Optical fiber probing method and related apparatus

Abstract

The application provides a kind of optical fiber detection method and related equipment, first to the light source less than preset linewidth is preset is split, obtain first test light source and local light;Second, the linewidth of the first test light source is widened by phase modulation, to obtain second test light source;Before the light source less than preset linewidth is preset is split, preset corresponding preset pulse width, the coherence length of the second test light source is set to be less than the preset pulse width;Then the second test light source is acoustooptically modulated, to obtain third test light source;Then the third test light source is injected into the optical fiber to be measured, to determine the Rayleigh scattering light of the optical fiber to be measured;Finally, the Rayleigh scattering light is coupled with the local light, and the output signal after the Rayleigh scattering light and the local light are coupled is detected, and the detection result can be concluded that the optical fiber link length measured by the method is longer than that of the related art, and the signal-to-noise ratio is higher.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical fiber detection, and in particular to a method and device for measuring the functional state of a Rayleigh scattering light measuring optical fiber of a broadened light source, an electronic device and a storage medium. BACKGROUND

[0002] Optical Time Domain Reflectometry (OTDR) is an optical fiber testing instrument, which is widely used in optical fiber link attenuation measurement, optical fiber connector and optical fiber fusion splice quality inspection, optical fiber defect inspection, optical fiber failure detection, and can measure the optical length of the optical fiber and analyze the loss distribution of the optical fiber link.

[0003] The traditional direct detection OTDR measures the transmission time difference between the injected pulse signal in the optical fiber and the back Rayleigh scattering and Fresnel reflection signal, and the signal intensity change, to realize the analysis of the optical fiber link length and the optical fiber line loss. However, there are problems in the traditional direct detection OTDR system. The back Rayleigh scattering signal light is too weak and uses direct detection, resulting in a small signal-to-noise ratio of the received signal and a limited measured optical fiber link length. Another problem is that coherent detection technology cannot be used to improve the signal-to-noise ratio. The reason is that the spectral width of the Rayleigh scattering light in the signal frequency domain after coherent detection is the convolution of the light source line width and the pulse spectrum, and the detector bandwidth is determined by the pulse width, which is the inverse of the pulse width. At this time, the spectral width in the signal frequency domain is much larger than the bandwidth of the detector, so most of the energy is outside the bandwidth of the detector, resulting in very low spectral utilization efficiency and low signal power, which cannot achieve the purpose of improving the signal-to-noise ratio. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a method and device for optical fiber detection, an electronic device and a storage medium to solve or partially solve the above technical problems.

[0005] To achieve the above purpose, the first aspect of the present application provides a method for optical fiber detection, which comprises:

[0006] Splitting a preset light source with a line width smaller than a preset line width to obtain a first test light source and a local oscillator light;

[0007] Broadening the line width of the first test light source by phase modulation to obtain a second test light source;

[0008] Before splitting the preset light source with a line width smaller than the preset line width, setting a corresponding preset pulse width, and setting the coherence length of the second test light source to be smaller than the preset pulse width;

[0009] Acousto-optically modulating the second test light source to obtain a third test light source;

[0010] injecting the third test light source into the to-be-tested optical fiber to determine Rayleigh scattered light of the to-be-tested optical fiber;

[0011] coupling the Rayleigh scattered light and the local light, and detecting an output signal after the coupling of the Rayleigh scattered light and the local light.

[0012] A second aspect of the present application provides a device for optical fiber detection, the device comprising:

[0013] a light source line width broadening module configured to split a preset light source with a line width less than a preset line width to obtain a first test light source and a local light, broaden the line width of the first test light source through phase modulation to obtain a second test light source, and set a coherence length of the second test light source to be less than a preset pulse width before splitting the preset light source with the line width less than the preset line width.

[0014] a modulation module configured to perform acousto-optic modulation on the second test light source to obtain a third test light source;

[0015] the Rayleigh scattered light detection module is configured to inject the third test light source into the to-be-tested optical fiber to determine Rayleigh scattered light of the to-be-tested optical fiber; and couple the Rayleigh scattered light and the local light, and detect an output signal after the coupling of the Rayleigh scattered light and the local light.

[0016] A third aspect of the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method of the first aspect or the second aspect.

[0017] A fourth aspect of the present application provides a non-transitory computer readable storage medium, which stores computer instructions for causing a computer to execute the method of the first aspect or the second aspect.

[0018] As can be seen from the above, the method, device, electronic device and storage medium for optical fiber detection provided by the present application broaden the light source on the basis of the coherent detection method to obtain a light source with broadened line width, which can solve the problem of limited length of the measured optical fiber link caused by the too weak Rayleigh scattered light scattered by the to-be-tested optical fiber and the low signal-to-noise ratio of the output signal due to the too narrow light source line width caused by direct detection in the traditional direct detection system, and the problem of the low light intensity points in the interference pattern obtained in the traditional coherent detection Φ-OTDR system which cannot directly represent the state of the to-be-tested optical fiber. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the application or the related art, the drawings needed to be used in the embodiments or the related art description will be briefly introduced. Obviously, the drawings in the following description only constitute the embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0020] Figure 1 A schematic diagram of the principle of the related art;

[0021] Figure 2 A schematic diagram of the test curve of the related art;

[0022] Figure 3 A schematic diagram of the flow of the optical fiber detection method of the embodiments of the application;

[0023] Figure 4 A schematic diagram of the principle of the optical fiber detection method of the embodiments of the application;

[0024] Figure 5 A schematic diagram of the comparison before and after the line width of the light source is broadened in the embodiments of the application;

[0025] Figure 6 A schematic diagram of the structure of the optical fiber detection device in the embodiments of the application;

[0026] Figure 7 A schematic diagram of the structure of the electronic device in the embodiments of the application. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the application clearer, the application will be further described in detail below with reference to the embodiments and the accompanying drawings.

[0028] It should be noted that, unless otherwise defined, the technical terms or scientific terms in the embodiments of the application should be understood as the general meanings understood by those skilled in the art to which the embodiments of the application belong. The words "first", "second" and the like used in the embodiments of the application do not represent any order, number or importance, but are only used to distinguish different components. The words "include" or "contain" and the like mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects. The words "connect" or "connected" and the like do not mean physical or mechanical connection, but can include electrical connection, whether direct or indirect. The words "up", "down", "left", "right" and the like only represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0029] OTDR is an important instrument recommended by the standards such as the Telecommunications Industry Association (TIA) and the International Electrotechnical Commission (IEC) for authenticating the performance of new optical fiber links and detecting problems of existing optical fiber links, and has advantages of simple implementation, low price, fast testing speed, high testing precision, etc. In the optical fiber cable construction and maintenance and the occasions related to optical fibers, the OTDR is as important as the multimeter for the production and debugging of electronic products, and thus has been widely concerned and favored by manufacturers at home and abroad.

[0030] Due to factors such as unevenness of the optical fiber structure, manufacturing defects of the optical fiber itself, and uneven distribution of internal doping, when the optical pulse propagates in the optical fiber, Rayleigh scattering signals in various directions will be generated. The signal scattered in the opposite direction of the optical signal propagation direction is called Rayleigh backscattering, and the reflection signal generated at the end face of the optical signal is called Fresnel reflection. The OTDR is an instrument device for analyzing the length of the optical fiber link, the optical fiber line loss, etc. by measuring the transmission time difference between the pulse signal injected into the optical fiber and the backscattering and Fresnel reflection signals, and the signal intensity change.

[0031] The basic structure of the conventional direct detection OTDR is shown in Figure 1 The optical pulse is generated by modulation in the laser, and is injected into the optical fiber to be measured through the circulator. The pulse interval should be large enough to ensure that the next pulse enters the optical fiber to be measured (FUT) when the previous pulse has left. The backscattering optical signal returned by the optical fiber to be measured is output through the circulator and is received by the photodetector (PD). The generated electrical signal is sent to the signal control and processing unit after being amplified by the amplifier and converted into a digital signal by the analog-to-digital converter (ADC) through the signal receiving device (Acq). The signal control and processing unit is responsible for maintaining the clock synchronization of the entire system, triggering the pulse generator, recording the optical signal intensity returned to the receiving end at different times, performing average calculation and logarithmic transformation, and taking the results as the ordinate and the time unit converted into the distance unit as the abscissa, so as to draw the loss curve of different scattering positions.

[0032] The light source of the conventional direct detection OTDR is generally a broadband light source with a bandwidth of about 2 nm, and thus the power-time curve measured is relatively smooth, as shown in Figure 2The OTDR curve can accurately locate the positions of connectors, joints or breaks in the link, and obtain the attenuation coefficient, length, refractive index of the optical fiber, and the insertion loss and return loss of the connector. The event types in the OTDR curve mainly include reflection events, non-reflection events and gain events: the reflection events are displayed as sharp peaks in the optical fiber curve, indicating that there may be connectors, mechanical joints or even poor fusion joints or cracks; the non-reflection events are manifested as discontinuous slopes of the curve signal drop, which are usually caused by joints, macro-bends or micro-bends in the optical fiber; the gain events are manifested as a significant increase in the power level at a certain point, indicating that the two sections of the spliced optical fiber have different backscattering characteristics, and the latter section of the optical fiber produces more backscattered light, which often occurs at the fusion point and the like.

[0033] Through the traditional direct detection OTDR system, the functional state of the optical fiber can be detected, including two main states of strong reflection and attenuation. These two states will affect the quality of the transmitted signal in the optical fiber, leading to an increase in the error code rate of communication, and therefore are the focus of attention.

[0034] The traditional direct detection OTDR measures the transmission time difference and signal intensity change between the injected pulse signal in the optical fiber and the backscattered Rayleigh signal and Fresnel reflection signal, to realize the analysis of the optical fiber link length and optical fiber line loss. However, due to the weak backscattered Rayleigh signal in the OTDR and the direct detection mode, the received signal-to-noise ratio is small, and the measured optical fiber link length is limited. Taking an optical pulse with a pulse width of 20us and a peak power of 15dBm as an example for analysis, assuming that the measured optical fiber link length is 50km, the scattering rate of the backscattered Rayleigh light is -73dB / m, and the received Rayleigh scattering light at the detection end attenuates at a rate of 0.4dB / km, the Rayleigh scattering light power at the starting end of the optical fiber is -25dBm, the total attenuation power of the entire optical fiber link is 20dB, and the Rayleigh scattering light power at the tail end of the optical fiber is -45dBm. If it is required that the received tail end Rayleigh scattering light signal-to-noise ratio is 6dB, i.e. the Rayleigh scattering signal is 4 times larger than the noise, then the noise needs to be less than -51dBm, which is lower than the noise power of a general detector, and it is difficult to achieve.

[0035] Another problem of the traditional direct detection OTDR system is that it cannot use coherent detection technology to improve the signal-to-noise ratio. The reason is that the spectral width of the Rayleigh scattering light in the frequency domain after coherent detection is the convolution of the light source line width and the pulse spectrum, and the detector bandwidth B c is determined by the pulse width, which is the inverse of the pulse width. At this time, the spectral width in the frequency domain is much larger than the bandwidth B c of the detector, so that most of the energy is outside the bandwidth of the detector, resulting in very low spectral utilization efficiency and low signal power, and it is impossible to achieve the purpose of improving the signal-to-noise ratio.

[0036] In the traditional coherent detection Ф-OTDR system, since the purpose is to detect the functional state of the optical fiber, including the two main states of strong reflection and attenuation. Since the traditional coherent detection Ф-OTDR system uses a narrow line width light source with strong coherence, the intensity fluctuation curve is caused on the interference pattern, which causes the intensity of some position points to be very low, and the attenuation rate or reflection value of the optical fiber cannot be directly represented.

[0037] Based on the above, the embodiment of the application provides a kind of optical fiber detection method, device, electronic equipment and storage medium. On the basis of coherent detection, the line width of light source is widened, which is a kind of optical fiber detection method compared with traditional direct detection OTDR, can increase the length of measured optical fiber link, improve the signal-to-noise ratio of detection signal, solve the problem of poor performance of traditional direct detection OTDR when monitoring optical fiber link.

[0038] Referring to Figure 3 , a flowchart of the optical fiber detection method of the embodiment of the application is shown.

[0039] As Figure 3 shown, the method for detecting optical fiber proposed by the embodiment comprises:

[0040] Step 301, the preset light source smaller than the preset line width is split by a coupler to obtain a first test light source and a local oscillator light.

[0041] In this step, the preset light source smaller than the preset line width is split by a coupler to obtain a first test light source and a local oscillator light. At this time, the center frequencies of the two light signals are f0.

[0042] In the above process, the first test light source and the local oscillator light obtained after the preset light source smaller than the preset line width is split, wherein the first test light source transmitted to the phase modulator for processing is mainly for preparing the Rayleigh scattered light finally obtained, and the other local oscillator light propagates downward, which is prepared for coherent detection.

[0043] Step 302, the line width of the first test light source is widened by phase modulation to obtain a second test light source; before the preset light source smaller than the preset line width is split, the corresponding preset pulse width is preset, and the coherence length of the second test light source is set to be smaller than the preset pulse width.

[0044] In this step, the first test light source is phase-modulated in a certain way to broaden its line width, so as to obtain a second test light source, and when the light source line width is broadened, the broadening degree is not the wider the better, and too wide may cause the signal spectrum to be far greater than the bandwidth of the photodetector when the photodetector is used to receive the signal, so that most of the energy cannot be received by the photodetector, so it is very important to set the coherence length of the second test light source to be less than the preset pulse width.

[0045] In the above process, the second test light source with broadened line width lays a foundation for the third test light source for fiber detection, and solves the problem that if coherent detection is performed, the line width of the third test light source input into the to-be-detected fiber is too narrow, and the intensity of Rayleigh scattering light of the to-be-detected fiber fluctuates to cause the intensity of some position points to be very low.

[0046] Step 303: The second test light source is acousto-optically modulated to obtain a third test light source.

[0047] In this step, when the second test light source is acousto-optically modulated by the acousto-optic modulator, the center frequency and the light source type of the second test light source are changed, the center frequency of the light source after acousto-optic modulation is shifted to the sum of the center frequency of the second test light source and the modulation frequency of the acousto-optic modulator, and the third test light source type becomes a light source that can enter the to-be-detected fiber.

[0048] In the above process, the third test light source obtained is prepared for inputting the light source into the fiber for detection, and the light source type becomes a light source that can enter the to-be-detected fiber, and the change of the center frequency is related to the properties of the acousto-optic modulator.

[0049] Step 304: The third test light source is injected into the to-be-detected fiber to determine the Rayleigh scattering light of the to-be-detected fiber.

[0050] In this step, the third test light source is input into the to-be-detected fiber through the circulator, and the to-be-detected fiber scatters back the Rayleigh scattering light, which is then output from the circulator. At this time, the center frequency of the Rayleigh scattering light signal output from the circulator is the sum of the center frequency of the second test light source and the modulation frequency of the acousto-optic modulator, and the spectrum is the convolution of the line width of the third test light source and the pulse spectrum of the third test light source. At this time, the task of the uplink light detecting the to-be-detected fiber is basically completed.

[0051] According to the above process, it can be known that this part is mainly the transmission process of the light source, and the circulator is used to transmit the light source.

[0052] Step 305: The Rayleigh scattering light is coupled with the local oscillator light, and the output signal after the coupling of the Rayleigh scattering light and the local oscillator light is detected.

[0053] In this step, the local light obtained in step 301 and the Rayleigh scattering light output in step 304 are combined through a coupler to obtain an output signal which is detected. The detection process includes conversion of optical signals and electrical signals and signal control and processing of the signals after entering the receiving device.

[0054] According to the above scheme, the local light obtained in step 301 and the Rayleigh scattering light output in step 304 are combined through a coupler to amplify the light intensity, thereby indirectly improving the signal-to-noise ratio of the output signal output in this step. The detection process includes conversion of optical signals and electrical signals and signal control and processing of the signals after entering the receiving device.

[0055] In some embodiments, before step 301, the method further comprises:

[0056] Before splitting the preset light source, the value of the pulse width is determined in advance. The size of the preset pulse width is determined by the user's demand for the system spatial resolution, for example, a pulse width of 20 ns corresponds to a system spatial resolution of 2 m. The system spatial resolution refers to the resolution of the minimum distance that can be actually detected.

[0057] In some embodiments, step 302 comprises:

[0058] Step 3021, the line width is broadened by using a pseudo-random binary sequence to disturb the phase of the first test light source to obtain a second test light source.

[0059] In specific implementation, a phase modulator driven by a pseudo-random binary sequence can be used to broaden the line width of the light source.

[0060] According to the above scheme, the second test light source is obtained by broadening the line width of the light source through a phase modulator driven by a pseudo-random binary sequence. At this time, the line width of the second test light source is proportional to the bit rate of the pseudo-random binary sequence.

[0061] In some embodiments, step 303 specifically comprises:

[0062] Step 3031, the center frequency of the second test light source is modulated.

[0063] Step 3032, according to the preset pulse width, an electrical pulse required for the acousto-optic modulation is determined; according to the electrical pulse, the second test light source is modulated into pulsed light to obtain the third test light source, and the pulse width of the pulsed light is the preset pulse width.

[0064] In the embodiment, before the acousto-optic modulation, the level of the electric pulse required for the photoelectric modulation is set according to the preset value of the preset pulse width, the high level of the light pulse is generated according to the high level of the electric pulse, and then the pulse width of the third test light source is obtained as the preset value. When the acousto-optic modulation is performed, the frequency modulation is performed on the second test light source, the center frequency of the third test light source is slightly different from that of the second test light source, and the value becomes f0+f AOM , wherein f0 is the center frequency of the second test light source, f AOM is the modulation frequency of the acousto-optic modulator, and the line width of the light source does not change in the modulation process. The type of the light source is changed from continuous light to pulsed light entering the optical fiber optical signal to be detected.

[0065] In the above scheme, due to the nature of the acousto-optic modulator, the center frequency and the type of the light source are changed, and when the optical fiber is detected, the pulsed light has the advantage that the subsequent output signal is easy to process and analyze.

[0066] In some embodiments, step 305 further includes:

[0067] Step 3051, converting the output signal into an optical signal and an electric signal by the photoelectric detector to obtain a detection signal.

[0068] Step 3052, determining a test curve of the detection signal.

[0069] Step 3053, detecting the optical fiber to be detected according to the test curve of the detection signal.

[0070] In the embodiment, the center frequency of the local oscillator light is f0, and the center frequency of the Rayleigh scattering light is f0+f AOM . After the beat frequency is performed in the photoelectric detector, the electric signal with the known center frequency f AOM is obtained, that is, the detection signal. At this time, the shape and width of the spectrum of the detection signal are the same as those of the Rayleigh scattering light mentioned above, only the center frequency is changed in position. Therefore, it can be said that the signal analysis of the detection signal represents the analysis of the Rayleigh scattering light, that is, the detection result of the optical fiber. The test curve is obtained by detecting the detection signal, and the functional state of the optical fiber to be detected and the measured length of the optical fiber to be detected can be obtained according to the characteristics of the test curve.

[0071] In the above scheme, the process of transmitting the output signal into the photoelectric detector is the process of converting the optical signal into the electric signal. By converting the optical signal into the electric signal, the test curve of the detection signal can be obtained by using the subsequent receiving device to process and analyze the signal, so that the functional state of the optical fiber to be detected and the length of the optical fiber to be detected can be clearly determined.

[0072] In some embodiments, before step 3051, further comprising setting the bandwidth of the photodetector to be greater than or equal to the full width at half maximum of the spectrum of the convolution of the line width of the third test light source and the pulse spectrum of the third test light source, to obtain the photodetector.

[0073] In implementation, the embodiment can be that, first, a first target spectrum is determined after the convolution of the line width of the third test light source and the pulse spectrum of the third test light source, then a second target spectrum is obtained after the first target spectrum is subjected to the coherent detection process, the center frequency of which is shifted to the modulation frequency f AOM of the acousto-optic modulator, and finally, the bandwidth of the photodetector is set to be greater than or equal to the full width at half maximum of the second target spectrum. The embodiment can also be that, in some cases, the bandwidth of the photodetector is directly set to be greater than or equal to the full width at half maximum of the spectrum of the convolution of the line width of the third test light source and the pulse spectrum of the third test light source, to obtain the photodetector.

[0074] Overall, the coherent detection includes three parts, first, a light source with a preset line width less than a preset line width is split by a coupler to obtain a first test light source and a local oscillator light, then the local oscillator light is coupled with the Rayleigh scattered light transmitted to obtain an output signal, and finally, a photodetector is used to beat the output signal to obtain a detection signal with a center frequency at f AOM The coherent detection process in the above scheme mainly includes the process of coupling the local oscillator light and the Rayleigh scattered light and then beating the coupled light by the photodetector. In addition, the bandwidth of the photodetector needs to be greater than or equal to the full width at half maximum of the convolution of the line width of the third test light source and the pulse spectrum of the third test light source, that is, the full width at half maximum of the spectrum of the Rayleigh scattered light signal. The above conditions ensure that the photodetector can receive all the output signal energy, avoid the problem that the photodetector cannot receive all the output signal energy due to the small bandwidth of the photodetector, and ensure that the signal-to-noise ratio of the signal will not be reduced in this process.

[0075] In some embodiments, in step 3052, specifically comprising:

[0076] Step 30521, determining the relative power of the Rayleigh scattered light and the distance of the to-be-measured optical fiber corresponding to each sampling time according to the detection signal;

[0077] Step 30522, determining the test curve according to the relative power and the distance of the to-be-measured optical fiber.

[0078] In the implementation, the power of the Rayleigh scattering signal amplified by the coherent detection along the fiber distance is obtained by analyzing the detection signal, that is, the Rayleigh scattering light beat signal is squared, filtered and processed in a series of processes, and finally the relative power of the detection signal is obtained. The fiber distance corresponding to each sampling time is taken as the horizontal coordinate, and the relative power of the detection signal is taken as the vertical coordinate, and a test curve is drawn.

[0079] In the above scheme, the position of the connector, joint or break in the fiber link to be tested can be accurately located by drawing the test curve, and the attenuation coefficient, length, refractive index of the fiber, and the insertion loss and return loss of the connector are obtained. According to the curve, the event type is determined, wherein the event type includes a reflection event, a non-reflection event and a gain event.

[0080] In order to more clearly illustrate the technical solutions of the application, the application can also be described more specifically:

[0081] Since the coherent detection Ф-OTDR system of the related art has the problem that the light intensity of some points on the interference pattern is very low and cannot directly represent the attenuation rate or reflection value of the fiber, on this basis, we need to expand the linewidth of the laser source, that is, to obtain the second test light source by expanding the first test light source, so that the coherence length of the second test light source is less than the preset pulse width, so as to eliminate the phenomenon of light intensity fluctuation. The embodiment of the application is shown in Figure 4 The linewidth expansion degree of the light source is determined by the preset pulse width, only the coherence length of the second test light source obtained after phase modulation is less than the preset pulse width, and it does not need to be expanded too much, otherwise the phenomenon that most of the energy cannot be received by the preset photodetector in the subsequent output signal will occur, which makes the frequency spectrum utilization rate very low and the output signal signal-to-noise ratio low.

[0082] In Figure 4 , the narrow linewidth laser outputs continuous light with a center frequency f0 and a linewidth Δv0, which is divided into two paths by a coupler. The phase of the uplink light is disturbed by a pseudo-random binary sequence, and the linewidth of the expanded light source is proportional to the bit rate of the pseudo-random binary sequence, which is Δv1. For example, Figure 5 , the left graph is a narrow linewidth light source without PRBS code disturbance phase, and its linewidth is about 1.4 MHz; the right graph is a specific expanded linewidth light source disturbed by a PRBS code of 50 Mbps, and its linewidth is about 40 MHz.

[0083] The second test light source with expanded linewidth is passed through a frequency fAOM The acousto-optic modulator modulates the acousto-optic modulator to be acousto-optic modulated into pulsed light with a center frequency of f0+f AOM , and a line width of Δv1, that is, a third test light source, is injected into the optical fiber to be measured, and the spectral width of the frequency domain of the received Rayleigh scattering light is related to the line width and pulse width of the third test light source. The other local oscillator light has a center frequency of f Lo =f0. After the local oscillator light and the uplink Rayleigh scattering light are combined by the coupler and enter the photodetector, the signal light after the beat frequency has a center frequency at f AOM . The spectral width of the signal in the frequency domain after the Rayleigh scattering light of the light source with a specific extended line width is injected into the optical fiber and then coherently detected is the convolution of the line width of the light source and the pulse spectrum, so the bandwidth B c of the photodetector needs to be greater than the full width at half maximum (FWHM) of the spectrum.

[0084] Compared with the related art conventional direct detection OTDR, the application has a higher signal-to-noise ratio under the same measurement time, the same measurement accuracy, and the same spatial resolution. Taking an optical pulse with a pulse width of 20us and a peak power of 15dBm as an example for analysis, assuming that the optical fiber link length to be measured is 50km, the scattering rate of the back Rayleigh scattering light is known to be -73dB / m, and the Rayleigh scattering light received at the detection end is attenuated by 0.4dB / km, then the Rayleigh scattering light power at the starting end of the optical fiber is -25dBm, and the total attenuation power of the entire optical fiber link is 20dB. Taking a photodetector bandwidth B c =350MHz as an example, in the case of direct detection, the signal light power is -45dBm, at this time the thermal noise is dominant, the noise power is about -34dBm, and the signal-to-noise ratio is -11dB, which cannot detect the Rayleigh scattering signal at the tail end. In the case of coherent detection, taking the local oscillator light of 5dBm as an example, the signal light after the beat frequency is -20dBm, at this time the shot noise is dominant, the noise power is about -32dBm, and the signal-to-noise ratio is 12dB, which is 23dB higher than the conventional direct detection OTDR scheme under the same conditions. Therefore, the application embodiment brings a higher signal-to-noise ratio and a longer measurement distance than the related art, that is, a better measurement performance is achieved.

[0085] Based on the same inventive concept, the application also provides an optical fiber detection device corresponding to any of the above-mentioned embodiment methods.

[0086] Reference Figure 6 The optical fiber detection device comprises:

[0087] The light source line width broadening module 601 is configured to split the preset light source with a line width less than a preset line width to obtain a first test light source and a local oscillator light; broaden the line width of the first test light source through phase modulation to obtain a second test light source; set the coherence length of the second test light source to be less than a preset pulse width before splitting the preset light source with a line width less than the preset line width.

[0088] The modulation module 602 is configured to perform acousto-optic modulation on the second test light source to obtain a third test light source.

[0089] The Rayleigh scattering light detection module 603 is configured to inject the third test light source into a to-be-detected optical fiber to determine Rayleigh scattering light of the to-be-detected optical fiber; couple the Rayleigh scattering light with the local oscillator light, and detect an output signal after the Rayleigh scattering light and the local oscillator light are coupled.

[0090] In some embodiments, the device further comprises:

[0091] The detector setting module is configured to set the bandwidth of the photodetector to be greater than or equal to the full width at half maximum of the spectrum obtained by convolving the line width of the third test light source with the pulse spectrum of the third test light source, to obtain the photodetector.

[0092] In some embodiments, the light source line width broadening module 601 specifically comprises:

[0093] The phase disturbance unit is configured to disturb the phase of the first test light source by using a pseudo-random binary sequence to broaden the line width to obtain a second test light source.

[0094] The line width determination unit is configured to set the coherence length of the second test light source to be less than the preset pulse width.

[0095] In some embodiments, the modulation module 602 specifically comprises:

[0096] The center frequency modulation unit is configured to modulate the center frequency of the second test light source.

[0097] The light source type modulation unit is configured to determine an electrical pulse required when performing the acousto-optic modulation according to the preset pulse width; and modulate the second test light source into pulsed light according to the electrical pulse to obtain the third test light source, wherein the pulse width of the pulsed light is the preset pulse width.

[0098] In some embodiments, the Rayleigh scattering light detection module 603 specifically comprises:

[0099] a Rayleigh scattering light determining unit configured to inject the third test light source into the optical fiber to be tested to determine Rayleigh scattering light of the optical fiber to be tested;

[0100] a coupling unit configured to couple the Rayleigh scattering light with the local light to obtain an output signal;

[0101] a first detecting unit configured to convert the output signal into an optical signal and an electrical signal by means of a photoelectric detector to obtain a detection signal;

[0102] a second detecting unit configured to determine a test curve of the detection signal, and detect the optical fiber to be tested according to the obtained test curve of the detection signal.

[0103] In some embodiments, the second detecting unit specifically comprises:

[0104] a detection signal detecting sub-unit configured to determine a relative power of the Rayleigh scattering light and a distance of the optical fiber to be tested corresponding to each sampling time according to the detection signal;

[0105] a test curve determining sub-unit configured to determine the test curve according to the relative power and the distance of the optical fiber to be tested.

[0106] For the convenience of description, the above apparatus is described in various modules in terms of functions. Of course, the functions of the modules can be implemented in one or more software and / or hardware in the implementation of the present application.

[0107] The apparatus of the above embodiments is used to implement the corresponding optical fiber detection method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be described here.

[0108] Based on the same inventive concept, the present application also provides an electronic device corresponding to the method of any of the above embodiments, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the optical fiber detection method of any of the above embodiments.

[0109] Figure 7 The present embodiment provides a more specific hardware structure schematic diagram of an electronic device. The device can include a processor 710, a memory 720, an input / output interface 730, a communication interface 740, and a bus 750. The processor 710, the memory 720, the input / output interface 730, and the communication interface 740 are connected to each other through the bus 750 for communication within the device.

[0110] The processor 710 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits, etc., for executing relevant programs to implement the technical solutions provided by the embodiments of the present specification.

[0111] The memory 720 can be implemented by a ROM (Read Only Memory), a RAM (Random Access Memory), a static storage device, a dynamic storage device, etc. The memory 720 can store an operating system and other application programs, and when the technical solutions provided by the embodiments of the present specification are implemented by software or firmware, the relevant program codes are stored in the memory 720 and called and executed by the processor 710.

[0112] The input / output interface 730 is configured to connect input / output modules to implement information input and output. The input / output modules can be configured as components in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. The input devices can include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output devices can include a display, a speaker, a vibrator, an indicator light, etc.

[0113] The communication interface 740 is configured to connect a communication module (not shown in the figure) to implement the communication interaction between the device and other devices. The communication module can realize communication through a wired manner (such as USB, network cable, etc.) or through a wireless manner (such as mobile network, WIFI, Bluetooth, etc.).

[0114] The bus 750 includes a path for transmitting information between various components (such as the processor 710, the memory 720, the input / output interface 730, and the communication interface 740) of the device.

[0115] It should be noted that although the above device only shows the processor 710, the memory 720, the input / output interface 730, the communication interface 740, and the bus 750, in the specific implementation process, the device can also include other components necessary for normal operation. In addition, those skilled in the art can understand that the above device can also only include the components necessary to implement the solutions of the embodiments of the present specification, and does not have to include all the components shown in the figure.

[0116] The electronic device of the above embodiments is used to implement the corresponding game user shunting method in any of the preceding embodiments, and has the beneficial effects of the corresponding method embodiments, which are not described here again.

[0117] Based on the same inventive concept, the application also provides a non-transitory computer readable storage medium storing computer instructions for causing a computer to perform the game user shunting method according to any of the above embodiments.

[0118] The computer readable medium of the embodiments can include permanent and non-permanent, removable and non-removable media, which can be realized by any method or technology to store information. The information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device.

[0119] The computer instructions stored in the storage medium of the above embodiments are used to cause a computer to perform the game user shunting method according to any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which are not described here.

[0120] Those skilled in the art should understand that the above discussion of any of the embodiments is only exemplary and is not intended to imply that the scope (including claims) of the application is limited to these examples; the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the embodiments of the application as described above. In order to be brief, they are not provided in detail.

[0121] Additionally, to simplify the description and discussion, and so as not to obscure the embodiments of the application being presented, the well-known functions or constructions of integrated circuit (IC) chips and other components can or can not be shown in the figures and will be omitted as not to unnecessarily obscure the embodiments of the application being presented. Moreover, the devices can be shown in block diagram form in order to avoid obscuring the embodiments of the application, and this also acknowledges the fact that the details in regard to the implementation of the block diagram devices are highly dependent on the platform within which the embodiments of the application are to be implemented (i.e., these details should be well within the purview of one of ordinary skill in the art). Where specific details are set forth in order to describe an illustrative embodiment of the application, it will be apparent to one of ordinary skill in the art that the embodiments of the application can be practiced without, or with variation of, these specific details. Thus, the description is to be considered as illustrative only and not restrictive in nature.

[0122] While the application has been described in connection with specific embodiments thereof, it will be understood that many modifications, substitutions and changes will be apparent to those of ordinary skill in the art once they have the benefit of the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) can use the embodiments discussed.

[0123] It is intended that the embodiments of the application encompass all such substitutions, modifications and variations as fall within the scope of the appended claims. Accordingly, any omission, modification, equivalent replacement, improvement, etc. made in the spirit and principle of the embodiments of the application should be included in the scope of protection of the application.

Claims

1. An optical fiber probing method, characterized by, The method comprises the following steps: The light source with a preset line width less than a preset line width is split to obtain a first test light source and a local oscillator light; The line width of the first test light source is expanded through phase modulation to obtain a second test light source; Before the step of splitting the light source with a preset line width less than a preset line width, a preset pulse width is preset, and a coherence length of the second test light source is set to be less than the preset pulse width; The preset pulse width is obtained based on system spatial resolution; The second test light source is subjected to acousto-optic modulation to obtain a third test light source; The third test light source is injected into a to-be-tested optical fiber to determine Rayleigh scattering light of the to-be-tested optical fiber; The Rayleigh scattering light is coupled with the local oscillator light, and an output signal after the coupling of the Rayleigh scattering light and the local oscillator light is detected; The step of expanding the line width of the first test light source through phase modulation to obtain a second test light source comprises the following steps: The line width is expanded through phase disturbance of the first test light source by using a pseudo-random binary sequence, and a second test light source is obtained, and the expansion degree of the line width is proportional to the bit rate of the pseudo-random binary sequence.

2. The method of claim 1, wherein, The step of acousto-optically modulating the second test light source to obtain a third test light source comprises the following steps: The center frequency of the second test light source is modulated; According to the preset pulse width, an electric pulse required when the acousto-optic modulation is performed is determined; According to the electric pulse, the second test light source is modulated into pulsed light to obtain the third test light source, and the pulse width of the pulsed light is the preset pulse width.

3. The method of claim 1, wherein, After the step of detecting the output signal after the coupling of the Rayleigh scattering light and the local oscillator light, the following steps are further included: The output signal is converted into an optical signal and an electrical signal by an optoelectronic detector to obtain a detection signal; A test curve of the detection signal is determined; According to the obtained test curve of the detection signal, the to-be-tested optical fiber is detected.

4. The method of claim 3, wherein, Before the step of converting the output signal into an optical signal and an electrical signal by an optoelectronic detector, the following step is included: The bandwidth of the optoelectronic detector is set to be greater than or equal to the full width at half maximum of the spectrum obtained by convolution of the line width of the third test light source and the pulse spectrum of the third test light source, to obtain the optoelectronic detector.

5. The method of claim 3, wherein, The test curve of the detection signal comprises the following steps: The relative power of the Rayleigh scattering light and the distance of the to-be-tested optical fiber corresponding to each sampling time are determined according to the detection signal; The test curve is determined according to the relative power and the distance of the to-be-tested optical fiber.

6. An optical fiber probing apparatus, characterized by, The method comprises the following steps: A light source line width expansion module, a modulation module, and a Rayleigh scattering light detection module are included. The light source line width expansion module is configured to split a light source with a preset line width less than a preset line width to obtain a first test light source and a local oscillator light, expand the line width of the first test light source through phase modulation to obtain a second test light source, preset a corresponding preset pulse width before the step of splitting the light source with a preset line width less than a preset line width, and set the coherence length of the second test light source to be less than the preset pulse width; and the preset pulse width is obtained based on system spatial resolution. The modulation module is configured to acousto-optically modulate the second test light source to obtain a third test light source. The Rayleigh scattering light detection module is configured to inject the third test light source into the optical fiber to be tested to determine Rayleigh scattering light of the optical fiber to be tested, couple the Rayleigh scattering light with the local light, and detect an output signal after the Rayleigh scattering light is coupled with the local light. The light source line width widening module is specifically configured to widen the line width by using a pseudo-random binary sequence to disturb the phase of the first test light source, to obtain a second test light source, and the widening degree of the line width is proportional to the bit rate of the pseudo-random binary sequence.

7. The apparatus of claim 6, wherein, Further comprising: A detector setting module; The detector setting module is configured to set the bandwidth of the photodetector to be greater than or equal to the full width at half maximum of the spectrum obtained by convolving the line width of the third test light source with the pulse spectrum of the third test light source, to obtain the photodetector. 8.An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the method of any one of claims 1 to 5 when executing the program. 9.A non-transitory computer readable storage medium storing computer instructions for causing a computer to perform the method of any one of claims 1 to 5.

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