CN108827175A - Distribution type fiber-optic dynamic strain sensing device and method based on wideband chaotic laser light - Google Patents

Abstract

The invention discloses a distributed optical fiber dynamic strain sensing device based on a broadband chaotic laser, which includes a broadband chaotic laser source (1), a 1×2 fiber coupler (2), a first polarization controller (3), a high-speed electro-optic Modulator (4), Programmable Optical Delay Generator (5), First Optical Amplifier (6), Optical Polarizer (7), Optical Isolator (8), Sensing Optical Fiber (9), Optical Circulator (10), second optical amplifier (11), semiconductor optical amplifier (12), second polarization controller (13), pulse signal generator (14), broadband microwave signal source (15), high-speed data acquisition and analysis system (16), photodetector (17), tunable optical filter (18). The invention uses a pulse signal generator to generate a high-speed pulse signal, and realizes synchronous control of a broadband microwave signal source, a semiconductor optical amplifier, and a high-speed data acquisition and analysis system, thereby ensuring the accuracy and real-time performance of the sensor system measurement.

Description

Distributed optical fiber dynamic strain sensing device and method based on broadband chaotic laser

technical field

The invention relates to a distributed optical fiber sensing system, in particular to a distributed optical fiber dynamic strain sensing device and method based on broadband chaotic laser.

Background technique

Distributed optical fiber sensing uses optical fibers as sensing elements and transmission elements, which can realize continuous distributed measurement of physical parameters such as temperature and strain at different positions of the entire optical fiber. As an important part of the health and safety monitoring network of large-scale building structures, distributed optical fiber sensing technology has been widely used in various fields such as petrochemical, civil engineering, electrical transmission, aerospace, transportation, etc., temperature, vibration and strain, etc. Real-time and high-precision monitoring of multiple parameters has become a major research hotspot.

At present, the distributed optical fiber sensing system based on Brillouin scattering has become the focus of research in the field of distributed optical fiber sensing due to the simultaneous measurement of temperature and strain, and its advantages in measurement accuracy, measurement distance, and spatial resolution. . Large-scale engineering health monitoring puts forward long-distance, high-resolution, large dynamic range, and real-time fast requirements for strain measurement. Under the current technical conditions, the research on strain measurement range and real-time monitoring in the field of distributed optical fiber dynamic strain monitoring has made great achievements. preliminary progress. Yair Peled and others at Tel Aviv University in Israel proposed the slope-assisted Brillouin optical time-domain analysis technique (SA-BOTDA), and finally realized the measurement of 100Hz dynamic strain on a 20m long optical fiber with a spatial resolution of 1m (Optics Express, 2013, 21(9):10697-10705). In order to extend the sensing distance, the team of Professor Dong Yongkang of Harbin Institute of Technology used differential double pulse and second-order sideband modulation (IEEE Photonics Journal, 2013, 5(3):2600407), multiple slope assistance (Optics Express, 2016, 24(9 ):9781-9793) and frequency agility (IEEE Photonics Journal, 2017, 9(3):7102908.) and many other technologies have realized the rapid measurement of tens of Hz strain in short-distance polarization-maintaining optical fibers. At the same time, A. Loayssa, University of Navarra, Spain, and others used multi-frequency pump pulses to adjust the linear region of the Brillouin gain spectrum (IEEE Photonics Journal, 2017, 9(3):6802710), which expanded the dynamic range of strain measurement; Shanghai Communications University He Zuyuan and others fused the Brillouin gain and the Brillouin phase, and used a new parameter Brillouin phase-gain ratio to characterize the expansion of the dynamic range (Journal of Lightwave Technology, 2017, 35(20): 4451- 4458). The above technologies all adopt the Brillouin optical time domain analysis system, which uses the pulse signal as the pump signal to realize the positioning sensing along the optical fiber. The rate is low, the highest is only up to the sub-meter level, and it is impossible to achieve dynamic strain measurement with both long-distance and high-resolution.

Compared with the time-domain system, the Brillouin optical coherent domain system injects coherent frequency-modulated probe light and pump light from both ends of the fiber into the sensing fiber to generate nonlinear stimulated Brillouin scattering. The coherence function of the latter can realize the distributed measurement of the sensing fiber. In the field of distributed dynamic strain measurement, K.Hotate et al. of the University of Tokyo, Japan, used the differential frequency modulation Brillouin optical coherence domain analysis system (DFM-BOCDA) to realize the measurement of 20Hz dynamic strain of 100m ordinary single-mode fiber (Optics Letters, 2011 , 36(11):2062-2064), He Zuyuan et al. used an ultra-high-speed single-point data acquisition device (LIA-free BOCDA) to achieve 8cm high-resolution measurement of dynamic strain with a maximum vibration frequency of 200Hz on a 20m sensing fiber (Optics Express, 2018, 26(6):6916-6928). In addition, K. Nakamura et al., Tokyo Institute of Technology, Japan proposed a slope-assisted Brillouin optical coherent domain reflection system (SA-BOCDR), and realized short-distance high-sensitivity dynamic strain measurement in high-loss plastic optical fibers (Journal of Lightwave Technology, 2017, 35(11):2304-2310). However, the traditional Brillouin optical coherent domain system uses a sinusoidal frequency modulated light source to transmit periodic correlation peaks in the optical fiber to be tested, and the stimulated Brillouin acoustic wave field is limited to correlation peaks with a full width at half maximum of sub-centimeters or millimeters In order to achieve high-resolution measurement, at the same time, in order to avoid the crosstalk of adjacent correlation peaks and ensure that there is only one peak in the fiber to be tested, the sensing distance is severely limited, and it is impossible to achieve large-scale dynamic strain real-time with both long-distance and high-resolution Measurement.

Based on this, it is necessary to invent a brand-new distributed optical fiber dynamic strain measurement system to overcome the difficulties in the existing technology that cannot achieve long-distance and high-resolution real-time measurement of large-scale dynamic strain, and to achieve long-distance, high-spatial resolution Rate, large dynamic range, real-time and fast distributed dynamic strain measurement.

Contents of the invention

The present invention aims to solve the difficulty that the existing distributed optical fiber sensing technology cannot realize long-distance and high-resolution real-time monitoring of large-scale dynamic strain, and provides a distributed optical fiber dynamic strain sensing device based on broadband chaotic laser and method.

The present invention is realized by adopting the following technical solutions:

A distributed optical fiber dynamic strain sensing device based on a broadband chaotic laser, including a broadband chaotic laser source, a 1×2 fiber coupler, a first polarization controller, a high-speed electro-optic modulator, a programmable optical delay generator, a first Optical amplifier, optical scrambler, optical isolator, sensing fiber, optical circulator, second optical amplifier, semiconductor optical amplifier, second polarization controller, pulse signal generator, broadband microwave signal source, tunable optical filter , Photodetector, high-speed data acquisition and analysis system.

Wherein, the output end of the broadband chaotic laser source is connected to the input end of the 1×2 fiber coupler; the first output end of the 1×2 fiber coupler is connected to the input end of the first polarization controller; the output end of the first polarization controller It is connected to the fiber input end of the high-speed electro-optic modulator; the RF output end of the broadband microwave signal source is connected to the RF input end of the high-speed electro-optic modulator through a high-frequency coaxial cable; the fiber output end of the high-speed electro-optic modulator is connected through a single-mode fiber jumper It is connected with the input end of the programmable optical delay generator; the output end of the programmable optical delay generator is connected with the input end of the first optical amplifier through a single-mode fiber jumper; the output end of the first optical amplifier is connected through a single-mode optical fiber The jumper is connected to the input end of the optical scrambler; the output end of the optical scrambler is connected to the input end of the optical isolator through a single-mode fiber jumper; the output end of the optical isolator is connected to one end of the sensing fiber; the sensing fiber The other end of the optical circulator is connected to the reflection end of the optical circulator; the second output end of the 1×2 fiber coupler is connected to the input end of the second polarization controller; the output end of the second polarization controller is connected to the semiconductor optical fiber through a single-mode fiber jumper The input end of the amplifier is connected; the output end of the semiconductor optical amplifier is connected to the input end of the second optical amplifier through a single-mode fiber jumper: the output end of the second optical amplifier is connected to the input end of the optical circulator through a single-mode fiber jumper; The output end of the optical circulator is connected to the input end of the tunable optical filter; the output end of the tunable optical filter is connected to the photodetector through a single-mode fiber jumper; the output end of the photodetector is connected to the The high-speed data acquisition and analysis system is connected to the data acquisition port; the RF output terminal I of the pulse signal generator is connected to the RF input terminal of the semiconductor optical amplifier through a high-frequency coaxial cable, and the RF output terminal II of the pulse signal generator is connected through a high-frequency coaxial The axial cable is connected to the radio frequency control port of the high-speed data acquisition card, and the radio frequency output terminal III of the pulse signal generator is connected to the external trigger port of the broadband microwave signal source through a high frequency coaxial cable.

Based on the above device, a distributed optical fiber dynamic strain sensing method based on broadband chaotic laser, as follows:

The chaotic laser output from the broadband chaotic laser source is incident on the 1×2 fiber coupler, and is divided into two paths through the 1×2 fiber coupler: one path is used as probe light, and the other path is used as pump light.

The probe light enters the high-speed electro-optic modulator through the first polarization controller, and the high-speed electro-optic modulator is modulated by the sinusoidal signal output by the microwave signal source, so that the center frequency of the probe light is shifted, and the frequency shift is equal to the Brillouin of the sensing fiber Frequency shift value (v _B ≈10.6GH _Z ); the optical signal after the frequency shift by the high-speed electro-optic modulator is input to the programmable optical delay generator, and the optical path of the probe light is adjusted by the programmable optical delay generator, and then incident on the The first optical amplifier amplifies the detection light through the first optical amplifier, and then enters the optical scrambler, and then enters the first optical isolator after passing through the optical scrambler. One end of the sensing fiber.

The pumping light enters the semiconductor optical amplifier through the second polarization controller, wherein the semiconductor optical amplifier is modulated by the high-speed pulse signal output by the pulse signal generator, and the chaotic optical signal after pulse modulation enters the second optical amplifier, and passes through the second optical amplifier. The amplifier is amplified and output to the input end of the optical circulator.

The oppositely transmitted probe light and pump light meet at a certain position in the sensing fiber, and at the same time stimulated Brillouin amplification occurs, and the amplified probe light signal is circulated by the optical circulator and enters the tunable optical filter filter to filter out unwanted signals and only retain Brillouin Stokes light; the filtered optical signal is connected to a photodetector to be converted into an electrical domain signal, and transmitted to a high-speed data acquisition and analysis system through a high-frequency coaxial cable.

The chaotic probe light and pump light will generate Brillouin gain at the position where the sensing fiber meets, and the Brillouin frequency difference is locked at the midpoint of the linear region of the Brillouin gain spectrum through a broadband microwave signal source, and a photodetector is used to Perform real-time Brillouin gain acquisition, and use the high-speed data acquisition and analysis system for real-time data processing and analysis. At the same time, the programmable optical delay generator (5) adjusts the optical path of the probe light, so that the probe light and pump light are in the sensing The stimulated Brillouin amplification occurs at different positions in the optical fiber, and the chaotic Brillouin gain spectrum information is obtained, thereby obtaining the strain information at any position of the sensing optical fiber.

Compared with the existing distributed optical fiber dynamic strain measurement system, the distributed optical fiber dynamic strain sensing device and method based on broadband chaotic laser according to the present invention has the following advantages and positive effects:

1. Compared with the traditional time-domain system, the distributed optical fiber dynamic strain sensing device based on broadband chaotic laser belongs to the coherent domain system and has higher spatial resolution, that is, the spatial resolution can be increased by 2 to 3 orders of magnitude.

2. The coherent domain system based on sinusoidal frequency modulation itself has a contradiction between the sensing distance and the spatial resolution, and the coherence function generated by the laser signal modulated by the sinusoidal signal frequency is periodic, which further limits the sensing distance. Increase. The distributed optical fiber dynamic strain sensing device based on broadband chaotic laser uses a continuous chaotic laser without delay as the detection signal, which can ensure that there is only one correlation peak in a sufficiently long sensing fiber, avoiding the crosstalk of correlation peaks, and greatly expanding the sensing distance.

3. The distributed optical fiber dynamic strain sensing system based on broadband chaotic laser according to the present invention uses a broadband chaotic signal with a flat spectrum as a light source: (1) The chaotic laser is divided into detection light and pump light with the same coherent state but frequency detuning The pump light is injected into the optical fiber separately. When the pump light contains different frequency components, each frequency component will produce a different Brillouin gain. At this time, the measured Brillouin gain spectrum is the linear superposition of the gain of each frequency component; The pump path of the system described in the present invention is a broadband chaotic signal, and each frequency component will generate a stable stimulated Brillouin gain, and a single measurement can be demodulated to obtain a Brillouin gain spectrum with increased spectral width and flat linear region . (2) In the same environment, any position of the fiber can be demodulated to obtain exactly the same Brillouin gain spectrum. By adjusting the spectrum of the chaotic signal, the shape of the Brillouin gain spectrum can be adjusted, and a larger Brillouin gain spectrum can be obtained in this way. Linear slope range and better linearity; take the midpoint of the linear region of the low-frequency band of the gain spectrum as a reference, lock the frequency mismatch between the probe light and the pump light as the frequency value at this point, and pass the single frequency point position Measurement of Brillouin gain, establishment of chaotic Brillouin gain spectrum unilateral slope control model, and the gain value is stable in the same environment; when a certain position of the fiber is in a special environment, the Brillouin frequency shift caused by dynamic strain As a result, the midpoint of the linear region of the low-frequency band of the gain spectrum shifts, and at this time the Brillouin gain value at the reference point changes significantly, that is, the actual Brillouin frequency shift is finally mapped to the change of the Brillouin gain, and using the above The unilateral slope control model of Brillouin gain spectrum realizes real-time demodulation of frequency shift, and high-resolution measurement of dynamic strain can be realized through real-time power acquisition.

4. For the dynamic distributed Brillouin optical fiber sensing device and method using frequency agility technology (Chinese invention patent, ZL2013102334483), the dynamic distributed Brillouin optical fiber sensing device and Method (Chinese invention patent, ZL2015101224127), a long-distance distributed large measurement range fast-response optical fiber dynamic strain sensing device using multi-frequency modulation detection light technology (Chinese invention patent, ZL2014101334620). The above-mentioned devices and methods all use the traditional time-domain system, and the spatial resolution is still limited; the frequency agility technology cannot realize the real-time monitoring of strain information, and the traditional slope-assisted method has a narrow linear region of the Brillouin gain spectrum, which leads to dynamic strain measurement. The scope is severely limited; multiple high-speed electro-optical modulation modules and arbitrary waveform generators are required for multi-frequency modulation continuous detection light to stitch Brillouin gain spectra, the system cost is high and the modulation width is limited; the coherent detection technology is complex in structure and difficult to implement. The external environment has a greater influence. The distributed optical fiber dynamic strain sensing system based on broadband chaotic laser uses chaotic laser with no time delay, flat spectrum and broadband as the detection signal to obtain the Brillouin gain spectrum with increased spectral width and flat linear region, without complex modulation methods Simplify the system structure and reduce the cost. On the basis of overcoming the problem of long sensing distance and high spatial resolution, develop Brillouin gain spectrum unilateral slope control technology to measure dynamic strain, and absorb slope-assisted system with short measurement time. Advantages, to achieve long-distance, high spatial resolution, real-time measurement of large-scale dynamic strain.

5. The distributed optical fiber dynamic strain sensing system based on broadband chaotic laser of the present invention utilizes a pulse signal generator to generate a high-speed pulse signal, and realizes synchronous control of a broadband microwave signal source, a semiconductor optical amplifier, and a high-speed data acquisition and analysis system , to ensure the accuracy and real-time performance of the sensing system measurement; compared with the cascade control model of multiple high-speed signal generators and broadband electro-optic modulators in the traditional Brillouin optical time domain analysis system, the sensing system structure of the present invention Simple and easy to integrate instrumented measurement equipment, it can realize large-scale engineering monitoring applications.

Description of drawings

Fig. 1 shows the structural schematic diagram of the device of the present invention.

In the figure: 1-broadband chaotic laser source, 2-1×2 fiber coupler, 3-first polarization controller, 4-high-speed electro-optic modulator, 5-programmable optical delay generator, 6-first optical amplifier, 7-optical polarization scrambler, 8-first optical isolator, 9-sensing fiber, 10-optical circulator, 11-second optical amplifier, 12-semiconductor optical amplifier, 13-second polarization controller, 14- Pulse signal generator, 15-broadband microwave signal source, 16-high-speed data acquisition and analysis system, 17-photoelectric detector, 18-tunable optical filter.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

A distributed optical fiber dynamic strain sensing device based on a broadband chaotic laser, as shown in Figure 1, includes a broadband chaotic laser source 1, a 1×2 fiber coupler 2, a first polarization controller 3, a high-speed electro-optic modulator 4, Programmable optical delay generator 5, first optical amplifier 6, optical scrambler 7, optical isolator 8, sensing fiber 9, optical circulator 10, second optical amplifier 11, semiconductor optical amplifier 12, second polarization Controller 13 , pulse signal generator 14 , broadband microwave signal source 15 , tunable optical filter 18 , photoelectric detector 17 , and high-speed data acquisition and analysis system 16 .

Wherein, the output end of broadband chaotic laser source 1 is connected with the input end of 1×2 fiber coupler 2; the first output end of 1×2 fiber coupler 2 is connected with the input end of first polarization controller 3; the first polarization The output end of the controller 3 is connected to the optical fiber input end of the high-speed electro-optic modulator 4; the radio frequency output end of the broadband microwave signal source 15 is connected to the radio frequency input end of the high-speed electro-optic modulator 4 through a high-frequency coaxial cable; The output end of the optical fiber is connected with the input end of the programmable optical delay generator 5 through a single-mode optical fiber jumper; the output end of the programmable optical delay generator 5 is connected with the input end of the first optical amplifier 6 through a single-mode optical fiber jumper The output end of the first optical amplifier 6 is connected to the input end of the optical scrambler 7 through a single-mode fiber jumper; the output end of the optical scrambler 7 is connected to the input end of the optical isolator 8 through a single-mode fiber jumper; The output end of the optical isolator 8 is connected to one end of the sensing fiber 9; the other end of the sensing fiber 9 is connected to the reflection end of the optical circulator 10; the second output end of the 1×2 fiber coupler 2 is connected to the second polarization control The input end of the second polarization controller 13 is connected with the input end of the semiconductor optical amplifier 12 through a single-mode fiber jumper; the output end of the semiconductor optical amplifier 12 is connected with the second optical amplifier 11 through a single-mode fiber jumper Input end connection: the output end of the second optical amplifier 11 is connected with the input end of the optical circulator 10 through a single-mode fiber jumper; the output end of the optical circulator 10 is connected with the input end of the tunable optical filter 18; The output end of filter 18 is connected with photodetector 17 by single-mode fiber jumper; The output end of photodetector 17 is connected with the data acquisition port of high-speed data acquisition and analysis system 16 by high-frequency coaxial cable; Pulse signal generator The radio frequency output terminal I of 14 is connected to the radio frequency input terminal of the semiconductor optical amplifier 12 through a high-frequency coaxial cable, and the radio frequency output terminal II of the pulse signal generator 14 is controlled by the radio frequency of the high-speed data acquisition and analysis system 16 through a high-frequency coaxial cable Port connection, the RF output terminal III of the pulse signal generator 14 is connected to the external trigger port of the broadband microwave signal source 15 through a high-frequency coaxial cable.

During specific implementation, the central wavelength of the broadband chaotic laser source is 1550nm, the spectral line width is greater than 6GHz, and the spectral bandwidth is greater than 10GHz. The high-speed electro-optic modulator 4 adopts the MX-LN-10 type high extinction ratio lithium niobate electro-optic intensity modulator. Programmable optical delay generator 5 adopts ODG-101 high precision programmable optical delay line. The first optical amplifier 6 is an ordinary erbium-doped fiber amplifier. The optical scrambler 7 is a PCD-104 type scrambler. The sensing fiber 12 adopts G652 single-mode fiber or G655 single-mode fiber, and its length is 50km. The second optical amplifier 11 is a pulsed erbium-doped fiber amplifier. The semiconductor optical amplifier 12 adopts KG-SOA-C-BAND series amplifiers. The pulse signal generator 14 is an Agilent-81150A signal generator. Broadband microwave signal source 15 adopts EXG-N5173B microwave signal source. The photodetector 17 adopts a low-bandwidth high-speed detector. The tunable optical filter 18 is an XTM-50 bandwidth tunable filter.

A distributed optical fiber dynamic strain sensing method based on broadband chaotic laser, as follows:

Broadband chaotic laser source 1 outputs no time delay, flat spectrum, wideband continuous chaotic laser, and enters 1×2 fiber coupler 2, which is divided into two paths through 1×2 fiber coupler 2: one path is used as probe light, and the other path as pump light. The probe light enters the high-speed electro-optic modulator 4 through the first polarization controller 3, wherein the high-speed electro-optic modulator 4 is modulated by the sinusoidal signal output by the microwave signal source 5, so that the center frequency of the probe light is shifted, and the frequency shift is close to the sensor The Brillouin frequency shift of an optical fiber. The optical signal frequency-shifted by the high-speed electro-optic modulator 4 is input to the programmable optical delay generator 5 , and the optical path of the detection light is adjusted by the programmable optical delay generator 5 , and then enters the first optical amplifier 6 . The detection light is amplified by the first optical amplifier 6 to compensate the optical signal loss caused by the programmable optical delay generator, and then enters the optical polarizer 7 . The optical scrambler is used to reduce the influence of the polarization state when the probe light and the pump light interfere in the sensing fiber, and enters the first optical isolator 8 after passing through the optical scrambler 7 . The first optical isolator 8 ensures that the detection light passes in one direction, so as to avoid the influence of backscattered light on the detection light. After being output by the first optical isolator 8 , the detection light is injected into one end of the sensing fiber 9 , and the other end of the sensing fiber 9 is connected to the reflection end of the optical circulator 10 . Another path of pumping light enters the semiconductor optical amplifier 12 through the second polarization controller 13, wherein the semiconductor optical amplifier 12 is modulated by the high-speed pulse signal output by the pulse signal generator 14 to realize the pulse positioning and time domain control of the sensing system. The pulse-modulated chaotic optical signal is incident to the second optical amplifier 11 , amplified by the second optical amplifier 11 and then output to the input end of the optical circulator 10 . The probing light and pumping light transmitted in opposite directions meet at a certain position in the sensing fiber 9, and at the same time, the stimulated Brillouin amplification occurs, and the amplified probing light signal goes through the optical circulator 10 and then enters the tunable The optical filter 18 filters out useless signals (including Rayleigh scattered light, noise, etc.), and only retains the Brillouin Stokes light; the filtered optical signal is connected to the photodetector 17 and converted into an electrical domain signal, and It is transmitted to the high-speed data acquisition and analysis system 16 through a high-frequency coaxial cable. The chaotic probe light and the pump light will generate Brillouin gain at the position where the sensing fiber 9 meets. Due to the linear relationship between the Brillouin frequency shift and the strain, the Brillouin frequency difference is locked in the cloth through the broadband microwave signal source 15. The midpoint of the linear region of the Brillouin gain spectrum, and the photodetector 17 is used for real-time Brillouin gain acquisition, and the pulse synchronously controlled high-speed data acquisition and analysis system 16 is used for real-time data processing and analysis, and the programmable optical delay occurs at the same time The detector 5 can adjust the optical path of the probe light, so that the probe light and the pump light can undergo stimulated Brillouin amplification at different positions in the sensing fiber 9. Combining the pulse positioning and time domain control technology, the sensing fiber can be arbitrarily Strain information at the location.

It should be pointed out that for those skilled in the art, some improvements and applications can be made without departing from the principle of the present invention, and these improvements and applications are also regarded as the protection scope of the present invention.

Claims (2)

1. A distributed optical fiber dynamic strain sensing device based on a broadband chaotic laser, characterized in that it includes a broadband chaotic laser source (1), a 1×2 fiber coupler (2), a first polarization controller (3), High-speed electro-optic modulator (4), programmable optical delay generator (5), first optical amplifier (6), optical scrambler (7), optical isolator (8), sensing fiber (9), optical ring liner (10), second optical amplifier (11), semiconductor optical amplifier (12), second polarization controller (13), pulse signal generator (14), broadband microwave signal source (15), high-speed data acquisition and Analysis system (16), photodetector (17), tunable optical filter (18); Among them, the output end of the broadband chaotic laser source (1) is connected to the input end of the 1×2 fiber coupler (2); the first output end of the 1×2 fiber coupler (2) is connected to the first polarization controller (3 ) to the input end; the output end of the first polarization controller (3) is connected to the optical fiber input end of the high-speed electro-optic modulator (4); the radio frequency output end of the broadband microwave signal source (15) is connected to the high-speed electro-optic modulation through a high-frequency coaxial cable connected to the RF input end of the high-speed electro-optic modulator (4); the fiber output end of the high-speed electro-optical modulator (4) is connected to the input end of the programmable optical delay generator (5) through a single-mode optical fiber jumper; the programmable optical delay generator The output end of (5) is connected to the input end of the first optical amplifier (6) through a single-mode fiber jumper; the output end of the first optical amplifier (6) is connected to the optical scrambler (7) through a single-mode fiber jumper The input end is connected; the output end of the optical scrambler (7) is connected to the input end of the optical isolator (8) through a single-mode fiber jumper; the output end of the optical isolator (8) is connected to one end of the sensing fiber (9) ; The other end of the sensing fiber (9) is connected to the reflection end of the optical circulator (10); the second output end of the 1×2 fiber coupler (2) is connected to the input end of the second polarization controller (13); The output end of the second polarization controller (13) is connected to the input end of the semiconductor optical amplifier (12) through a single-mode fiber jumper; the output end of the semiconductor optical amplifier (12) is connected to the second optical amplifier (11) through a single-mode fiber jumper ) input terminal connection: the output terminal of the second optical amplifier (11) is connected to the input terminal of the optical circulator (10) through a single-mode fiber jumper; the output terminal of the optical circulator (10) is connected to the tunable optical filter ( 18) is connected to the input end; the output end of the tunable optical filter (18) is connected to the photodetector (17) through a single-mode fiber jumper; the output end of the photodetector (17) is connected to the high-speed The data acquisition port of the data acquisition and analysis system (16) is connected; the radio frequency output terminal I of the pulse signal generator (14) is connected with the radio frequency input terminal of the semiconductor optical amplifier (12) through a high-frequency coaxial cable, and the pulse signal generator ( The radio frequency output terminal II of 14) is connected to the radio frequency control port of the high-speed data acquisition and analysis system (16) through a high-frequency coaxial cable, and the radio frequency output terminal III of the pulse signal generator (14) is connected to the broadband microwave microwave port through a high-frequency coaxial cable External trigger port connection for signal source (15). 2. A distributed optical fiber dynamic strain sensing method based on broadband chaotic laser, characterized in that: chaotic laser output from broadband chaotic laser source (1) is incident on 1×2 fiber coupler (2), coupled by 1×2 fiber The device (2) is divided into two paths: one path is used as probe light, and the other path is used as pump light; The probe light enters the high-speed electro-optic modulator (4) through the first polarization controller (3), wherein the high-speed electro-optic modulator (4) is modulated by the sinusoidal signal output by the microwave signal source (15), so that the central frequency of the probe light is shifted ; The optical signal after the frequency shift by the high-speed electro-optical modulator (4) is input to the programmable optical delay generator (5), and the optical path of the detection light is adjusted by the programmable optical delay generator (5), and then incident on the first The optical amplifier (6) amplifies the detection light through the first optical amplifier (6), and then enters the optical scrambler (7), and then enters the first optical isolator (8) after passing through the optical scrambler (7) , after being output by the first optical isolator (8), the detection light is injected into one end of the sensing fiber (9); The pumping light enters the semiconductor optical amplifier (12) through the second polarization controller (13), wherein the semiconductor optical amplifier (12) is modulated by the high-speed pulse signal output by the pulse signal generator (14), and the chaotic light after pulse modulation The signal is incident to the second optical amplifier (11), amplified by the second optical amplifier (11), and then output to the input end of the optical circulator (10); The probing light and pumping light transmitted in opposite directions meet at a certain position in the sensing fiber (9), at the same time stimulated Brillouin amplification occurs, and the amplified probing light signal is circulated by the optical circulator (10) After entering the tunable optical filter (18), the useless signal is filtered out and only the Brillouin Stokes light is retained; the filtered optical signal is connected to the photodetector (17) to be converted into an electrical domain signal, and passed through the high frequency The coaxial cable is transmitted to the high-speed data acquisition and analysis system (16); The chaotic probe light and pump light will generate Brillouin gain at the meeting position of the sensing fiber (9), and the Brillouin frequency difference will be locked in the linear region of the Brillouin gain spectrum through the broadband microwave signal source (15) point, and use the photodetector (17) for real-time Brillouin gain acquisition, and use the high-speed data acquisition and analysis system (16) for real-time data processing and analysis. At the same time, the programmable optical delay generator (5) adjusts the light of the detection light process, so that the probe light and the pump light undergo stimulated Brillouin amplification at different positions in the sensing fiber (9) to obtain chaotic Brillouin gain spectrum information, thereby obtaining strain information at any position of the sensing fiber.