High-speed rail track fracture fault detection system and method based on photon fusion detection technology

Abstract

The invention provides a high-speed rail track fracture fault detection system and method based on a photon fusion detection technology, and belongs to the technical field of distributed optical fiber sensing. The defects of the traditional distributed sound wave sensing technology are overcome; the system comprises a photoinduced ultrasonic module, a distributed sound wave sensing module, a data processing module and an optical cable laid on the side wall of a track. By introducing the photoinduced ultrasonic technology, broken rail monitoring and fault positioning in the non-operation period of the high-speed rail are achieved. According to the system, a narrow-bandwidth laser with the wavelength of 1550 nm is adopted as a light source, an acousto-optic modulator is added to generate pulse laser which serves as a light source for sound wave excitation and sound wave detection, meanwhile, a plurality of one-to-three single-mode optical fibers are combined to emit laser beams to a track to generate ultrasonic waves, and multi-point monitoring is achieved. When it is detected that the high-speed railway track is broken, the system can give an alarm in time. The overall structure of the system is good in applicability, high in anti-interference capability, and lower in hardware cost compared with a multi-laser scheme.

Description

Technical Field

[0001] The present application relates to the field of distributed optical fiber sensing technology, and in particular to a high-speed railway track fracture fault detection system and method based on photon fusion detection technology. Background Art

[0002] my country's rail transit industry is developing rapidly. However, as high-speed railways gain years of operation, operational safety and quality issues caused by track fractures are gradually emerging. Factors such as friction and collisions during long-term operation can cause deformation and even fractures in the track structure. This not only affects passenger comfort but can also damage vehicles and even endanger driving safety. Therefore, the need for real-time monitoring of track fractures is becoming increasingly urgent. Monitoring and fault location for track fractures have become a crucial technical means to ensure the safe operation of high-speed railways.

[0003] In recent years, distributed acoustic sensing (DAS) technology has been increasingly adopted for track monitoring. Using optical fiber to sense vibration signals, it enables passive monitoring of track conditions. However, DAS technology is limited by the influence of ambient noise excitation sources and lacks sensitivity to small rail cracks. Abnormal acoustic signals caused by broken rails can typically only be detected when a train is in motion. However, when high-speed trains operate over sections of track with broken rails, this poses a serious potential safety hazard. Therefore, early identification and early warning of high-speed rail broken rails using DAS technology during non-operating periods has become a critical technical challenge that needs to be addressed in the rail transit sector.

[0004] To overcome these bottlenecks, photoacoustic technology, as an active excitation method, has gradually gained attention. This technology uses pulsed lasers to excite materials to generate ultrasonic waves. The DAS system can then demodulate the acoustic signal based on the propagation characteristics of the sound waves and determine if there are any fractures in the track. Therefore, it is necessary to explore a track measurement system that combines photoacoustic technology with distributed acoustic sensing technology. Summary of the Invention

[0005] In order to overcome the shortcomings of traditional distributed acoustic wave sensing technology, this application proposes a high-speed railway track fracture fault detection system and method based on photon fusion detection technology. By introducing photo-induced ultrasonic technology, broken rail monitoring and fault location can be realized during the non-operating period of high-speed railway.

[0006] The technical solution adopted in this application is: a high-speed railway track fracture fault detection system based on photon fusion detection technology, including a photo-induced ultrasonic module, a distributed acoustic wave sensing module, a data processing module and an optical cable laid on the track side wall; The distributed acoustic wave sensing module includes a narrow-bandwidth laser, a first isolator, a first fiber coupler, a first polarization controller, a pulse generator, an acousto-optic modulator, a second fiber coupler, a second polarization controller, a first erbium-doped fiber amplifier, a first wavelength division multiplexer, a circulator, a second wavelength division multiplexer, and a third fiber coupler. The output end of the narrow-linewidth laser is connected to the input end of the first isolator; the output end of the first isolator is connected to the input end a of the first fiber coupler; the output end b of the first fiber coupler is connected to the input end of the first polarization controller, and the output end of the first polarization controller is connected to the input end b of the third fiber coupler. The c output end of the first fiber coupler is connected to the input end of the acousto-optic modulator; the output end of the pulse generator is connected to the input end of the acousto-optic modulator; the output end of the acousto-optic modulator is connected to the a input end of the second fiber coupler; the b output end of the second fiber coupler is connected to the input end of the second polarization controller; and the c output end of the second fiber coupler is connected to the input end of the photo-ultrasound module. The output end of the second polarization controller is connected to the input end of the first erbium-doped fiber amplifier; the output end of the first erbium-doped fiber amplifier is connected to the input end of the first wavelength division multiplexer; the output end of the first wavelength division multiplexer is connected to the input end a of the circulator; the output end b of the circulator is connected to the input end of the second wavelength division multiplexer; the output end of the second wavelength division multiplexer is connected to the input end c of the third fiber coupler; the output end a of the third fiber coupler is connected to the input end of the data processing module; The c output end of the circulator is connected to the input end of the optical cable; the output end of the optical cable is connected to the input end of the second isolator.

[0007] Furthermore, the photo-ultrasound module includes a second erbium-doped fiber amplifier and at least one 1-to-n single-mode fiber. The c output end of the second fiber coupler is connected to the input end of the second erbium-doped fiber amplifier, the output end of the second erbium-doped fiber amplifier is connected to the input end of the 1-to-n single-mode fiber, and the n output ends of the 1-to-n single-mode fiber respectively output laser light after passing through a focusing lens and a filter.

[0008] Furthermore, the photo-ultrasound module also includes a fourth fiber coupler, the output end of the second erbium-doped fiber amplifier is connected to the input end a of the fourth fiber coupler, and the output ends b and c of the fourth fiber coupler are respectively connected to the input end of a 1-to-n single-mode fiber.

[0009] Furthermore, the 1-to-n single-mode optical fiber adopts a split single-mode optical fiber, including a first 1-to-3 single-mode optical fiber and a second 1-to-3 single-mode optical fiber, and the b output end of the fourth optical fiber coupler is connected to the input end of the first 1-to-3 single-mode optical fiber; the first 1-to-3 single-mode optical fiber emits three laser beams, the first laser beam is focused by a first focusing lens and then filtered out invalid optical signals by a first filter, the second laser beam is focused by a second focusing lens and then filtered out invalid optical signals by a second filter, and the third laser beam is focused by a third focusing lens and then filtered out invalid optical signals by a third filter; The c output end of the fourth optical fiber coupler is connected to the input end of a second 1-to-3 single-mode optical fiber. The second 1-to-3 single-mode optical fiber emits three laser beams. The first laser beam is focused by a fourth focusing lens and then filtered out by a fourth filter to remove invalid optical signals. The second laser beam is focused by a fifth focusing lens and then filtered out by a fifth filter to remove invalid optical signals. The third laser beam is focused by a sixth focusing lens and then filtered out by a sixth filter to remove invalid optical signals. After the laser signals are irradiated by the laser spot track coating on the track, they are absorbed into the track to generate ultrasonic waves, which are detected by the optical cable.

[0010] Furthermore, the data processing module includes a photoelectric converter, a data acquisition card and a computer, the output end a of the third optical fiber coupler is connected to the input end of the photoelectric converter, the output end of the photoelectric converter is connected to the input end of the data acquisition card; the output end of the data acquisition card is connected to the input end of the computer.

[0011] Furthermore, the first fiber coupler adopts a fiber coupler with a coupling ratio of 1:99, wherein 1% of the light is input to the first polarization controller and 99% of the light is input to the acousto-optic modulator.

[0012] Furthermore, the second optical fiber coupler adopts an optical fiber coupler with a coupling ratio of 50:50.

[0013] A high-speed railway track fracture fault detection method based on photon fusion detection technology, using the high-speed railway track fracture fault detection system based on photon fusion detection technology, includes the following steps: S1: The narrow-linewidth laser emits a continuous narrow-linewidth laser, which is stabilized by the first isolator and then input into the first fiber coupler. The first fiber coupler splits the laser into two parts, 1% and 99%. The 1% light is input into the first polarization controller, and the 99% light is input into the acousto-optic modulator to modulate the continuous light into pulsed light. The first polarization controller is used to adjust the polarization state of the light and transmit it to the third fiber coupler. The pulse generator generates pulses and inputs them into the acousto-optic modulator. The acousto-optic modulator inputs the modulated pulsed light into the second fiber coupler. The second fiber coupler splits the light into two parts, 50% and 50%, of which the 50% part is input into the second polarization controller to adjust the polarization state of the light. S2: The light regulated by the second polarization controller is input into the first erbium-doped fiber amplifier for amplification and then input into the first wavelength division multiplexer. From the first wavelength division multiplexer, the optical signal is input into the a input port of the circulator and then transmitted from the c output port of the circulator to the optical cable used to monitor the acoustic wave signal transmitted from the track. S3: The second fiber coupler inputs the remaining 99% of the pulsed laser into the second erbium-doped fiber amplifier for amplification, and then inputs the amplified optical signal into a 1-to-n single-mode fiber to emit n laser beams; S4: n laser beams are focused and filtered out of invalid optical signals before being irradiated onto the track, where they are absorbed by the track and stimulated to vibrate and generate ultrasonic waves. The optical cable laid on the side wall of the track senses the ultrasonic signal through the photoelastic effect, causing the photons in the optical cable to undergo Rayleigh backscattering. The backscattered light passes through the second isolator to eliminate possible Fresnel reflections and reduce interference, and then returns to the circulator. It enters the second wavelength division multiplexer through the b output end of the circulator to separate light of different wavelengths. The optical signal separated by the second wavelength division multiplexer and the biased local oscillator light output by the first polarization controller are coupled through the third optical fiber coupler and input into the data processing module for data processing to obtain fault location information of the track abnormality.

[0014] Furthermore, in step S4, a laser dot track coating is coated on the track, and n laser beams are focused, invalid light signals are filtered out, and then irradiated onto the laser dot track coating coated on the track and enhanced by the laser dot track coating.

[0015] Furthermore, the signal coupled by the third optical fiber coupler is input into the photoelectric converter, which converts the optical signal into an electrical signal and enters the data acquisition card; the data acquisition card inputs the collected and processed data into the computer for further processing; when the system detects an abnormality in the track, the computer will issue an abnormality alarm and provide fault location information.

[0016] The beneficial effects of this application compared to the prior art are: 1. This application uses photoacoustic technology to actively emit controllable laser pulses, which can locally excite high-frequency ultrasonic waves on the track surface. Normally, it is necessary to rely on acoustic signals from high-speed rail operation to provide feedback on the track structure status. However, photoacoustic technology breaks through the limitations of traditional DAS systems that rely on passive monitoring of environmental noise and can actively generate acoustic excitation. When sound waves encounter cracks during propagation, they produce reflections, scattering, and mode conversions due to material discontinuities. The DAS system captures these perturbation signals through optical fibers and can detect tiny surface cracks and internal defects. The detection efficiency and accuracy are higher than traditional manual inspections.

[0017] 2. This application uses a distributed acoustic wave sensing system. Traditional methods for detecting track fractures often rely on manual inspections and are unable to achieve comprehensive and efficient monitoring. In contrast, the distributed acoustic wave sensing system uses optical fiber laid across the entire track, combined with the multiple excitation points of the photoacoustic module, to monitor the acoustic wave signals transmitted from the track in real time using optical fiber, thereby accurately capturing subtle changes in the track structure. At the same time, the distributed acoustic wave sensing system can also capture relevant vibration information in real time during the high-speed rail operation period, thereby more accurately detecting the structural status of the track.

[0018] 3. This application is based on a distributed acoustic wave sensing system and combines photoacoustic technology to perform fault detection for track fracture problems. Photoacoustic technology provides active and controllable sound source excitation to generate standardized detection signals to eliminate environmental interference; the DAS system passively senses the propagation characteristics of sound waves through optical fiber sensing to achieve all-weather vibration monitoring. The two work together to build an "excitation-propagation-perception" closed loop, and combined with subsequent algorithms, they can dynamically distinguish between interference events such as high-speed rail passing noise and deformation and real broken rail signals. The system actively stimulates acoustic wave scanning during the non-operating period of the high-speed rail, and combines the passive monitoring data during the daytime operating period to predict the trend of crack expansion, providing a quantitative basis for track maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present application will be further described below with reference to the accompanying drawings: Figure 1 A schematic structural diagram of a high-speed railway track fracture fault detection system based on photon fusion detection technology provided in an embodiment of the present application.

[0020] In the figure: 1 is a narrow bandwidth laser, 2 is a first isolator, 3 is a first fiber coupler, 4 is a first polarization controller, 5 is a pulse generator, 6 is an acousto-optic modulator, 7 is a second fiber coupler, 8 is a second polarization controller, 9 is a first erbium-doped fiber amplifier, 10 is a first wavelength division multiplexer, 11 is a circulator, 12 is a second wavelength division multiplexer, 13 is a third fiber coupler, 14 is a photoelectric converter, 15 is a data acquisition card, 16 is a computer, 17 is a second erbium-doped fiber amplifier, 18 is a fourth fiber coupler, 19 is a first wavelength division multiplexer, 20 is a second wavelength division multiplexer, 21 is a second wavelength division multiplexer, 22 is a second wavelength division multiplexer, 23 is a third fiber coupler, 24 is a first wavelength division multiplexer, 25 is a second wavelength division multiplexer, 26 is a second wavelength division multiplexer, 27 is a second wavelength division multiplexer, 28 is a second wavelength division multiplexer, 29 is a second wavelength division multiplexer, 30 is a second wavelength division multiplexer, 31 is a second wavelength division multiplexer, 32 is a second wavelength division multiplexer, 33 is a third fiber coupler, 34 is a first wavelength division multiplexer, 35 is a second wavelength division multiplexer, 36 is a second wavelength division multiplexer, 37 is a second wavelength division multiplexer, 38 is a second wavelength division multiplexer, 39 is a second wavelength division multiplexer, 40 is a second wavelength division multiplexer, 41 is a second wavelength division multiplexer, 42 is a second wavelength division multiplexer, 43 is a second wavelength division multiplexer, 44 is a second wavelength division multiplexer, 45 is a second wavelength division multiplexer, 46 is a 9 is the first 1-to-3 single-mode optical fiber, 20 is the second 1-to-3 single-mode optical fiber, 21 is the first focusing lens, 22 is the second focusing lens, 23 is the third focusing lens, 24 is the fourth focusing lens, 25 is the fifth focusing lens, 26 is the sixth focusing lens, 27 is the first filter, 28 is the second filter, 29 is the third filter, 30 is the fourth filter, 31 is the fifth filter, 32 is the sixth filter, 33 is the optical cable, 34 is the second isolator, 35 is the laser dot track coating, 36 is the track, and 37 is the high-speed rail body. DETAILED DESCRIPTION

[0021] like Figure 1As shown, the present application provides a high-speed railway track fracture fault detection system based on photon fusion detection technology, including a narrow bandwidth laser 1, a first isolator 2, a first fiber coupler 3, a first polarization controller 4, a pulse generator 5, an acousto-optic modulator 6, a second fiber coupler 7, a second polarization controller 8, a first erbium-doped fiber amplifier 9, a first wavelength division multiplexer 10, a circulator 11, a second wavelength division multiplexer 12, a third fiber coupler 13, an optoelectronic converter 14, a data acquisition card 15, a computer 16, A second erbium-doped fiber amplifier 17, a fourth fiber coupler 18, a first 1-to-3 single-mode fiber 19, a second 1-to-3 single-mode fiber 20, a first focusing lens 21, a second focusing lens 22, a third focusing lens 23, a fourth focusing lens 24, a fifth focusing lens 25, a sixth focusing lens 26, a first filter 27, a second filter 28, a third filter 29, a fourth filter 30, a fifth filter 31, a sixth filter 32, an optical cable 33, a second isolator 34 and a laser spot track coating 35.

[0022] Among them, the output end of the narrow linewidth laser 1 is connected to the input end of the first isolator 2; the output end of the first isolator 2 is connected to the a input end of the first fiber coupler 3; the b output end of the first fiber coupler 3 is connected to the input end of the first polarization controller 4, and the output end of the first polarization controller 4 is connected to the b input end of the third fiber coupler 13.

[0023] The c output end of the first fiber coupler 3 is connected to the input end of the acousto-optic modulator 6; the output end of the pulse generator 5 is connected to the input end of the acousto-optic modulator 6; the output end of the acousto-optic modulator 6 is connected to the a input end of the second fiber coupler 7; the b output end of the second fiber coupler 7 is connected to the input end of the second polarization controller 8; the output end of the second polarization controller 8 is connected to the input end of the first erbium-doped fiber amplifier 9; the output end of the first erbium-doped fiber amplifier 9 is connected to the input end of the first wavelength division multiplexer 10; the output end of the first wavelength division multiplexer 10 is connected to the a input end of the circulator 11; the b output end of the circulator 11 is connected to the input end of the second wavelength division multiplexer 12; the output end of the second wavelength division multiplexer 12 is connected to the c input end of the third fiber coupler 13; the a output end of the third fiber coupler 13 is connected to the input end of the photoelectric converter 14; the output end of the photoelectric converter 14 is connected to the input end of the data acquisition card 15; and the output end of the data acquisition card 15 is connected to the input end of the computer 16.

[0024] The c output end of the second fiber coupler 7 is connected to the input end of the second erbium-doped fiber amplifier 17; the output end of the second erbium-doped fiber amplifier 17 is connected to the a input end of the fourth fiber coupler 18; the b output end of the fourth fiber coupler 18 is connected to the input end of the first 1-to-3 single-mode fiber 19; the first 1-to-3 single-mode fiber 19 emits three laser beams. The first laser beam is focused by the first focusing lens 21 and then filtered out by the first filter 27 to remove invalid optical signals. The second laser beam is focused by the second focusing lens 22 and then filtered out by the second filter 28 to remove invalid optical signals. The third laser beam is focused by the third focusing lens 23 and then filtered out by the third filter 29 to remove invalid optical signals.

[0025] The c-output end of the fourth fiber coupler 18 is connected to the input end of a second 1-to-3 single-mode fiber 20. The second 1-to-3 single-mode fiber 20 emits three laser beams. The first laser beam is focused by a fourth focusing lens 24 and filtered out by a fourth filter 30 to remove invalid optical signals. The second laser beam is focused by a fifth focusing lens 25 and filtered out by a fifth filter 31 to remove invalid optical signals. The third laser beam is focused by a sixth focusing lens 26 and filtered out by a sixth filter 32 to remove invalid optical signals. After the laser signals are irradiated by a laser spot track coating 35 coated on the track, they are absorbed into the track 36 and generate ultrasonic waves, which are detected by an optical cable 33. The c-output end of the circulator 11 is connected to the input end of an optical cable 33. The output end of the optical cable 33 is connected to the input end of a second isolator 34. The optical cable 33 is laid on the side wall of the track 36.

[0026] In the embodiment of the present application, the laser point track coating 35 is a coating that can achieve laser absorption, and is used to enhance the absorption of laser by the track (36).

[0027] The method for detecting high-speed railway track fracture faults based on the above system includes the following steps: S1: The narrow-linewidth laser 1 emits a continuous narrow-linewidth laser with a central wavelength of 1550nm, which is input to the input end of the first isolator 2 to stabilize the optical signal; the output end of the first isolator 2 is connected to the a input end of the first fiber coupler 3; the first fiber coupler 3 divides the laser into two parts, 1% and 99%, the 1% light is input to the input end of the first polarization controller 4, and the 99% light is input to the acousto-optic modulator 6 to modulate the continuous light into pulsed light; the first polarization controller 4 is used to adjust the polarization state of the light and transmit it to the b input end of the third fiber coupler 13; the pulse generator 5 generates a pulse and inputs it to the acousto-optic modulator 6; the acousto-optic modulator 6 inputs the modulated pulse light into the second fiber coupler 7; the second fiber coupler 7 divides the light into two parts, 50% and 50%, of which the 50% part is input to the second polarization controller 8 to adjust the polarization state of the light.

[0028] S2: The light regulated by the second polarization controller 8 is input to the first erbium-doped fiber amplifier 9, which amplifies the light and then inputs it to the input end of the first wavelength division multiplexer 10; the optical signal is input from the first wavelength division multiplexer 10 to the a input end of the circulator 11, and then transmitted from the c output end of the circulator 11 to the optical cable 33. The optical cable 33 is laid on the side wall of the track 36 to monitor the acoustic wave signal transmitted from the track. The tail end of the optical cable 33 is connected to the second isolator 32.

[0029] S3: The second fiber coupler 7 inputs the remaining 50% of the pulsed laser light into the second erbium-doped fiber amplifier 17 for amplification, and inputs the amplified optical signal into the a input terminal of the fourth fiber coupler 18; the fourth fiber coupler 18 splits the pulsed laser light into two paths, one path is transmitted from the b output terminal of the fourth fiber coupler 18 to the first 1-to-3 single-mode optical fiber 19 and then divided into three laser beams for emission; the other path is transmitted from the c output terminal of the fourth fiber coupler 18 to the second 1-to-3 single-mode optical fiber 20 and then divided into three laser beams for emission.

[0030] S4: The first 1-to-3 single-mode optical fiber 19 emits three laser beams. The first laser beam is focused by the first focusing lens 21 and then filtered out by the first filter 27 to remove invalid optical signals. The second laser beam is focused by the second focusing lens 22 and then filtered out by the second filter 28 to remove invalid optical signals. The third laser beam is focused by the third focusing lens 23 and then filtered out by the third filter 29 to remove invalid optical signals. The second 1-to-3 single-mode optical fiber 20 emits three laser beams. The first laser beam is focused by the fourth focusing lens 24 and then filtered out by the fourth filter 30 to remove invalid optical signals. The second laser beam is focused by the fifth focusing lens 25 and then filtered out by the fifth filter 31 to remove invalid optical signals. The third laser beam is focused by the sixth focusing lens 26 and then filtered out by the sixth filter 32 to remove invalid optical signals. The six laser signals are irradiated onto the laser dot track coating 35 coated on the track and are enhanced by the laser dot track coating 35 and then reflected by the track 36. Absorb and excite vibration to generate ultrasonic waves; after the optical cable 33 laid on the side wall of the track 36 senses the ultrasonic signal through the photoelastic effect, it causes the photons in the optical cable 33 to undergo Rayleigh backscattering; the backscattered light passes through the second isolator 34 to eliminate possible Fresnel reflection and reduce interference, and then returns to the circulator 11, and enters the second wavelength division multiplexer 12 through the b output end of the circulator 11 to separate light of different wavelengths; the optical signal separated by the second wavelength division multiplexer 12 and the biased local oscillator light output by the first polarization controller 4 are coupled through the third optical fiber coupler 13 and input into the photoelectric converter 14, the photoelectric converter 14 converts the optical signal into an electrical signal, and enters the data acquisition card 15; the data acquisition card 15 inputs the collected and processed data into the computer 16 for further processing; when the system detects an abnormality in the track, the computer 16 will issue an abnormality alarm and provide fault location information.

[0031] This application combines photo-induced ultrasound technology with distributed acoustic sensing technology to construct a comprehensive "excitation-propagation-sensing" detection system. This system can detect abnormal acoustic signals indicating broken rails during high-speed rail non-operation periods and promptly issue an alarm, significantly improving safety. Compared to traditional dynamic ranging methods, this system has broader practical application prospects.

[0032] The system in this application uses a narrow-bandwidth laser with a wavelength of 1550nm as a light source, and adds an acousto-optic modulator to generate pulsed lasers, which serve as the light sources for acoustic excitation and acoustic detection respectively. At the same time, multiple 1-to-3 single-mode optical fibers are combined to transmit laser beams to the track to generate ultrasonic waves, achieving multi-point monitoring. When a high-speed railway track fracture is detected, the system can issue an alarm in a timely manner. The overall system structure has good applicability and strong anti-interference capabilities, and the hardware cost is lower than that of a multi-laser solution.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-speed railway track fracture fault detection system based on photon fusion detection technology, characterized by: It includes a photo-ultrasound module, a distributed acoustic wave sensing module, a data processing module, and an optical cable (33) laid on the side wall of the track (36); The distributed acoustic wave sensing module comprises a narrow-bandwidth laser (1), a first isolator (2), a first optical fiber coupler (3), a first polarization controller (4), a pulse generator (5), an acousto-optic modulator (6), a second optical fiber coupler (7), a second polarization controller (8), a first erbium-doped optical fiber amplifier (9), a first wavelength division multiplexer (10), a circulator (11), a second wavelength division multiplexer (12) and a third optical fiber coupler (13), wherein the output end of the narrow-linewidth laser (1) is connected to the input end of the first isolator (2); the output end of the first isolator (2) is connected to the a input end of the first optical fiber coupler (3); the b output end of the first optical fiber coupler (3) is connected to the input end of the first polarization controller (4); and the output end of the first polarization controller (4) is connected to the b input end of the third optical fiber coupler (13); The c output end of the first optical fiber coupler (3) is connected to the input end of the acousto-optic modulator (6); the output end of the pulse generator (5) is connected to the input end of the acousto-optic modulator (6); the output end of the acousto-optic modulator (6) is connected to the a input end of the second optical fiber coupler (7); the b output end of the second optical fiber coupler (7) is connected to the input end of the second polarization controller (8); and the c output end of the second optical fiber coupler (7) is connected to the input end of the photo-ultrasound module; The output end of the second polarization controller (8) is connected to the input end of the first erbium-doped fiber amplifier (9); the output end of the first erbium-doped fiber amplifier (9) is connected to the input end of the first wavelength division multiplexer (10); the output end of the first wavelength division multiplexer (10) is connected to the a input end of the circulator (11); the b output end of the circulator (11) is connected to the input end of the second wavelength division multiplexer (12); the output end of the second wavelength division multiplexer (12) is connected to the c input end of the third fiber coupler (13); the a output end of the third fiber coupler (13) is connected to the input end of the data processing module; The c output end of the circulator (11) is connected to the input end of the optical cable (33); the output end of the optical cable (33) is connected to the input end of the second isolator (34).

2. A high-speed railway track fracture fault detection system based on photon fusion detection technology according to claim 1, characterized in that: The photo-induced ultrasound module comprises a second erbium-doped fiber amplifier (17), at least one 1-to-n single-mode fiber, the c output end of the second fiber coupler (7) is connected to the input end of the second erbium-doped fiber amplifier (17), the output end of the second erbium-doped fiber amplifier (17) is connected to the input end of the 1-to-n single-mode fiber, and the n output ends of the 1-to-n single-mode fiber respectively output laser light after passing through a focusing lens and a filter.

3. A high-speed railway track fracture fault detection system based on photon fusion detection technology according to claim 2, characterized in that: The photo-ultrasound module further comprises a fourth optical fiber coupler (18), the output end of the second erbium-doped optical fiber amplifier (17) is connected to the input end a of the fourth optical fiber coupler (18), and the output ends b and c of the fourth optical fiber coupler (18) are respectively connected to the input end of a 1-to-n single-mode optical fiber.

4. A high-speed railway track fracture fault detection system based on photon fusion detection technology according to claim 3, characterized in that: The 1-to-n single-mode optical fiber adopts a 1-to-3 single-mode optical fiber, including a first 1-to-3 single-mode optical fiber (19) and a second 1-to-3 single-mode optical fiber (20), and the output end b of the fourth optical fiber coupler (18) is connected to the input end of the first 1-to-3 single-mode optical fiber (19); the first 1-to-3 single-mode optical fiber (19) emits three laser beams, the first laser beam is focused by a first focusing lens (21), and then an invalid optical signal is filtered out by a first filter (27); the second laser beam is focused by a second focusing lens (22), and then an invalid optical signal is filtered out by a second filter (28); the third laser beam is focused by a third focusing lens (23), and then an invalid optical signal is filtered out by a third filter (29); The output end c of the fourth optical fiber coupler (18) is connected to the input end of the second 1-to-3 single-mode optical fiber (20); the second 1-to-3 single-mode optical fiber (20) emits three laser beams, the first laser beam is focused by the fourth focusing lens (24), and then the invalid optical signal is filtered out by the fourth filter (30); the second laser beam is focused by the fifth focusing lens (25), and then the invalid optical signal is filtered out by the fifth filter (31); the third laser beam is focused by the sixth focusing lens (26), and then the invalid optical signal is filtered out by the sixth filter (32); after the laser signal is irradiated by the laser spot track coating (35) coated on the track, it is absorbed into the track (36) and generates ultrasonic waves, and the ultrasonic signals are detected by the optical cable (33).

5. A high-speed railway track fracture fault detection system based on photon fusion detection technology according to claim 2, characterized in that: The data processing module includes a photoelectric converter (14), a data acquisition card (15) and a computer (16), wherein the output end a of the third optical fiber coupler (13) is connected to the input end of the photoelectric converter (14), the output end of the photoelectric converter (14) is connected to the input end of the data acquisition card (15); and the output end of the data acquisition card (15) is connected to the input end of the computer (16).

6. A high-speed railway track fracture fault detection system based on photon fusion detection technology according to claim 1, characterized in that: The first optical fiber coupler (3) uses an optical fiber coupler with a coupling ratio of 1:99, wherein 1% of the light is input to the first polarization controller (4) and 99% of the light is input to the acousto-optic modulator (6).

7. A high-speed railway track fracture fault detection system based on photon fusion detection technology according to claim 1, characterized in that: The second optical fiber coupler (7) uses an optical fiber coupler with a coupling ratio of 50:

50.

8. A high-speed railway track fracture fault detection method based on photon fusion detection technology, characterized by: A high-speed railway track fracture fault detection system based on photon fusion detection technology according to any one of claims 1 to 7 comprises the following steps: S1: The narrow linewidth laser (1) emits a continuous narrow linewidth laser, which is stabilized by the first isolator (2) and then input into the first fiber coupler (3); the first fiber coupler (3) divides the laser into two parts, 1% and 99%, the 1% light is input into the first polarization controller (4), and the 99% light is input into the acousto-optic modulator (6) to modulate the continuous light into pulsed light; the first polarization controller (4) is used to adjust the polarization state of the light and transmit it to the third fiber coupler (13); the pulse generator (5) generates a pulse and inputs it into the acousto-optic modulator (6); the acousto-optic modulator (6) inputs the modulated pulsed light into the second fiber coupler (7); the second fiber coupler (7) divides the light into two parts, 50% and 50%, of which the 50% part is input into the second polarization controller (8) to adjust the polarization state of the light; S2: The light regulated by the second polarization controller (8) is input to the first erbium-doped fiber amplifier (9) for amplification and then input to the first wavelength division multiplexer (10); the optical signal is input from the first wavelength division multiplexer (10) to the input end a of the circulator (11), and then transmitted from the output end c of the circulator (11) to the optical cable (33), which is used to monitor the acoustic wave signal transmitted from the track; S3: The second fiber coupler (7) inputs the remaining 50% of the pulsed laser light into the second erbium-doped fiber amplifier (17) for amplification, and inputs the amplified optical signal into a 1-to-n single-mode fiber to emit n laser beams; S4: n laser beams are focused and filtered to remove invalid optical signals and then irradiated onto the track (36), where they are absorbed by the track (36) and stimulated to vibrate and generate ultrasonic waves; the optical cable (33) laid on the side wall of the track (36) senses the ultrasonic signal through the photoelastic effect, causing the photons in the optical cable (33) to undergo Rayleigh backscattering; the backscattered light passes through the second isolator (34) to eliminate possible Fresnel reflection and reduce interference, and then returns to the circulator (11), enters the second wavelength division multiplexer (12) through the output end b of the circulator (11) to separate light of different wavelengths; the optical signal separated by the second wavelength division multiplexer (12) and the biased local oscillator light output by the first polarization controller (4) are coupled through the third optical fiber coupler (13) and input into the data processing module for data processing to obtain fault location information of the track abnormality.

9. A high-speed railway track fracture fault detection method based on photon fusion detection technology according to claim 8, characterized in that: In step S4, a laser dot track coating (35) is coated on the track (36), and n laser beams are respectively focused and filtered to remove invalid light signals, and then irradiate the laser dot track coating (35) coated on the track and are enhanced by the laser dot track coating (35).

10. A high-speed railway track fracture fault detection method based on photon fusion detection technology according to claim 8, characterized in that: The signal coupled by the third optical fiber coupler (13) is input to the photoelectric converter (14), which converts the optical signal into an electrical signal and enters the data acquisition card (15); the data acquisition card (15) inputs the collected and processed data into the computer (16) for further processing; when the system detects an abnormality in the track, the computer (16) will issue an abnormality alarm and provide fault location information.

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