Optical fiber link detection method and device, and optical fiber communication system

Abstract

The invention discloses an optical fiber link detection method and device and an optical fiber communication system, and belongs to the technical field of communication. And the optical sending device generates a first optical signal carrying the detection sequence, and sends the first optical signal through the optical fiber link. The optical receiving device receives a first optical signal through the optical fiber link, and the optical receiving device demodulates the first optical signal to obtain a detection sequence; and the optical receiving equipment determines the transmission performance of the optical fiber link according to the demodulated detection sequence. According to the optical fiber link detection method and device, the transmission performance of the optical fiber link is detected through the existing optical sending device and the existing optical receiving device of the optical fiber communication system, the optical fiber link can be detected without deploying additional devices in the optical fiber link, hardware for detecting the optical fiber link is easy to achieve, and the detection cost is low.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a method and apparatus for detecting an optical fiber link, and an optical fiber communication system. Background Art

[0002] An optical fiber communication system generally includes an optical transmitting device, an optical receiving device, and an optical fiber link. The optical transmitting device is connected to the optical receiving device through the optical fiber link. The optical transmitting device is configured to modulate information to be transmitted onto an optical signal and then send the optical signal to the optical receiving device through the optical fiber link. The optical receiving device is configured to receive the optical signal through the optical fiber link and demodulate the information carried by the optical signal. An abnormal optical fiber link may cause multi-path interference (MPI) noise, mode partition noise (MPN), etc., resulting in deterioration of the signal-to-noise ratio of the optical signal received by the optical receiving device. Therefore, it is necessary to detect the transmission performance of the optical fiber link.

[0003] Currently, an optical time domain reflectometer (OTDR) is generally used to detect the transmission performance of an optical fiber link. For example, an OTDR is deployed in the optical fiber link, the OTDR is controlled to send an optical signal to the optical fiber link, and the OTDR is controlled to detect the reflected signal of the optical signal, and the transmission performance of the optical fiber link is determined according to the reflected signal detected by the OTDR.

[0004] However, currently, an additional OTDR is required to detect an optical fiber link, which results in complex hardware implementation for detecting the optical fiber link and high detection cost. Summary of the Invention

[0005] This application provides a method and apparatus for detecting an optical fiber link, and an optical fiber communication system. The hardware implementation for detecting the optical fiber link in this application is simple and the detection cost is low. The solution of this application is as follows.

[0006] In a first aspect, a method for detecting an optical fiber link is provided, which is applied to an optical transmitting device. The method includes: generating a first optical signal, where the first optical signal carries a detection sequence, an autocorrelation curve corresponding to the detection sequence satisfies a preset condition, and the detection sequence is used to detect the transmission performance of the optical fiber link; sending the first optical signal through the optical fiber link.

[0007] The technical solution provided by this application can implement the detection of an optical fiber link without deploying additional devices such as an OTDR in the optical fiber link. Therefore, the hardware implementation for detecting the optical fiber link is simple and the detection cost is low.

[0008] Optionally, the autocorrelation curve corresponding to the detection sequence satisfying a preset condition includes: the autocorrelation curve corresponding to the detection sequence has a characteristic peak. For example, the autocorrelation curve corresponding to the detection sequence has only one characteristic peak.

[0009] In the technical solution provided by this application, the autocorrelation curve corresponding to the detection sequence carried by the first optical signal has a characteristic peak, which facilitates the optical receiving device to determine the transmission performance of the optical fiber link according to the characteristic peak of the autocorrelation curve corresponding to the detection sequence carried by the received first optical signal.

[0010] Optionally, the detection sequence includes a first sequence and a second sequence. The autocorrelation curve corresponding to the detection sequence is determined according to the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence. The autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation value of this position point on the autocorrelation curve of the first sequence and the autocorrelation value of this position point on the autocorrelation curve of the second sequence. That is, the autocorrelation curve corresponding to the detection sequence is the superposition curve of the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence.

[0011] Optionally, the first optical signal carries multiple detection sequences, and the multiple detection sequences are periodically distributed; there is a boundary identifier between adjacent detection sequences among the multiple detection sequences; or, adjacent detection sequences among the multiple detection sequences are continuous.

[0012] In the technical solution provided by this application, multiple periodically distributed detection sequences are carried in the first optical signal, which facilitates the optical receiving device to demodulate the detection sequence from the first optical signal, and then determine the transmission performance of the optical fiber link according to the demodulated detection sequence. For example, if the first optical signal only carries one detection sequence, the optical receiving device needs to accurately demodulate the detection sequence to determine the transmission performance of the optical fiber link according to the detection sequence; while if the first optical signal carries multiple detection sequences, as long as the optical receiving device can demodulate one of the multiple detection sequences, it can determine the transmission performance of the optical fiber link according to the detection sequence, thereby reducing the difficulty of the optical receiving device to demodulate the detection sequence from the first optical signal.

[0013] Moreover, when there is a boundary identifier between adjacent detection sequences among the multiple detection sequences, the optical receiving device can identify the detection sequence carried by the first optical signal according to the boundary identifier, reducing the difficulty of the optical receiving device to identify the detection sequence carried by the first optical signal.

[0014] Optionally, the detection sequence includes any one of the following: a pseudo-random code sequence; a Gray complementary sequence.

[0015] Optionally, the first optical signal also carries a data signal. That is, the first optical signal carries a detection sequence and a data signal.

[0016] The technical solution provided by this application carries a data signal and a detection sequence for detecting the transmission performance of an optical fiber link in the same optical signal, and can realize the in-path detection of the transmission performance of the optical fiber link.

[0017] Optionally, in the first optical signal, the modulation depth of the detection sequence is less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal.

[0018] For the technical solution provided by this application, since the detection sequence belongs to noise for the data signal, the modulation depth of the detection sequence is set to be less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal. In this way, while realizing the in-path detection of the transmission performance of the optical fiber link, the detection sequence can be prevented from affecting the data signal.

[0019] Optionally, in the first optical signal, the ratio of the modulation depth of the detection sequence to the modulation depth of the data signal is less than a preset ratio; the difference between the baud rate of the detection sequence and the baud rate of the data signal is within a preset range.

[0020] For the technical solution provided by this application, since the difference between the baud rate of the detection sequence and the baud rate of the data signal is within a preset range, the baud rate of the detection sequence is less than the baud rate of the data signal, but the baud rate of the detection sequence is not too small. In this way, while preventing the detection sequence from affecting the data signal, it can be avoided that the baud rate of the detection sequence is too small to make it difficult to detect the optical fiber link.

[0021] Optionally, generating the first optical signal includes: modulating the driving signal of the light source with the detection sequence to make the light source emit the first optical signal. That is, the detection sequence is modulated in the first optical signal by using the direct modulation method. The direct modulation method is also called the internal modulation method.

[0022] Optionally, generating the first optical signal includes: modulating the optical signal emitted by the light source with the detection sequence to obtain the first optical signal. That is, the detection sequence is modulated in the first optical signal by using the external modulation method.

[0023] Optionally, generating the first optical signal includes: modulating the driving signal of the light source with the data signal modulated with the detection sequence to make the light source emit the first optical signal. That is, the detection sequence and the data signal are modulated in the first optical signal by using the direct modulation method.

[0024] Optionally, the method is executed by an optical transmitting device, an optical module in the optical transmitting device, or an optical line card in the optical transmitting device.

[0025] In a second aspect, a method for detecting an optical fiber link is provided, which is applied to an optical receiving device. The method includes: receiving a first optical signal through the optical fiber link, where the first optical signal carries a detection sequence, and the autocorrelation curve corresponding to the detection sequence satisfies a preset condition; demodulating the first optical signal to obtain the detection sequence; and determining the transmission performance of the optical fiber link according to the demodulated detection sequence.

[0026] In the technical solution provided by this application, the optical transmitting device and the optical receiving device cooperate to detect the transmission performance of the optical fiber link. Without deploying additional devices such as OTDR in the optical fiber link, the detection of the optical fiber link can be realized. The hardware implementation for detecting the optical fiber link is simple, and the detection cost is relatively low.

[0027] Optionally, the autocorrelation curve corresponding to the detection sequence satisfying the preset condition includes: the autocorrelation curve corresponding to the detection sequence has a characteristic peak. For example, the autocorrelation curve corresponding to the detection sequence has only one characteristic peak.

[0028] Optionally, the detection sequence includes a first sequence and a second sequence. The autocorrelation curve corresponding to the detection sequence is determined according to the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence. The autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation value of this position point on the autocorrelation curve of the first sequence and the autocorrelation value of this position point on the autocorrelation curve of the second sequence. That is, the autocorrelation curve corresponding to the detection sequence is the superimposed curve of the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence.

[0029] Optionally, the first optical signal carries multiple detection sequences, and the multiple detection sequences are periodically distributed; there is a boundary identifier between adjacent detection sequences among the multiple detection sequences; or, adjacent detection sequences among the multiple detection sequences are consecutive.

[0030] In the technical solution provided by this application, multiple detection sequences that are periodically distributed are carried in the first optical signal, which is convenient for the optical receiving device to demodulate the detection sequence from the first optical signal, and then determine the transmission performance of the optical fiber link according to the demodulated detection sequence. For example, if the first optical signal only carries one detection sequence, the optical receiving device needs to accurately demodulate the detection sequence to determine the transmission performance of the optical fiber link according to the detection sequence; while if the first optical signal carries multiple detection sequences, as long as the optical receiving device can demodulate one of the multiple detection sequences, it can determine the transmission performance of the optical fiber link according to the detection sequence, thereby reducing the difficulty for the optical receiving device to demodulate the detection sequence from the first optical signal.

[0031] Optionally, the first optical signal carries a plurality of detection sequences, and there is a boundary identifier between adjacent detection sequences in the plurality of detection sequences. Demodulating the first optical signal to obtain the detection sequences includes: determining the plurality of detection sequences carried by the first optical signal according to the boundary identifier carried by the first optical signal.

[0032] In the technical solution provided by this application, there is a boundary identifier between adjacent detection sequences in the plurality of detection sequences, and the optical receiving device identifies the detection sequences carried by the first optical signal according to the boundary identifier, reducing the difficulty for the optical receiving device to identify the detection sequences carried by the first optical signal.

[0033] Optionally, the first optical signal carries a plurality of detection sequences, and adjacent detection sequences in the plurality of detection sequences are continuous. Demodulating the first optical signal to obtain the detection sequences includes: determining the plurality of detection sequences carried by the first optical signal according to the characteristics of the detection sequences.

[0034] In the technical solution provided by this application, the optical receiving device determines the detection sequences carried by the first optical signal according to the characteristics of the detection sequences, facilitating the optical receiving device to determine the transmission performance of the optical fiber link according to the detection sequences carried by the first optical signal.

[0035] Optionally, determining the transmission performance of the optical fiber link according to the demodulated detection sequences includes: obtaining a correlation curve corresponding to the demodulated detection sequences, where the correlation curve is an autocorrelation curve or a cross-correlation curve, and the cross-correlation curve is determined according to the demodulated detection sequences and the pre-obtained detection sequences; determining the transmission performance of the optical fiber link according to the characteristic peaks of the correlation curve corresponding to the demodulated detection sequences.

[0036] In the technical solution provided by this application, the cross-correlation curve determined according to the demodulated detection sequences and the pre-obtained detection sequences can also be regarded as the autocorrelation curve of the detection sequences. Since the autocorrelation curve corresponding to the detection sequences carried by the first optical signal has a characteristic peak, the optical receiving device can determine the transmission performance of the optical fiber link according to the characteristic peaks of the autocorrelation curve or the cross-correlation curve corresponding to the detection sequences carried by the received first optical signal.

[0037] Optionally, determining the transmission performance of the optical fiber link according to the characteristic peaks of the correlation curve corresponding to the demodulated detection sequences includes: when the correlation curve corresponding to the demodulated detection sequences has only one characteristic peak, determining that the optical fiber link has no fault; when the correlation curve corresponding to the demodulated detection sequences has multiple characteristic peaks, determining that the optical fiber link has a fault.

[0038] In the technical solution provided by this application, the correlation curve corresponding to the demodulated detection sequence is an autocorrelation curve or a cross-correlation curve. The cross-correlation curve is determined according to the demodulated detection sequence and a pre-acquired detection sequence, and the cross-correlation curve can also be regarded as the autocorrelation curve of the detection sequence. Since the autocorrelation curve corresponding to the detection sequence modulated on the first optical signal by the optical transmission device has a characteristic peak, therefore, when the correlation curve (autocorrelation curve or cross-correlation curve) corresponding to the detection sequence demodulated by the optical receiving device from the first optical signal has multiple characteristic peaks, it can be considered that some of these characteristic peaks are caused by the noise generated by the multiple reflections of the first optical signal in the optical fiber link. And the fault point in the optical fiber link usually reflects the optical signal. Therefore, when the correlation curve corresponding to the detection sequence demodulated from the first optical signal has multiple characteristic peaks, the optical receiving device determines that there is a fault in the optical fiber link; when the correlation curve corresponding to the detection sequence demodulated from the first optical signal has only one characteristic peak, the optical receiving device determines that there is no fault in the optical fiber link.

[0039] Optionally, determining the transmission performance of the optical fiber link according to the characteristic peaks of the correlation curve corresponding to the demodulated detection sequence further includes: when the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks, determining the fault point on the optical fiber link according to the main peak and the secondary peaks among the multiple characteristic peaks. Among them, the multiple characteristic peaks include a main peak and at least one secondary peak, and the peak values of the at least one secondary peak are all smaller than the peak value of the main peak.

[0040] In the technical solution provided by this application, when the correlation curve corresponding to the detection sequence demodulated from the first optical signal has multiple characteristic peaks, the optical receiving device determines the fault point on the optical fiber link according to the main peak and the secondary peaks among the multiple characteristic peaks, thereby realizing fault location. Therefore, in this application, there is no need for staff to carry instruments to the station for fault location during fault location, the implementation process is simple, and the labor cost of detection is relatively low.

[0041] Optionally, the detection sequence includes any one of the following: a pseudo-random code sequence; a Gray complementary sequence.

[0042] Optionally, the first optical signal also carries a data signal. That is, the first optical signal carries a detection sequence and a data signal.

[0043] In the technical solution provided by this application, carrying the data signal and the detection sequence for detecting the transmission performance of the optical fiber link in the same optical signal can realize the on-path detection of the transmission performance of the optical fiber link.

[0044] Optionally, in the first optical signal, the modulation depth of the detection sequence is less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal.

[0045] In the technical solution provided by the present application, the modulation depth of the detection sequence is set to be less than that of the data signal, and the baud rate of the detection sequence is less than that of the data signal, so that while the transmission performance of the fiber optic link can be detected along the way, the detection sequence can be prevented from affecting the data signal.

[0046] Optionally, in the first optical signal, the ratio of the modulation depth of the detection sequence to the modulation depth of the data signal is less than a preset ratio; the difference between the baud rate of the detection sequence and the baud rate of the data signal is within a preset range.

[0047] In the technical solution provided by the present application, since the difference between the baud rate of the detection sequence and the baud rate of the data signal is within a preset range, therefore, the baud rate of the detection sequence is less than that of the data signal, but the baud rate of the detection sequence is not too small. In this way, while the detection sequence can be prevented from affecting the data signal, it can be prevented that the baud rate of the detection sequence is too small to make it difficult to detect the fiber optic link.

[0048] Optionally, demodulating the first optical signal includes: filtering the first optical signal.

[0049] That is, filtering the first optical signal to separate the detection sequence and the data signal carried by the first optical signal.

[0050] Optionally, the method is executed by an optical receiving device, an optical module in the optical receiving device, or an optical fiber card in the optical receiving device.

[0051] In a third aspect, a detection device for a fiber optic link is provided, including at least one functional module, and the at least one functional module is used to execute the method provided in the first aspect or any optional manner of the first aspect as 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 specific implementations.

[0052] Optionally, the detection device is an optical transmitting device, an optical module in the optical transmitting device, or an optical fiber card in the optical transmitting device, or the detection device is integrated in the optical transmitting device, the optical module in the optical transmitting device, or the optical fiber card in the optical transmitting device.

[0053] In a fourth aspect, a detection device for a fiber optic link is provided, including at least one functional module, and the at least one functional module is used to execute the method provided in the second aspect or any optional manner of the second aspect as 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 specific implementations.

[0054] Optionally, the detection device is an optical receiving device, an optical module in the optical receiving device, or an optical line card in the optical receiving device, or the detection device is integrated in the optical receiving device, the optical module in the optical receiving device, or the optical line card in the optical receiving device.

[0055] In a fifth aspect, there is provided a detection device for an optical fiber link, including a memory and a processor; the memory is used for storing a computer program; the processor is used for executing the computer program stored in the memory so that the detection device for the optical fiber link executes the method provided in the first aspect or any optional manner of the first aspect as described above.

[0056] Optionally, the detection device is an optical transmitting device, an optical module in the optical transmitting device, or an optical line card in the optical transmitting device, or the detection device is integrated in the optical transmitting device, the optical module in the optical transmitting device, or the optical line card in the optical transmitting device.

[0057] In a sixth aspect, there is provided a detection device for an optical fiber link, including a memory and a processor; the memory is used for storing a computer program; the processor is used for executing the computer program stored in the memory so that the detection device for the optical fiber link executes the method provided in the second aspect or any optional manner of the second aspect as described above.

[0058] Optionally, the detection device is an optical receiving device, an optical module in the optical receiving device, or an optical line card in the optical receiving device, or the detection device is integrated in the optical receiving device, the optical module in the optical receiving device, or the optical line card in the optical receiving device.

[0059] In a seventh aspect, there is provided a detection device for an optical fiber link, including a main control board and an interface board, and the main control board and the interface board are used for implementing the method provided in the first aspect or any optional manner of the first aspect as described above.

[0060] In an eighth aspect, there is provided a detection device for an optical fiber link, including a main control board and an interface board, and the main control board and the interface board are used for implementing the method provided in the second aspect or any optional manner of the second aspect as described above.

[0061] In a ninth aspect, there is provided an optical fiber communication system, including an optical transmitting device, an optical receiving device, and an optical fiber link, and the optical transmitting device is connected to the optical receiving device through the optical fiber link; the optical transmitting device includes the detection device for the optical fiber link provided in the third aspect, the fifth aspect, or the seventh aspect as described above; the optical receiving device includes the detection device for the optical fiber link provided in the fourth aspect, the sixth aspect, or the eighth aspect as described above.

[0062] In a tenth aspect, a computer-readable storage medium is provided. A computer program is stored in the computer-readable storage medium. When the computer program is executed, at least some steps of the method provided in the first aspect or any optional implementation manner of the first aspect are implemented, or at least some steps of the method provided in the second aspect or any optional implementation manner of the second aspect are implemented.

[0063] In an eleventh aspect, a computer program product is provided. The computer program product includes a program or code. When the program or code is executed, at least some steps of the method provided in the first aspect or any optional implementation manner of the first aspect are implemented, or at least some steps of the method provided in the second aspect or any optional implementation manner of the second aspect are implemented.

[0064] In a twelfth aspect, a chip is provided. The chip includes a programmable logic circuit and / or program instructions. When the chip runs, it is used to implement at least some steps of the method provided in the first aspect or any optional implementation manner of the first aspect, or at least some steps of the method provided in the second aspect or any optional implementation manner of the second aspect.

[0065] For the technical effects of the third aspect to the twelfth aspect above, reference can be made to the technical effects of the first aspect to the second aspect, which will not be elaborated here. Description of the Drawings

[0066] Figure 1 is a schematic diagram of an optical fiber communication system provided by an embodiment of the present application;

[0067] Figure 2 is a schematic diagram of an application scenario provided by an embodiment of the present application;

[0068] Figure 3 is a flowchart of a method for detecting an optical fiber link provided by an embodiment of the present application;

[0069] Figure 4 is a schematic diagram of a first sequence provided by an embodiment of the present application;

[0070] Figure 5 is a schematic diagram of a second sequence provided by an embodiment of the present application;

[0071] Figure 6 is a schematic diagram of an autocorrelation curve of a first sequence and an autocorrelation curve of a second sequence provided by an embodiment of the present application;

[0072] Figure 7 is a schematic diagram of an autocorrelation curve corresponding to a detection sequence modulated in a first optical signal provided by an embodiment of the present application;

[0073] Figure 8It is a schematic diagram of the distribution of multiple detection sequences provided in an embodiment of the present application in the first optical signal;

[0074] Figure 9 It is another schematic diagram of the distribution of multiple detection sequences provided in an embodiment of the present application in the first optical signal;

[0075] Figure 10 It is a schematic diagram of generating the first optical signal provided in an embodiment of the present application;

[0076] Figure 11 It is another schematic diagram of generating the first optical signal provided in an embodiment of the present application;

[0077] Figure 12 It is still another schematic diagram of generating the first optical signal provided in an embodiment of the present application;

[0078] Figure 13 It is yet another schematic diagram of generating the first optical signal provided in an embodiment of the present application;

[0079] Figure 14 It is yet another schematic diagram of generating the first optical signal provided in an embodiment of the present application;

[0080] Figure 15 It is yet another schematic diagram of generating the first optical signal provided in an embodiment of the present application;

[0081] Figure 16 It is yet another schematic diagram of generating the first optical signal provided in an embodiment of the present application;

[0082] Figure 17 It is yet another schematic diagram of generating the first optical signal provided in an embodiment of the present application;

[0083] Figure 18 It is a schematic diagram of the correlation curve corresponding to the detection sequence demodulated from the first optical signal provided in an embodiment of the present application;

[0084] Figure 19 It is a schematic diagram of a detection method for an optical fiber link provided in an embodiment of the present application;

[0085] Figure 20 It is another schematic diagram of a detection method for an optical fiber link provided in an embodiment of the present application;

[0086] Figure 21 It is a schematic diagram of a detection device for an optical fiber link provided in an embodiment of the present application;

[0087] Figure 22 It is another schematic diagram of a detection device for an optical fiber link provided in an embodiment of the present application;

[0088] Figure 23It is a schematic diagram of another optical fiber link detection device provided by an embodiment of the present application;

[0089] Figure 24 It is a schematic diagram of another optical fiber link detection device provided by an embodiment of the present application. Detailed implementation manners

[0090] The following will further describe the embodiments of the present application in detail with reference to the accompanying drawings.

[0091] An optical fiber communication system is a communication system that uses optical fibers as transmission media. By modulating information onto optical signals and using optical fibers for transmission, the optical fiber communication system can achieve high-speed, long-distance, and large-capacity communication transmission.

[0092] An optical fiber communication system generally includes an optical transmitting device, an optical receiving device, and an optical fiber link. The optical transmitting device and the optical receiving device are connected through the optical fiber link. The optical transmitting device is used to modulate the information to be transmitted onto an optical signal and then send the optical signal to the optical receiving device through the optical fiber link. The optical receiving device is used to receive the optical signal through the optical fiber link and demodulate the information carried by the optical signal. Abnormalities in the optical fiber link can cause multi-path interference (MPI) noise, mode partition noise (MPN), etc., resulting in deterioration of the signal-to-noise ratio (SNR) of the optical signal received by the optical receiving device. Specifically, the optical fiber link usually includes multiple segments of optical fiber and multiple connectors. The connectors are used to achieve the connection between the optical transmitting device, the optical receiving device, and the optical fiber. If the end face of the connector is dirty or the connector is loose, etc., resulting in poor contact, it will cause a large reflection of the optical signal transmitted in the optical fiber link (for the convenience of distinction, this optical signal is called the original optical signal) at the connector. The optical signals reflected back and forth between different connectors will be superimposed on the original optical signal, generating MPI noise that is related to the original optical signal but has a large delay. The magnitude of the delay of the MPI noise depends on the length of the optical fiber between the two connectors that reflect the MPI noise back and forth. In a multimode scenario, multiple reflections caused by the connector will also trigger MPN. Both MPI noise and MPN will cause deterioration of the signal-to-noise ratio of the optical signal received by the optical receiving device, affecting the transmission performance of the optical fiber transmission system, and even causing the optical fiber link to flash (a situation where the noise is superimposed on the original optical signal, resulting in the optical receiving device being unable to correctly demodulate the service data carried by the received optical signal within a short period of time). Among them, the signal-to-noise ratio of the optical signal is also called the optical signal-to-noise ratio (OSNR). The optical transmitting device and the optical receiving device are collectively referred to as optical communication devices. The optical transmitting device and the optical receiving device are relative. Any optical communication device in the optical fiber communication system can be used as an optical transmitting device or an optical receiving device.

[0093] For example, please refer to Figure 1 , which shows a schematic diagram of an optical fiber communication system. The optical fiber communication system includes Site 110 and Site 120. Site 110 and Site 120 are connected through optical fiber link 130, and Site 110 and Site 120 are also connected through optical fiber link 140. Both Site 110 and Site 120 are optical communication devices. Optical fiber link 130 is a unidirectional link for communication between Site 110 and Site 120. Optical fiber link 130 includes multiple segments of optical fiber 131 and multiple connectors 132 ( Figure 1Two connectors 132 are shown, and adjacent two segments of optical fibers 131 are connected by the connectors 132. The optical fiber link 140 is a unidirectional link for communication between site 120 and site 110. The optical fiber link 140 includes multiple segments of optical fibers 141 and multiple connectors 142( Figure 1 Two connectors 142 are shown, and adjacent two segments of optical fibers 141 are connected by the connectors 142. After modulating the information to be transmitted onto an optical signal, site 110 sends the optical signal (e.g., called the original optical signal 1) to site 120 through the optical fiber link 130. Site 120 is used to receive the optical signal through the optical fiber link 130 and demodulate the information carried by the optical signal. During the transmission of the original optical signal 1 in the optical fiber link 130, if the end face of the connector 132 in the optical fiber link 130 is dirty or the connector 132 is loose, etc., resulting in poor contact, a large reflection of the original optical signal 1 will occur at the connector 132. The optical signals that have undergone multiple round-trip reflections will be superimposed on the original optical signal 1, generating MPI noise that is related to the original optical signal 1 but has a large delay. In a multimode scenario, multiple reflections caused by the connector 132 will also trigger MPN. Both MPI noise and MPN will deteriorate the signal-to-noise ratio of the optical signal received by site 120, affecting the transmission performance of the optical fiber transmission system, and even causing the optical fiber link 130 to flash off. Similarly, after modulating the information to be transmitted onto an optical signal, site 120 sends the optical signal (e.g., called the original optical signal 2) to site 110 through the optical fiber link 140. Site 110 is used to receive the optical signal through the optical fiber link 140 and demodulate the information carried by the optical signal. During the transmission of the original optical signal 2 in the optical fiber link 140, if the end face of the connector 142 in the optical fiber link 140 is dirty or the connector 142 is loose, etc., resulting in poor contact, a large reflection of the original optical signal 2 will occur at the connector 142. The optical signals that have undergone multiple round-trip reflections will be superimposed on the original optical signal 2, generating MPI noise that is related to the original optical signal 2 but has a large delay. In a multimode scenario, multiple reflections caused by the connector 142 will also trigger MPN. Both MPI noise and MPN will deteriorate the signal-to-noise ratio of the optical signal received by site 110, affecting the transmission performance of the optical fiber transmission system, and even causing the optical fiber link 140 to flash off.

[0094] Based on the above description, it can be seen that the optical fiber link is crucial for the transmission performance of the optical fiber transmission system. Therefore, in order to avoid abnormal conditions of the optical fiber link from affecting the transmission performance of the optical fiber transmission system, it is necessary to detect the optical fiber link. For example, the length of a common optical fiber link is usually several meters to dozens of kilometers. The optical fiber link can be detected when the transmission performance of the optical fiber transmission system deteriorates, or the optical fiber link can be detected regularly when the transmission performance of the optical fiber transmission system has not deteriorated to give an early warning of the transmission performance of the optical fiber link.

[0095] Currently, the transmission performance of an optical fiber link is usually detected by an optical time domain reflectometer (OTDR). The OTDR detects the transmission performance of an optical fiber link based on time domain reflection technology, such as detecting the loss, attenuation, reflection, and fault location of the optical fiber link. For example, an OTDR is deployed in an optical fiber link, the OTDR is controlled to send an optical signal to the optical fiber link, and the OTDR is controlled to detect the reflected signal of the optical signal. The transmission performance of the optical fiber link is determined according to the reflected signal detected by the OTDR. For example, whether there is a fault in the optical fiber link and the fault location of the optical fiber link are determined according to information such as the time, intensity, and waveform of the reflected signal detected by the OTDR. Specifically, the OTDR includes a laser and a detector. The laser and the detector are deployed at the same end of the optical fiber link. The laser is used to send an optical signal to the optical fiber link, and the detector is used to detect the reflected signal of the optical signal after the laser sends the optical signal to the optical fiber link. In order for the reflected signal to enter the detector, a circulator or a power splitter also needs to be set on the optical fiber link, and the detector is connected to the optical fiber link through the circulator or the power splitter. The reflected signal is coupled to the detector through the power splitter or the circulator for the detector to detect the reflected signal.

[0096] However, the solution of using an OTDR to detect an optical fiber link requires the deployment of hardware such as an OTDR and a circulator (or a power splitter) in the optical fiber link, and fiber plugging and unplugging are required. This results in a complex hardware implementation for detecting the optical fiber link, a high detection cost, and a complex implementation process.

[0097] In addition to the solution of using an OTDR to detect an optical fiber link, currently, a staff member can also carry an instrument to the station to locate the fault of the optical fiber link. However, this solution is cumbersome to operate, has a complex implementation process, and has a high labor cost for detection.

[0098] The embodiments of the present application provide a method and device for detecting an optical fiber link and an optical fiber communication system. The optical fiber communication system includes an optical transmitting device, an optical receiving device, and an optical fiber link. The optical transmitting device is connected to the optical receiving device through the optical fiber link. The optical transmitting device sends an optical signal carrying a detection sequence to the optical receiving device through the optical fiber link, and the optical receiving device determines the transmission performance of the optical fiber link according to the detection sequence carried by the optical signal, thereby realizing the detection of the optical fiber link. It can be seen that the embodiments of the present application use the existing optical transmitting device and optical receiving device of the optical fiber communication system to detect the transmission performance of the optical fiber link, without deploying additional devices such as an OTDR and a circulator (or a power splitter) in the optical fiber link, and without fiber plugging and unplugging, the detection of the optical fiber link can be realized. Therefore, the hardware implementation for detecting the optical fiber link is simple, the detection cost is low, and in-line detection can be realized. And there is no need for a staff member to carry an instrument to the station for fault location, and the labor cost for detection is low.

[0099] The technical solutions of the embodiments of the present application will be introduced below. First, the application scenarios of the embodiments of the present application will be introduced.

[0100] Please refer to Figure 2 , which shows a schematic diagram of an application scenario provided by an embodiment of the present application. This application scenario provides an optical fiber communication system. The optical fiber communication system includes an optical transmission device 210, an optical reception device 220, and an optical fiber link 230. The optical transmission device 210 is connected to the optical reception device 220 through the optical fiber link 230. The optical fiber link 230 includes multiple segments of optical fiber 231 and multiple connectors 232, and adjacent two segments of optical fiber 231 are connected through the connector 232. The optical fiber link 230 can be a bidirectional optical fiber link between the optical transmission device 210 and the optical reception device 220, or a unidirectional optical fiber link between the optical transmission device 210 and the optical reception device 220. That is, the optical fiber link 230 is used for the optical transmission device 210 to send an optical signal to the optical reception device 220 and for the optical reception device 220 to send an optical signal to the optical transmission device 210. Or, the optical fiber link 230 is used for the optical transmission device 210 to send an optical signal to the optical reception device 220 and is not used for the optical reception device 220 to send an optical signal to the optical transmission device 210.

[0101] The optical transmission device 210 and the optical reception device 220 are collectively referred to as optical communication devices. The optical communication devices include optical modules and / or optical line cards, and the optical modules or the optical line cards perform functions related to optical signal processing. Optionally, the optical modules and / or the optical line cards are detachably arranged in the optical communication devices. For example, the optical communication device includes a slot, and the optical module and / or the optical line card are inserted into the slot to be arranged in the optical communication device. In the embodiments of the present application, the optical communication device is a network device, a terminal device, or a server. The network device can be an optical transport network device, a switch, a router, etc. The terminal device can be a personal computer (PC), a desktop computer, a printer, a camera, etc. Exemplarily, the optical module is detachably arranged in the optical transport network device, the switch, the router, or the terminal device, and the optical line card is detachably arranged in the optical transport network device or the data communication device.

[0102] In the embodiments of the present application, the optical transmitting device 210 includes any one of a network device, a terminal device, or a server, and the optical receiving device 220 includes any one of a network device, a terminal device, or a server. The optical transmitting device 210 and the optical receiving device 220 may be of the same type of optical communication device or different types of optical communication devices. In one example, both the optical transmitting device 210 and the optical receiving device 220 are network devices. For example, both the optical transmitting device 210 and the optical receiving device 220 are switches or routers. In another example, both the optical transmitting device 210 and the optical receiving device 220 are terminal devices. For example, both the optical transmitting device 210 and the optical receiving device 220 are PCs or desktop computers. In yet another example, both the optical transmitting device 210 and the optical receiving device 220 are servers. In still another example, the optical transmitting device 210 is a network device, and the optical receiving device 220 is a terminal device or a server. In still another example, the optical transmitting device 210 is a terminal device, and the optical receiving device 220 is a network device or a server. In still another example, the optical transmitting device 210 is a server, and the optical receiving device 220 is a network device or a terminal device.

[0103] In the embodiments of the present application, the optical transmitting device 210 may send an optical signal carrying a detection sequence to the optical receiving device 220 through the optical fiber link 230. The optical receiving device 220 receives the optical signal through the optical fiber link 230, demodulates the optical signal to obtain the detection sequence, and determines the transmission performance of the optical fiber link 230 according to the demodulated detection sequence. Thus, the cooperation between the optical transmitting device 210 and the optical receiving device 220 realizes the detection of the optical fiber link 230. There is no need to deploy additional devices such as an OTDR and a circulator (or a power splitter) in the optical fiber link 230, and there is no need to perform optical fiber plugging and unplugging, etc. to realize the detection of the optical fiber link 230. The hardware implementation of detecting the optical fiber link 230 is simple, the detection cost is low, and in-path detection can be realized. There is no need for staff to go to the site for fault location, and the labor cost of detection is low.

[0104] It should be noted that Figure 2The application scenarios shown are only for illustration 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, the length of the optical fiber link 230, the number of connectors 232 included in the optical fiber link 230, etc. can be adjusted according to actual needs. In addition, the application scenarios of the embodiments of this application may also include control devices or network management devices, etc. The control device or network management device can be respectively connected to the optical transmission device 210 and the optical reception device 220, and the control device or network management device can control the optical transmission device 210 and the optical reception device 220. For example, the control device or network management device controls the optical transmission device 210 to send an optical signal carrying a detection sequence to the optical reception device 220 through the optical fiber link 230, and controls the optical reception device 220 to demodulate the optical signal to obtain the detection sequence. Furthermore, the optical reception device 220 determines the transmission performance of the optical fiber link 230 according to the demodulated detection sequence. The embodiments of this application do not limit this.

[0105] The above is the introduction of the application scenarios of the embodiments of this application. Next, the method embodiments of this application will be introduced.

[0106] Please refer to Figure 3 , which shows a flowchart of a method for detecting an optical fiber link provided by an embodiment of this application. This detection method is cooperatively executed by an optical transmission device and an optical reception device in an optical fiber communication system. For example, this optical fiber communication system is as Figure 2 shown, and this detection method is cooperatively executed by the optical transmission device 210 and the optical reception device 220. Refer to Figure 3 , this detection method includes the following steps S301 to S305.

[0107] S301. The optical transmission device generates a first optical signal. The first optical signal carries a detection sequence X, and the autocorrelation curve corresponding to the detection sequence X satisfies a preset condition. The detection sequence X is used to detect the transmission performance of the optical fiber link Z.

[0108] Exemplarily, the optical transmission device is Figure 2 the optical transmission device 210 in the optical fiber communication system shown, and the optical fiber link Z is the optical fiber link 230.

[0109] In an alternative embodiment, the autocorrelation curve corresponding to the detection sequence X satisfying the preset condition includes: the autocorrelation curve corresponding to the detection sequence X has a characteristic peak. For example, the autocorrelation curve corresponding to the detection sequence X has only one characteristic peak. By way of example, the autocorrelation curve corresponding to the detection sequence X has only one characteristic peak, and the autocorrelation values at each position point on the autocorrelation curve corresponding to the detection sequence X except for this characteristic peak are all 0. In one example, the detection sequence X includes any one of a pseudo random binary sequence (PRBS) or a Gray complementary sequence. The Gray complementary sequence is a pulse coding sequence. The autocorrelation curves corresponding to the PRBS and the Gray complementary sequence both have a characteristic peak. Therefore, the embodiments of the present application can use the PRBS or the Gray complementary sequence as the detection sequence X.

[0110] In an alternative embodiment, the detection sequence X includes a first sequence A and a second sequence B, and the autocorrelation curve corresponding to the detection sequence X is determined based on the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B. By way of example, the autocorrelation curve corresponding to the detection sequence X is a superimposed curve of the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B. The position points on the autocorrelation curve corresponding to the detection sequence X, the position points on the autocorrelation curve of the first sequence A, and the position points on the autocorrelation curve of the second sequence B correspond one by one. 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 value of this position point on the autocorrelation curve of the first sequence A and the autocorrelation value of this position point on the autocorrelation curve of the second sequence B. Among them, the peak value of the autocorrelation curve of the first sequence A (i.e., the autocorrelation value of the characteristic peak) is greater than the first threshold, and the autocorrelation values of all position points on the autocorrelation curve of the first sequence A except the peak value are less than the second threshold. The peak value of the autocorrelation curve of the second sequence B (i.e., the autocorrelation value of the characteristic peak) is greater than the first threshold, and the autocorrelation values of all position points on the autocorrelation curve of the second sequence B except the peak value are less than the 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 the actual situation. That is to say, the peak value of the autocorrelation curve of the first sequence A is relatively large (e.g., very large), the autocorrelation values of all position points on the autocorrelation curve of the first sequence A except the peak value are relatively small (e.g., very small), the peak value of the autocorrelation curve of the second sequence B is relatively large (e.g., very large), and the autocorrelation values of all position points on the autocorrelation curve of the second sequence B except the peak value are relatively small (e.g., very small). By way of example, the peak value of the autocorrelation curve of the first sequence A is very large, the autocorrelation values of all position points on the autocorrelation curve of the first sequence A except the peak value are very small, the peak value of the autocorrelation curve of the second sequence B is relatively large, the autocorrelation values of all position points on the autocorrelation curve of the second sequence B except the peak value are very small, and moreover, the autocorrelation values of all position points on the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B except the peak value are opposite to each other. As a result, the autocorrelation curve corresponding to the detection sequence X determined based on the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B (e.g., the superimposed curve of the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B) has only one characteristic peak, and the autocorrelation values of all position points on this autocorrelation curve except this characteristic peak are 0. In one embodiment, in the detection sequence X, the second sequence B is located after the first sequence A and is adjacent to the first sequence A. The lengths of both the first sequence A and the second sequence B are fixed lengths, and the length of the first sequence A and the length of the second sequence B may be equal or may not be equal. For example, the length of the first sequence A is equal to the length of the second sequence B.

[0111] In one example, the first sequence A is 1, 1, 1, -1, 1, 1, -1, 1, and the second sequence B is 1, 1, 1, -1, -1, -1, 1, -1. The first sequence A is as shown in Figure 4 (the horizontal axis represents the number of symbols included in the first sequence A, and the vertical axis represents the amplitude of the symbols included in the first sequence A), and the second sequence B is as shown in Figure 5 (the horizontal axis represents the number of symbols included in the second sequence B, and the vertical axis represents the amplitude of the symbols included in the second sequence B). The autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B are as shown in Figure 6 . Referring to Figure 6 , the peak value of the autocorrelation curve of the first sequence A is very large, and the autocorrelation values at each position point on the autocorrelation curve of the first sequence A except the peak value are very small. The peak value of the autocorrelation curve of the second sequence B is very large, and the autocorrelation values at each position point on the autocorrelation curve of the second sequence B except the peak value are very small, and the autocorrelation values at each position point on the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B except the peak value are opposite. For example, the detection sequence X includes the first sequence A and the second sequence B, the second sequence B is located after the first sequence A, and the second sequence B is adjacent to the first sequence A. The detection sequence X is 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, 1, -1. The autocorrelation curve corresponding to the detection sequence X is the superimposed curve of the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B ( Figure 6 the superimposed curve of the two curves in), and the autocorrelation curve corresponding to the detection sequence X is as shown in Figure 7 . Referring to Figure 7 , the autocorrelation curve corresponding to the detection sequence X has a characteristic peak, and the autocorrelation values at each position point on the autocorrelation curve except the characteristic peak are 0. In Figure 6 and Figure 7 , the horizontal axis represents the number of time-shifted symbols, and the vertical axis represents the autocorrelation value (i.e., the correlation degree). It should be noted that when obtaining the autocorrelation curve of a certain sequence, one of the two sequences needs to be shifted by a certain number of symbols (i.e., the number of time-shifted symbols) compared to the other sequence. In Figure 6 and Figure 7 , the negative number representing the number of time-shifted symbols and the positive number representing the number of time-shifted symbols represent different moving directions. For example, the negative number representing the number of time-shifted symbols represents moving to the left, and the positive number representing the number of time-shifted symbols represents moving to the right.

[0112] In an alternative embodiment, the detection sequence X is a Golay complementary sequence. There are many methods for generating Golay complementary sequences. For example, a Golay complementary sequence of length 2L can be generated based on a Golay complementary sequence of length L, a Golay complementary sequence of length 4L can be generated based on a Golay complementary sequence of length 2L, a Golay complementary sequence of length 8L can be generated based on a Golay complementary sequence of length 4L, and so on.

[0113] Exemplarily, the Golay complementary sequence is generated by the recurrence formula shown in Equation (1) below. A higher-order Golay complementary sequence (i.e., a Golay complementary sequence with a longer length) can be generated based on a lower-order Golay complementary sequence (i.e., a Golay complementary sequence with a shorter length) and Equation (1) below.

[0114]

[0115] In Equation (1) above, the symbol "|" represents concatenation, and "A|B" means placing sequence B to the right (or behind) of sequence A. represents taking the negation of B. For example, if B = 1, then if B = -1, then

[0116] In one example, the Golay complementary sequence of length 1 is The process of generating a Golay complementary sequence of length 2 based on this Golay complementary sequence of length 1 is shown in Equation (2) below.

[0117]

[0118] The process of generating a Golay complementary sequence of length 4 based on this Golay complementary sequence of length 2 is shown in Equation (3) below.

[0119]

[0120] The process of generating a Golay complementary sequence of length 8 based on this Golay complementary sequence of length 4 is shown in Equation (4) below.

[0121]

[0122] By analogy, higher-order Golay complementary sequences can be generated. For example, a Golay complementary sequence of length 16 can be generated based on a Golay complementary sequence of length 8, a Golay complementary sequence of length 32 can be generated based on a Golay complementary sequence of length 16, a Golay complementary sequence of length 64 can be generated based on a Golay complementary sequence of length 32, and so on. By way of example, as described above, the first sequence A is 1, 1, 1, -1, 1, 1, -1, 1, and the second sequence B is 1, 1, 1, -1, -1, -1, 1, -1. According to the above formula (4), it can be seen that the first sequence A and the second sequence B are two subsets of the Golay complementary sequence of length 8 expressed by the above formula (4). The detection sequence X can be the Golay complementary sequence expressed by the above formula (4) or a higher-order Golay complementary sequence. In the embodiment of the present application, taking the detection sequence X as the Golay complementary sequence expressed by the above formula (4) as an example, the autocorrelation curve corresponding to the detection sequence X is as Figure 7 shown.

[0123] The above description takes the determination of the autocorrelation curve corresponding to the detection sequence X based on the autocorrelation curves of the first sequence A and the second sequence B as an example, and mainly takes the detection sequence X as a Golay complementary sequence as an example. The above description regarding the autocorrelation curve corresponding to the detection sequence X is equally applicable to the case where the detection sequence X is a pseudo-random code sequence. In the case where the detection sequence X is a pseudo-random code sequence, the autocorrelation calculation can also be directly performed on the detection sequence X to obtain the autocorrelation curve of the detection sequence X, and the embodiment of the present application does not limit this.

[0124] In an optional embodiment, the first optical signal carries a plurality of detection sequences X, and the plurality of detection sequences X are periodically distributed. That is, the plurality of detection sequences X are distributed in the first optical signal according to a period. Among them, the plurality of detection sequences X are all used to detect the transmission performance of the optical fiber link Z. In the embodiment of the present application, carrying a plurality of detection sequences X in the first optical signal can facilitate the optical receiving device to demodulate the detection sequence X from the first optical signal, and then determine the transmission performance of the optical fiber link Z according to the demodulated detection sequence X. For example, if the first optical signal only carries one detection sequence X, the optical receiving device needs to accurately demodulate the detection sequence X to determine the transmission performance of the optical fiber link Z according to the detection sequence X; while if the first optical signal carries a plurality of detection sequences X, as long as the optical receiving device can demodulate one of the plurality of detection sequences X, it can determine the transmission performance of the optical fiber link Z according to the detection sequence X, reducing the difficulty of the optical receiving device in demodulating the detection sequence X from the first optical signal.

[0125] In one embodiment, the first optical signal carries a plurality of detection sequences X, which are periodically distributed, and there is a boundary identifier between adjacent detection sequences X in the plurality of detection sequences X. The boundary identifier is used for the optical receiving device to determine the start position and / or end position of the detection sequence X, so as to determine the detection sequence X. For example, the boundary identifier is an idle sequence. The idle sequence can be an all-0 sequence (that is, all symbols in the idle sequence are 0), or a sequence with an amplitude smaller than that of the detection sequence. For example, the amplitude of the idle sequence is half of the amplitude of the detection sequence. As an example, please refer to Figure 8 , which shows a schematic diagram of the distribution of a plurality of detection sequences X in the first optical signal. The first optical signal carries n detection sequences X, there is a boundary identifier between adjacent detection sequences X, the n detection sequences X are periodically distributed, and each period has one detection sequence X and one boundary identifier, where n is a positive integer. The length of the detection sequence X and the length of the boundary identifier can be different, and the lengths of the detection sequence X and the boundary identifier are both set according to the actual situation. When the length of the boundary identifier is 0, it can be considered that there is no boundary identifier. When the length of the boundary identifier is greater than 0, it can be considered that there is a boundary identifier between adjacent detection sequences X in the plurality of detection sequences X, and it can be considered that there is an interval between the adjacent detection sequences X, or that the adjacent detection sequences X are not continuous.

[0126] In another embodiment, the first optical signal carries a plurality of detection sequences X, which are periodically distributed, the adjacent detection sequences X in the plurality of detection sequences X are continuous, there is no boundary identifier between the adjacent detection sequences X in the plurality of detection sequences X, and there is no interval between the adjacent detection sequences X in the plurality of detection sequences X. As an example, please refer to Figure 9 , which shows another schematic diagram of the distribution of the plurality of detection sequences X in the first optical signal. The first optical signal carries n detection sequences X, the adjacent detection sequences X in the plurality of detection sequences X are continuous, there is no interval between adjacent detection sequences X, the n detection sequences X are periodically distributed, and each period has one detection sequence X, where n is a positive integer. Among them, the length of the detection sequence X is a specific length, and the length of the detection sequence X can be set according to the actual situation.

[0127] In an alternative embodiment, the first optical signal further carries a data signal Y. That is, the first optical signal carries a detection sequence X and a data signal Y. Thus, in the embodiments of the present application, the detection sequence X and the data signal Y are carried in the same optical signal, and the transmission performance of the optical fiber link Z can be detected along the way. Since the detection sequence X is noise for the data signal Y, in the first optical signal, the modulation depth of the detection sequence X is less than the modulation depth of the data signal Y, and the baud rate of the detection sequence X is less than the baud rate of the data signal Y. In this way, while detecting the transmission performance of the optical fiber link Z along the way, the detection sequence X can be prevented from affecting the data signal Y.

[0128] In an alternative embodiment, in the first optical signal, the ratio of the modulation depth of the detection sequence X to the modulation depth of the data signal Y is less than a preset ratio, and the difference between the baud rate of the detection sequence X and the baud rate of the data signal Y is within a preset range. Both the preset ratio and the preset range can be set according to the actual situation. 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 data signal Y is less than the preset ratio, the baud rate of the detection sequence X is less than the baud rate of the data signal Y, and the difference between the baud rate of the detection sequence X and the baud rate of the data signal Y is within the preset range, it is possible to prevent the detection sequence X from affecting the data signal Y while avoiding the baud rate of the detection sequence X being too small to make it difficult to detect the optical fiber link.

[0129] In the embodiments of the present application, the optical transmission device may generate a first optical signal by using a direct modulation method and / or an external modulation method. The direct modulation method refers to a modulation method performed inside the light source, specifically, a modulation method of directly controlling the light source (for example, the light source is a laser, and the pump source of the laser is directly controlled) to modulate the optical signal emitted by the light source. The direct modulation method is also referred to as the internal modulation method. The external modulation method refers to a modulation method performed outside the light source, specifically, a modulation method of using a modulator outside the light source to modulate the optical signal emitted by the light source. In the embodiments of the present application, the light source may be various possible light sources such as a laser or a laser diode (LD). The laser may include any one of a vertical cavity surface emitting laser (VCSEL), an electro-absorption modulated laser (EML), and a directly modulated laser (DML). The modulator may be various possible modulators such as a Mach-Zehnder modulator (MZM) and an electrical variable optical attenuator (EVOA). The embodiments of the present application do not limit the light source and the modulator.

[0130] The following introduces the implementation manners of the optical transmission device generating the first optical signal in two implementation manners.

[0131] The first implementation manner: The optical transmission device modulates the detection sequence X into the first optical signal by using the direct modulation method.

[0132] Specifically, the optical transmission device modulates the drive signal (such as drive current) of the light source by using the detection sequence X so that the light source emits the first optical signal carrying the detection sequence X. When the first optical signal also carries the data signal Y, the optical transmission device may modulate the data signal Y into the first optical signal by using the direct modulation method or may modulate the data signal Y into the first optical signal by using the external modulation method.

[0133] In an example, the first optical signal carries the detection sequence X and does not carry the data signal Y. The optical transmission device modulates the detection sequence X into the first optical signal by using the direct modulation method, and the optical transmission device generates the first optical signal by using the direct modulation method. Please refer to Figure 10 , which shows a schematic diagram of the optical transmission device provided by the embodiments of the present application for generating the first optical signal. As Figure 10As shown, the optical transmission device includes a light source. The optical transmission device modulates the driving signal of the light source using the detection sequence X so that the light source emits a first optical signal carrying the detection sequence X.

[0134] In another example, the first optical signal carries the detection sequence X and the data signal Y. The optical transmission device uses direct modulation to modulate the detection sequence X and the data signal Y in the first optical signal. The optical transmission device uses direct modulation to generate the first optical signal carrying the detection sequence X and the data signal Y. Please refer to Figure 11 , which shows another schematic diagram of the optical transmission device provided by the embodiments of the present application for generating the first optical signal. As Figure 11 shown, the optical transmission device includes a light source. The optical transmission device sequentially modulates the driving signal of the light source using the detection sequence X and the data signal Y so that the light source emits a first optical signal carrying the detection sequence X and the data signal Y. Figure 11 Taking the example that the optical transmission device first modulates the driving signal of the light source using the detection sequence X and then modulates the driving signal of the light source using the data signal Y. In some embodiments, the optical transmission device first modulates the driving signal of the light source using the data signal Y and then modulates the driving signal of the light source using the detection sequence X. In some other embodiments, as Figure 12 shown, the optical transmission device modulates the detection sequence X on the data signal Y. The optical transmission device uses the data signal Y modulated with the detection sequence X to modulate the driving signal of the light source so that the light source emits a first optical signal carrying the detection sequence X and the data signal Y. The embodiments of the present application do not limit this.

[0135] In yet another example, the first optical signal carries the detection sequence X and the data signal Y. The optical transmission device uses direct modulation to modulate the detection sequence X in the first optical signal. The optical transmission device uses external modulation to modulate the data signal Y in the first optical signal. The optical transmission device uses direct modulation and external modulation to generate the first optical signal carrying the detection sequence X and the data signal Y. Please refer to Figure 13 , which shows yet another schematic diagram of the optical transmission device provided by the embodiments of the present application for generating the first optical signal. As Figure 13 shown, the optical transmission device includes a light source and a modulator. The optical transmission device modulates the driving signal of the light source using the detection sequence X so that the light source emits a first optical signal carrying the detection sequence X. The first optical signal carrying the detection sequence X emitted by the light source enters the modulator. The modulator modulates the first optical signal carrying the detection sequence X using the data signal Y to obtain a first optical signal carrying the detection sequence X and the data signal Y.

[0136] The second implementation method: The optical transmission device uses external modulation to modulate the detection sequence X in the first optical signal.

[0137] Specifically, the optical transmission device uses the detection sequence X to modulate the optical signal emitted by the light source to obtain a first optical signal carrying the detection sequence X. When the first optical signal also carries the data signal Y, the optical transmission device can modulate the data signal Y into the first optical signal by using a direct modulation method or an external modulation method.

[0138] In one example, the first optical signal carries the detection sequence X and does not carry the data signal Y. The optical transmission device uses an external modulation method to modulate the detection sequence X into the first optical signal, and the optical transmission device uses an external modulation method to generate the first optical signal. Please refer to Figure 14 , which shows another schematic diagram of the optical transmission device provided by the embodiment of the present application for generating the first optical signal. As Figure 14 shown, the optical transmission device includes a light source and a modulator. The modulator uses the detection sequence X to modulate the optical signal emitted by the light source to obtain a first optical signal carrying the detection sequence X.

[0139] In another example, the first optical signal carries the detection sequence X and the data signal Y. The optical transmission device uses an external modulation method to modulate the detection sequence X and the data signal Y into the first optical signal, and the optical transmission device uses an external modulation method to generate a first optical signal carrying the detection sequence X and the data signal Y. Please refer to Figure 15 , which shows another schematic diagram of the optical transmission device provided by the embodiment of the present application for generating the first optical signal. As Figure 15 shown, the optical transmission device includes a light source, a modulator 1, and a modulator 2. The modulator 1 uses the detection sequence X to modulate the optical signal emitted by the light source to obtain a first optical signal carrying the detection sequence X. The first optical signal after being modulated by the modulator 1 is incident on the modulator 2. The modulator 2 uses the data signal Y to modulate the first optical signal carrying the detection sequence X to obtain a first optical signal carrying the detection sequence X and the data signal Y. That is, the optical transmission device sequentially uses the detection sequence X and the data signal Y to modulate the optical signal emitted by the light source to obtain a first optical signal carrying the detection sequence X and the data signal Y. Figure 15 Taking the example that the optical transmission device first uses the detection sequence X to modulate the optical signal and then uses the data signal Y to modulate the optical signal. In some embodiments, the optical transmission device first uses the data signal Y to modulate the optical signal and then uses the detection sequence X to modulate the optical signal. In other embodiments, as Figure 16 shown, the optical transmission device modulates the detection sequence X on the data signal Y, and the optical transmission device uses the data signal Y modulated with the detection sequence X to modulate the optical signal emitted by the light source to obtain a first optical signal carrying the detection sequence X and the data signal Y. The embodiments of the present application do not limit this.

[0140] In another example, the first optical signal carries a detection sequence X and a data signal Y. The optical transmission device modulates the data signal Y onto the first optical signal in a direct modulation manner, and modulates the detection sequence X onto the first optical signal in an external modulation manner. The optical transmission device generates the first optical signal carrying the detection sequence X and the data signal Y by using the direct modulation manner and the external modulation manner. Please refer to Figure 17 , which shows another schematic diagram of the optical transmission device provided by the embodiment of the present application for generating the first optical signal. As Figure 17 shown, the optical transmission device includes a light source and a modulator. The optical transmission device modulates the driving signal of the light source with the data signal Y to make the light source emit the first optical signal carrying the data signal Y. The first optical signal carrying the data signal Y emitted by the light source enters the modulator, and the modulator modulates the first optical signal carrying the data signal Y with the detection sequence X to obtain the first optical signal carrying the detection sequence X and the data signal Y.

[0141] In an optional embodiment, when the first optical signal carries the detection sequence X and the data signal Y, for Figure 11 , 12 , and the modulation methods shown in 16, the first optical signal can be expressed by the following formula (5). For Figure 13 , Figure 15 , Figure 17 and the modulation methods shown, the first optical signal can be expressed by the following formula (6).

[0142] P(t)=(P0(t)+C)*(1 + m*Patt detect ) Formula (5).

[0143] P(t)=P0(t)+m*Patt detect Formula (6).

[0144] In the above formula (5) and formula (6), P0(t) represents the data signal Y, Patt detect represents the detection sequence X, m represents the ratio of the modulation depth of the detection sequence X to the modulation depth of the data signal Y (when the modulation depth of the data signal Y is 1, m represents the modulation depth of the detection sequence X), C is a constant DC bias, C is a constant, and the existence of C is to make P0(t)+C greater than 0. The symbol "*" represents the multiplication sign.

[0145] S302. The optical transmission device sends the first optical signal through the optical fiber link Z.

[0146] Exemplarily, the optical transmission device includes an interface corresponding to the optical fiber link Z, and the optical transmission device transmits a first optical signal through this interface to transmit the first optical signal through the optical fiber link Z. Among them, this interface is a physical (PHY) interface. For example, this interface is a gigabyte Ethernet (GE) interface (such as a 400GE interface), a terabit Ethernet (TE) interface, etc.

[0147] S303. The optical receiving device receives the first optical signal through the optical fiber link Z.

[0148] Exemplarily, the optical receiving device is Figure 2 the optical receiving device 220 in the shown optical fiber communication system, and the optical fiber link Z is the optical fiber link 230.

[0149] Exemplarily, the optical receiving device includes an interface corresponding to the optical fiber link Z, and the optical receiving device receives the first optical signal through this interface to receive the first optical signal through the optical fiber link Z. Among them, this interface is a PHY interface. For example, this interface is a GE interface, a TE interface, etc.

[0150] S304. The optical receiving device demodulates the first optical signal to obtain the detection sequence X.

[0151] In an optional embodiment, the first optical signal carries multiple detection sequences X, and the multiple detection sequences X are periodically distributed. The optical receiving device demodulates the first optical signal to obtain the multiple detection sequences X.

[0152] In one embodiment, in the first optical signal, there is a boundary identifier between adjacent detection sequences X among the multiple detection sequences X. The optical receiving device determines the detection sequence X carried by the first optical signal according to the boundary identifier carried by the first optical signal. In a specific embodiment, the optical receiving device searches for the boundary identifier in the first optical signal; the optical receiving device identifies the start position and / or end position of the detection sequence X carried by the first optical signal according to the boundary identifier carried by the first optical signal; the optical receiving device determines the detection sequence X according to the start position and / or end position of the detection sequence X; the optical receiving device can determine at least one detection sequence X from the first optical signal. For example, the optical receiving device identifies the start position and the end position of the detection sequence X carried by the first optical signal according to the boundary identifier carried by the first optical signal, and the optical receiving device determines the part between the start position of the detection sequence X and the end position of the detection sequence X as the detection sequence X. For another example, the optical receiving device identifies the start position of the detection sequence X carried by the first optical signal according to the boundary identifier carried by the first optical signal, and the optical receiving device determines the part between adjacent start positions as a detection sequence X. For still another example, the optical receiving device identifies the end position of the detection sequence X carried by the first optical signal according to the boundary identifier carried by the first optical signal, and the optical receiving device determines the part between adjacent end positions as a detection sequence X. In an optional embodiment, since the multiple detection sequences X are periodically distributed in the first optical signal, in some embodiments, after the optical receiving device determines one detection sequence X carried by the first optical signal according to the boundary identifier carried by the first optical signal, the optical receiving device determines other detection sequences X carried by the first optical signal according to the distribution period of the multiple detection sequences X. The embodiments of the present application do not limit this.

[0153] In another embodiment, in the first optical signal, adjacent detection sequences X among the multiple detection sequences X are consecutive, and there is no boundary identifier between adjacent detection sequences X among the multiple detection sequences X. The optical receiving device determines the detection sequence X carried by the first optical signal according to the characteristics of the detection sequence X. The characteristics of the detection sequence X may be the distribution characteristics, correlation characteristics (such as autocorrelation characteristics), etc. of the detection sequence X. In one implementation, the optical receiving device extracts a sequence (such as a randomly extracted sequence) from the first optical signal according to the length of the detection sequence X (such as the detection sequence X pre-negotiated between the optical transmitting device and the optical receiving device, the detection sequence X pre-configured in the optical receiving device, etc.) pre-acquired by the optical receiving device. For the convenience of description, the sequence extracted by the optical receiving device from the first optical signal is called the sequence to be verified, and the length of the sequence to be verified is less than or equal to the length of the detection sequence X pre-acquired by the optical receiving device. The optical receiving device verifies whether the sequence to be verified is the detection sequence X according to the detection sequence X pre-acquired by the optical receiving device. When it is determined through verification that the sequence to be verified is the detection sequence X, the optical receiving device determines that a detection sequence X has been found in the first optical signal, and the optical receiving device determines other detection sequences X carried by the first optical signal according to the distribution period of the multiple detection sequences X. When it is determined through verification that the sequence to be verified is not the detection sequence X, the optical receiving device re-extracts the sequence to be verified from the first optical signal and verifies whether the re-extracted sequence to be verified is the detection sequence X until the optical receiving device finds a detection sequence X in the first optical signal. In an example, the length of the sequence to be verified is equal to the length of the detection sequence X pre-acquired by the optical receiving device, and the optical receiving device performs a correlation calculation on the sequence to be verified and the pre-acquired detection sequence X. The optical receiving device determines whether the sequence to be verified is the detection sequence X according to the correlation calculation result. In a specific embodiment, the optical receiving device performs a correlation calculation on the sequence to be verified and the pre-acquired detection sequence X to obtain a cross-correlation curve of the sequence to be verified and the pre-acquired detection sequence X. The optical receiving device compares the cross-correlation curve with the autocorrelation curve of the pre-acquired detection sequence X to determine whether the cross-correlation curve and the autocorrelation curve of the pre-acquired detection sequence X match; when it is determined through comparison that the cross-correlation curve and the autocorrelation curve of the pre-acquired detection sequence X match, the optical receiving device determines that the sequence to be verified is the detection sequence X; when it is determined through comparison that the cross-correlation curve and the autocorrelation curve of the pre-acquired detection sequence X do not match, the optical receiving device determines that the sequence to be verified is not the detection sequence X.In another example, the length of the sequence to be verified is less than or equal to the length of the detection sequence X pre-acquired by the optical receiving device. The optical receiving device compares the sequence to be verified with the pre-acquired detection sequence X to determine whether the sequence to be verified matches the pre-acquired detection sequence X. When it is determined through comparison that the sequence to be verified matches the pre-acquired detection sequence X, the optical receiving device determines that the sequence to be verified is the detection sequence X. When it is determined through comparison that the sequence to be verified does not match the pre-acquired detection sequence X, the optical receiving device determines that the sequence to be verified is not the detection sequence X. It should be noted that the matching described in this paragraph includes but is not limited to being approximately the same or exactly the same. Being approximately the same means being basically the same but may have minor differences. For example, for the sake of description, the cross-correlation curve of the sequence to be verified and the pre-acquired detection sequence X is called the cross-correlation curve Q1, and the autocorrelation curve of the pre-acquired detection sequence X is called the autocorrelation curve Q2. The cross-correlation curve Q1 being approximately the same as the autocorrelation curve Q2 includes that the number of time-shift symbols at each position point on the cross-correlation curve Q1 is the same as the number of time-shift symbols at the corresponding position point on the autocorrelation curve Q2, and the correlation value at each position point of 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 between the correlation values is less than a threshold). By way of example, the cross-correlation curve Q1 and the autocorrelation curve Q2 respectively include position points from -m to m. The correlation value at the position point -m on the cross-correlation curve Q1 is approximately the same as the correlation value at the position point -m on the autocorrelation curve Q2, the correlation value at the position point -m + 1 on the cross-correlation curve Q1 is approximately the same as the correlation value at the position point -m + 1 on the autocorrelation curve Q2, the correlation value at the position point -m + 2 on the cross-correlation curve Q1 is approximately the same as the correlation value at the position point -m + 2 on the autocorrelation curve Q2, and so on. Another example is that the sequence to be verified matching the pre-acquired detection sequence X includes that the number of symbols of the sequence to be verified is less than or equal to the number of symbols of the pre-acquired detection sequence X, and multiple symbols of the sequence to be verified correspond one by one to multiple symbols of the pre-acquired detection sequence X, and the amplitude of the symbol of the sequence to be verified is approximately the same as the amplitude of the corresponding symbol of the pre-acquired detection sequence X (for example, the amplitudes are equal, or the difference between the amplitudes is less than a threshold). By way of example, the pre-acquired detection sequence X is 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, then the sequence to be verified matches the pre-acquired detection sequence X.

[0154] In an alternative embodiment, the optical receiving device converts the first optical signal into an electrical signal, and the optical receiving device demodulates based on the electrical signal to obtain the detection sequence X. In a specific embodiment, the optical receiving device performs optoelectronic conversion on the first optical signal to obtain a first electrical signal, and the first electrical signal is an analog electrical signal; the optical receiving device converts the first electrical signal into a digital electrical signal (for ease of description, this digital electrical signal is referred to as the second electrical signal); the optical receiving device determines the detection sequence X according to the second electrical signal. In one embodiment, the first optical signal carries a plurality of periodically distributed detection sequences X, and there is a boundary identifier between adjacent detection sequences X among the plurality of detection sequences X. Therefore, the second electrical signal includes a plurality of periodically distributed detection sequences X, and there is a boundary identifier between adjacent detection sequences X among the plurality of detection sequences X. The optical receiving device searches for the boundary identifier in the second electrical signal, and the optical receiving device identifies the start position and / or end position of the detection sequence X in the second electrical signal according to the boundary identifier in the second electrical signal. The optical receiving device determines the detection sequence X according to the start position and / or end position of the detection sequence X, and the optical receiving device can determine at least one detection sequence X from the second electrical signal. In another embodiment, the first optical signal carries a plurality of periodically distributed detection sequences X, and there is no boundary identifier between adjacent detection sequences X among the plurality of detection sequences X. Therefore, the second electrical signal includes a plurality of periodically distributed detection sequences X, and there is no boundary identifier between adjacent detection sequences X among the plurality of detection sequences X. The optical receiving device determines at least one detection sequence X from the second electrical signal according to the characteristics of the detection sequence X. Optionally, since there is usually noise in the second electrical signal, before the optical receiving device determines the detection sequence X from the second electrical signal, the optical receiving device performs noise reduction processing, equalization processing, etc. on the second electrical signal to reduce the influence of noise on the second electrical signal. The optical receiving device determines the detection sequence X from the second electrical signal after noise reduction processing and equalization processing, thereby avoiding the influence of noise on the optical receiving device to determine the detection sequence X from the second electrical signal. In the embodiments of the present application, the process of the optical receiving device determining the detection sequence X from the second electrical signal can be referred to as a synchronization process. By way of example, the optical receiving device includes a synchronization unit, and the synchronization unit determines the detection sequence X from the second electrical signal. The embodiments of the present application do not limit this.

[0155] In an alternative embodiment, the first optical signal further carries a data signal Y. That is, the first optical signal carries a detection sequence X and a data signal Y. For example, the first optical signal carries a data signal Y and a plurality of periodically distributed detection sequences X. The demodulation of the first optical signal by the optical receiving device further includes: the optical receiving device filters the first optical signal to obtain a detection signal, and the detection signal includes the detection sequence X. For example, the detection signal includes a plurality of periodically distributed detection sequences X. When the first optical signal further carries a boundary identifier, the detection signal further includes the boundary identifier. Wherein, the detection signal includes noise, and a part of the noise in the noise of the detection signal may be the data signal Y. In a specific embodiment, the optical receiving device performs photoelectric conversion on the first optical signal to obtain a first electrical signal; the optical receiving device converts the first electrical signal into a digital electrical signal (i.e., a second electrical signal); the optical receiving device filters the second electrical signal to obtain a filtered second electrical signal, and the filtered second electrical signal is the detection signal, and the optical receiving device determines the detection sequence X according to the filtered second electrical signal. In another specific implementation, the optical receiving device performs photoelectric conversion on the first optical signal to obtain a first electrical signal; the optical receiving device filters the first electrical signal to obtain a filtered first electrical signal; the optical receiving device converts the filtered first electrical signal into a digital electrical signal (i.e., a second electrical signal), and the second electrical signal is the detection signal, and the optical receiving device determines the detection sequence X according to the second electrical signal. Wherein, the optical receiving device filters the first electrical signal using an analog filter, and the optical receiving device filters the second electrical signal using a digital filter.

[0156] Exemplarily, in the first optical signal, the modulation depth of the detection sequence X is less than the modulation depth of the data signal Y, and the baud rate of the detection sequence X is less than the baud rate of the data signal Y. The filter is a low-pass filter.

[0157] S305. The optical receiving device determines the transmission performance of the optical fiber link Z according to the detection sequence X demodulated from the first optical signal.

[0158] It should be noted that when the first optical signal carries multiple detection sequences X, in S304, the optical receiving device can demodulate at least one detection sequence X from the first optical signal. In S305, the optical receiving device can determine the transmission performance of the optical fiber link Z according to one or more of the at least one detection sequence X. For example, in order to ensure the reliability of the detection result, the optical receiving device determines the transmission performance of the optical fiber link Z according to the multiple detection sequences X demodulated from the first optical signal. The implementation process of the optical receiving device determining the transmission performance of the optical fiber link Z according to any two of the multiple detection sequences X is the same. The following takes the optical receiving device determining the transmission performance of the optical fiber link Z according to one detection sequence X demodulated from the first optical signal as an example for introduction. The implementation process of the optical receiving device determining the transmission performance of the optical fiber link Z according to each of the multiple detection sequences X demodulated from the first optical signal can refer to the following description.

[0159] In the embodiments of the present application, the autocorrelation curve corresponding to the detection sequence X modulated by the optical transmitting device on the first optical signal satisfies a preset condition. Therefore, the optical receiving device can determine the transmission performance of the optical fiber link Z according to whether the correlation curve corresponding to the detection sequence X demodulated from the first optical signal satisfies the preset condition. Among them, the correlation curve can be an autocorrelation curve or a cross-correlation curve. The autocorrelation curve corresponding to the demodulated detection sequence X is determined according to the demodulated detection sequence X. The cross-correlation curve corresponding to the demodulated detection sequence X is determined according to the demodulated detection sequence and the detection sequence X pre-acquired by the optical receiving device. The detection sequence X pre-acquired by the optical receiving device is the detection sequence X modulated by the optical transmitting device on the first optical signal pre-acquired by the optical receiving device. The detection sequence X pre-acquired by the optical receiving device can be pre-negotiated between the optical transmitting device and the optical receiving device, or can be pre-configured in the optical receiving device. The cross-correlation curve determined according to the demodulated detection sequence X and the pre-acquired detection sequence X can also be regarded as the autocorrelation curve of the detection sequence X.

[0160] In a specific embodiment, the optical receiving device obtains the correlation curve (autocorrelation curve or cross-correlation curve) corresponding to the detection sequence X demodulated from the first optical signal. The optical receiving device determines whether the correlation curve (autocorrelation curve or cross-correlation curve) satisfies the preset condition. When the optical receiving device determines that the correlation curve satisfies the preset condition, the optical receiving device determines that the optical fiber link Z has no fault. When the optical receiving device determines that the correlation curve does not satisfy the preset condition, the optical receiving device determines that the optical fiber link Z has a fault.

[0161] In an alternative embodiment, the autocorrelation curve corresponding to the detection sequence X modulated on the first optical signal by the optical transmitting device satisfies a preset condition, including that the autocorrelation curve corresponding to the detection sequence X has a characteristic peak. The optical receiving device determines the transmission performance of the optical fiber link Z based on the characteristic peak of the correlation curve (autocorrelation curve or cross-correlation curve) corresponding to the detection sequence X demodulated from the first optical signal. In a specific embodiment, the optical receiving device determines whether there is a fault in the optical fiber link Z based on the characteristic peak of the correlation curve corresponding to the detection sequence X demodulated from the first optical signal. In one embodiment, the correlation curve corresponding to the detection sequence X modulated on the first optical signal by the optical transmitting device satisfies a preset condition, including that the autocorrelation curve corresponding to the detection sequence X has only one characteristic peak, and the autocorrelation values at each position point on the autocorrelation curve corresponding to the detection sequence X except this characteristic peak are all 0. The optical receiving device determines the number of characteristic peaks of the correlation curve corresponding to the detection sequence X demodulated from the first optical signal. When the optical receiving device determines that the correlation curve corresponding to the detection sequence X demodulated from the first optical signal has only one characteristic peak, the optical receiving device determines that the optical fiber link Z has no fault. When the optical receiving device determines that the correlation curve corresponding to the detection sequence X demodulated from the first optical signal has multiple characteristic peaks, the optical receiving device determines that there is a fault in the optical fiber link.

[0162] In an alternative embodiment, when the optical receiving device determines that the correlation curve corresponding to the detection sequence X demodulated from the first optical signal has multiple characteristic peaks, the optical receiving device determines the fault point on the optical fiber link Z based on the main peak and the secondary peaks among the multiple characteristic peaks. Among them, the multiple characteristic peaks include a main peak and at least one secondary peak, and the peak values of the at least one secondary peak are all smaller than the peak value of the main peak. Each of the at least one secondary peak corresponds to two reflection points on the optical fiber link Z, and at least one of the two reflection points is a fault point. Moreover, the partial reflection points corresponding to different secondary peaks may be the same or different. For example, secondary peak 1 corresponds to reflection point 1 and reflection point 2, and secondary peak 2 corresponds to reflection point 1 and reflection point 3, then the partial reflection points corresponding to secondary peak 1 and secondary peak 2 are the same.

[0163] In a specific embodiment, the horizontal axis of the correlation curve corresponding to the detection sequence X demodulated from the first optical signal represents the number of time-shifted symbols. When the correlation curve includes a main peak and at least one secondary peak, for each of the at least one secondary peak, the optical receiving device determines the difference between the number of time-shifted symbols corresponding to the secondary peak and the number of time-shifted symbols corresponding to the main peak (for ease of description, this difference is referred to as the time-shifted symbol difference corresponding to the secondary peak); the optical receiving device determines the transmission duration of the reflected signal between the two reflection points corresponding to the secondary peak according to the time-shifted symbol difference corresponding to the secondary peak and the baud rate at which the optical transmitting device modulates the detection sequence X on the first optical signal; the optical receiving device determines the distance between the two reflection points corresponding to the secondary peak on the optical fiber link Z according to the transmission duration, and further determines the fault point on the optical fiber link Z according to the distance between the two reflection points. For example, poor contact caused by dirt on the end face of the connector in the optical fiber link or loose connection of the connector will cause reflection of the optical signal at the connector. The reflection points on the optical fiber link Z are usually located at the position of the connector. The optical receiving device can determine the fault point on the optical fiber link Z according to the distance between the two reflection points corresponding to the secondary peak in combination with the deployment of the optical fiber link Z.

[0164] Among them, the time-shifted symbol difference corresponding to the secondary peak may be positive or negative. A positive value indicates that the signal of the detection sequence in this period is reflected by the reflection point corresponding to the secondary peak, and a negative value indicates that the signal of the detection sequence in the previous period reflected by the reflection point corresponding to the secondary peak is delayed to the signal of the detection sequence in this period. When the time-shifted symbol difference corresponding to the secondary peak is positive, the optical receiving device determines the product of the time-shifted symbol difference corresponding to the secondary peak and the symbol period (i.e., the reciprocal of the baud rate) at which the optical transmitting device modulates the detection sequence X on the first optical signal as the transmission duration of the reflected signal between the two reflection points corresponding to the secondary peak. When the time-shifted symbol difference corresponding to the secondary peak is negative, the optical receiving device determines the sum of the time-shifted symbol difference corresponding to the secondary peak and the length of the target sequence. The optical receiving device determines the sum of the time-shifted symbol difference corresponding to the secondary peak and the length of the target sequence as the number of delayed symbols corresponding to the secondary peak. The optical receiving device determines the product of the number of delayed symbols corresponding to the secondary peak and the symbol period (i.e., the reciprocal of the baud rate) at which the optical transmitting device modulates the detection sequence X on the first optical signal as the transmission duration of the reflected signal between the two reflection points corresponding to the secondary peak. Among them, the target sequence is the sequence used to obtain the correlation curve corresponding to the demodulated detection sequence X. The target sequence may be the first sequence, the second sequence, or the detection sequence X.

[0165] Exemplarily, for each of the at least one secondary peak, the optical receiving device determines the distance between the two reflection points corresponding to the secondary peak on the optical fiber link Z according to the transmission duration of the reflected signal between the two reflection points corresponding to the secondary peak, and uses the distance-time formula. Exemplarily, the distance-time formula is D = v * T / 2. Here, v represents the transmission speed of the first optical signal in the optical fiber link Z, T represents the transmission duration of the reflected signal between the two reflection points corresponding to the secondary peak, D represents the distance between the two reflection points corresponding to the secondary peak, the symbol "*" represents the multiplication sign, and the symbol " / " represents the division sign. In an optional embodiment, the reflection ability of the end face of the laser of the optical transmitting device is relatively strong, and it can be considered that the end face of the laser of the optical transmitting device is a fixed reflection point. In this case, "D" in the distance-time formula represents the distance between a fault point (the fault point corresponding to the secondary peak) in the optical fiber link Z and the optical transmitting device (specifically, the distance between the fault point corresponding to the secondary peak and the end face of the laser of the optical transmitting device). When the optical receiving device determines the distance between the two reflection points corresponding to the secondary peak, it also determines the distance between the fault point corresponding to the secondary peak and the end face of the laser of the optical transmitting device, that is, determines the position of the fault point corresponding to the secondary peak.

[0166] As an example, please refer to Figure 18 , which shows a schematic diagram of the correlation curve corresponding to the detection sequence X demodulated from the first optical signal by the optical receiving device. The correlation curve can be an autocorrelation curve corresponding to the detection sequence X demodulated from the first optical signal, or a cross-correlation curve determined according to the detection sequence X demodulated from the first optical signal and the detection sequence X pre-acquired by the optical receiving device. Refer to Figure 18 , the correlation curve has two characteristic peaks. Assuming that it is known that the reflection ability of the end face of the laser of the optical transmitting device is relatively strong and it is a fixed reflection point, the optical receiving device determines that there is a fault in the optical fiber link Z according to the characteristic peaks of the correlation curve. Further, the two characteristic peaks include a main peak and a secondary peak. The number of symbol shifts corresponding to the main peak is 0, and the number of symbol shifts corresponding to the secondary peak is 2. Therefore, the optical receiving device determines that the symbol shift difference corresponding to the secondary peak is 2 (2 - 0 = -2). The optical receiving device multiplies the symbol shift difference corresponding to the secondary peak by the symbol period of modulating the detection sequence X on the first optical signal by the optical transmitting device to determine the transmission duration of the reflected signal between the two reflection points (the end face of the laser of the optical transmitting device and a fault point) corresponding to the secondary peak. The optical receiving device determines the distance between the two reflection points corresponding to the secondary peak according to the transmission duration using the above distance-time formula. Furthermore, the optical receiving device determines the fault point corresponding to the secondary peak on the optical fiber link Z according to the distance between the two reflection points and the known position of the end face of the laser of the optical transmitting device.

[0167] In an alternative embodiment, when the optical receiving device determines that the correlation curve corresponding to the detected sequence X demodulated from the first optical signal has multiple characteristic peaks, the optical receiving device further determines the reflection degree of the reflection point (including the fault point) corresponding to each sub-peak among the multiple characteristic peaks according to the amplitude of each sub-peak. For example, the vertical axis of the correlation curve corresponding to the detected sequence X represents the degree of correlation, and the amplitude of each sub-peak is used to reflect the reflection degree of the reflection point (including the fault point) corresponding to the sub-peak. The amplitude of the sub-peak is positively correlated with the reflection degree of the reflection point corresponding to the sub-peak. The larger the amplitude of the sub-peak, the stronger the reflection degree of the reflection point (including the fault point) corresponding to the sub-peak. The smaller the amplitude of the sub-peak, the weaker the reflection degree of the reflection point (including the fault point) corresponding to the sub-peak.

[0168] In the embodiment of the present application, the optical receiving device can not only determine whether there is a fault in the optical fiber link Z according to the correlation curve corresponding to the detected sequence X demodulated from the first optical signal. When it is determined that there is a fault in the optical fiber link Z, the optical receiving device can also determine the fault point on the optical fiber link Z according to the characteristic peaks of the correlation curve, so as to realize fault location of the optical fiber link Z. Therefore, in the embodiment of the present application, there is no need for the staff to carry instruments to the site for fault location during fault location, and the implementation process is simple. In addition, when it is determined that there is a fault in the optical fiber link Z, the optical receiving device can also determine the reflection degree of the reflection point (including the fault point) corresponding to the sub-peak according to the amplitude of the sub-peak of the correlation curve, so as to qualitatively determine the magnitude of the fault degree of the fault point.

[0169] In an alternative embodiment, the correlation curve corresponding to the detected sequence X demodulated from the first optical signal can be an autocorrelation curve or a cross-correlation curve. The autocorrelation curve corresponding to the demodulated detected sequence X is determined according to the demodulated detected sequence X. The cross-correlation curve corresponding to the demodulated detected sequence X is determined according to the demodulated detected sequence and the detected sequence X pre-acquired by the optical receiving device. The detected sequence X pre-acquired by the optical receiving device is the detected sequence X modulated by the optical transmitting device on the first optical signal pre-acquired by the optical receiving device.

[0170] In one embodiment, the correlation curve corresponding to the detected sequence X demodulated from the first optical signal is an autocorrelation curve, and the optical receiving device determines the autocorrelation curve according to the demodulated detected sequence X. In a specific embodiment, the detected sequence X modulated by the optical transmitting device on the first optical signal is a Gray complementary sequence or a pseudo-random code sequence, and the detected sequence X includes a first sequence A and a second sequence B. After the optical receiving device demodulates the detected sequence X from the first optical signal, the optical receiving device determines the first sequence A and the second sequence B from the demodulated detected sequence X, and the optical receiving device determines the autocorrelation curve corresponding to the demodulated detected sequence X according to the first sequence A and the second sequence B determined from the demodulated detected sequence X. By way of example, in the detected sequence X, the second sequence B is located after the first sequence A and is adjacent to the first sequence A, and the lengths of both the first sequence A and the second sequence B are of a fixed length. For example, the length of the first sequence A is a first length, and the length of the second sequence B is a second length. The optical receiving device determines the sequence with a length of the first length starting from the starting position of the demodulated detected sequence X as the first sequence A, and the optical receiving device determines the sequence other than the first sequence A in the demodulated detected sequence X as the second sequence B. It should be noted that the first sequence A involved in the subsequent description of this paragraph refers to the first sequence A determined from the demodulated detected sequence X, and the second sequence B involved in the subsequent description of this paragraph refers to the second sequence B determined from the demodulated detected sequence X. In one embodiment, the optical receiving device performs autocorrelation calculation on the first sequence A to obtain the autocorrelation curve of the first sequence A; the optical receiving device performs autocorrelation calculation on the second sequence B to obtain the autocorrelation curve of the second sequence B; the optical receiving device determines the autocorrelation curve corresponding to the demodulated detected sequence X according to the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B. In a specific embodiment, the position points on the autocorrelation curve of the first sequence A correspond one-to-one with the position points on the autocorrelation curve of the second sequence B, and the optical receiving device adds the amplitudes on the autocorrelation curve of the first sequence A and the amplitudes on the autocorrelation curve of the second sequence B according to the corresponding position points, and the optical receiving device draws a curve according to the added amplitudes to obtain the autocorrelation curve corresponding to the demodulated detected sequence X. In one example, both the autocorrelation curve of the first sequence A and the autocorrelation curve of the second sequence B include position points from -m to m, where m is a positive integer. The position points from -m to m on the autocorrelation curve of the first sequence A correspond one-to-one with the position points from -m to m on the autocorrelation curve of the second sequence B. The optical receiving device adds the amplitude corresponding to the position point -m on the autocorrelation curve of the first sequence A and the amplitude corresponding to the position point -m on the autocorrelation curve of the second sequence B to obtain the superimposed amplitude corresponding to the position point -m.The optical receiving device adds the amplitude corresponding to the position point -m + 1 on the autocorrelation curve of the first sequence A to the amplitude corresponding to the position point -m + 1 on the autocorrelation curve of the second sequence B to obtain the superimposed amplitude corresponding to the position point -m + 1. The optical receiving device adds the amplitude corresponding to the position point -m + 2 on the autocorrelation curve of the first sequence A to the amplitude corresponding to the position point -m + 2 on the autocorrelation curve of the second sequence B to obtain the superimposed amplitude corresponding to the position point -m + 2. By analogy, the optical receiving device can determine the superimposed amplitudes corresponding to the position points -m to m one by one. The optical receiving device draws a curve based on the position points -m to m and the superimposed amplitudes corresponding to the position points -m to m one by one. The curve drawn by the optical receiving device is the autocorrelation curve corresponding to the detected sequence X demodulated from the first optical signal. For this embodiment, the target sequence described in the foregoing embodiment may be the first sequence A or the second sequence B.

[0171] In another embodiment, the correlation curve corresponding to the detected sequence X demodulated from the first optical signal is a cross-correlation curve. The optical receiving device determines the cross-correlation curve according to the demodulated detected sequence X and the detected sequence X pre-acquired by the optical receiving device. In a specific embodiment, the detected sequence X modulated by the optical transmitting device on the first optical signal is a Gray complementary sequence or a pseudo-random code sequence, and the detected sequence X includes a first sequence A and a second sequence B. After the optical receiving device demodulates the detected sequence X from the first optical signal, the optical receiving device determines the first sequence A and the second sequence B from the demodulated detected sequence X, and the optical receiving device determines the first sequence and the second sequence from the pre-acquired detected sequence X. For ease of description, the first sequence determined by the optical receiving device from the pre-acquired detected sequence X is referred to as the first sequence A', and the second sequence determined by the optical receiving device from the pre-acquired detected sequence X is referred to as the second sequence B'. The optical receiving device determines the cross-correlation curve corresponding to the demodulated detected sequence X according to the first sequence A and the second sequence B determined from the demodulated detected sequence X, and according to the first sequence A' and the second sequence B' determined from the pre-acquired detected sequence X. By way of example, in the detected sequence X, the second sequence B is located after the first sequence A and is adjacent to the first sequence A, and the lengths of both the first sequence A and the second sequence B are of a fixed length. For example, the length of the first sequence A is the first length, and the length of the second sequence B is the second length. The optical receiving device determines the sequence with a length of the first length starting from the starting position of the demodulated detected sequence X as the first sequence A, and the optical receiving device determines the sequence other than the first sequence A in the demodulated detected sequence X as the second sequence B. The optical receiving device determines the sequence with a length of the first length starting from the starting position of the pre-acquired detected sequence X as the first sequence A', and the optical receiving device determines the sequence other than the first sequence A' in the pre-acquired detected sequence X as the second sequence B'. It should be noted that the first sequence A involved in the subsequent description of this paragraph refers to the first sequence A determined from the demodulated detected sequence X, and the second sequence B involved in the subsequent description of this paragraph refers to the second sequence B determined from the demodulated detected sequence X. In one embodiment, the optical receiving device performs a cross-correlation calculation on the first sequence A and the first sequence A' to obtain the cross-correlation curve of the first sequence A and the first sequence A'; the optical receiving device performs a cross-correlation calculation on the second sequence B and the second sequence B' to obtain the cross-correlation curve of the second sequence B and the second sequence B'; the optical receiving device determines the cross-correlation curve corresponding to the demodulated detected sequence X according to the cross-correlation curve of the first sequence A and the first sequence A' and the cross-correlation curve of the second sequence B and the second sequence B'.For example, the cross-correlation curve of the first sequence A and the first sequence A' is called the cross-correlation curve 1, and the cross-correlation curve of the second sequence B and the second sequence B' is called the cross-correlation curve 2. The cross-correlation curve corresponding to the demodulated detection sequence X is the superimposed curve of the cross-correlation curve 1 and the cross-correlation curve 2. In a specific embodiment, the position points on the cross-correlation curve 1 correspond one-to-one with the position points on the cross-correlation curve 2. The optical receiving device adds the amplitudes on the cross-correlation curve 1 and the amplitudes on the cross-correlation curve 2 according to the corresponding position points, and the optical receiving device draws a curve based on the added amplitudes to obtain the cross-correlation curve corresponding to the demodulated detection sequence X. In an example, both the cross-correlation curve 1 and the cross-correlation curve 2 include position points from -m to m, where m is a positive integer. The position points from -m to m on the cross-correlation curve 1 correspond one-to-one with the position points from -m to m on the cross-correlation curve 2. The optical receiving device adds the amplitude corresponding to the position point -m on the cross-correlation curve 1 and the amplitude corresponding to the position point -m on the cross-correlation curve 2 to obtain the superimposed amplitude corresponding to the position point -m. The optical receiving device adds the amplitude corresponding to the position point -m + 1 on the cross-correlation curve 1 and the amplitude corresponding to the position point -m + 1 on the cross-correlation curve 2 to obtain the superimposed amplitude corresponding to the position point -m + 1. The optical receiving device adds the amplitude corresponding to the position point -m + 2 on the cross-correlation curve and the amplitude corresponding to the position point -m + 2 on the cross-correlation curve 2 to obtain the superimposed amplitude corresponding to the position point -m + 2. And so on. The optical receiving device can determine the superimposed amplitudes corresponding one-to-one to the position points from -m to m. The optical receiving device draws a curve based on the position points from -m to m and the superimposed amplitudes corresponding one-to-one to the position points from -m to m. The curve drawn by the optical receiving device is the cross-correlation curve corresponding to the demodulated detection sequence X. For this embodiment, the target sequence described in the foregoing embodiment may be the first sequence A, the second sequence B, the first sequence A', or the second sequence B'.

[0172] In another embodiment, the correlation curve corresponding to the detection sequence X demodulated from the first optical signal is the autocorrelation curve of the demodulated detection sequence X, and the detection sequence X may be a pseudo-random code sequence. After the optical receiving device demodulates the detection sequence X from the first optical signal, the optical receiving device performs autocorrelation calculation on the demodulated detection sequence X to obtain the autocorrelation curve of the demodulated detection sequence X. For this embodiment, the target sequence described in the foregoing embodiment may be the demodulated detection sequence X.

[0173] In another embodiment, the correlation curve corresponding to the detected sequence X demodulated from the first optical signal is the cross-correlation curve between the demodulated detected sequence X and the pre-acquired detected sequence X. The detected sequence X may be a pseudo-random code sequence. After the optical receiving device demodulates the detected sequence X from the first optical signal, the optical receiving device performs a cross-correlation calculation on the demodulated detected sequence X and the pre-acquired detected sequence X by the optical receiving device to obtain the cross-correlation curve between the demodulated detected sequence X and the pre-acquired detected sequence X. For this embodiment, the target sequence described in the foregoing embodiment may be the demodulated detected sequence X or the pre-acquired detected sequence X.

[0174] To facilitate understanding of the implementation process of S305, the implementation principle of S305 will be introduced below.

[0175] Exemplarily, the first optical signal carries multiple detected sequences X, which are periodically distributed. Each of the multiple detected sequences X includes a first sequence A and a second sequence B. The second sequence B is located after the first sequence A and is adjacent to the first sequence A. For ease of description, an example is given where the optical transmitting device modulates the first optical signal with a detection signal. The detection signal includes multiple detected sequences X. For example, the detection signal is composed of the multiple detected sequences X. Exemplarily, the detection signal modulated by the optical transmitting device on the first optical signal is Patt detect- Tx = [A B A B AB……]. Patt detect- Tx represents the detection signal modulated by the optical transmitting device on the first optical signal. "A" represents the first sequence A, and "B" represents the second sequence B. Without considering the attenuation and faults of the optical fiber link Z, etc., the detection signal obtained by the optical receiving device demodulating the first optical signal is Patt detect- Rx = [A B A B A B……]. Patt detect- Rx represents the detection signal obtained by the optical receiving device demodulating the first optical signal. It can be seen that without considering the attenuation and faults of the optical fiber link Z, etc., the detection signal obtained by the optical receiving device demodulating the first optical signal is the same as the detection signal modulated by the optical transmitting device on the first optical signal.

[0176] However, the optical fiber link Z inevitably has attenuation and faults, etc. The detection signal actually obtained by the optical receiving device demodulating the first optical signal includes noise caused by reflection at the fault point. This noise can be expressed as Data_Per = β * Patt detect-Tx(t - t0). Data_Per represents noise, t0 represents the delay time of this noise relative to the detection signal, and β represents the attenuation coefficient of this noise (the fault point in the optical fiber link Z causes multiple reflections of the detection signal to form this noise, and β is the attenuation coefficient caused by the multiple reflections). If there are multiple fault points in the optical fiber link Z, there will be multiple terms on the right side of the above noise expression, and the delay time of the noise represented by each term relative to the detection signal is different, and the attenuation coefficient may also be different. Therefore, the detection signal actually demodulated by the optical receiving device for the first optical signal is Patt detect- Rx = Patt detect- Tx + Data_Per.

[0177] In the embodiment of the present application, the optical receiving device determines the detection sequence X from the demodulated detection signal, and the optical receiving device obtains the correlation curve corresponding to the demodulated detection sequence X. When the demodulated detection sequence X does not include noise, the correlation curve corresponding to the demodulated detection sequence X can be the Figure 7 self - correlation curve shown as follows. This correlation curve has a characteristic peak, and the amplitudes of all position points on this correlation curve except this characteristic peak are 0. However, when the demodulated detection sequence X includes the noise caused by the reflection of the fault point, the correlation curve corresponding to the demodulated detection sequence X can be as Figure 18 shown. This correlation curve not only has a characteristic peak (main peak) similar to Figure 7 shown, but also has a secondary peak. This secondary peak is generated by the superposition of the autocorrelation of the first half (corresponding to the first sequence A) and the autocorrelation of the second half (corresponding to the second sequence B) of the noise Data_Per, or is the superposition of the cross - correlation of the first half (corresponding to the first sequence A) of Data_Per and the first half (corresponding to the first sequence A') of the pre - obtained detection sequence X, and the cross - correlation of the second half (corresponding to the second sequence B) of Data_Per and the first half (corresponding to the second sequence A') of the pre - obtained detection sequence X. Therefore, in the embodiment of the present application, the transmission duration of the reflected signal between the two reflection points corresponding to this secondary peak can be determined according to the difference between the number of time - shift symbols corresponding to this main peak and the number of time - shift symbols corresponding to this secondary peak, and then the fault point on the optical fiber link Z corresponding to this secondary peak can be determined according to this transmission duration to achieve fault location.

[0178] In an alternative embodiment, after the optical receiving device determines the transmission performance of the optical fiber link according to the detection sequence X carried by the first optical signal, for example, after the optical receiving device determines that there is a fault in the optical fiber link, the optical receiving device may issue a fault warning. In one example, the optical receiving device controls the indicator light of the optical receiving device to blink, emit light, etc. to issue a fault warning. In another example, the optical receiving device outputs a warning message to a device having a display component and / or a voice broadcast component to issue a fault warning. The device having the display component and / or the voice broadcast component may present the warning message in a display or voice broadcast manner to issue a fault warning, which is not limited in the embodiments of the present application.

[0179] It should be noted that both the optical transmitting device and the optical receiving device may include an optical module and / or an optical line card. Figure 3 In the description of the illustrated embodiment, all or part of the operations performed by the optical transmitting device are performed by the optical module and / or the optical line card in the optical transmitting device, and all or part of the operations performed by the optical receiving device are performed by the optical module and / or the optical line card in the optical receiving device. For example, the optical transmitting device includes an optical module or an optical line card, and a light source, a modulator, etc. are all located on the optical module or the optical line card. The optical receiving device includes an optical module or an optical line card, and a filter is located on the optical module or the optical line card.

[0180] In summary, for the optical fiber link detection method provided by the embodiments of the present application, the optical transmitting device sends an optical signal carrying a detection sequence to the optical receiving device through the optical fiber link, and the optical receiving device determines the transmission performance of the optical fiber link according to the detection sequence carried by the optical signal, thereby realizing the detection of the optical fiber link. It can be seen that the embodiments of the present application provide a transmissive detection scheme, which uses the existing optical transmitting device and optical receiving device in the optical fiber communication system to detect the transmission performance of the optical fiber link, without deploying additional devices such as an OTDR and a circulator (or a power splitter) in the optical fiber link, and without fiber plugging and unplugging, so that the hardware implementation of detecting the optical fiber link is simple, the detection cost is low, the in-line detection can be realized, and the fault location can be realized. When locating a fault, there is no need for a staff member to carry an instrument to the station for location, the implementation process is simple, and the labor cost of detection is low.

[0181] Based on the descriptions of the above embodiments, the embodiments of the present application can detect the transmission performance of an optical fiber link by using an in-band detection method or an out-of-band detection method. The in-band detection method, also known as the in-channel detection method, refers to carrying a detection sequence and a data signal in the same optical signal and sending them through an optical fiber link to detect the transmission performance of the optical fiber link based on the detection sequence. The out-of-band detection method refers to carrying a detection sequence in an independent optical signal and sending it through an optical fiber link to detect the transmission performance of the optical fiber link, that is, the detection sequence and the data signal are carried in different optical signals. In an optional embodiment, the optical transmitting device includes a switching unit, which is used to switch the data signal and the detection sequence so that the optical transmitting device modulates the optical signal with the detection sequence or the data signal. For example, in the detection mode, the optical transmitting device modulates the optical signal with the detection sequence; in the non-detection mode, the optical transmitting device modulates the optical signal with the data signal. The optical receiving device may also include a switching unit, which is used to switch the data signal and the detection sequence so that the optical receiving device demodulates the detection sequence or the data signal from the optical signal. For example, in the detection mode, the optical receiving device demodulates the detection sequence from the optical signal; in the non-detection mode, the optical receiving device demodulates the data signal from the optical signal. Among them, the working process of the switching unit can be controlled by a control device, and the control device can be respectively connected to the optical transmitting device and the optical receiving device. The embodiments of the present application do not limit this.

[0182] To facilitate the understanding of the technical solutions of the embodiments of the present application, the technical solutions of the embodiments of the present application will be introduced below with two specific examples.

[0183] Please refer to Figure 19 , which shows a schematic diagram of a method for detecting an optical fiber link provided by an embodiment of the present application. Figure 19 Taking the out-of-band detection method for detecting an optical fiber link as an example for illustration. As Figure 19 shown, the control device is respectively connected to the optical transmitting device 210 and the optical receiving device 220.

[0184] As Figure 19As shown, the optical transmission device 210 includes a transmitter, a switching unit, a detection sequence generation unit, and a data signal generation unit. The switching unit is respectively connected to the transmitter, the detection sequence generation unit, and the data signal generation unit. The optical reception device 220 includes a receiver, a sampling and quantization unit, a switching unit, a detection sequence demodulation unit, and a data signal demodulation unit. The receiver, the sampling and quantization unit, and the switching unit are connected in sequence, and the switching unit is respectively connected to the detection sequence demodulation unit and the data signal demodulation unit. The transmitter is connected to the receiver through the optical fiber link 230, so that the optical transmission device 210 and the optical reception device 220 are connected through the optical fiber link 230. Exemplarily, the optical transmission device 210 and the optical reception device 220 respectively include optical modules ( Figure 19 not shown in the figure). The optical module in the optical transmission device 210 includes the transmitter, the switching unit, the detection sequence generation unit, and the data signal generation unit. The optical module in the optical reception device 220 includes the receiver, the sampling and quantization unit, the switching unit, the detection sequence demodulation unit, and the data signal demodulation unit.

[0185] Among them, the control device is used to control the optical transmission device 210 and the optical reception device 220 to enter the detection mode or the non-detection mode respectively. After the optical transmission device 210 and the optical reception device 220 enter the detection mode, the optical transmission device 210 and the optical reception device 220 cooperate to detect the transmission performance of the optical fiber link 230. After the optical transmission device 210 and the optical reception device 220 enter the non-detection mode, the optical transmission device 210 and the optical reception device 220 perform data communication. Specifically, the control device controls the switching unit in the optical transmission device 210 to conduct the detection sequence generation unit and the transmitter, thereby controlling the optical transmission device 210 to enter the detection mode; the control device controls the switching unit in the optical reception device 220 to conduct the sampling and quantization unit and the detection sequence demodulation unit, thereby controlling the optical reception device 220 to enter the detection mode. The control device controls the switching unit in the optical transmission device 210 to conduct the data signal generation unit and the transmitter, thereby controlling the optical transmission device 210 to enter the non-detection mode; the control device controls the switching unit in the optical reception device 220 to conduct the sampling and quantization unit and the data signal demodulation unit, thereby controlling the optical reception device 220 to enter the non-detection mode.

[0186] In the optical transmission device 210, a detection sequence generation unit is configured to generate a detection sequence, a data signal generation unit is configured to generate a data signal, and a switching unit is configured to control the connection between the detection sequence generation unit or the data signal generation unit and the transmitter. When the detection sequence generation unit is connected to the transmitter, the optical transmission device 210 is in the detection mode. The transmitter modulates an optical signal with the detection sequence generated by the detection sequence generation unit and transmits the optical signal carrying the detection sequence through the optical fiber link 230. When the data signal generation unit is connected to the transmitter, the optical transmission device 210 is in the non-detection mode. The transmitter modulates an optical signal with the data signal generated by the data signal generation unit and transmits the optical signal carrying the data signal through the optical fiber link 230. In the optical reception device 220, a receiver is configured to receive an optical signal through the optical fiber link 230 and convert the optical signal into an analog electrical signal, a sampling and quantization unit is configured to sample and quantize the analog electrical signal to obtain a digital electrical signal, and a switching unit is configured to control the connection between the detection sequence demodulation unit or the data signal demodulation unit and the sampling and quantization unit. When the detection sequence demodulation unit is connected to the sampling and quantization unit, the optical reception device 220 is in the detection mode. The detection sequence demodulation unit demodulates the digital electrical signal to obtain a detection sequence and determines the transmission performance of the optical fiber link 230 according to the detection sequence. When the data signal demodulation unit is connected to the sampling and quantization unit, the optical reception device 220 is in the non-detection mode. The data signal demodulation unit demodulates the digital electrical signal to obtain a data signal.

[0187] In one example, both the optical transmission device 210 and the optical reception device 220 are in the detection mode. The transmitter modulates an optical signal with the detection sequence generated by the detection sequence generation unit to obtain an optical signal carrying the detection sequence, and the transmitter transmits the optical signal through the optical fiber link 230. The receiver receives the optical signal through the optical fiber link 230, and the receiver converts the optical signal into an analog electrical signal. The sampling and quantization unit samples and quantizes the analog electrical signal to obtain a digital electrical signal. The detection sequence demodulation unit demodulates the digital electrical signal to obtain the detection sequence, and the detection sequence demodulation unit determines the transmission performance of the optical fiber link 230 according to the detection sequence.

[0188] In another example, both the optical transmission device 210 and the optical reception device 220 are in the non-detection mode. The transmitter modulates an optical signal with the data signal generated by the data signal generation unit to obtain an optical signal carrying the data signal, and the transmitter transmits the optical signal through the optical fiber link 230. The receiver receives the optical signal through the optical fiber link 230, and the receiver converts the optical signal into an analog electrical signal. The sampling and quantization unit samples and quantizes the analog electrical signal to obtain a digital electrical signal. The data signal demodulation unit demodulates the digital electrical signal to obtain the data signal.

[0189] Please refer to Figure 20 , which shows a schematic diagram of another method for detecting an optical fiber link provided by an embodiment of the present application. Figure 20 Taking the in-band detection method for detecting the optical fiber link as an example for illustration. As Figure 20 shown, the control device is respectively connected to the optical transmission device 210 and the optical reception device 220.

[0190] As Figure 20 shown, the optical transmission device 210 includes a transmitter, a detection sequence generation unit, and a data signal generation unit, and the transmitter is respectively connected to the detection sequence generation unit and the data signal generation unit. The optical reception device 220 includes a receiver, a sampling and quantization unit, a detection sequence demodulation unit, and a data signal demodulation unit, and the sampling and quantization unit is respectively connected to the receiver, the detection sequence demodulation unit, and the data signal demodulation unit. The transmitter is connected to the receiver through the optical fiber link 230, so that the optical transmission device 210 and the optical reception device 220 are connected through the optical fiber link 230. Exemplarily, the optical transmission device 210 and the optical reception device 220 respectively include optical modules ( Figure 20 not shown in the figure), the optical module in the optical transmission device 210 includes the transmitter, the detection sequence generation unit, and the data signal generation unit, and the optical module in the optical reception device 220 includes the receiver, the sampling and quantization unit, the detection sequence demodulation unit, and the data signal demodulation unit.

[0191] Among them, the control device is used to control the optical transmission device 210 and the optical reception device 220 to enter the detection mode or the non-detection mode respectively. After the optical transmission device 210 and the optical reception device 220 enter the detection mode respectively, the optical transmission device 210 and the optical reception device 220 cooperate to detect the transmission performance of the optical fiber link 230, and the optical transmission device 210 and the optical reception device 220 perform data communication. After the optical transmission device 210 and the optical reception device 220 enter the non-detection mode respectively, the optical transmission device 210 and the optical reception device 220 perform data communication. Exemplarily, the control device controls the transmitter to modulate a detection sequence in the optical signal, so as to control the optical transmission device 210 to enter the detection mode; the control device controls the detection sequence demodulation unit in the optical reception device 220 to demodulate the detection sequence carried by the optical signal, so as to control the optical reception device 220 to enter the detection mode. The control device controls the transmitter not to modulate the detection sequence in the optical signal, so as to control the optical transmission device 210 to enter the non-detection mode; the control device controls the data signal demodulation unit in the optical reception device 220 not to demodulate the detection sequence carried by the optical signal, so as to control the optical reception device 220 to enter the non-detection mode.

[0192] In the optical transmission device 210, a detection sequence generation unit is used to generate a detection sequence, and a data signal generation unit is used to generate a data signal. When the optical transmission device 210 is in the detection mode, the transmitter modulates an optical signal with the detection sequence generated by the detection sequence generation unit and the data signal generated by the data signal generation unit, and transmits the optical signal carrying the detection sequence and the data signal through the optical fiber link 230. When the optical transmission device 210 is in the non-detection mode, the transmitter modulates an optical signal with the data signal generated by the data signal generation unit and transmits the optical signal carrying the data signal through the optical fiber link 230. In the optical reception device 220, a receiver is used to receive the optical signal through the optical fiber link 230 and convert the optical signal into an analog electrical signal, and a sampling and quantization unit is used to sample and quantize the analog electrical signal to obtain a digital electrical signal. When the optical reception device 220 is in the detection mode, a detection sequence demodulation unit demodulates the digital electrical signal to obtain the detection sequence, and determines the transmission performance of the optical fiber link 230 according to the detection sequence, and a data signal demodulation unit demodulates the digital electrical signal to obtain the data signal. When the optical reception device 220 is in the non-detection mode, the data signal demodulation unit demodulates the digital electrical signal to obtain the data signal.

[0193] In one example, both the optical transmission device 210 and the optical reception device 220 are in the detection mode. The transmitter modulates an optical signal with the detection sequence generated by the detection sequence generation unit and the data signal generated by the data signal generation unit to obtain an optical signal carrying the detection sequence and the data signal, and the transmitter transmits the optical signal through the optical fiber link 230. The receiver receives the optical signal through the optical fiber link 230, and the receiver converts the optical signal into an analog electrical signal. The sampling and quantization unit samples and quantizes the analog electrical signal to obtain a digital electrical signal. The detection sequence demodulation unit demodulates the digital electrical signal to obtain the detection sequence, and the detection sequence demodulation unit determines the transmission performance of the optical fiber link 230 according to the detection sequence. The data signal demodulation unit demodulates the digital electrical signal to obtain the data signal.

[0194] In another example, both the optical transmission device 210 and the optical reception device 220 are in the non-detection mode. The transmitter modulates an optical signal with the data signal generated by the data signal generation unit to obtain an optical signal carrying the data signal, and the transmitter transmits the optical signal through the optical fiber link 230. The receiver receives the optical signal through the optical fiber link 230, and the receiver converts the optical signal into an analog electrical signal. The sampling and quantization unit samples and quantizes the analog electrical signal to obtain a digital electrical signal. The data signal demodulation unit demodulates the digital electrical signal to obtain the data signal.

[0195] It should be noted that Figure 3The light source, modulator, etc. involved in the illustrated embodiments may all be located in the transmitter of the optical transmission device. Figure 3 The filter involved in the illustrated embodiments may be located in the detection sequence demodulation unit of the optical reception device. The embodiments of the present application do not limit this.

[0196] The above is an introduction to the method embodiments of the present application. Next, the device embodiments of the present application will be introduced. The devices of the present application are used to execute the methods of the present application. For details not disclosed in the device embodiments, please refer to the method embodiments.

[0197] Please refer to Figure 21 , which shows a schematic diagram of a detection device 2100 for an optical fiber link provided by an embodiment of the present application. The detection device 2100 is applied to an optical transmission device. The detection device 2100 may be an optical transmission device or a functional component in an optical transmission device. For example, the detection device 2100 is an optical transmission device, an optical module in an optical transmission device, an optical line card in an optical transmission device, or the detection device 2100 is integrated in an optical transmission device, integrated in an optical module in an optical transmission device, or integrated in an optical line card in an optical transmission device. The detection device 2100 is used to execute Figure 3 the steps executed by the optical transmission device in the detection method provided by the illustrated embodiments. By way of example, the optical transmission device is Figure 2 the optical transmission device 210 in the illustrated application scenario. Refer to Figure 21 , the detection device 2100 includes a generation module 2110 and a transmission module 2120.

[0198] The generation module 2110 is used to generate a first optical signal. The first optical signal carries a detection sequence. The autocorrelation curve corresponding to the detection sequence satisfies a preset condition. The detection sequence is used to detect the transmission performance of the optical fiber link. The transmission module 2120 is used to transmit the first optical signal through the optical fiber link. Among them, the implementation of the function of the generation module 2110 can refer to the relevant description in S301 above. The implementation of the function of the transmission module 2120 can refer to the relevant description in S302 above.

[0199] Optionally, the autocorrelation curve corresponding to the detection sequence satisfying the preset condition includes that the autocorrelation curve corresponding to the detection sequence has a characteristic peak.

[0200] Optionally, the detection sequence includes a first sequence and a second sequence. The autocorrelation curve corresponding to the detection sequence is determined according to the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence. The autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation value of the position point on the autocorrelation curve of the first sequence and the autocorrelation value of the position point on the autocorrelation curve of the second sequence.

[0201] Optionally, the first optical signal carries a plurality of detection sequences, which are periodically distributed; there are boundary identifiers between adjacent detection sequences in the plurality of detection sequences; alternatively, adjacent detection sequences in the plurality of detection sequences are continuous.

[0202] Optionally, the detection sequence includes any one of the following: a pseudo-random code sequence; a Gray complementary sequence.

[0203] Optionally, the first optical signal further carries a data signal.

[0204] Optionally, in the first optical signal, the modulation depth of the detection sequence is less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal.

[0205] Optionally, in the first optical signal, the ratio of the modulation depth of the detection sequence to the modulation depth of the data signal is less than a preset ratio; the difference between the baud rate of the detection sequence and the baud rate of the data signal is within a preset range.

[0206] Optionally, the generating module 2110 is configured to modulate the driving signal of the light source by using the detection sequence so that the light source emits the first optical signal.

[0207] Optionally, the generating module 2110 is configured to modulate the optical signal emitted by the light source by using the detection sequence to obtain the first optical signal.

[0208] Optionally, the generating module 2110 is configured to modulate the driving signal of the light source by using the data signal modulated with the detection sequence so that the light source emits the first optical signal.

[0209] In summary, for the technical solution provided in the embodiment of the present application, the optical transmission device transmits an optical signal carrying a detection sequence through the optical fiber link, which can facilitate the optical receiving device to determine the transmission performance of the optical fiber link according to the detection sequence carried by the optical signal, thereby realizing the detection of the optical fiber link. It can be seen that the embodiment of the present application provides a transmissive detection scheme, which uses the existing optical transmission device and optical receiving device in the optical fiber communication system to detect the transmission performance of the optical fiber link, and can realize the detection of the optical fiber link without deploying additional devices such as OTDR in the optical fiber link. Therefore, the hardware implementation for detecting the optical fiber link is simple, the detection cost is low, and fault location can be realized. When fault location is performed, it is not necessary for the staff to carry instruments to the station for location and it is not necessary to insert and unplug the optical fiber. The implementation process is simple, and in-path detection can be realized.

[0210] Please refer to Figure 22, which shows a schematic diagram of another optical fiber link detection device 2200 provided by an embodiment of the present application. The detection device 2200 is applied to an optical receiving device, and the detection device 2200 can be an optical receiving device or a functional component in the optical receiving device. For example, the detection device 2200 is an optical receiving device, an optical module in the optical receiving device, an optical line card in the optical receiving device, or the detection device 2200 is integrated in the optical receiving device, integrated in the optical module in the optical receiving device, or integrated in the optical line card in the optical receiving device. The detection device 2200 is used to execute Figure 3 the steps performed by the optical receiving device in the detection method provided by the embodiment shown. By way of example, the optical receiving device is Figure 2 the optical receiving device 220 in the application scenario shown. Refer to Figure 22 . The detection device 2200 includes a receiving module 2210, a demodulation module 2220, and a determination module 2230.

[0211] The receiving module 2210 is configured to receive a first optical signal through an optical fiber link, where the first optical signal carries a detection sequence, and the autocorrelation curve corresponding to the detection sequence satisfies a preset condition; the demodulation module 2220 is configured to demodulate the first optical signal to obtain the detection sequence; the determination module 2230 is configured to determine the transmission performance of the optical fiber link according to the demodulated detection sequence. Among them, the implementation of the function of the receiving module 2210 can refer to the relevant description in S303 above. The implementation of the function of the demodulation module 2220 can refer to the relevant description in S304 above. The implementation of the function of the determination module 2230 can refer to the relevant description in S305 above.

[0212] Optionally, the autocorrelation curve corresponding to the detection sequence satisfying the preset condition includes that the autocorrelation curve corresponding to the detection sequence has a characteristic peak.

[0213] Optionally, the detection sequence includes a first sequence and a second sequence, the autocorrelation curve corresponding to the detection sequence is determined according to the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence, and the autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation value of the position point on the autocorrelation curve of the first sequence and the autocorrelation value of the position point on the autocorrelation curve of the second sequence.

[0214] Optionally, the first optical signal carries a plurality of detection sequences, and the plurality of detection sequences are periodically distributed; there is a boundary identifier between adjacent detection sequences in the plurality of detection sequences; or, adjacent detection sequences in the plurality of detection sequences are continuous.

[0215] Optionally, the first optical signal carries a plurality of detection sequences, and there are boundary identifiers between adjacent detection sequences among the plurality of detection sequences. The demodulation module 2220 is configured to determine the plurality of detection sequences carried by the first optical signal according to the boundary identifiers carried by the first optical signal.

[0216] Optionally, the first optical signal carries a plurality of detection sequences, and the adjacent detection sequences among the plurality of detection sequences are consecutive. The demodulation module 2220 is configured to determine the plurality of detection sequences carried by the first optical signal according to the characteristics of the detection sequences.

[0217] Optionally, the determination module 2230 is configured to: obtain a correlation curve corresponding to the demodulated detection sequence, where the correlation curve is an autocorrelation curve or a cross-correlation curve, and the cross-correlation curve is determined according to the demodulated detection sequence and the pre-obtained detection sequence; determine the transmission performance of the optical fiber link according to the characteristic peaks of the correlation curve corresponding to the demodulated detection sequence.

[0218] Optionally, the determination module 2230 is configured to: determine that the optical fiber link has no fault when the correlation curve corresponding to the demodulated detection sequence has only one characteristic peak; determine that the optical fiber link has a fault when the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks.

[0219] Optionally, the determination module 2230 is further configured to: when the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks, determine a fault point on the optical fiber link according to the main peak and the secondary peaks among the multiple characteristic peaks. Wherein, the multiple characteristic peaks include a main peak and at least one secondary peak, and the peak values of the at least one secondary peak are all smaller than the peak value of the main peak.

[0220] Optionally, the detection sequence includes any one of the following: a pseudo-random code sequence; a Gray complementary sequence.

[0221] Optionally, the first optical signal further carries a data signal. That is, the first optical signal carries a detection sequence and a data signal.

[0222] Optionally, in the first optical signal, the modulation depth of the detection sequence is less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal.

[0223] Optionally, in the first optical signal, the ratio of the modulation depth of the detection sequence to the modulation depth of the data signal is less than a preset ratio; the difference between the baud rate of the detection sequence and the baud rate of the data signal is within a preset range.

[0224] Optionally, the demodulation module 2220 is configured to: filter the first optical signal.

[0225] In summary, for the technical solution provided in the embodiment of the present application, the optical transmission device sends an optical signal carrying a detection sequence through the optical fiber link, and the optical reception device determines the transmission performance of the optical fiber link according to the detection sequence carried by the optical signal, thereby realizing the detection of the optical fiber link. It can be seen that the embodiment of the present application provides a transmission detection scheme, which uses the existing optical transmission device and optical reception device in the optical fiber communication system to detect the transmission performance of the optical fiber link, and can realize the detection of the optical fiber link without deploying additional devices such as OTDR in the optical fiber link. Therefore, the hardware implementation for detecting the optical fiber link is simple, the detection cost is low, and fault location can be achieved. When performing fault location, it is not necessary for the staff to carry instruments to the site for location and there is no need to insert and unplug the optical fiber. The implementation process is simple, and in-line detection can be realized.

[0226] It should be understood that the detection device for the optical fiber link provided in the embodiment of the present application can also be implemented by an application-specific integrated circuit (ASIC) or a programmable logic device (PLD). The above PLD can be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof. The detection method for the optical fiber link provided in the above method embodiment can also be implemented by software. When the detection method for the optical fiber link provided in the above method embodiment is implemented by software, each module in the detection device for the optical fiber link can also be a software module.

[0227] The embodiment of the present application provides a detection device for an optical fiber link. The detection device includes a memory and a processor. The memory is used to store a computer program. The processor is used to execute the computer program stored in the memory so that the detection device executes all or part of the steps of the detection method for the optical fiber link provided in the embodiment as Figure 3 shown. For example, the detection device is caused to execute steps S304, S305, etc. in the detection method for the optical fiber link provided in the embodiment as Figure 3 shown. Among them, the detection device can be an optical transmission device, an optical module in the optical transmission device, an optical line card in the optical transmission device, an optical reception device, an optical module in the optical reception device, an optical line card in the optical reception device, etc. The optical transmission device can be a network device, a terminal device, or a server, and the optical reception device can also be a network device, a terminal device, or a server.

[0228] In one embodiment, please refer to Figure 23, which shows a schematic diagram of another optical fiber link detection device 2300 provided by the embodiments of the present application. The detection device 2300 may be a network device, a terminal device, or a server. The detection device 2300 includes at least one processor 2301( Figure 23 illustrated by taking two processors 2301 as an example), a communication bus 2302, a memory 2303, and at least one communication interface 2304. The at least one processor 2301, the memory 2303, and the at least one communication interface 2304 are connected through the communication bus 2302. The at least one processor 2301, the memory 2303, and the at least one communication interface 2304 may also be connected in a connection manner other than the communication bus 2302.

[0229] The memory 2303 is used to store a computer program for executing the technical solution of the present application and is controlled by the processor 2301 for execution. The computer program stored in the memory 2303 includes, but is not limited to, program code, program instructions, data, etc. The memory 2303 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or 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 compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 2303 may exist independently and be connected to the processor 2301 through the communication bus 2302. The memory 2303 may also be integrated with the processor 2301, and the embodiments of the present application do not make any limitations thereto.

[0230] The processor 2301 can be a general-purpose processor or a special-purpose processor. A general-purpose processor is a processor that executes specific steps and / or operations by reading and executing a computer program stored in a memory (such as the memory 2303). The general-purpose processor may use the computer program stored in the memory (such as the memory 2303) during the execution of the above steps and / or operations, and the stored computer program can be executed to implement the related functions of the foregoing demodulation module 2220, determination module 2230, etc. The general-purpose processor is, for example but not limited to, a central processing unit (CPU). A special-purpose processor is a processor specifically designed to execute specific steps and / or operations. The special-purpose processor is, for example but not limited to, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The processor 2301 can implement or execute various logic blocks, modules, and circuits described in connection with the disclosure of the embodiments of the present application. The processor 2301 can also be a combination that implements computing functions, such as including a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and so on. The processor can be used to: demodulate the first optical signal to obtain the detection sequence, and determine the transmission performance of the optical fiber link according to the detection sequence.

[0231] The communication bus 2302 is used to transfer information between the processor 2301, the communication interface 2304, and the memory 2303. The communication bus 2302 can be a peripheral component interconnect (PCI) bus, an extended industry standard architecture (EISA) bus, or the like. The communication bus 2302 can be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, Figure 23 only a thick line is used to represent it in the figure, but it does not mean that there is only one bus or one type of bus.

[0232] The communication interface 2304 includes interfaces such as input / output (I / O) interfaces, physical interfaces, and logical interfaces for implementing the interconnection of components inside the detection device 2300, as well as interfaces for implementing the interconnection between the detection device 2300 and other communication devices. The physical interface can be an Ethernet interface, a fast Ethernet (FE) interface, a gigabit Ethernet (GE) interface, a Terabit Ethernet (TbE) interface, a 400GE interface, an asynchronous transfer mode (ATM) interface, etc., which are used to implement the interconnection between the detection device 2300 and other devices. The logical interface is an interface inside the detection device 2300, which is used to implement the interconnection of components inside the detection device 2300. It is easy to understand that the communication interface 2304 is used for the detection device 2300 to communicate with other devices or communication networks. For example, the communication interface 2304 is used for the transmission and reception of optical signals between the detection device 2300 and other devices or communication networks. The communication interface 2304 can be a device using any transceiver (such as a transmitter, a receiver), and the communication network can be Ethernet, an optical transport network (OTN), a secret private network (SPN), a fiber channel, an infiniband, etc.

[0233] In a specific implementation, as an embodiment, the detection device 2300 includes multiple processors 2301, and each of these multiple processors 2301 can be a single-CPU processor or a multi-CPU processor. The processor here can refer to one or more devices, circuits, and / or processing cores for processing data (such as computer program instructions).

[0234] In a specific embodiment, when the detection device 2300 is an optical transmission device, the communication interface 2304 in the detection device 2300 is used to transmit an optical signal carrying a detection sequence. When the detection device 2300 is an optical reception device, the communication interface 2304 in the detection device 2300 is used to receive an optical signal carrying a detection sequence. Correspondingly, the processor 2301 in the detection device 2300 is used to: demodulate the optical signal to obtain the detection sequence, and determine the transmission performance of the optical fiber link according to the detection sequence. For the detailed processing process of the processor 2301, please refer to the relevant description in the method embodiment shown above Figure 3 and will not be elaborated here.

[0235] In another embodiment, please refer to Figure 24 , which shows a schematic diagram of another optical fiber link detection device 2400 provided by the embodiments of the present application. The detection device 2400 may be a network device, such as a data communication device like a switch or a router. As Figure 24 shown, the detection device 2400 includes a main control board and one or more interface boards, and the main control board is communicatively connected to the interface boards. The main control board is also referred to as a main processing unit (MPU) or a route processor card. The main control board is responsible for controlling and managing each component in the detection device 2400, including routing calculation, device management, and maintenance functions. The interface board is also referred to as a line processing unit (LPU) or a line card. The interface board is used to forward data. In some embodiments, the detection device 2400 may also include a switching fabric board, which is communicatively connected to the main control board and the interface boards. The switching fabric board is used to forward data between the interface boards, and the switching fabric board may also be referred to as a switch fabric unit (SFU). The interface board includes a central processing unit, a memory, a forwarding chip, and a physical interface card (PIC). The central processing unit is communicatively connected to the memory, the forwarding chip, and the physical interface card respectively. The memory is used to store the forwarding table. The forwarding chip is used to forward the received data frames based on the forwarding table stored in the memory. If the destination address of the data frame is the address of the detection device 2400, the data frame is sent to the CPU for processing; if the destination address of the data frame is not the address of the detection device 2400, the next hop and the outgoing interface corresponding to the destination address are found from the forwarding table according to the destination address, and the data frame is forwarded to the outgoing interface corresponding to the destination address. The forwarding chip may be a network processor (NP). The PIC is also referred to as a daughter card and can be installed on the interface board. It is responsible for converting optical and electrical signals into data frames, performing a legality check on the data frames, and then forwarding them to the forwarding chip for processing. In some embodiments, the central processing unit may also perform the function of the forwarding chip, such as implementing software forwarding based on a general-purpose CPU, so that the interface board does not require a forwarding chip. The communication connections between the main control board, the interface boards, and the switching fabric board can be realized through a bus. The forwarding chip can be implemented by an ASIC or an FPGA.

[0236] Logically, the detection device 2400 includes a control plane and a forwarding plane. The control plane includes a main control board and a central processing unit, and the forwarding plane includes various components for performing forwarding, such as a memory, a PIC, and an NP. The control plane performs functions such as generating a forwarding table for the router, processing signaling and protocol packets, and configuring and maintaining states. The control plane sends the generated forwarding table to the forwarding plane. In the forwarding plane, the NP performs table lookup and forwarding on the packets received by the PIC of the detection device 2400 based on the forwarding table sent by the control plane. The forwarding table sent by the control plane can be stored in the memory. In some embodiments, the control plane and the forwarding plane can be completely separated and not on the same device.

[0237] In a specific embodiment, when the detection device 2400 is an optical transmission device, the interface board in the detection device 2400 is used to generate an optical signal carrying a detection sequence and send the optical signal. For the specific process, please refer to the relevant descriptions in S301 to S302 above. When the detection device 2400 is an optical receiving device, the interface board in the detection device 2400 is used to receive the optical signal carrying the detection sequence, demodulate the optical signal to obtain the detection sequence, and determine the transmission performance of the optical fiber link according to the detection sequence. For the specific process, please refer to the relevant descriptions in S303 to S305 above. When the detection device 2400 is an optical receiving device, the main control board can also be used to determine the transmission performance of the optical fiber link according to the detection sequence. For the specific process, please refer to the relevant description in S305 above, which will not be elaborated here.

[0238] In a 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 through the IPC channel.

[0239] Based on the same inventive concept, an embodiment of the present application provides an optical fiber communication system. The optical fiber communication system includes an optical transmission device, an optical receiving device, and an optical fiber link. The optical transmission device is connected to the optical receiving device through the optical fiber link. The optical transmission device includes the detection device of the optical fiber link as provided in Figure 21 , Figure 23 or Figure 24 . The optical receiving device includes the detection device of the optical fiber link as provided in Figures 22 to 24 .

[0240] Exemplarily, the optical fiber communication system is as shown in Figure 1 or Figure 2 .

[0241] Based on the same inventive concept, an embodiment of the present application provides a computer-readable storage medium. A computer program is stored in the computer-readable storage medium. When the computer program is executed (for example, executed by a network device, a terminal device, a server, an optical module, and / or an optical line card, etc.), at least some steps of the method embodiment as shown in Figure 3 are implemented. For example, steps S304 and S305 are implemented.

[0242] Based on the same inventive concept, an embodiment of the present application provides a computer program product. The computer program product includes a program or code. When the program or code is executed (for example, executed by a network device, a terminal device, a server, an optical module, and / or an optical line card, etc.), at least some steps of the method embodiment as shown in Figure 3 are implemented. For example, steps S304 and S305 are implemented.

[0243] Based on the same inventive concept, an embodiment of the present application provides a chip. The chip includes a programmable logic circuit and / or program instructions. When the chip runs, it is used to implement at least some steps of the method embodiment as shown in Figure 3 For example, steps S304 and S305 are implemented.

[0244] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a computer network, or other programmable devices. 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 by wire (such as coaxial cable, optical fiber, digital subscriber line) or wirelessly (such as infrared, wireless, microwave, etc.). 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 includes one or more integrated available media. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium, or a semiconductor medium (for example, a solid-state drive), etc.

[0245] It should be understood that the term "at least one" in this application means one or more, and "a plurality" means two or more. In this application, unless otherwise specified, the symbol " / " generally means "or". For example, A / B can mean A or B. The term "and / or" in this application is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, for the convenience of clear description, this application uses terms such as "first", "second", "third", etc. to distinguish identical or similar items with basically the same functions and roles. Those skilled in the art can understand that the terms "first", "second", "third", etc. do not limit the quantity and execution order.

[0246] The method embodiments, device embodiments and other different types of embodiments provided in the embodiments of this application can all refer to each other. The order of operations in the method embodiments can be adjusted appropriately, and the operations can also be increased or decreased according to the situation. Any method of change that can be easily thought of by any person skilled in the art within the technical scope disclosed in this application should be covered within the protection scope of this application, so no further elaboration will be provided.

[0247] In the corresponding embodiments provided in this application, it should be understood that the disclosed devices and the like can be implemented in other constitutive manners. For example, the device embodiments described above are merely illustrative. For example, the division of modules is only a logical function division. In actual implementation, there can be other division methods. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of devices or modules can be in an electrical or other form. The modules described as separate components may or may not be physically separated. The components described as modules may or may not be physical modules. They can be located in one place or distributed to multiple network nodes. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0248] As described above, it is only an exemplary embodiment of this application, but the protection scope of this application is not limited thereto. Any equivalent modifications or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed in this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A detection method for an optical fiber link, characterized in that Applied to an optical transmission device, the method includes: Generating a first optical signal, where the first optical signal carries a detection sequence, and the autocorrelation curve corresponding to the detection sequence satisfies a preset condition, and the detection sequence is used to detect the transmission performance of the optical fiber link; Transmitting the first optical signal through the optical fiber link.

2. The method according to claim 1, wherein The autocorrelation curve corresponding to the detection sequence satisfying the preset condition includes: the autocorrelation curve corresponding to the detection sequence has a characteristic peak.

3. The method according to claim 1 or 2, characterized in that, The detection sequence includes a first sequence and a second sequence, and the autocorrelation curve corresponding to the detection sequence is determined according to the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence. The autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation value of the position point on the autocorrelation curve of the first sequence and the autocorrelation value of the position point on the autocorrelation curve of the second sequence.

4. The method according to any one of claims 1 to 3, characterized in that The first optical signal carries a plurality of the detection sequences, and the plurality of detection sequences are periodically distributed; There is a boundary identifier between adjacent detection sequences among the plurality of detection sequences; or, Adjacent detection sequences among the plurality of detection sequences are continuous.

5. The method according to any one of claims 1 to 4, characterized in that, The first optical signal further carries a data signal.

6. The method according to claim 5, characterized in that In the first optical signal, the modulation depth of the detection sequence is less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal.

7. The method according to any one of claims 1 to 6, characterized in that, The generating of the first optical signal includes: Modulating the drive signal of the light source with the detection sequence to make the light source emit the first optical signal; or, Modulating the optical signal emitted by the light source with the detection sequence to obtain the first optical signal; or, Modulating the drive signal of the light source with a data signal modulated with the detection sequence to make the light source emit the first optical signal.

8. A detection method for an optical fiber link, characterized in that, Applied to an optical receiving device, the method includes: Receiving a first optical signal through the optical fiber link, where the first optical signal carries a detection sequence, and the autocorrelation curve corresponding to the detection sequence satisfies a preset condition; Demodulating the first optical signal to obtain the detection sequence; Determining the transmission performance of the optical fiber link according to the demodulated detection sequence.

9. The method according to claim 8, characterized in that, The autocorrelation curve corresponding to the detection sequence satisfying the preset condition includes: the autocorrelation curve corresponding to the detection sequence has a characteristic peak.

10. The method according to claim 8 or 9, characterized in that The detection sequence includes a first sequence and a second sequence, and the autocorrelation curve corresponding to the detection sequence is determined according to the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence. The autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation value of the position point on the autocorrelation curve of the first sequence and the autocorrelation value of the position point on the autocorrelation curve of the second sequence.

11. The method according to any one of claims 8 to 10, characterized in that, The first optical signal carries a plurality of the detection sequences, and there is a boundary identifier between adjacent detection sequences among the plurality of detection sequences, The demodulating of the first optical signal to obtain the detection sequence includes: Determine multiple detection sequences carried by the first optical signal according to the boundary identifier carried by the first optical signal.

12. The method according to any one of claims 8 to 10, characterized in that The first optical signal carries multiple detection sequences, and adjacent detection sequences among the multiple detection sequences are consecutive. The demodulation of the first optical signal to obtain the detection sequence includes: Determine multiple detection sequences carried by the first optical signal according to the characteristics of the detection sequence.

13. The method according to any one of claims 8 to 12, characterized in that The determination of the transmission performance of the optical fiber link according to the demodulated detection sequence includes: Obtain a correlation curve corresponding to the demodulated detection sequence, where the correlation curve is an autocorrelation curve or a cross-correlation curve, and the cross-correlation curve is determined according to the demodulated detection sequence and the pre-acquired detection sequence; Determine the transmission performance of the optical fiber link according to the characteristic peak of the correlation curve corresponding to the demodulated detection sequence.

14. The method according to claim 13, characterized in that The determination of the transmission performance of the optical fiber link according to the characteristic peak of the correlation curve corresponding to the demodulated detection sequence includes: When the correlation curve corresponding to the demodulated detection sequence has only one characteristic peak, determine that the optical fiber link is fault-free; When the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks, determine that the optical fiber link has a fault.

15. The method according to claim 14, characterized in that The determination of the transmission performance of the optical fiber link according to the characteristic peak of the correlation curve corresponding to the demodulated detection sequence further includes: When the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks, determine the fault point on the optical fiber link according to the main peak and the secondary peak among the multiple characteristic peaks.

16. The method according to any one of claims 8 to 15, characterized in that, The first optical signal also carries a data signal.

17. The method according to claim 16, wherein In the first optical signal, the modulation depth of the detection sequence is less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal.

18. The method according to any one of claims 8 to 17, characterized in that The demodulation of the first optical signal includes: filtering the first optical signal.

19. A detection device for an optical fiber link, characterized in that, Applied to an optical transmission device, the device includes: A generation module for generating a first optical signal, where the first optical signal carries a detection sequence, and the autocorrelation curve corresponding to the detection sequence satisfies a preset condition, and the detection sequence is used to detect the transmission performance of the optical fiber link; A transmission module for transmitting the first optical signal through the optical fiber link.

20. The device according to claim 19, characterized in that, The autocorrelation curve corresponding to the detection sequence satisfying the preset condition includes: the autocorrelation curve corresponding to the detection sequence has one characteristic peak.

21. The device according to claim 19 or 20, characterized in that, The detection sequence includes a first sequence and a second sequence. The autocorrelation curve corresponding to the detection sequence is determined according to the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence. The autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation value of the position point on the autocorrelation curve of the first sequence and the autocorrelation value of the position point on the autocorrelation curve of the second sequence.

22. The device according to any one of claims 19 to 21, wherein the first optical signal carries a plurality of the detection sequences, and the plurality of detection sequences are periodically distributed; there is a boundary identifier between adjacent detection sequences among the plurality of detection sequences; or, adjacent detection sequences among the plurality of detection sequences are continuous.

23. The device according to any one of claims 19 to 22, characterized in that, The first optical signal further carries a data signal.

24. The device according to claim 23, characterized in that, In the first optical signal, the modulation depth of the detection sequence is less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal.

25. The device according to any one of claims 19 to 24, characterized in that The generating module is configured to: modulate the driving signal of the light source with the detection sequence to cause the light source to emit the first optical signal; or, modulate the optical signal emitted by the light source with the detection sequence to obtain the first optical signal; or, modulate the driving signal of the light source with the data signal modulated with the detection sequence to cause the light source to emit the first optical signal.

26. A detection device for an optical fiber link, characterized in that, Applied to an optical receiving device, the device includes: a receiving module, configured to receive a first optical signal through the optical fiber link, the first optical signal carrying a detection sequence, and the autocorrelation curve corresponding to the detection sequence satisfies a preset condition; a demodulation module, configured to demodulate the first optical signal to obtain the detection sequence; a determination module, configured to determine the transmission performance of the optical fiber link according to the demodulated detection sequence.

27. The device according to claim 26, characterized in that, That the autocorrelation curve corresponding to the detection sequence satisfies a preset condition includes: the autocorrelation curve corresponding to the detection sequence has a characteristic peak.

28. The device according to claim 26 or 27, characterized in that, The detection sequence includes a first sequence and a second sequence. The autocorrelation curve corresponding to the detection sequence is determined according to the autocorrelation curve of the first sequence and the autocorrelation curve of the second sequence. The autocorrelation value of each position point on the autocorrelation curve corresponding to the detection sequence is equal to the sum of the autocorrelation value of the position point on the autocorrelation curve of the first sequence and the autocorrelation value of the position point on the autocorrelation curve of the second sequence.

29. The device according to any one of claims 26 to 28, characterized in that, The first optical signal carries a plurality of the detection sequences, and there is a boundary identifier between adjacent detection sequences among the plurality of detection sequences. The demodulation module is configured to determine the plurality of detection sequences carried by the first optical signal according to the boundary identifier carried by the first optical signal.

30. The device according to any one of claims 26 to 28, characterized in that, The first optical signal carries a plurality of the detection sequences, and adjacent detection sequences among the plurality of detection sequences are continuous. The demodulation module is configured to determine the plurality of detection sequences carried by the first optical signal according to the characteristics of the detection sequence.

31. The device according to any one of claims 26 to 30, characterized in that The determination module is configured to: Obtain the correlation curve corresponding to the demodulated detection sequence, where the correlation curve is an autocorrelation curve or a cross-correlation curve, and the cross-correlation curve is determined according to the demodulated detection sequence and the pre-obtained detection sequence; Determine the transmission performance of the optical fiber link according to the characteristic peaks of the correlation curve corresponding to the demodulated detection sequence.

32. The apparatus according to claim 31, wherein The determining module is configured to: When the correlation curve corresponding to the demodulated detection sequence has only one characteristic peak, determine that the optical fiber link has no fault; When the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks, determine that the optical fiber link has a fault.

33. The apparatus according to claim 32, wherein The determining module is further configured to: when the correlation curve corresponding to the demodulated detection sequence has multiple characteristic peaks, determine the fault point on the optical fiber link according to the main peak and the secondary peak among the multiple characteristic peaks.

34. The device according to any one of claims 26 to 33, characterized in that, The first optical signal also carries a data signal.

35. The device according to claim 34, characterized in that, In the first optical signal, the modulation depth of the detection sequence is less than the modulation depth of the data signal, and the baud rate of the detection sequence is less than the baud rate of the data signal.

36. The apparatus according to any one of claims 26 to 35, wherein The demodulation module is configured to filter the first optical signal.

37. A detection device for an optical fiber link, characterized in that, Comprising a memory and a processor; The memory is used to store a computer program; the processor is used to execute the computer program stored in the memory so that the detection apparatus executes at least some of the steps in the method according to any one of claims 1 to 18.

38. An optical fiber communication system, characterized in that, Comprising an optical transmission device, an optical reception device, and an optical fiber link, the optical transmission device is connected to the optical reception device through the optical fiber link, the optical transmission device comprises the detection apparatus according to any one of claims 19 to 25, 37, and the optical reception device comprises the detection apparatus according to any one of claims 26 to 37.

39. A computer-readable storage medium, characterized in that, A computer program is stored in the computer-readable storage medium, and when the computer program is executed, at least some of the steps in the method according to any one of claims 1 to 18 are implemented.

40. A computer program product, characterized in that, The computer program product comprises a program or code, and when the program or code is executed, at least some of the steps in the method according to any one of claims 1 to 18 are implemented.

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