A kind of sending out submarine cable distributed optical fiber on-line monitoring device

Abstract

The application relates to a sending-out-sea-cable distributed optical fiber online monitoring device, which generates pump laser through a pump laser module; modulates the pump laser pulse by using an electro-optic modulator; amplifies the pump laser pulse through a first optical fiber amplifier; adjusts the polarization state of the pump laser through a polarization disturbance module; detects the backscattering signal through a photoelectric detector; collects the detected backscattering signal data by using a data acquisition module; measures the light frequency through a microwave frequency meter; controls the temperature and current of the pump laser through a control circuit; blocks the pump laser pulse through a one-way isolator; distributes the pump laser pulse through a Raman pump laser; couples the light signals through a plurality of optical fiber couplers; separates or combines the light signals of different wavelengths through a wavelength division multiplexer; and controls the paths of the pump laser pulse and the detection laser through a first optical switch and a second optical switch.

Description

TECHNICAL FIELD

[0001] The application relates to a kind of sending out sea cable distributed optical fiber online monitoring device, belongs to the field of optical fiber sensing. BACKGROUND

[0002] At present, offshore wind farm site resources have become scarce, and offshore wind power development has moved towards "deep sea". Deep sea wind power resources are abundant and have great development potential. The typical technical route of offshore wind power grid connection includes AC transmission and flexible DC transmission. AC transmission technology has technical and cost advantages in offshore wind farms, but in the application scenario of large-capacity and far-sea wind power grid connection, the capacitance effect of AC cable will greatly increase the reactive power loss and reduce the effective load capacity of the cable. Compared with AC transmission, flexible DC transmission technology uses DC cable transmission, avoids the problem of limited transmission distance caused by AC cable charging power, and has technical advantages such as effectively isolating the mutual influence between onshore AC power grid and offshore wind farm, providing stable grid-connected voltage for offshore wind farm, and flexible system operation mode regulation. It is currently recognized as the mainstream technology for deep-sea wind power transmission.

[0003] Distributed optical fiber monitoring of transmission cable is a distributed optical fiber sensing technology based on Brillouin scattering effect. Deep-sea wind power also has higher requirements for the effective measurement distance of transmission cable online monitoring. Measurement distance is a core indicator of distributed optical fiber sensor and a key for online monitoring of transmission cable in deep-sea wind power projects. The increase of measurement distance will cause two serious problems: 1) limited by optical fiber transmission loss, as the length of optical fiber increases, the backscattering signal of optical fiber decays exponentially with distance, and the scattered signal returned from the far end is too large to be detected due to too much loss, affecting the measurement accuracy of temperature, strain and other parameters; 2) limited by the nonlinearity of optical fiber, the longer the length of optical fiber, the smaller the power of narrow linewidth laser allowed to be transmitted in the optical fiber, which will directly lead to a significant reduction in the backscattering signal of the optical fiber, affecting the measurement accuracy of temperature, strain and other parameters. The measurement distance of single distributed optical fiber temperature and strain monitoring technology currently used at home and abroad is only 50-60 km, which cannot meet the monitoring requirements of deep-sea offshore wind power transmission cable.

[0004] The distributed optical fiber online monitoring device based on stimulated Brillouin scattering effect realizes distributed temperature and strain sensing by the interaction of pump light and probe light. In order to realize the control and frequency scanning of the pump light and the probe light, the existing distributed optical fiber online monitoring device sets the pump light source and the probe light source on one side of the sensing optical fiber, and the sensing optical fiber adopts a U-shaped back-and-forth configuration (loop structure). In this way, the pump light and the probe light need to pass through an optical fiber length twice the sensing distance to realize measurement. Specifically, if a sensing distance of 50km is to be realized, the pump light and the probe light need to pass through an optical fiber length of 100km, which not only wastes the energy of the pump light and the probe light and the measurement time, but more importantly, the input optical power of the pump light is limited with the increase of the optical fiber length, thereby affecting the measurement accuracy of the sensor.

[0005] The application number CN202111350139.5 "A submarine cable fault online diagnosis and positioning method based on optical fiber sensing technology" mentioned that the detection optical fiber is used to realize real-time online measurement of submarine cable strain data, and obtain submarine cable strain data information, which has the limitation of measurement distance. Compared with the present application, the advantages of the present application are: 1. In the single-pass relay amplifier of the offshore booster station, the blocking of the pulsed laser emitted by the pump laser is realized, which blocks the further transmission of the pulsed laser in the loop-back optical fiber, that is, the transmission distance of the pulsed laser is shortened, which means that the power of the pulsed laser can be improved and the repetition frequency of the pulsed laser can be improved. The former makes the scattering signal of the loop-back optical fiber stronger, and the latter makes the number of cumulative averages more in the same measurement time, both of which can effectively improve the effective detection distance; 2. An optical fiber amplifier EDFA is added in the middle of the loop-back optical fiber. Since the gain is relatively large, the power of the continuous laser emitted by the probe laser and entering the loop-back optical fiber can be greatly reduced. When the continuous laser transmitted in the opposite direction in the loop-back optical fiber reaches the optical fiber amplifier EDFA, the continuous laser is relayed and amplified, which compensates for the transmission loss of the continuous laser in the loop-back optical fiber; 3. The single-pass relay amplification technology is innovatively adopted to change the traditional single-end loop structure, realize relay blocking of the pump laser and relay amplification of the probe laser, effectively reduce the nonlinear effect and the transmission interval of the laser pulse, and increase the effective measurement distance by 1 times without sacrificing the spatial resolution and the measurement accuracy, thereby realizing 120km ultra-long distance submarine cable distributed optical fiber online monitoring. SUMMARY

[0006] In order to solve the problems existing in the prior art, the present application provides a submarine cable distributed optical fiber online monitoring device.

[0007] The technical scheme of the present application is as follows:

[0008] The application provides a submarine cable distributed optical fiber on-line monitoring device, which comprises a sensing optical fiber, a communication optical fiber, a single-pass relay amplifier and a monitoring host.

[0009] The single-pass relay amplifier is connected with one end of the sensing optical fiber and the communication optical fiber respectively, and the monitoring host is connected with the other end of the sensing optical fiber and the communication optical fiber respectively.

[0010] The single-pass relay amplifier is used for relaying and amplifying a probe laser.

[0011] The monitoring host is used for generating and processing monitoring signals, and collecting and analyzing monitoring data.

[0012] Preferably, the sensing optical fiber and the communication optical fiber are used for constructing a loop-back optical fiber optical path structure based on stimulated Brillouin scattering effect.

[0013] Preferably, the monitoring host is arranged in a land-based centralized control center, and comprises a pump laser module, a probe laser module, an electro-optic modulator EMO, an optical attenuator VOA, a first optical fiber amplifier EDFA1, a polarization scrambling module PS, a photoelectric detector, a data acquisition module, a microwave frequency meter, a control circuit, an optical fiber circulator, a first Raman pump laser, a first optical fiber coupler, a second optical fiber coupler, a third optical fiber coupler, a first wavelength division multiplexer, a first 1×N optical switch and a second 1×N optical switch.

[0014] Preferably, the single-pass relay amplifier is arranged in a sea-based booster station, and comprises a one-way isolator and a second optical fiber amplifier EDFA2.

[0015] As preferred, the pump laser module is used for generating pump laser; the probe laser module is used for amplifying backscattering signal generated by sensing fiber; the electro-optic modulator EOM is connected with the pump laser module and used for generating pump laser pulse with pulse width of 10-100 ns; the variable optical attenuator VOA is connected with the probe laser module and used for adjusting intensity of probe laser signal; the first fiber amplifier EDFA1 is connected with the sensing fiber and used for amplifying pump laser pulse; the polarization scrambler PS is connected with the variable optical attenuator VOA and used for adjusting polarization state of probe laser; the photoelectric detector is used for detecting backscattering signal; the data acquisition module is connected with the photoelectric detector and used for acquiring data; the microwave frequency meter is connected with the pump laser module and the probe laser module and used for measuring optical frequency; the control circuit is connected with the pump laser module and used for controlling temperature and current of pump laser; the first Raman pump laser is connected with the first wavelength division multiplexer WDM1 and used for distributedly enhancing pump laser pulse; the fiber couplers C1, C2 and C3 are used for coupling optical signals; the first wavelength division multiplexer WDM1 is used for combining pump laser pulses with different wavelengths and the first Raman pump laser; the first 1×N optical switch and the second 1×N optical switch are respectively used for controlling paths of pump laser pulse and probe laser.

[0016] As preferred, the unidirectional isolator is connected with the sensing fiber and the second fiber amplifier EDFA2 and used for preventing pump laser pulse from passing and allowing probe laser to pass.

[0017] As preferred, the single-pass relay amplifier further comprises a second wavelength division multiplexer WDM2 and a second Raman pump laser, the second wavelength division multiplexer WDM2 is used for combining probe laser with different wavelengths and the second Raman pump laser, and the second Raman pump laser is used for distributedly enhancing probe laser.

[0018] The application further provides a method for sending out a submarine cable distributed optical fiber on-line monitoring method, and the method comprises the following steps:

[0019] The pump laser generated by the pump laser module is branched by the fiber coupler C1, the probe laser generated by the probe laser module is branched by the fiber coupler C2, and the pump laser and the probe laser enter the fiber coupler C3 together and are detected by the microwave frequency meter; the temperature and the current of the pump laser module are controlled by the control circuit, the frequency of the pump laser is tuned, so that the frequency difference between the pump laser and the probe laser covers the Brillouin spectrum of the sensing optical fiber; the pump laser generated by the pump laser module is modulated into pump laser pulses with a pulse width of 10-100 ns by the electro-optical modulator EOM; the pump laser pulses are amplified by the first optical fiber amplifier EDFA1; and the pump laser pulses enter the sensing optical fiber in turn through the optical fiber circulator CIR, the first wavelength division multiplexer WDM1 and the first 1xN optical switch, and are blocked after reaching the isolator of the single-pass relay amplifier; the probe laser generated by the probe laser module is adjusted in polarization state after the probe laser passes through the optical attenuator VOA and the polarization disturbance module PS, enters the communication optical fiber through the second 1xN optical switch, and the probe laser is amplified by the second optical fiber amplifier EDFA2 of the single-pass relay amplifier; the probe laser enters the sensing optical fiber through the isolator, and is converted into an electrical signal by the photoelectric detector after passing through the first 1xN optical switch, the first wavelength division multiplexer WDM1 and the optical fiber circulator CIR, and is collected by the data acquisition module; the first Raman pump laser 1 realizes distributed forward enhanced pump laser pulses through the first wavelength division multiplexer WDM1; the second Raman pump laser 2 realizes distributed reverse enhanced pump laser pulses through the second wavelength division multiplexer WDM2; the paths of the pump laser pulses and the probe laser are controlled by the first 1xN optical switch and the second 1xN optical switch, and multi-channel measurement is realized.

[0020] The present application has the following beneficial effects:

[0021] 1、The present application realizes the blocking of the pulse laser emitted by the pump laser in the single-pass relay amplifier of the offshore booster station, blocks the further transmission of the pulse laser in the loopback optical fiber, that is, shortens the transmission distance of the pulse laser, which means that the power of the pulse laser can be improved and the repetition frequency of the pulse laser can be improved, the former makes the scattering signal of the loopback optical fiber stronger, and the latter makes the number of cumulative averages more in the same measurement time, both of which can effectively improve the effective detection distance.

[0022] 2、The present application increases the optical fiber amplifier EDFA in the middle of the loopback optical fiber, and because the gain is relatively large, the power of the continuous laser emitted by the probe laser and entering the loopback optical fiber can be reduced by a large margin; when the continuous laser transmitted in the reverse direction in the loopback optical fiber reaches the optical fiber amplifier EDFA, the continuous laser is relayed and amplified, and the transmission loss of the continuous laser in the loopback optical fiber is compensated.

[0023] 3、The application changes the traditional single-end loop structure, innovatively adopts single-pass relay amplification technology, realizes pump laser relay blocking and detection laser relay amplification, effectively reduces nonlinear effects and laser pulse transmission interval, can increase 1 times effective measurement distance without sacrificing spatial resolution and measurement accuracy, and realizes 120km ultra-long distance submarine cable distributed optical fiber online monitoring. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is an online monitoring device schematic diagram of the application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0026] It should be understood that the step numbers used herein are only for the convenience of description, and are not limited to the execution sequence of the steps.

[0027] It should be understood that the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in the specification and the appended claims of the application, unless otherwise clear from the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0028] The terms "include" and "contain" indicate the presence of the described features, whole, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0029] The term "and / or" means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0030] Embodiment one:

[0031] This embodiment refers to Figure 1 A submarine cable distributed optical fiber online monitoring device, characterized in that it comprises a sensing optical fiber, a communication optical fiber, a single-pass relay amplifier and a monitoring host;

[0032] The single-pass relay amplifier is connected with one end of the sensing optical fiber and the communication optical fiber respectively; the monitoring host is connected with the other end of the sensing optical fiber and the communication optical fiber respectively;

[0033] The single-pass relay amplifier is used for relaying and amplifying the probe laser;

[0034] The monitoring host is used for generating and processing monitoring signals, and collecting and analyzing monitoring data.

[0035] As a preferred embodiment of the present embodiment, the sensing fiber and the communication fiber are used to construct a loop-back fiber optical path structure based on stimulated Brillouin scattering effect.

[0036] As a preferred embodiment of the present embodiment, the monitoring host is arranged in a land centralized control center, and includes a pump laser module, a probe laser module, an electro-optical modulator EOM, an optical attenuator VOA, a first fiber amplifier EDFA1, a polarization scrambling module PS, a photoelectric detector, a data acquisition module, a microwave frequency meter, a control circuit, a fiber loop, a first Raman pump laser, a first fiber coupler, a second fiber coupler, a third fiber coupler, a first wavelength division multiplexer, a first 1×N optical switch and a second 1×N optical switch.

[0037] As a preferred embodiment of the present embodiment, the single-pass relay amplifier is arranged in a sea booster station, and includes a unidirectional isolator and a second fiber amplifier EDFA2.

[0038] As a preferred embodiment of the present embodiment, the pump laser module is used for generating pump laser; the probe laser module is used for amplifying backscattering signals generated by the sensing fiber; the electro-optical modulator EOM, connected with the pump laser module, is used for generating pump laser pulses with a pulse width of 10-100 ns; the optical attenuator VOA, connected with the probe laser module, is used for adjusting the intensity of the probe laser signal; the first fiber amplifier EDFA1, connected with the sensing fiber, is used for amplifying the pump laser pulses; the polarization scrambling module PS, connected with the optical attenuator VOA, is used for adjusting the polarization state of the probe laser; the photoelectric detector is used for detecting backscattering signals; the data acquisition module, connected with the photoelectric detector, is used for acquiring data; the microwave frequency meter, connected with the pump laser module and the probe laser module, is used for measuring optical frequency; the control circuit, connected with the pump laser module, is used for controlling the temperature and current of the pump laser; the first Raman pump laser, connected with the first wavelength division multiplexer WDM1, is used for distributedly enhancing the pump laser pulses; the fiber couplers C1, C2 and C3 are used for coupling optical signals; the first wavelength division multiplexer WDM1 is used for merging pump laser pulses and the first Raman pump laser of different wavelengths; the first 1×N optical switch and the second 1×N optical switch are respectively used for controlling the paths of the pump laser pulses and the probe laser.

[0039] As a preferred embodiment of the present embodiment, the unidirectional isolator, connected with the sensing optical fiber and the second optical fiber amplifier EDFA2, is used to prevent the pump laser pulse from passing through and allow the probe laser to pass through.

[0040] As a preferred embodiment of the present embodiment, the unidirectional isolator, connected with the sensing optical fiber and the second optical fiber amplifier EDFA2, is used to prevent the pump laser pulse from passing through and allow the probe laser to pass through.

[0041] As a preferred embodiment of the present embodiment, the unidirectional isolator, connected with the sensing optical fiber and the second optical fiber amplifier EDFA2, is used to prevent the pump laser pulse from passing through and allow the probe laser to pass through.

[0042] As a preferred embodiment of the present embodiment, the unidirectional isolator, connected with the sensing optical fiber and the second optical fiber amplifier EDFA2, is used to prevent the pump laser pulse from passing through and allow the probe laser to pass through.

[0043] The present embodiment also provides a method for distributing optical fiber online monitoring of outgoing submarine cable, which comprises the following steps:

[0044] The pump laser generated by the pump laser module is split by the fiber coupler C1, the probe laser generated by the probe laser module is split by the fiber coupler C2, and the two enter the fiber coupler C3 together and are detected by the microwave frequency meter; the temperature and current of the pump laser module are controlled by the control circuit to tune the frequency of the pump laser, so that the frequency difference between the pump laser and the probe laser covers the Brillouin spectrum of the sensing fiber; the pump laser generated by the pump laser module is modulated into pump laser pulses with a pulse width of 10-100 ns by the electro-optical modulator EOM; the pump laser pulses are amplified by the first optical fiber amplifier EDFA1; and the pump laser pulses enter the sensing fiber in turn through the optical fiber circulator CIR, the first wavelength division multiplexer WDM1 and the first 1×N optical switch, and are blocked after reaching the isolator of the single-pass relay amplifier; the probe laser generated by the probe laser module is adjusted in polarization state after the optical attenuator VOA and the polarization scrambling module PS, enters the communication fiber through the second 1×N optical switch, and the probe laser is amplified by the second optical fiber amplifier EDFA2 of the single-pass relay amplifier; after passing through the isolator, the probe laser enters the sensing fiber, and after passing through the first 1×N optical switch, the first wavelength division multiplexer WDM1 and the optical fiber circulator CIR, the probe laser is converted into an electrical signal by the photoelectric detector, and is collected by the data acquisition module; the first Raman pump laser 1 passes through the first wavelength division multiplexer WDM1 to realize distributed forward enhanced pump laser pulses; the second Raman pump laser 2 passes through the second wavelength division multiplexer WDM2 to realize distributed reverse enhanced pump laser pulses; the paths of the pump laser pulses and the probe laser are controlled by the first 1×N optical switch and the second 1×N optical switch to realize multi-channel measurement.

[0045] In the embodiments of the present application, "at least one" means one or more, and "multiple" means two or more. The association relationship of the associated objects is described by "and / or", which means that there can be three kinds of relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects. "At least one of the following" and the like means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b and c can mean: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, and c can be single or multiple.

[0046] Those of ordinary skill in the art can realize that the units and algorithm steps described in the embodiments disclosed herein can be realized by electronic hardware, computer software and a combination of electronic hardware and computer software. Whether the functions are realized in hardware or software mode depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0047] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the system, device and unit described above can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0048] In several embodiments provided in the present application, any function, if realized in the form of a software function unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the parts that make contributions to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (Read-Only Memory; hereinafter referred to as: ROM), a random access memory (Random Access Memory; hereinafter referred to as: RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0049] The above is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent flow transformation, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A distributed optical fiber on-line monitoring device for outgoing submarine cable, characterized in that, The device comprises a sensing fiber, a communication fiber, a single-pass relay amplifier and a monitoring host; The single-pass relay amplifier is connected with one end of the sensing fiber and the communication fiber respectively, and the monitoring host is connected with the other end of the sensing fiber and the communication fiber respectively; The single-pass relay amplifier is used for relay amplifying the probe laser; The monitoring host is used for generating and processing monitoring signals, and collecting and analyzing monitoring data; The sensing fiber and the communication fiber are used for constructing a loop-back fiber optical path structure based on stimulated Brillouin scattering effect; The monitoring host is arranged in a land-based control center and comprises a pump laser module, a probe laser module, an electro-optical modulator, an optical attenuator, a first fiber amplifier, a polarization disturbance module, a photoelectric detector, a data acquisition module, a microwave frequency meter, a control circuit, a fiber loop, a first Raman pump laser, a first fiber coupler, a second fiber coupler, a third fiber coupler, a first wavelength division multiplexer, a first optical switch and a second optical switch; The single-pass relay amplifier is arranged in a sea-based booster station and comprises a one-way isolator and a second fiber amplifier; The one-way isolator is connected with the sensing fiber and the second fiber amplifier and is used for preventing the pump laser pulse from passing through and allowing the probe laser to pass through; The single-pass relay amplifier further comprises a second wavelength division multiplexer and a second Raman pump laser, the second wavelength division multiplexer is used for merging probe lasers of different wavelengths and the second Raman pump laser is used for distributedly enhancing the probe laser.

2. The device according to claim 1, wherein the pump laser module is used for generating pump laser, the probe laser module is used for amplifying the back Brillouin scattering signal generated by the sensing fiber, the electro-optical modulator is connected with the pump laser module and is used for generating pump laser pulse with a pulse width of 10-100 ns, the optical attenuator is connected with the probe laser module and is used for adjusting the intensity of the probe laser signal, the first fiber amplifier is connected with the sensing fiber and is used for amplifying the pump laser pulse, the polarization disturbance module is connected with the optical attenuator and is used for adjusting the polarization state of the probe laser, the photoelectric detector is used for detecting the back scattering signal, the data acquisition module is connected with the photoelectric detector and is used for acquiring data, the microwave frequency meter is connected with the pump laser module and the probe laser module and is used for measuring the optical frequency, the control circuit is connected with the pump laser module and is used for controlling the temperature and current of the pump laser, the first Raman pump laser is connected with the first wavelength division multiplexer and is used for distributedly enhancing the pump laser pulse, the fiber coupler is used for coupling optical signals, the first wavelength division multiplexer is used for merging pump laser pulses of different wavelengths and the first Raman pump laser, and the first optical switch and the second optical switch are respectively used for controlling the paths of the pump laser pulse and the probe laser. The method comprises the following steps:

3. A method for monitoring a submarine cable distribution optical fiber online, based on the submarine cable distribution optical fiber online monitoring device of any one of claims 1-2, characterized in that, ​ The pump laser generated by the pump laser module is split by the first fiber coupler, the probe laser generated by the probe laser module is split by the second fiber coupler, and they enter the third fiber coupler together and are detected by the microwave frequency meter; the temperature and current of the pump laser module are controlled by the control circuit to tune the frequency of the pump laser, so that the frequency difference between the pump laser and the probe laser covers the Brillouin spectrum of the sensing optical fiber; the pump laser generated by the pump laser module is modulated into pump laser pulses with a pulse width of 10-100 ns by the electro-optical modulator; the pump laser pulses are amplified by the first fiber amplifier, and then enter the sensing optical fiber through the optical fiber circulator, the first wavelength division multiplexer and the first optical switch, and are blocked after reaching the isolator of the single-pass relay amplifier; the probe laser generated by the probe laser module is adjusted in polarization state by the optical attenuator and the polarization disturbance module, enters the communication optical fiber through the second optical switch, and is amplified by the second fiber amplifier of the single-pass relay amplifier; after passing through the isolator, it enters the sensing optical fiber, and is converted into an electrical signal by the photoelectric detector after passing through the first optical switch, the first wavelength division multiplexer and the optical fiber circulator, and is collected by the data acquisition module; the first Raman pump laser passes through the first wavelength division multiplexer to realize distributed forward enhanced pump laser pulses; the second Raman pump laser passes through the second wavelength division multiplexer to realize distributed reverse enhanced pump laser pulses; the paths of the pump laser pulses and the probe laser are controlled by the first optical switch and the second optical switch to realize multi-channel measurement.

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