installed on the interface board and is responsible for converting photoelectric signals into data frames, performing validity checks on the data frames, and forwarding them to the forwarding chip for processing. In some embodiments, the central processing unit can also perform the functions of the forwarding chip, such as implementing software forwarding based on a general-purpose CPU, thus eliminating the need for a forwarding chip on the interface board. Communication between the main control board, interface board, and switching network board can be achieved through a bus. The forwarding chip can be implemented using an ASIC or FPGA.

[0343] Logically, the fiber breakage detection device 1500 includes a control plane and a forwarding plane. The control plane includes a main control board and a central processing unit, while the forwarding plane includes various components that perform forwarding, such as a memory, a PIC, and an NP chip. The control plane performs functions such as generating routing and forwarding tables, processing signaling and protocol messages, and configuring and maintaining status. The control plane sends the generated forwarding table to the forwarding plane. In the forwarding plane, the NP chip looks up the messages received by the PIC of the fiber breakage detection device 1500 based on the forwarding table sent by the control plane and forwards them. The forwarding table sent by the control plane can be stored in memory. In some embodiments, the control plane and the forwarding plane can be completely separated and not on the same device.

[0344] In specific embodiments, when the fiber breakage detection device 1500 is the second device in the aforementioned embodiments, the interface board in the fiber breakage detection device 1500 is used to generate a second optical signal and transmit the second optical signal through the optical fiber link. For the specific implementation process, please refer to the relevant descriptions in S401 to S402 and S1103 to S1104 above. When the fiber breakage detection device 1500 is the first device in the aforementioned embodiments, the interface board in the fiber breakage detection device 1500 is used to receive a first optical signal including the second optical signal through the optical fiber link, collect the first optical signal to obtain a collected signal, and determine the location of the fiber breakage point based on the collected signal. For the specific implementation process, please refer to the relevant descriptions in S403 to S405 and S1105 to S1107 above. Furthermore, when the fiber breakage detection device 1500 is the first device in the aforementioned embodiments, the main control board can also be used to determine the location of the fiber breakage point based on the collected signal. For the specific implementation process, please refer to the relevant descriptions in S405 and S1107 above. This application embodiment does not limit this aspect.

[0345] In one possible implementation, an inter-process communication (IPC) channel is established between the main control board and the interface board, and the main control board and the interface board communicate with each other through the IPC channel.

[0346] It should be noted that, Figure 15 The fiber breakage detection device 1500 shown can be a frame-type device. Figure 15 This is merely an example of a fiber breakage detection device in this application and is not intended to limit the specific structure of the fiber breakage detection device. The technical solutions provided in this application can also be applied to cassette devices; therefore, the fiber breakage detection device in this application can also be a cassette device. Furthermore, the fiber breakage detection device in this application can be any device capable of implementing the technical solutions provided in this application, and this application does not limit the structure of the device implementing the technical solutions provided in this application.

[0347] This application embodiment also provides a fiber breakage detection device, which includes a processor and an optical device. The optical device is used to perform actions such as... Figure 4 or Figure 11 The transmit and receive operations in the method embodiment shown. The processor is used to perform, as... Figure 4 or Figure 11 The illustrated method embodiments include operations other than the transmit and receive operations. In optional embodiments, the processor includes an optical digital signal processor (ODSP), and the optical device includes at least one of an optical transmitter or an optical receiver. The fiber breakage detection device can be an optical module or a fiber optic card.

[0348] Based on the same inventive concept, this application provides an optical fiber communication system. The optical fiber communication system includes a first device, a second device, and an optical fiber link, with the first device and the second device connected via the optical fiber link. The first device includes, as shown in the example... Figure 12 , Figure 14 or Figure 15 The illustrated embodiment provides a fiber breakage detection device. The second device includes, as shown in the example... Figures 13 to 15 The fiber breakage detection device provided in any of the embodiments shown.

[0349] For example, the fiber optic communication system is as follows: Figure 1 or Figure 2 As shown.

[0350] Based on the same inventive concept, embodiments of this application provide a computer-readable storage medium storing a computer program. When the computer program is executed (e.g., by a network device, terminal device, server, fiber breakage detection device, optical module, and / or fiber optic card, etc.), it performs the following: Figure 4 or Figure 11 At least some steps of the method embodiment shown. For example, implementing as... Figure 4 S404 and S405 in the method embodiment shown, and as in Figure 11 S1106 and S1107 in the method embodiment shown.

[0351] Based on the same inventive concept, embodiments of this application provide a computer program product, which includes a program or code. When the program or code is executed (e.g., by a network device, terminal device, server, fiber breakage detection device, optical module, and / or optical fiber card, etc.), it achieves the following: Figure 4 or Figure 11 At least some steps of the method embodiment shown. For example, implementing as... Figure 4 S404 and S405 in the method embodiment shown, and as in Figure 11 S1106 and S1107 in the method embodiment shown.

[0352] Based on the same inventive concept, embodiments of this application provide a chip, which includes programmable logic circuitry and / or program instructions, and which, when running, is used to implement, as... Figure 4 or Figure 11 At least some steps of the method embodiment shown. For example, implementing as... Figure 4 S404 and S405 in the method embodiment shown, and as in Figure 11 S1106 and S1107 in the method embodiment shown.

[0353] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented entirely or partially as a computer program product, which includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium, or a semiconductor medium (e.g., solid-state drive), etc.

[0354] It should be understood that the term "at least one" in this application refers to one or more, and "multiple" refers to two or more. The term "and / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In addition, for the sake of clarity, this application uses the terms "first," "second," and "third" to distinguish identical or similar items with essentially the same function and role. The terms "first," "second," and "third" do not limit the quantity or execution order.

[0355] The different types of embodiments, such as the method embodiments and device embodiments provided in this application, can be referenced to each other. The order of operations in the method embodiments can be adjusted appropriately, and the operations can be added or removed in response to the situation. Any variations that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application, and therefore will not be described in detail.

[0356] In the corresponding embodiments provided in this application, it should be understood that the disclosed devices, etc., can be implemented through other configurations. For example, the device embodiments ...

Claims

1. A method for detecting fiber breakage, characterized in that, Applied to a first device, the method includes: A first optical signal is received via an optical fiber link, which is deployed between the first device and the second device. The first optical signal includes a second optical signal and a reflected optical signal. The second optical signal is an optical signal generated by the second device, and the reflected optical signal is an optical signal reflected during the transmission of the second optical signal via the optical fiber link. Based on the fact that the received optical power of the first optical signal is less than a first power threshold and greater than a second power threshold, the first optical signal is collected to obtain a collected signal; The location of the break point in the optical fiber link is determined based on the acquired signals.

2. The method according to claim 1, characterized in that, The second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point in the optical fiber link. Determining the location of the fiber optic link breakpoint based on the acquired signal includes: The acquired signal is demodulated to obtain the detection sequence; The location of the break point in the optical fiber link is determined based on the demodulated detection sequence.

3. The method according to claim 2, characterized in that, Determining the location of the fiber optic link breakpoint based on the demodulated detection sequence includes: Obtain the correlation curve corresponding to the demodulated detection sequence. The correlation curve is an autocorrelation curve or a cross-correlation curve. The cross-correlation curve is determined based on the demodulated detection sequence and the detection sequence known by the first device. The location of the fiber optic link breakpoint is determined based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence.

4. The method according to claim 3, characterized in that, The reflected optical signal includes a first sub-reflected optical signal, which is the optical signal reflected from the second optical signal between the break point of the optical fiber link and the reflective end face of the second device. Determining the location of the break point of the optical fiber link based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence includes: Based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence, the delay of the first sub-reflected light signal compared to the second light signal is determined; The distance between the break point of the optical fiber link and the reflective end face of the second device is determined based on the delay of the first sub-reflected optical signal compared to the second optical signal.

5. The method according to claim 1, characterized in that, The second optical signal carries a continuous wave (CW) optical signal, which is used by the first device to determine the location of the break point in the optical fiber link. The reflected optical signal includes a CW reflected optical signal, which is the optical signal reflected during the transmission of the CW optical signal through the optical fiber link. Determining the location of the fiber optic link breakpoint based on the acquired signal includes: The target spectrum of the CW reflected light signal is determined based on the acquired signal; The location of the break point in the optical fiber link is determined based on the target spectrum.

6. The method according to claim 5, characterized in that, The target spectrum includes a first spectral curve, which is the spectral curve of a first CW sub-reflected optical signal. The first CW sub-reflected optical signal is the optical signal reflected between the CW optical signal at the break point of the optical fiber link and the reflective end face of the second device. The CW reflected optical signal includes the first CW sub-reflected optical signal. Determining the location of the fiber optic link break point based on the target spectrum includes: determining the distance between the fiber optic link break point and the reflective end face of the second device based on the frequency corresponding to the characteristic peak of the first spectrum curve.

7. The method according to claim 1, characterized in that, Determining the location of the fiber optic link breakpoint based on the acquired signal includes: The cepstral spectrum of the acquired signal is determined based on the acquired signal; The location of the break point in the optical fiber link is determined based on the cepstral spectrum of the acquired signal.

8. The method according to any one of claims 1 to 7, characterized in that, The second optical signal also carries service signals.

9. The method according to any one of claims 5 to 7, characterized in that, The second optical signal is the CW optical signal.

10. A method for detecting fiber breakage, characterized in that, Applied to a first device, the method includes: A first optical signal is received via an optical fiber link deployed between the first device and the second device. The first optical signal includes a second optical signal and a reflected optical signal. The second optical signal is an optical signal generated by the second device based on a notification message sent by the first device. The notification message is sent by the first device to the second device when the received optical power of the optical signal received via the optical fiber link is less than a first power threshold and greater than a second power threshold. The reflected optical signal is an optical signal reflected during the transmission of the second optical signal via the optical fiber link. The first optical signal is acquired to obtain the acquired signal; The location of the break point in the optical fiber link is determined based on the acquired signals.

11. The method according to claim 10, characterized in that, The second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point in the optical fiber link. Determining the location of the fiber optic link breakpoint based on the acquired signal includes: The acquired signal is demodulated to obtain the detection sequence; The location of the break point in the optical fiber link is determined based on the demodulated detection sequence.

12. The method according to claim 10, characterized in that, The second optical signal carries a continuous wave (CW) optical signal, which is used by the first device to determine the location of the break point in the optical fiber link. The reflected optical signal includes a CW reflected optical signal, which is the optical signal reflected during the transmission of the CW optical signal through the optical fiber link. Determining the location of the fiber optic link breakpoint based on the acquired signal includes: The target spectrum of the CW reflected light signal is determined based on the acquired signal; The location of the break point in the optical fiber link is determined based on the target spectrum.

13. The method according to claim 10, characterized in that, Determining the location of the fiber optic link breakpoint based on the acquired signal includes: The cepstral spectrum of the acquired signal is determined based on the acquired signal; The location of the break point in the optical fiber link is determined based on the cepstral spectrum of the acquired signal.

14. The method according to any one of claims 10 to 13, characterized in that, The second optical signal carries the service signal.

15. The method according to claim 12 or 13, characterized in that, The second optical signal is the CW optical signal.

16. The method according to any one of claims 10 to 15, characterized in that, The method further includes: stopping the acquisition of the first optical signal based on the fact that the received optical power of the first optical signal received through the optical fiber link is less than the second power threshold.

17. A method for detecting fiber breakage, characterized in that, Applied to a second device, the method includes: The notification message is sent by the first device to the second device when the received optical power of the optical signal received through the optical fiber link is less than a first power threshold and greater than a second power threshold, and the optical fiber link is deployed between the first device and the second device. A second optical signal is generated based on the notification message; The second optical signal is sent to the first device through the optical fiber link. After being transmitted through the optical fiber link, the second optical signal becomes a first optical signal. The first optical signal includes the second optical signal and a reflected optical signal. The reflected optical signal is the optical signal reflected during the transmission of the second optical signal through the optical fiber link. The first device is used to determine the location of the break point of the optical fiber link based on the first optical signal.

18. The method according to claim 17, characterized in that, The second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point in the optical fiber link; or, The second optical signal carries a continuous wave (CW) optical signal, which is used by the first device to determine the location of the break point in the optical fiber link.

19. The method according to claim 17 or 18, characterized in that, The second optical signal carries the service signal.

20. The method according to claim 19, characterized in that, The second optical signal is the CW optical signal.

21. A fiber breakage detection device, characterized in that, The fiber breakage detection device, applied to the first device, includes: A receiving module is used to receive a first optical signal via an optical fiber link, the optical fiber link being deployed between the first device and the second device. The first optical signal includes a second optical signal and a reflected optical signal. The second optical signal is an optical signal generated by the second device, and the reflected optical signal is an optical signal reflected during the transmission of the second optical signal via the optical fiber link. The acquisition module is used to acquire the first optical signal based on the fact that the received optical power of the first optical signal is less than a first power threshold and greater than a second power threshold, and to obtain an acquired signal. The determination module is used to determine the location of the break point of the optical fiber link based on the acquired signal.

22. The fiber breakage detection device according to claim 21, characterized in that, The second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point in the optical fiber link. The determining module is used to: The acquired signal is demodulated to obtain the detection sequence; The location of the break point in the optical fiber link is determined based on the demodulated detection sequence.

23. The fiber breakage detection device according to claim 22, characterized in that, The determining module is used for: Obtain the correlation curve corresponding to the demodulated detection sequence. The correlation curve is an autocorrelation curve or a cross-correlation curve. The cross-correlation curve is determined based on the demodulated detection sequence and the detection sequence known by the first device. The location of the fiber optic link breakpoint is determined based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence.

24. The fiber breakage detection device according to claim 23, characterized in that, The reflected optical signal includes a first sub-reflected optical signal, which is the optical signal obtained by reflecting the second optical signal between the break point of the optical fiber link and the reflective end face of the second device. The determining module is used for: Based on the characteristic peak of the correlation curve corresponding to the demodulated detection sequence, the delay of the first sub-reflected light signal compared to the second light signal is determined; The distance between the break point of the optical fiber link and the reflective end face of the second device is determined based on the delay of the first sub-reflected optical signal compared to the second optical signal.

25. The fiber breakage detection device according to claim 21, characterized in that, The second optical signal carries a continuous wave (CW) optical signal, which is used by the first device to determine the location of the break point in the optical fiber link. The reflected optical signal includes a CW reflected optical signal, which is the optical signal reflected during the transmission of the CW optical signal through the optical fiber link. The determining module is used for: The target spectrum of the CW reflected light signal is determined based on the acquired signal; The location of the break point in the optical fiber link is determined based on the target spectrum.

26. The fiber breakage detection device according to claim 25, characterized in that, The target spectrum includes a first spectral curve, which is the spectral curve of a first CW sub-reflected optical signal. The first CW sub-reflected optical signal is the optical signal reflected by the CW optical signal between the break point of the optical fiber link and the reflective end face of the second device. The CW reflected optical signal includes the first CW sub-reflected optical signal. The determining module is used to determine the distance between the break point of the optical fiber link and the reflective end face of the second device based on the target spectrum.

27. The fiber breakage detection device according to claim 21, characterized in that, The determining module is used for: The cepstral spectrum of the acquired signal is determined based on the acquired signal; The location of the break point in the optical fiber link is determined based on the cepstral spectrum of the acquired signal.

28. The fiber breakage detection device according to any one of claims 21 to 27, characterized in that, The second optical signal also carries service signals.

29. The fiber breakage detection device according to any one of claims 25 to 27, characterized in that, The second optical signal is the CW optical signal.

30. A fiber breakage detection device, characterized in that, The fiber breakage detection device, applied to the first device, includes: A receiving module is configured to receive a first optical signal via an optical fiber link deployed between the first device and the second device. The first optical signal includes a second optical signal and a reflected optical signal. The second optical signal is an optical signal generated by the second device based on a notification message sent by the first device. The notification message is sent by the first device to the second device when the received optical power of the optical signal received via the optical fiber link is less than a first power threshold and greater than a second power threshold. The reflected optical signal is an optical signal reflected during the transmission of the second optical signal via the optical fiber link. The acquisition module is used to acquire the first optical signal to obtain the acquired signal; The determination module is used to determine the location of the break point of the optical fiber link based on the acquired signal.

31. The fiber breakage detection device according to claim 30, characterized in that, The second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point in the optical fiber link. The determining module is used to: The acquired signal is demodulated to obtain the detection sequence; The location of the break point in the optical fiber link is determined based on the demodulated detection sequence.

32. The fiber breakage detection device according to claim 30, characterized in that, The second optical signal carries a continuous wave (CW) optical signal, which is used by the first device to determine the location of the break point in the optical fiber link. The reflected optical signal includes a CW reflected optical signal, which is the optical signal reflected during the transmission of the CW optical signal through the optical fiber link. The determining module is used for: The target spectrum of the CW reflected light signal is determined based on the acquired signal; The location of the break point in the optical fiber link is determined based on the target spectrum.

33. The fiber breakage detection device according to claim 30, characterized in that, The determining module is used for: The cepstral spectrum of the acquired signal is determined based on the acquired signal; The location of the break point in the optical fiber link is determined based on the cepstral spectrum of the acquired signal.

34. The fiber breakage detection device according to any one of claims 30 to 33, characterized in that, The second optical signal carries the service signal.

35. The fiber breakage detection device according to claim 32 or 33, characterized in that, The second optical signal is the CW optical signal.

36. The fiber breakage detection device according to any one of claims 30 to 35, characterized in that, The acquisition module is further configured to stop acquiring the first optical signal if the received optical power of the first optical signal received through the optical fiber link is less than the second power threshold.

37. A fiber breakage detection device, characterized in that, The fiber breakage detection device, applied to the second device, includes: A receiving module is used to receive a notification message, which is sent by the first device to the second device when the received optical power of the optical signal received through the optical fiber link is less than a first power threshold and greater than a second power threshold, wherein the optical fiber link is deployed between the first device and the second device. The generation module is used to generate a second optical signal based on the notification message; The transmitting module is used to transmit the second optical signal to the first device through the optical fiber link. The second optical signal is transformed into a first optical signal after being transmitted through the optical fiber link. The first optical signal includes the second optical signal and a reflected optical signal. The reflected optical signal is the optical signal reflected during the transmission of the second optical signal through the optical fiber link. The first device is used to determine the location of the break point of the optical fiber link based on the first optical signal.

38. The fiber breakage detection device according to claim 37, characterized in that, The second optical signal carries a detection sequence, which is used by the first device to determine the location of the break point in the optical fiber link; or, The second optical signal carries a continuous wave (CW) optical signal, which is used by the first device to determine the location of the break point in the optical fiber link.

39. The fiber breakage detection device according to claim 37 or 38, characterized in that, The second optical signal carries the service signal.

40. The fiber breakage detection device according to claim 39, characterized in that, The second optical signal is the CW optical signal.

41. A fiber breakage detection device, characterized in that, Including memory and processor; The memory is used to store computer programs; The processor is configured to execute a computer program stored in the memory to cause the fiber breakage detection device to perform at least some of the steps in the method as described in any one of claims 1 to 20.

42. A fiber breakage detection device, characterized in that, Including processors and optical devices; The optical device is used to perform the transmit / receive operation in the method as described in any one of claims 1 to 20; The processor is used to perform operations other than the send / receive operation in the method as described in any one of claims 1 to 20.

43. The fiber breakage detection device according to claim 42, characterized in that, The processor includes an optical digital signal processor (ODSP); The optical device includes at least one of an optical transmitter or an optical receiver.

44. The fiber breakage detection device according to claim 42 or 43, characterized in that, The fiber breakage detection device is an optical module or a fiber optic card.

45. An optical fiber communication system, characterized in that, It includes a first device, a second device, and an optical fiber link, wherein the first device and the second device are connected via the optical fiber link, and the first device includes the fiber breakage detection device according to any one of claims 21 to 29 and 41 to 44.

46. ​​An optical fiber communication system, characterized in that, It includes a first device, a second device, and an optical fiber link, wherein the first device and the second device are connected through the optical fiber link, and the first device includes the fiber breakage detection device according to any one of claims 30 to 36, 41 to 44; The second device includes the fiber breakage detection device as described in any one of claims 37 to 44.

47. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed, implements at least some of the steps in the method as described in any one of claims 1 to 20.

48. A computer program product, characterized in that, The computer program product includes a program or code that, when executed, implements at least some of the steps in the method as described in any one of claims 1 to 20.

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