Automatic analysis method for optical signal attenuation of fixed network broadband user optical fiber link

Abstract

The invention belongs to the technical field of optical signal detection and analysis, and particularly relates to a fixed network broadband user optical fiber link optical signal attenuation automatic analysis method, which comprises the following steps: S1) system deployment: selecting a fixed network broadband user optical fiber link needing to be monitored; one end of the optical fiber link is connected with a pulse laser; the other end of the optical fiber link is connected with a photon detector; s2) signal excitation: using a pulse laser to periodically emit light pulses into an optical fiber link; s3) signal detection; s4) signal analysis; a single-photon detector and a TCSPC technical scheme are adopted, detection of extremely weak light signals is achieved, the sensitivity and the dynamic range of a system are improved, and the technical bottleneck of a traditional OTDR is broken through; through combination of event segment division of segment spatial resolution and path track information of an optical fiber link, a fault point can be accurately positioned, and the troubleshooting efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of optical signal detection and analysis, and in particular, relates to an automatic analysis method for optical signal attenuation of a fixed-line broadband user optical fiber link. Background Art

[0002] Fixed broadband

[0003] With the popularization of optical distribution network (ODN) lines and fiber-to-the-home (FTTH) line technologies for fiber-optic communications, the number of fixed-line broadband users has increased dramatically, which has put forward higher requirements for the reliability and maintenance efficiency of fiber-optic links. The attenuation of optical signals in fiber-optic links is one of the key factors affecting network quality. Timely and accurate detection and location of fiber-optic link faults are essential to ensure stable network operation and improve user experience. However, the existing fiber-optic link fault detection technology and analysis methods have the following shortcomings:

[0004] Traditional optical time domain reflectometers (OTDRs) have limited sensitivity and dynamic range and rely heavily on the pulse bandwidth and sampling frequency accuracy of analog signals. They have difficulty detecting weak backscattered light signals, which limits their ability to monitor long-distance, high-loss optical fiber links.

[0005] Conventional optical signal classification algorithms and statistical analysis methods require a large amount of accurate data for training and model building. The data collection cost is high and the calculation is complex, which increases the time and cost of troubleshooting. Summary of the invention

[0006] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a method for automatically analyzing the attenuation of optical signals in the optical fiber link of fixed-line broadband users; improves the sensitivity and dynamic range of optical fiber link fault detection; and an accurate analysis and calculation method, so as to provide a more effective and intelligent solution for ensuring the stable operation of fixed-line broadband networks.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link comprises the following steps:

[0009] S1) System deployment:

[0010] Select the fixed broadband user optical fiber link that needs to be monitored;

[0011] A pulse laser is connected to one end of the optical fiber link to emit an optical pulse signal;

[0012] A photon detector is connected to the other end of the optical fiber link to receive the backscattered light signal;

[0013] S2) Signal excitation:

[0014] A pulsed laser is used to periodically emit light pulses into the optical fiber link to stimulate the scattering effect of the optical fiber (such as Raman scattering or Brillouin scattering).

[0015] S3) Signal detection:

[0016] Optical signal processing:

[0017] Using a photon detector to receive backscattered light signals in the optical fiber link and convert the optical signals into electrical signals;

[0018] At the same time, the time-correlated single photon counting technique (TCSPC) is used to record the arrival time of each photon and accumulate the photon counting data within multiple pulse cycles;

[0019] The data is transmitted to a signal analyzer to construct a photon count-time histogram of the pulse signal;

[0020] Electrical signal processing:

[0021] Peak limiting and amplification of the electrical signal using a voltage limiter circuit and a transimpedance amplifier (TIA) or a commercial power limiter and a low noise amplifier (LNA);

[0022] The amplified electrical signal is sampled and digitized at high speed using a digital storage oscilloscope (DSO);

[0023] The data is transmitted to the signal analyzer to construct a time-amplitude waveform diagram of the pulse signal;

[0024] S4) Signal analysis: By analyzing the photon count-time histogram and time-amplitude waveform of the pulse signal, the performance indicators of the optical fiber link are calculated; the performance indicators include spatial resolution and dynamic range.

[0025] Preferably, the step of calculating the spatial resolution includes:

[0026] Analyze adjacent event peaks: Select two adjacent, clearly distinguishable event peaks in the time histogram as an event segment; including fiber breakpoints and connector failures;

[0027] Convert the time axis to the distance axis: According to the propagation speed v of the optical signal in the optical fiber, convert the time interval Δt into the corresponding spatial distance ΔL; the conversion formula is as follows:

[0028] LP = ΔL = v * Δt / 2;

[0029] In the formula, LP represents the spatial resolution, that is, the corresponding spatial distance ΔL;

[0030] The spatial distance ΔL between two adjacent event peaks is the spatial resolution of the system.

[0031] Preferably, the step of calculating the dynamic range includes:

[0032] When there is no signal input or the signal is very weak, the average noise power of the system output is measured. The average noise power at this time represents the minimum signal strength P that can be detected. min ;

[0033] Identify the peak amplitude of the pulse signal in the time-amplitude waveform. The peak amplitude represents the maximum signal strength P. max ;

[0034] The dynamic range can be expressed as the ratio of the maximum signal strength to the minimum signal strength, usually expressed in decibels (dB), and the calculation formula is:

[0035]

[0036] In the formula, Q represents the dynamic range, P max is the maximum signal strength, P min is the minimum signal strength.

[0037] S5) Calculate the light attenuation coefficient of each event segment by spatial resolution and dynamic range:

[0038] Divide event segments: Divide the path trajectory of the optical fiber link into multiple event segments of different lengths according to the spatial resolution;

[0039] According to the spatial resolution and dynamic range, the maximum signal intensity and the minimum signal intensity of each event segment were obtained.

[0040] Calculate the light attenuation coefficient of each event segment (unit: dB / km); the calculation formula is expressed as:

[0041]

[0042] In the formula, dB represents the light attenuation coefficient, ΔL is the spatial distance of the event segment, and P max is the maximum signal intensity of the event segment, P min is the minimum signal strength of this event segment.

[0043] S6) Calculate the path trajectory information of the optical fiber link through the data obtained by the photon detector:

[0044] The distributed optical fiber sensing system uses the principle of Raman scattering or Brillouin scattering to convert the time delay information of the backscattered light obtained by the photon detector into the corresponding path trajectory information according to the propagation speed of the optical signal in the optical fiber;

[0045] Preferably, step S62 further includes: calculating the temperature and strain distribution information of the path trajectory of the optical fiber link; and obtaining the connector distribution information in the path trajectory of the optical fiber link; for distinguishing the fault type as an optical fiber fault or a connector fault.

[0046] S7) Fault identification and location:

[0047] Different types of fiber link faults will cause different degrees of optical attenuation. The fault type of each event segment can be identified by analyzing the attenuation coefficient of the event segment.

[0048] According to the spatial resolution of event division and the path trajectory information of the optical fiber link, the specific location of the fault event on the optical fiber link is calculated.

[0049] Fiber link fault types include fiber breakage, fiber microbend / squeezing, and connector failure.

[0050] Beneficial effects of the present invention:

[0051] 1. Use single-photon detectors and TCSPC technology to detect extremely weak optical signals, improve the sensitivity and dynamic range of the system, and break through the technical bottleneck of traditional OTDR.

[0052] 2. Combining the event segment division of segment spatial resolution and the path trajectory information of the optical fiber link, the fault point can be accurately located and the troubleshooting efficiency can be improved.

[0053] 3. By calculating the optical attenuation coefficient of each event segment fault and matching it with the optical attenuation coefficient database of typical types of faults, the optical fiber link fault can be automatically judged and located, thus reducing operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0055] Figure 1 The present invention is a schematic diagram of system deployment of a method for automatically analyzing optical signal attenuation in a fixed-line broadband user optical fiber link.

[0056] Figure 2 The present invention is a flow chart of a method for automatically analyzing optical signal attenuation in a fixed-line broadband user optical fiber link.

[0057] Figure 3 The present invention provides a flow chart for calculating the optical attenuation coefficient in a method for automatically analyzing optical signal attenuation in a fixed-line broadband user optical fiber link. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] See also Figure 1-Figure 3 As shown, a method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link comprises the following steps:

[0060] S1) System deployment:

[0061] Select the fixed broadband user optical fiber link that needs to be monitored;

[0062] A pulse laser is connected to one end of the optical fiber link to emit an optical pulse signal;

[0063] A photon detector is connected to the other end of the optical fiber link to receive the backscattered light signal;

[0064] Specifically, the optical fiber link includes an optical distribution network (ODN) line and a fiber-to-the-home (FTTH) line.

[0065] Specifically, select pulsed lasers and photon detectors: select pulsed lasers with high stability and photon detectors with high sensitivity;

[0066] Pulsed lasers can be distributed feedback lasers (DFB) or external cavity lasers (ECL);

[0067] DFB lasers have good wavelength stability, usually up to ±0.1nm or even lower.

[0068] ECL lasers can achieve higher wavelength stability, but they are also more expensive.

[0069] The photon detector may be a single photon avalanche photodiode (SPAD), a photomultiplier tube (PMT), or a superconducting nanowire single photon detector (SNSPD).

[0070] It should be noted that this system deployment uses the optical fiber itself as a sensing system, using the Raman scattering or Brillouin scattering principle to monitor the environmental indicators of the optical fiber link in real time;

[0071] Among them, environmental indicators include:

[0072] Temperature: Fiber optic sensors can detect the temperature distribution along the optical fiber through Raman scattering or Brillouin scattering techniques.

[0073] Strain: Brillouin scattering technology can be used to detect changes in strain on optical fibers.

[0074] Pressure: Combining strain and temperature data, it is possible to infer the pressure changes experienced by the fiber.

[0075] Displacement: The displacement of the optical fiber can be calculated by integrating the strain data.

[0076] S2) Signal excitation:

[0077] A pulsed laser is used to periodically emit light pulses into the optical fiber link to stimulate the scattering effect of the optical fiber (such as Raman scattering or Brillouin scattering).

[0078] Specifically, it includes setting parameters such as the pulse width and pulse repetition frequency of the pulse laser.

[0079] S3) Signal detection:

[0080] Optical signal processing:

[0081] Using a photon detector to receive backscattered light signals in the optical fiber link and convert the optical signals into electrical signals;

[0082] At the same time, the time-correlated single photon counting technique (TCSPC) is used to record the arrival time of each photon and accumulate the photon counting data within multiple pulse cycles;

[0083] The data is transmitted to a signal analyzer to construct a photon count-time histogram of the pulse signal;

[0084] Electrical signal processing:

[0085] Peak limiting and amplification of the electrical signal using a voltage limiter circuit and a transimpedance amplifier (TIA) or a commercial power limiter and a low noise amplifier (LNA);

[0086] The amplified electrical signal is sampled and digitized at high speed using a digital storage oscilloscope (DSO);

[0087] The data is transferred to a signal analyzer to construct a time-amplitude waveform of the pulse signal.

[0088] It should be noted that the main difference between the photon counting OTDR detection system of the present invention and the traditional OTDR system is that the digital instrument used by the photon counting OTDR realizes the digital identification of the pulse signal, so that the detector outputs a standard level signal, and then uses a time-related single photon counter to accurately record the pulse arrival time. The system repeatedly measures the time interval between the scattered signal and the excitation pulse to establish a photon count-time histogram, thereby constructing the scattered signal trajectory along the optical fiber link.

[0089] The detection process of the time-correlated single-photon counting technology solution based on single-photon detection is discrete. On the one hand, it can detect ultra-low-power optical signals at the single-photon level, and the system performance improvement is no longer limited by the noise equivalent power. On the other hand, this digital discrete detection and recording method makes the system spatial resolution independent of the detection bandwidth, which can well overcome the bottleneck existing in traditional OTDR and realize OTDR detection and analysis with ultra-high spatial resolution and high dynamic range.

[0090] S4) Signal analysis: Calculate the performance indicators of the optical fiber link by analyzing the photon count-time histogram and time-amplitude waveform of the pulse signal; the performance indicators include spatial resolution and dynamic range;

[0091] Specifically, based on high-performance single-photon detection and combined with time-correlated single-photon counting technology (TCSPC), the performance level of photon counting OTDR has been greatly improved, achieving higher spatial resolution; in addition, peak limiting and amplification of electrical signals have been performed to achieve a higher dynamic amplitude measurement range;

[0092] Photon count-time histograms and time-amplitude waveforms provide complementary information about the characteristics of a fiber link.

[0093] Photon count-time histograms are primarily used to identify events and calculate spatial resolution.

[0094] The time-amplitude waveform is mainly used to measure signal amplitude and calculate dynamic range.

[0095] Spatial resolution refers to the ability of a fiber optic sensing system to distinguish the spatial distance between two adjacent events along the length of the fiber; events include breakpoints and bends. High spatial resolution means that the system can analyze the distance of each event in the fiber link and accurately locate small changes or faults in the fiber.

[0096] Dynamic range refers to the ratio between the maximum and minimum signal strengths that a fiber optic sensing system can detect. A high dynamic range enables the system to work effectively in both strong and weak signal environments, and is suitable for detecting optical signals of different intensities.

[0097] Further, S41) the step of calculating the spatial resolution includes:

[0098] Analyze adjacent event peaks: Select two adjacent, clearly distinguishable event peaks in the photon count-time histogram as an event segment;

[0099] Specifically, the event segment contains various types of fault information, including fiber breakage, fiber microbend / extrusion, connector failure, etc.

[0100] Convert the time axis to the distance axis: According to the propagation speed v of the optical signal in the optical fiber, convert the time interval Δt into the corresponding spatial distance ΔL; the conversion formula is as follows:

[0101] LP = ΔL = v*Δt / 2; where LP represents the spatial resolution, i.e. the corresponding spatial distance ΔL;

[0102] The spatial distance ΔL between two adjacent event peaks is the spatial resolution of the system.

[0103] It should be noted that after the photon count-time histogram is converted from time to distance, the horizontal axis already represents the distance information on the optical fiber link. Therefore, the distance between the two peaks directly reflects the minimum spatial distance that the system can distinguish, that is, the spatial resolution. Therefore, there is no need to calculate the spatial resolution by measuring the sampling rate and pulse width in the conventional way.

[0104] Further, S42) the calculation step of the dynamic range includes:

[0105] When there is no signal input or the signal is very weak, the average noise power of the system output is measured. The average noise power at this time represents the minimum signal strength P that can be detected. min ;

[0106] Identify the peak amplitude of the pulse signal in the time-amplitude waveform. The peak amplitude represents the maximum signal strength P. max ;

[0107] The dynamic range can be expressed as the ratio of the maximum signal strength to the minimum signal strength, usually expressed in decibels (dB), and the calculation formula is:

[0108]

[0109] In the formula, Q represents the dynamic range, P max is the maximum signal strength, P min is the minimum signal strength.

[0110] It should be noted that since the minimum amplitude in the time-amplitude waveform is usually submerged by noise and difficult to determine accurately, using the minimum amplitude for calculation will lead to an overestimation of the dynamic range; using the average noise level instead of the minimum amplitude can more accurately reflect the actual dynamic range of the optical fiber link.

[0111] S5) Calculate the light attenuation coefficient of each event segment:

[0112] Divide event segments: Divide the path trajectory of the optical fiber link into multiple event segments of different lengths according to the spatial resolution;

[0113] Specifically, for example: the distance segment of event 1 is 0.002 km; the distance segment of event 2 is 0.0006 km; and the distance segment of event 3 is 1.5 km.

[0114] According to the spatial resolution and dynamic range, the maximum signal intensity and the minimum signal intensity of each event segment were obtained.

[0115] Calculate the light attenuation coefficient of each event segment (unit: dB / km); the calculation formula is expressed as:

[0116]

[0117] In the formula, dB represents the light attenuation coefficient, ΔL is the spatial distance of the event segment, and P max is the maximum signal intensity of the event segment, P min is the minimum signal strength of this event segment.

[0118] It should be noted that signal strength refers to the signal strength of light scattering. Through high spatial resolution and high dynamic range, it is possible to accurately measure the signal strength distribution of light scattering in the optical fiber link and identify changes and anomalies in the signal strength of light scattering.

[0119] Optical attenuation coefficient: specifically refers to the rate of change of the signal intensity of light scattering at the spatial distance where an event occurs; it can quantitatively analyze the optical attenuation in the optical fiber link, identify the specific cause of optical attenuation, and optimize the performance and maintenance of the optical fiber network.

[0120] In practice, a fiber link usually contains multiple components and different types of losses, such as connectors, splices, fiber bends, etc. Each failure event will cause different degrees of attenuation of the optical signal.

[0121] The length of the event segment is usually determined by the spatial resolution of the system. The higher the spatial resolution, the shorter the event segment can be divided, so as to more accurately analyze the optical loss of each fault event and locate the fault point.

[0122] S6) Calculate the path trajectory information of the optical fiber link and its temperature and strain distribution information:

[0123] The distributed optical fiber sensing system uses the principles of Raman scattering or Brillouin scattering to monitor the environmental indicators of the optical fiber link in real time, measure the temperature and strain distribution information of the optical fiber link path trajectory, and obtain the connector distribution information in the optical fiber link path trajectory; it is used to distinguish the fault type as optical fiber fault or connector fault;

[0124] Specifically, the implementation steps are as follows:

[0125] According to the propagation speed of the optical signal in the optical fiber, the time delay information of the backscattered light obtained by the photon detector is converted into corresponding path trajectory information.

[0126] The backscattered light (Raman scattered light or Brillouin scattered light) from different positions of the optical fiber is received and analyzed using a spectrometer.

[0127] The spectral information is converted into corresponding temperature or strain values ​​using the demodulation algorithm of Raman scattering or Brillouin scattering.

[0128] The temperature or strain value at each position is matched with the trajectory path information, and the temperature and strain distribution diagram of the path trajectory of the optical fiber link is drawn.

[0129] S7) Fault identification and location:

[0130] Different types of fiber link faults will cause different degrees of optical attenuation, so the fault type of each event segment can be identified by analyzing the attenuation coefficient of the event segment.

[0131] According to the spatial resolution of event division and the path trajectory information of the optical fiber link, the specific location of the fault event on the optical fiber link is calculated.

[0132] Fiber link fault types include fiber breakage, fiber microbend / squeezing, and connector failure.

[0133] Specifically, a database of optical attenuation coefficient ranges for different types of optical fiber link faults is pre-established;

[0134] According to the path trace information of the event segment on the optical fiber link, such as optical fiber breakage, the fault point can be directly located.

[0135] For some faults that are difficult to locate accurately, such as optical fiber microbends, the approximate fault area can be located based on the spatial resolution of the event.

[0136] The following are common fixed-line broadband optical fiber link fault types, and their typical optical attenuation coefficient ranges are defined to build a database for reference in fault diagnosis:

[0137] Fault type: Attenuation coefficient (dB / km)

[0138] Fiber breakage:>3*10 -2 dB / km.

[0139] Fiber macrobend: 0.5-10*10 -3 dB / km.

[0140] Fiber microbending / extrusion: 0.1-5*10 -3 dB / km.

[0141] Fiber splicing point failure: 0.1-1*10 -3 dB / km.

[0142] Connector failure: 0.5-3*10 -3 dB.

[0143] The present invention provides an automatic analysis method for optical signal attenuation of a fixed broadband user optical fiber link, which combines distributed optical fiber sensing technology with photon counting OTDR to achieve comprehensive monitoring of the optical fiber link, and can not only monitor the impact of environmental factors, but also analyze the optical attenuation of the optical link itself. The single photon detector and TCSPC technical solution are used to detect extremely weak optical signals, improve the sensitivity and dynamic range of the system, and break through the technical bottleneck of traditional OTDR.

[0144] Combining the event segment division of segment space resolution and the path trajectory information of the optical fiber link, the fault point can be accurately located and the troubleshooting efficiency can be improved.

[0145] By calculating the optical attenuation coefficient of each event segment fault and matching it with the optical attenuation coefficient of typical type faults, the optical fiber link fault can be automatically judged and located, reducing operation and maintenance costs, ensuring the stable operation of the optical fiber link and providing users with high-quality network services.

[0146] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0147] In addition, each functional unit in the specific embodiment of the present application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units.

[0148] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk and other media that can store program code.

[0149] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specifically", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0150] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for automatically analyzing optical signal attenuation of a fixed broadband user optical fiber link, characterized in that: The following steps are involved: S1) System deployment: Select the fixed broadband user optical fiber link that needs to be monitored; A pulse laser is connected to one end of the optical fiber link to emit an optical pulse signal; A photon detector is connected to the other end of the optical fiber link to receive the backscattered light signal; S2) Signal excitation: Use a pulsed laser to periodically emit light pulses into the optical fiber link to stimulate the scattering effect of the optical fiber; S3) Signal detection: Optical signal processing: Using a photon detector to receive backscattered light signals in the optical fiber link and convert the optical signals into electrical signals; Time-correlated single photon counting technology is used to record the arrival time of each photon and accumulate photon counting data within multiple pulse cycles; The data is transmitted to a signal analyzer to construct a photon count-time histogram of the pulse signal; Electrical signal processing: Peak limiting and amplification of electrical signals using a voltage limiter circuit and a transimpedance amplifier or a commercial power limiter and a low noise amplifier; A digital storage oscilloscope is used to perform high-speed sampling and digitization of the amplified electrical signal; The data is transmitted to the signal analyzer to construct a time-amplitude waveform diagram of the pulse signal; S4) Signal analysis: Calculating the performance indicators of the optical fiber link by analyzing the photon count-time histogram and time-amplitude waveform of the pulse signal; the performance indicators include spatial resolution and dynamic range; S5) calculating the light attenuation coefficient of each event segment by spatial resolution and dynamic range; S6) calculating the path trajectory information of the optical fiber link through the data obtained by the photon detector; S7) Fault identification and location: The fault type of each event segment is identified by analyzing the attenuation coefficient of the event segment; According to the spatial resolution of event division and the path trajectory information of the optical fiber link, the specific location of the fault event on the optical fiber link is calculated.

2. The method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link according to claim 1, characterized in that: In step S1) system deployment, the optical fiber link includes an optical distribution network line or a fiber-to-the-home line.

3. The method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link according to claim 1, characterized in that: In step S1) system deployment, the pulse laser is a distributed feedback laser or an external cavity laser; The photon detector is a single-photon avalanche photodiode, a photomultiplier tube or a superconducting nanowire single-photon detector.

4. The method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link according to claim 1, characterized in that: In step S4) signal analysis, the step of calculating the spatial resolution includes: Select two adjacent and clearly distinguishable event peaks in the photon count-time histogram as an event segment; Convert the time axis to the distance axis: According to the propagation speed v of the optical signal in the optical fiber, convert the time interval Δt into the corresponding spatial distance ΔL; the conversion formula is as follows: LP=△L=v*△t / 2: In the formula, LP represents the spatial resolution, that is, the corresponding spatial distance ΔL; The spatial distance ΔL between two adjacent event peaks is the spatial resolution of the fiber link.

5. The method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link according to claim 1, characterized in that: In step S4) signal analysis, the step of calculating the dynamic range includes: When there is no signal input or the signal is very weak, the average noise power of the system output is measured. The average noise power at this time represents the minimum signal strength P that can be detected. min ; Identify the peak amplitude of the pulse signal in the time-amplitude waveform. The peak amplitude represents the maximum signal strength P. max ; The dynamic range can be expressed as the ratio of the maximum signal strength to the minimum signal strength, usually expressed in decibels (dB), and the calculation formula is: In the formula, Q represents the dynamic range, P max is the maximum signal strength, P min is the minimum signal strength.

6. The method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link according to claim 1, characterized in that: The specific implementation process of step S5) includes: According to the spatial resolution, the path trajectory of the optical fiber link is divided into multiple event segments of different lengths; According to the spatial resolution and dynamic range, the maximum signal intensity and the minimum signal intensity of each event segment are obtained; Calculate the light attenuation coefficient of each event segment; the calculation formula is expressed as: In the formula, dB represents the light attenuation coefficient, ΔL is the spatial distance of the event segment, and P max is the maximum signal intensity of the event segment, P min is the minimum signal strength of this event segment.

7. The method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link according to claim 1, characterized in that: In step S7) fault identification and location, the optical fiber link fault types include optical fiber breakage, optical fiber macrobend, optical fiber microbend / extrusion, optical fiber fusion point failure, and connector failure.

8. The method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link according to claim 1, characterized in that: The step S6) further comprises: Calculate the temperature and strain distribution information of the path trajectory of the optical fiber link; and obtain the connector distribution information in the path trajectory of the optical fiber link; used to distinguish the fault type as optical fiber fault or connector fault.

9. The method for automatically analyzing optical signal attenuation of a fixed-line broadband user optical fiber link according to claim 8, characterized in that: The steps for calculating the temperature and strain distribution information of the path trajectory of the optical fiber link are as follows: According to the propagation speed of the optical signal in the optical fiber, the time delay information of the backscattered light is converted into the corresponding trajectory path information; Receive backscattered light from different positions of the optical fiber and analyze it using a spectrometer; Using the demodulation algorithm of Raman scattering or Brillouin scattering, the spectral information is converted into the corresponding temperature or strain value; The temperature or strain value at each position is matched with the trajectory path information, and the temperature and strain distribution diagram of the path trajectory of the optical fiber link is drawn.

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