CN115824378A - Vibration detection method of high-frequency-response distributed optical fiber acoustic wave sensor - Google Patents

Abstract

The invention provides a vibration detection method of a high-frequency response distributed optical fiber acoustic wave sensor, which comprises the following steps: step 1: the data acquisition card 7 acquires an electric signal; step 2: performing time-frequency analysis on the electric signal to obtain a beat frequency-optical frequency fingerprint graph of the backward Rayleigh scattering light of the sensing optical fiber 5; and step 3: detecting the translation amount of the backward Rayleigh scattering light at the position to be detected of the sensing optical fiber 5 in the beat frequency direction by adopting an image matching method, thereby obtaining the position of the backward Rayleigh scattering light at the position to be detected in the whole beat frequency-optical frequency fingerprint graph; and 4, step 4: and obtaining the instantaneous optical frequency shift corresponding to the position to be measured, thereby solving the strain magnitude of the sensing optical fiber 5 at the position to be measured. The invention effectively inhibits the crosstalk of the high-frequency vibration of the front section of the sensing optical fiber to the vibration detection of the rear section of the sensing optical fiber, improves the corresponding bandwidth of the sensing system and improves the distributed vibration measurement capability of the sensing system.

Description

Vibration Detection Method of High Frequency Response Distributed Optical Fiber Acoustic Sensor

technical field

The invention relates to the technical field of optical fiber sensing, in particular to a vibration detection method of a high-frequency response distributed fiber optic acoustic wave sensor, especially a vibration detection method of a high frequency response distributed fiber optic acoustic wave sensor capable of suppressing crosstalk.

Background technique

Distributed Fiber-optic Acoustic Sensor (DAS) has more and more applications in important fields such as oil and gas resource exploration, oil and gas pipeline monitoring, and railway track monitoring. DAS can use ordinary single-mode communication optical fiber as a sensor, and each small section of optical fiber on the optical fiber can be regarded as a microphone that can detect sound and vibration signals in the environment, and the position of the vibration signal can be accurately located, and more importantly, The waveform of the sound vibration signal can be quantitatively acquired for further analysis. Compared with traditional acoustic wave sensors based on mechanical or electromagnetic principles, DAS not only has the advantages of general optical fiber sensors, such as anti-electromagnetic interference, corrosion resistance, intrinsic passive, etc., but also has distributed measurement capabilities, which is easy to achieve large-scale The acoustic wave sensor multiplexing avoids the problems of power supply and signal transmission in the traditional acoustic wave sensor multiplexing scheme. In scenarios such as aircraft fuselage structure monitoring, turbine blade status monitoring, and sound source localization in fluids, the DAS system is required to have a high spatial resolution. Most of the current DAS technologies are based on optical time domain reflectometer technology, and the spatial resolution is in the range of More than one meter, it is difficult to directly apply to the above scene.

The spatial resolution of the DAS system based on Optical Frequency Domain Reflectometry (OFDR) or Time-gated Digital OFDR (TGD-OFDR) is determined by the scanning range of the probe light , thus decoupling the spatial resolution and the duration of the probe light, can guarantee a very high spatial resolution of the DAS system. However, due to the long duration of the detection light in this scheme, when the optical fiber is vibrated, the phase modulation imposed by the vibration on the detection light is no longer a constant value during the duration of the detection light, resulting in the strain demodulation of the vibration to its subsequent position. Crosstalk even causes the demodulation method to fail, making the current high spatial resolution DAS system unable to detect high-frequency vibration signals correctly, and the response bandwidth is severely limited.

The patent document whose publication number is CN113295257A discloses a fiber optic acoustic wave sensor signal demodulation method and system, which differs in that it includes the following steps: Step 1: the broadband light provided by the light source passes through the fiber optic acoustic wave sensor, and the broadband light interferes; step 2: After the interfering broadband light is screened, it becomes narrow-band light with a certain wavelength interval of N channels; Step 3: Obtain the corresponding N-channel interference light intensity from the N-channel different wavelengths of the narrow-band light; the N-channel interference light intensity Convert to N-channel corresponding voltage signals; Step 4: Multi-channel sampling of N-channel voltage signals, and sample N demodulation working point voltages; Step 5: Obtain one channel signal with the best intensity demodulation effect as the demodulation signal; Step 6: The demodulated signal is processed and restored to become a sound wave signal. The invention increases demodulation stability and reliability, and improves the batch practical ability of the optical fiber acoustic wave sensor. However, this solution is only suitable for solving the problem of sensor static operating point drift under changing environmental factors, and cannot solve the problem of crosstalk caused by the vibration on the optical fiber and the strain demodulation of its subsequent position.

Contents of the invention

Aiming at the defects in the prior art, the object of the present invention is to provide a vibration detection method of a high frequency response distributed fiber optic acoustic wave sensor.

According to the vibration detection method of the high frequency response distributed fiber optic acoustic wave sensor provided by the present invention, it includes the high frequency response distributed fiber optic acoustic wave sensor, and the high frequency response distributed fiber optic acoustic wave sensor includes a laser module, a fiber optic coupler, a fiber optic circulator, Sensing optical fiber, coherent detection module, data acquisition card and data processor;

The laser light output by the laser module is divided into probe light and local light through the fiber coupler, and the probe light is input into the sensing fiber through the fiber circulator to form backward Rayleigh scattered light, and the backward Rayleigh scattered light passes through the fiber ring The device is used as a signal light input to the coherent detection module, the local light is input to the coherent detection module, the coherent detection module can beat the backward Rayleigh scattered light and the local light and form an electrical signal output, and the data acquisition card can Collecting electrical signals, the data processor is capable of processing electrical signals;

The detection light input into the optical fiber circulator is a frequency-sweeping light pulse train;

The vibration detection method of the high frequency response distributed fiber optic acoustic sensor also includes the following steps:

Step 1: The data acquisition card collects electrical signals;

Step 2: Use time-frequency analysis on the electrical signal to obtain the beat frequency-optical frequency domain fingerprint image of the Rayleigh backscattered light;

Step 3: Use the image matching method to detect the translation of the Rayleigh backscattered light at the position to be measured by the sensing fiber in the beat frequency-optical frequency domain fingerprint image, so as to obtain the Rayleigh backscattered light at the position to be measured in the entire beat frequency - position within the optical frequency domain fingerprint image;

Step 4: According to the position of the back Rayleigh scattered light of the position to be measured in the entire beat frequency-optical frequency domain fingerprint image, obtain the instantaneous light-frequency frequency shift corresponding to the position to be measured, and thus calculate the strain size.

Preferably, in step 1, after the data acquisition card collects the electrical signal, a two-dimensional array is formed by using a time-frequency analysis method, and marked according to the order of emission time;

The time-frequency analysis method includes short-time Fourier transform and wavelet transform.

Preferably, in step 2, after time-frequency analysis is performed on the electrical signal, the beat frequency-optical frequency domain fingerprint image of the back Rayleigh scattered light at each position of the sensing fiber at the nth detection is obtained.

Preferably, said step 3 includes the following steps:

Step 3.1: Using an image matching method, the image matching method includes: taking the beat frequency-optical frequency domain fingerprint image of the backward Rayleigh scattered light obtained in the first detection and corresponding to a certain position L of the sensing fiber in space , the sub-region at a certain time point t in time is defined as the reference sub-region, and the image is used near the reference sub-region on the beat frequency-optical frequency domain fingerprint image of the back Rayleigh scattered light obtained by the nth detection Matching, find the sub-area to be measured that best matches the reference sub-area, and obtain the translation of the back Rayleigh scattered light in the beat frequency-optical frequency domain corresponding to the temporal and spatial back Rayleigh scattered light at the position L of the sensing fiber to be measured quantity;

Step 3.2: Change the time point t and repeat step 3.1 until the location of the Rayleigh backscattered light corresponding to the location to be measured in space in the entire beat frequency-optical frequency domain fingerprint image is obtained.

Preferably, said step 4 includes the following steps:

Step 4.1: According to the position of the backward Rayleigh scattered light corresponding to the position L to be measured in space obtained by the nth detection in the entire beat frequency-optical frequency domain fingerprint image, the instantaneous light corresponding to the position L to be measured is obtained frequency shift;

Step 4.2: According to the instantaneous light-frequency shift, obtain the spectrum or phase change information of the Rayleigh backscattered light corresponding to the position L to be measured obtained by the nth detection, so as to obtain the strain.

Preferably, step 5 is also included: changing n and L, repeating steps 3-4, until the strain distribution on the entire sensing optical fiber (5) varies with time.

Preferably, in step 4.2, according to the instantaneous light-frequency frequency shift corresponding to the position L to be measured, the spectral frequency shift Δν of the back Rayleigh scattered light at the position to be measured is obtained, and the strain amount is

Among them, K _ε-ν is the strain-frequency shift coefficient, and ν ₀ is the center frequency.

Preferably, in step 4.2, according to the instantaneous light-frequency frequency shift corresponding to the position L to be measured, the differential phase change Δφ of the back Rayleigh scattered light at the position to be measured is obtained, and the strain amount is

Among them, K _ε-φ is the strain-phase coefficient, and ΔL is the differential distance.

Preferably, the laser module adopts a frequency-sweeping laser, and the frequency-sweeping laser can output a frequency-sweeping optical pulse train.

Preferably, the laser module adopts a narrow linewidth laser, and the high frequency response distributed fiber optic acoustic wave sensor also includes a radio frequency signal module and an optical modulator, and the optical modulator is arranged between the fiber coupler and the fiber circulator, The radio frequency signal module can input a frequency-sweeping radio frequency pulse train signal to the optical modulator, and the detection light can form a frequency-sweeping optical pulse train through the optical modulator.

Compared with the prior art, the present invention has the following beneficial effects:

The invention effectively suppresses the crosstalk of the high-frequency vibration of the front section of the sensing fiber to the vibration detection of the rear section of the sensing fiber, increases the corresponding bandwidth of the sensing system, and improves the distributed vibration measurement capability of the sensing system.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is the structure schematic diagram of medium and high frequency response distributed optical fiber acoustic wave sensor of the present invention;

Fig. 2 is the time-frequency analysis diagram of frequency-sweeping optical pulse train among the present invention;

Fig. 3 is the beat frequency-optical frequency domain fingerprint image of backward Rayleigh scattered light among the present invention;

Fig. 4 is the strain distribution diagram near the vibrating region of the present invention;

shown in the figure

Frequency swept laser 1 Sensing fiber 5

Fiber coupler 2 Coherent detection module 6

Optical fiber amplifier 3 Data acquisition card 7

Optical Circulator 4 Data Processor 8

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

The invention discloses a vibration detection method of a high-frequency response distributed optical fiber acoustic wave sensor, which can eliminate the crosstalk caused by the high-frequency vibration of the front section of the optical fiber in the optical frequency domain reflectometer and the time-gated optical frequency domain reflectometer to the vibration detection of the rear section of the optical fiber For any position to be measured on the sensing fiber 5, detect the change information of the beat frequency shift over time caused by the high-frequency vibration on the front section of the fiber to the phase modulation of the frequency-sweeping detection optical signal (that is, obtain the information corresponding to the spatial The moving curve of the back Rayleigh scattering spectral domain fingerprint at the position L to be measured in the entire pulse width) to obtain the correct instantaneous light-frequency frequency shift corresponding to the position to be measured, thereby eliminating the impact of the beat frequency shift on vibration demodulation, Then, according to the corrected instantaneous beat frequency, the spectrum or phase change of the back Rayleigh scattered light at the position to be measured is measured to realize strain detection without crosstalk on the entire optical fiber and improve the response bandwidth of the sensing system.

According to the vibration detection method of the high frequency response distributed fiber optic acoustic wave sensor provided by the present invention, as shown in Fig. device 2, optical fiber circulator 4, sensing optical fiber 5, coherent detection module 6, data acquisition card 7 and data processor 8;

The laser light output by the laser module is divided into detection light and local light through the fiber coupler 2, and the detection light is input into the sensing fiber 5 through the optical fiber circulator 4 to form backward Rayleigh scattered light, and the backward Rayleigh scattered light The coherent detection module 6 is input through the optical fiber circulator 4, and the local light is input into the coherent detection module 6, and the coherent detection module 6 can beat the back Rayleigh scattered light and the local light and form an electrical signal output, the said The data acquisition card 7 can collect electrical signals, and the data processor 8 can process electrical signals; the laser module adopts a frequency-sweeping laser 1, and the frequency-sweeping laser 1 can output a frequency-sweeping optical pulse train; or, The laser module adopts a narrow-linewidth laser, and the high-frequency-response distributed fiber optic acoustic wave sensor also includes a radio frequency signal module and an optical modulator, and the optical modulator is arranged between the fiber coupler 2 and the fiber optic circulator 4, so The radio frequency signal module can input a frequency-sweeping radio frequency pulse train signal to the optical modulator, and the detection light can form a frequency-sweeping optical pulse train through the optical modulator. The power of the probe light is greater than the local light, and the probe light input into the fiber optic circulator 4 is a frequency-sweeping light pulse train; preferably, a fiber amplifier 3 is also included, and the fiber amplifier 3 is arranged between the fiber coupler 2 and the fiber optic circulator 4 In between, the probe light is amplified by the fiber amplifier 3 and then input to the fiber circulator 4, and the fiber amplifier 3 is an erbium-doped fiber amplifier. The data acquisition card 7 includes a dual-channel data acquisition card. The fiber coupler 2 adopts a single-mode fiber coupler with a coupling ratio of 90:10.

Example 1:

This embodiment provides a distributed vibration detection system based on an optical frequency domain reflectometer. The optical frequency domain reflectometer includes a swept laser 1, a fiber coupler 2, a fiber circulator 4, a sensing fiber 5, a Module 6, data acquisition card 7 and data processor 8, wherein: the frequency-sweeping laser 1 outputs a high-power, large-bandwidth frequency-sweeping optical pulse train, the optical pulse train is divided into two paths, one path has a higher optical power, As the detection light, it is input to the sensing fiber 5 through the optical fiber circulator 4, and the other path has a lower optical power, which is input to the coherent detection module 6 as local light; the back Rayleigh scattered light generated by the sensing fiber 5 passes through the optical fiber circulator 4 Enter the coherent detection module 6; the backward Rayleigh scattered light is divided into two polarization states of X and Y in the coherent detection module 6, which are respectively marked as S-X and S-Y light; similarly, the local light is also divided into L-X and L-Y two states of light; the light of the two states of Rayleigh backscattered light and the two states of the corresponding local light beat respectively, and then are photoelectrically converted into electrical signals of two states of I-X and I-Y respectively Output; finally the data acquisition card 7 and the data processor 8 collect and process the I-X and I-Y state electrical signals respectively.

Example 2

This embodiment provides a distributed vibration detection system based on a time-gated optical frequency domain reflectometer. The time-gated optical frequency domain reflectometer includes a radio frequency signal module, a narrow linewidth laser, a fiber coupler 2, an optical modulation device, optical fiber circulator 4, sensing fiber 5, coherent detection module 6, data acquisition card 7 and data processor 8, wherein: the radio frequency signal module includes a connected radio frequency signal generator and a radio frequency signal amplifier, and inputs to the optical modulator Frequency-sweeping radio frequency pulse train signal; the highly coherent and high-power laser output by the narrow-linewidth laser is divided into two paths by the fiber coupler 2, one path has a lower optical power, and is input into the coherent detection module 6 as local light, and the other path has Higher optical power is input to the optical modulator; the optical modulator outputs a frequency-sweeping optical pulse train, which is input to the sensing fiber 5 through the optical fiber circulator 4; the back Rayleigh scattered light generated by the sensing optical fiber 5 passes through the optical fiber circulator 4 Enter the coherent detection module 6; the backward Rayleigh scattered light is divided into two polarization states of X and Y in the coherent detection module 6, which are respectively marked as S-X and S-Y light; similarly, the local light is also divided into L-X and L-Y two states of light; the light of the two states of Rayleigh backscattered light and the two states of the corresponding local light beat respectively, and then are photoelectrically converted into electrical signals of two states of I-X and I-Y respectively Output; finally the data acquisition card 7 and the data processor 8 collect and process the I-X and I-Y state electrical signals respectively.

The vibration detection method of the high frequency response distributed fiber optic acoustic sensor also includes the following steps:

Step 1: After the data acquisition card 7 collects electrical signals, a two-dimensional array is formed by using a time-frequency analysis method, and marked in order of transmission time; the time-frequency analysis method includes short-time Fourier transform and wavelet transform.

Step 2: After time-frequency analysis is performed on the electrical signal, the beat frequency-optical frequency domain fingerprint image of the back Rayleigh scattered light at each position of the sensing fiber 5 at the nth detection is obtained.

Step 3: Use the image matching method to detect the translation of the Rayleigh backscattered light at the position to be measured by the sensing fiber 5 in the beat frequency-optical frequency domain fingerprint image, so as to obtain the Rayleigh backscattered light at the position to be measured at The location within the entire beat-optical frequency domain fingerprint image;

Step 4: According to the position of the backward Rayleigh scattered light of the position to be measured in the entire beat frequency-optical frequency domain fingerprint image, the instantaneous light-frequency frequency shift corresponding to the position to be measured is obtained, so as to obtain the position of the sensing fiber 5 to be measured strain size.

Described step 3 comprises the steps:

Step 3.1: Using an image matching method, the image matching method includes: taking the beat frequency-optical frequency domain fingerprint image of the back Rayleigh scattered light obtained in the first detection corresponding to a position to be measured in the sensing fiber 5 in space At L, the sub-region at a certain time point t in time is defined as the reference sub-region, which is used near the reference sub-region on the beat frequency-optical frequency domain fingerprint image of the back Rayleigh scattered light obtained by the nth detection Image matching, find the sub-area to be measured that best matches the reference sub-area, and obtain the back Rayleigh scattered light corresponding to time and space in the beat frequency-optical frequency domain fingerprint image at the position L of the sensing fiber 5 to be measured the amount of translation;

As shown in Figure 3, where:

(a): The beat frequency of the Rayleigh backscattered light obtained in the first detection is shown in the white dotted box - the fingerprint image in the optical frequency domain corresponds to a certain position L of the sensing fiber 5 in space, and a certain position L in time. the subregion at time point t;

(b): In the white dotted line box is the beat frequency of the Rayleigh backscattered light obtained by the nth detection - near the reference sub-region on the optical frequency domain fingerprint image, use image matching to find the target that best matches the reference sub-region Measuring sub-area;

Step 3.2: Change the time point t and repeat step 3.1 until the location of the Rayleigh backscattered light corresponding to the location to be measured in space in the entire beat frequency-optical frequency domain fingerprint image is obtained.

Described step 4 comprises the steps:

Step 4.1: According to the position of the backward Rayleigh scattered light corresponding to the position L to be measured in space obtained by the nth detection in the entire beat frequency-optical frequency domain fingerprint image, the instantaneous light corresponding to the position L to be measured is obtained frequency shift;

Step 4.2: According to the instantaneous light-frequency shift, obtain the spectrum or phase change information of the Rayleigh backscattered light corresponding to the position L to be measured obtained by the nth detection, so as to obtain the strain.

其中，K_ε-ν为应变-频移系数，ν₀为中心频率。In step 4.2, according to the corresponding instantaneous light-frequency frequency shift at the position L to be measured, the spectral frequency shift Δν of the back Rayleigh scattered light at the position to be measured is obtained, and the strain is

Among them, K _ε-ν is the strain-frequency shift coefficient, and ν ₀ is the center frequency.

其中，K_ε-φ为应变-相位系数，ΔL为差分距离。In step 4.2, according to the instantaneous light-frequency frequency shift corresponding to the position L to be measured, the differential phase change Δφ of the back Rayleigh scattered light at the position to be measured is obtained, and the strain amount is

Among them, K _ε-φ is the strain-phase coefficient, and ΔL is the differential distance.

Also includes step 5: changing n and L, repeating steps 3-4, as shown in Figure 4, until the strain distribution on the entire sensing fiber 5 changes with time, so as to achieve strain detection without crosstalk on the entire optical fiber , to increase the response bandwidth of the sensing system.

In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description, rather than indicating or implying the referred device Or elements must have a certain orientation, be constructed and operate in a certain orientation, and thus should not be construed as limiting the application.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims (10)

1. a vibration detection method of a high frequency response distributed fiber optic acoustic wave sensor, characterized in that, comprising a high frequency response distributed fiber optic acoustic wave sensor, said high frequency response distributed fiber optic acoustic wave sensor comprising a laser module, an optical fiber coupler (2 ), optical fiber circulator (4), sensing optical fiber (5), coherent detection module (6), data acquisition card (7) and data processor (8); The laser light output by the laser module is divided into detection light and local light through the fiber coupler (2), and the detection light is input into the sensing fiber (5) through the optical fiber circulator (4) to form backward Rayleigh scattered light. Rearward Rayleigh scattered light passes through the optical fiber circulator (4) as a signal light input coherent detection module (6), the local light input coherent detection module (6), and the coherent detection module (6) can convert the backward Rayleigh scattered light and local light beat frequency and form an electrical signal output, the data acquisition card (7) can collect the electrical signal, and the data processor (8) can process the electrical signal; The detection light of the input fiber optic circulator (4) is a frequency-sweeping light pulse train; The vibration detection method of the high frequency response distributed fiber optic acoustic sensor also includes the following steps: Step 1: the data acquisition card (7) collects electrical signals; Step 2: Use time-frequency analysis on the electrical signal to obtain the beat frequency-optical frequency domain fingerprint image of the Rayleigh backscattered light; Step 3: Using an image matching method to detect the translation of the Rayleigh backscattering light of the sensing fiber (5) at the position to be measured in the beat frequency-optical frequency domain fingerprint image, thereby obtaining the Rayleigh backscattering of the position to be measured The position of light within the entire beat-optical frequency domain fingerprint image; Step 4: Obtain the instantaneous light-frequency frequency shift corresponding to the position to be measured according to the position of the back Rayleigh scattered light of the position to be measured in the entire beat frequency-optical frequency domain fingerprint image, thereby calculating the sensing fiber (5) to be tested The magnitude of the strain at the location. 2. the vibration detection method of high frequency response distributed optical fiber acoustic wave sensor according to claim 1, is characterized in that, in step 1, after data acquisition card (7) collects electric signal, adopts time-frequency analysis method to form two-dimensional array , and marked in order of launch time; The time-frequency analysis method includes short-time Fourier transform and wavelet transform. 3. the vibration detection method of high-frequency response distributed optical fiber acoustic wave sensor according to claim 1, it is characterized in that, in step 2, after using time-frequency analysis to electric signal, obtain sensing optical fiber (5) when detecting for the nth time ) The beat frequency-optical frequency domain fingerprint image of Rayleigh backscattered light at each position. 4. the vibration detection method of high frequency response distributed optical fiber acoustic wave sensor according to claim 3, is characterized in that, described step 3 comprises the steps: Step 3.1: Using an image matching method, the image matching method includes: taking the beat frequency-optical frequency domain fingerprint image of the Rayleigh backscattered light obtained in the first detection corresponding to a certain target of the sensing fiber (5) in space. At the measured position L, the sub-area at a certain time point t in time is defined as the reference sub-area, and the beat frequency of the back Rayleigh scattered light obtained in the nth detection-optical frequency domain fingerprint image of the reference sub-area Use image matching nearby to find the sub-area to be measured that best matches the reference sub-area, and obtain the Rayleigh scattered light at the position L of the sensing fiber (5) corresponding to the time and space in the beat frequency-optical frequency The amount of translation in the domain fingerprint image; Step 3.2: Change the time point t and repeat step 3.1 until the location of the Rayleigh backscattered light corresponding to the location to be measured in space in the entire beat frequency-optical frequency domain fingerprint image is obtained. 5. the vibration detection method of high frequency response distributed fiber optic acoustic wave sensor according to claim 3, is characterized in that, described step 4 comprises the steps: Step 4.1: According to the position of the backward Rayleigh scattered light corresponding to the position L to be measured in space obtained by the nth detection in the entire beat frequency-optical frequency domain fingerprint image, the instantaneous light corresponding to the position L to be measured is obtained frequency shift; Step 4.2: According to the instantaneous light-frequency shift, obtain the spectrum or phase change information of the Rayleigh backscattered light corresponding to the position L to be measured obtained by the nth detection, so as to obtain the strain. 6. The vibration detection method of the high frequency response distributed fiber optic acoustic wave sensor according to claims 4 and 5, further comprising step 5: changing n and L, repeating steps 3-4, until the whole root sensor is obtained The strain distribution on the optical fiber (5) varies with time. 7. The vibration detection method of the high-frequency-response distributed fiber optic acoustic wave sensor according to claim 5, wherein in step 4.2, according to the instantaneous light-frequency frequency shift corresponding to the position L to be measured, the position to be measured is obtained and the direction to Rui The spectral frequency shift Δν of the scattered light, the strain is

Among them, K _ε-ν is the strain-frequency shift coefficient, and ν ₀ is the center frequency. 8. The vibration detection method of the high-frequency-response distributed fiber optic acoustic wave sensor according to claim 5, wherein in step 4.2, according to the instantaneous light-frequency frequency shift corresponding to the position L to be measured, the position to be measured is obtained and the direction to Rui The differential phase change Δφ of the scattered light, the strain is

Among them, K _ε-φ is the strain-phase coefficient, and ΔL is the differential distance. 9. The vibration detection method of the high-frequency-response distributed fiber optic acoustic wave sensor according to claim 1, wherein the laser module adopts a frequency-sweeping laser (1), and the frequency-sweeping laser (1) can output frequency-sweeping train of light pulses. 10. The vibration detection method of the high frequency response distributed fiber optic acoustic wave sensor according to claim 1, wherein the laser module adopts a narrow linewidth laser, and the high frequency response distributed fiber optic acoustic wave sensor also includes a radio frequency signal module and an optical modulator, the optical modulator is arranged between the optical fiber coupler (2) and the optical fiber circulator (4), the radio frequency signal module can input a frequency-sweeping radio frequency pulse train signal to the optical modulator, and the detection Light passing through an optical modulator can form a frequency-swept optical pulse train.

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