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

Abstract

The application provides a vibration detection method of a high-frequency-response distributed optical fiber acoustic wave sensor, and comprises the following steps: step 1: a data acquisition card 7 collects an electric signal; step 2: time-frequency analysis is performed on the electric signal to obtain a beat frequency-optical frequency fingerprint pattern of back Rayleigh scattering light of a sensing optical fiber 5; step 3: an image matching method is used to detect the translation amount of the back Rayleigh scattering light of the sensing optical fiber 5 at a to-be-detected position in the beat frequency direction, so that the position of the back Rayleigh scattering light of the to-be-detected position in the entire beat frequency-optical frequency fingerprint pattern is obtained; and step 4: an instantaneous optical frequency shift corresponding to the to-be-detected position is obtained, so that the strain size at the to-be-detected position of the sensing optical fiber 5 is calculated. The application effectively suppresses the crosstalk of high-frequency vibration of the front section of the sensing optical fiber on 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

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical fiber sensing, in particular to a vibration detection method of a high-frequency-response distributed optical fiber acoustic sensor, and especially to a vibration detection method of a high-frequency-response distributed optical fiber acoustic sensor capable of suppressing crosstalk. BACKGROUND

[0002] 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 environmental sound vibration signals. Moreover, the position of the vibration signal can be accurately located, and more importantly, the waveform of the sound vibration signal can be quantitatively obtained for further analysis. Compared with traditional acoustic sensors based on mechanical or electromagnetic principles, DAS has the advantages of general optical fiber sensors, such as anti-electromagnetic interference, corrosion resistance, and intrinsic passivity. In addition, DAS has distributed measurement capability, which is easy to realize large-scale acoustic sensor multiplexing and avoids the problems of power supply and signal transmission in traditional acoustic sensor multiplexing schemes. In the scenarios of aircraft fuselage structure monitoring, turbine blade state monitoring, and sound source positioning in fluids, it is necessary for the DAS system to have a high spatial resolution. Most of the current DAS technologies are based on optical time domain reflectometry technology, and the spatial resolution is more than one meter, which is difficult to be directly applied to the above-mentioned scenarios.

[0003] 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 sweep range of the probe light, so the spatial resolution and the duration of the probe light are decoupled, which can ensure that the DAS system has a very high spatial resolution. However, due to the long duration of the probe light in this scheme, when the optical fiber is subjected to vibration, the phase modulation exerted by the vibration on the probe light is no longer a constant value within the duration of the probe light, which causes crosstalk in the strain demodulation of the subsequent position due to the vibration, and even causes the demodulation method to fail. Therefore, the current high spatial resolution DAS system cannot correctly detect high-frequency vibration signals, and the response bandwidth is severely limited.

[0004] The patent document with the publication number CN113295257A discloses a kind of optical fiber acoustic sensor signal demodulation method and system, its difference lies in, including the following steps: step 1: broadband light provided by light source passes through optical fiber acoustic sensor, broadband light occurs interference;Step 2: after interference, broadband light becomes N wavelength interval certain narrowband light after screening;Step 3: corresponding N route interference light intensity is obtained from the N route different wavelength of narrowband light;The N route interference light intensity is converted into N route corresponding voltage signal;Step 4: N route voltage signal is sampled in multiple channels, and N demodulation working point voltages are sampled;Step 5: obtain the signal of intensity demodulation effect best, as demodulation signal;Step 6: the demodulation signal is processed and restored, becomes acoustic wave signal.The application increases the stability and reliability of demodulation, improves the batch practical ability of optical fiber acoustic sensor.But this scheme is only applicable to solve the problem of sensor static working point drift under the change of environmental factors, cannot solve the problem of crosstalk caused by strain demodulation of subsequent position of vibration received on optical fiber. SUMMARY

[0005] In view of the defects in the prior art, the purpose of the present application is to provide a vibration detection method for a high-frequency-response distributed optical fiber acoustic sensor.

[0006] The vibration detection method for a high-frequency-response distributed optical fiber acoustic sensor provided by the present application comprises a high-frequency-response distributed optical fiber acoustic sensor, which comprises a laser module, a fiber coupler, a fiber circulator, a sensing optical fiber, a coherent detection module, a data acquisition card and a data processor.

[0007] The laser output by the laser module is divided into probe light and local light by the fiber coupler, the probe light forms back Rayleigh scattering light after being input into the sensing optical fiber through the fiber circulator, the back Rayleigh scattering light is input into the coherent detection module as signal light through the fiber circulator, the local light is input into the coherent detection module, the coherent detection module can beat the back Rayleigh scattering light and the local light and form an electrical signal output, the data acquisition card can collect the electrical signal, and the data processor can process the electrical signal.

[0008] The probe light input into the fiber circulator is a sweep frequency light pulse train.

[0009] The vibration detection method for a high-frequency-response distributed optical fiber acoustic sensor further comprises the following steps:

[0010] Step 1: the data acquisition card collects the electrical signal.

[0011] Step 2: time-frequency analysis is used on the electrical signal to obtain a beat frequency-optical frequency domain fingerprint image of the back Rayleigh scattering light.

[0012] Step 3: using image matching method, detecting the shift of the back Rayleigh scattering light of the position to be measured in the beat frequency-optical frequency domain fingerprint image, so as to obtain the position of the back Rayleigh scattering light of the position to be measured in the whole beat frequency-optical frequency domain fingerprint image;

[0013] Step 4: according to the position of the back Rayleigh scattering light of the position to be measured in the whole beat frequency-optical frequency domain fingerprint image, obtaining the corresponding instantaneous optical frequency shift of the position to be measured, so as to obtain the strain size at the position to be measured of the sensing optical fiber.

[0014] Preferably, in step 1, after the data acquisition card collects the electrical signal, a time-frequency analysis method is used to form a two-dimensional array, and the time sequence is marked;

[0015] The time-frequency analysis method includes short-time Fourier transform and wavelet transform.

[0016] Preferably, in step 2, after the time-frequency analysis is used on the electrical signal, the beat frequency-optical frequency domain fingerprint image of the back Rayleigh scattering light of each position of the sensing optical fiber in the nth detection is obtained.

[0017] Preferably, the step 3 includes the following steps:

[0018] Step 3.1: using image matching method, the image matching method includes: taking the sub-region corresponding to a position to be measured L on the space and a time point t on the time of the back Rayleigh scattering light of the beat frequency-optical frequency domain fingerprint image obtained in the first detection as the reference sub-region, using image matching in the vicinity of the reference sub-region of the back Rayleigh scattering light of the beat frequency-optical frequency domain fingerprint image obtained in the nth detection to find the measured sub-region most matched with the reference sub-region, obtaining the shift of the back Rayleigh scattering light corresponding to the position to be measured L on the space in the beat frequency-optical frequency domain fingerprint image on the time;

[0019] Step 3.2: repeating step 3.1 by changing the time point t until the position of the back Rayleigh scattering light corresponding to the position to be measured L on the space in the whole beat frequency-optical frequency domain fingerprint image is obtained.

[0020] Preferably, the step 4 includes the following steps:

[0021] Step 4.1: obtaining the corresponding instantaneous optical frequency shift of the position to be measured L according to the position of the back Rayleigh scattering light corresponding to the position to be measured L on the space in the whole beat frequency-optical frequency domain fingerprint image obtained in the nth detection;

[0022] Step 4.2: obtaining the frequency spectrum or phase change information of the back Rayleigh scattering light corresponding to the position to be measured L obtained in the nth detection according to the instantaneous optical frequency shift, so as to obtain the strain size.

[0023] Preferably, further comprising step 5: changing n and L, repeating steps 3-4 until the strain distribution on the whole sensing optical fiber (5) is obtained.

[0024] Preferably, in step 4.2, the frequency shift Δν of the backscattered Rayleigh light at the position L to be measured is obtained according to the corresponding instantaneous optical frequency shift at the position L to be measured, and the strain amount is

[0025] Wherein, K ε-ν is the strain-frequency coefficient, and v0 is the central frequency.

[0026] Preferably, in step 4.2, the differential phase change Δφ of the backscattered Rayleigh light at the position L to be measured is obtained according to the corresponding instantaneous optical frequency shift at the position L to be measured, and the strain amount is

[0027] Wherein, K ε-φ is the strain-phase coefficient, and ΔL is the differential distance.

[0028] Preferably, the laser module uses a swept laser, and the swept laser can output a swept optical pulse train.

[0029] Preferably, the laser module uses a narrow linewidth laser, and the high-frequency response distributed optical fiber acoustic wave sensor further comprises a radio frequency signal module and an optical modulator, the optical modulator is arranged between the optical fiber coupler and the optical fiber ring, the radio frequency signal module can input a swept radio frequency pulse train signal to the optical modulator, and the probe light can form a swept optical pulse train through the optical modulator.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The present application effectively suppresses the crosstalk of 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. BRIEF DESCRIPTION OF DRAWINGS

[0032] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0033] Figure 1 It is a structural schematic diagram of the high-frequency response distributed optical fiber acoustic wave sensor in the present application;

[0034] Figure 2 It is a time-frequency analysis diagram of the swept optical pulse train in the present application;

[0035] Figure 3 It is a beat frequency-optical frequency domain fingerprint image of the backscattered Rayleigh light in the present application;

[0036] Figure 4 Strain distribution map near the vibration region of the present application;

[0037] The figure shows

[0038] Sweep laser 1 Sensing fiber 5

[0039] Fiber coupler 2 Coherent detection module 6

[0040] Fiber amplifier 3 Data acquisition card 7

[0041] Fiber circulator 4 Data processor 8 DETAILED DESCRIPTION

[0042] The present application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of changes and improvements can be made. These are within the scope of the present application.

[0043] The present application discloses a kind of high frequency response distributed optical fiber acoustic wave sensor vibration detection method, can eliminate the high frequency vibration of optical frequency domain reflectometer and time gate optical frequency domain reflectometer in front section of fiber to the crosstalk of rear section fiber vibration detection of distributed vibration, on sensing fiber 5 on any to be measured position, detect the beat frequency frequency shift caused by the phase modulation of high frequency vibration on front section fiber to sweep detection light signal with time variation information (i.e. obtain the moving curve corresponding to the back Rayleigh scattering spectrum domain fingerprint in entire pulse width at spatial to be measured position L), obtain the correct instantaneous optical frequency shift corresponding to the to be measured position, to eliminate the influence of beat frequency frequency shift on vibration demodulation, then according to the corrected instantaneous beat frequency, the spectrum or phase change of back Rayleigh scattering light of the to be measured position is measured, realize strain detection without crosstalk to whole optical fiber, improve the response bandwidth of sensing system.

[0044] According to the high frequency response distributed optical fiber acoustic wave sensor vibration detection method provided by the present application, as shown in Figure 1 The present application discloses a kind of high frequency response distributed optical fiber acoustic wave sensor vibration detection method, which can eliminate the high frequency vibration of optical frequency domain reflectometer and time gate optical frequency domain reflectometer in front section of fiber to the crosstalk of rear section fiber vibration detection of distributed vibration, on sensing fiber 5 on any to be measured position, detect the beat frequency frequency shift caused by the phase modulation of high frequency vibration on front section fiber to sweep detection light signal with time variation information (i.e. obtain the moving curve corresponding to the back Rayleigh scattering spectrum domain fingerprint in entire pulse width at spatial to be measured position L), obtain the correct instantaneous optical frequency shift corresponding to the to be measured position, to eliminate the influence of beat frequency frequency shift on vibration demodulation, then according to the corrected instantaneous beat frequency, the spectrum or phase change of back Rayleigh scattering light of the to be measured position is measured, realize strain detection without crosstalk to whole optical fiber, improve the response bandwidth of sensing system.

[0045] The laser module outputs laser light, which is split into probe light and local light by the fiber coupler 2. The probe light is input into the sensing optical fiber 5 through the optical fiber circulator 4 to form back Rayleigh scattering light. The back Rayleigh scattering light is input into the coherent detection module 6 through the optical fiber circulator 4. The local light is input into the coherent detection module 6. The coherent detection module 6 can beat the back Rayleigh scattering light and the local light to form an electrical signal output. The data acquisition card 7 can collect the electrical signal. The data processor 8 can process the electrical signal. The laser module uses a swept laser 1, which can output a swept light pulse train. Alternatively, the laser module uses a narrow linewidth laser. The high-frequency response distributed optical fiber acoustic wave sensor further comprises a radio frequency signal module and an optical modulator. The optical modulator is arranged between the fiber coupler 2 and the optical fiber circulator 4. The radio frequency signal module can input a swept radio frequency pulse train signal to the optical modulator. The probe light can form a swept light pulse train through the optical modulator. The power of the probe light is greater than that of the local light. The probe light input into the optical fiber circulator 4 is a swept light pulse train. Preferably, the high-frequency response distributed optical fiber acoustic wave sensor further comprises an optical fiber amplifier 3. The optical fiber amplifier 3 is arranged between the fiber coupler 2 and the optical fiber circulator 4. The probe light is input into the optical fiber circulator 4 after power amplification through the optical fiber amplifier 3. The optical fiber amplifier 3 uses an erbium-doped optical fiber amplifier. The data acquisition card 7 comprises a double-channel data acquisition card. The fiber coupler 2 uses a single-mode fiber coupler with a coupling ratio of 90 to 10.

[0046] Embodiment 1

[0047] The present embodiment provides a distributed vibration detection system based on an optical frequency domain reflectometer. The optical frequency domain reflectometer comprises a swept laser 1, a fiber coupler 2, an optical fiber circulator 4, a sensing optical fiber 5, a coherent detection module 6, a data acquisition card 7, and a data processor 8. The swept laser 1 outputs a high-power and large-bandwidth swept light pulse train. The light pulse train is divided into two paths. One path has a higher optical power and is input into the sensing optical fiber 5 as probe light through the optical fiber circulator 4. The other path has a lower optical power and is input into the coherent detection module 6 as local light. The back Rayleigh scattering light generated by the sensing optical fiber 5 is input into the coherent detection module 6 through the optical fiber circulator 4. The back Rayleigh scattering light is divided into X and Y polarization state lights in the coherent detection module 6, which are marked as S-X and S-Y lights, respectively. Similarly, the local light is also divided into L-X and L-Y state lights. The two state lights of the back Rayleigh scattering light and the corresponding two state lights of the local light are beat, and then are photoelectrically converted into I-X and I-Y state electrical signal outputs, respectively. Finally, the data acquisition card 7 and the data processor 8 collect and process the I-X and I-Y state electrical signals, respectively.

[0048] Embodiment 2

[0049] The embodiment provides a distributed vibration detection system based on a time-gated optical frequency domain reflectometer, the time-gated optical frequency domain reflectometer comprising a radio frequency signal module, a narrow-linewidth laser, a fiber coupler 2, an optical modulator, a fiber circulator 4, a sensing optical fiber 5, a coherent detection module 6, a data acquisition card 7 and a data processor 8, wherein: the radio frequency signal module comprises a radio frequency signal generator and a radio frequency signal amplifier connected in sequence, and inputs a swept radio frequency pulse train signal to the optical modulator; high-coherence and high-power laser output by the narrow-linewidth laser is divided into two paths by the fiber coupler 2, one path has lower optical power and is input to the coherent detection module 6 as local light, and the other path has higher optical power and is input to the optical modulator; the optical modulator outputs a swept optical pulse train, which is input to the sensing optical fiber 5 through the fiber circulator 4; backscattered Rayleigh light generated by the sensing optical fiber 5 enters the coherent detection module 6 through the fiber circulator 4; the backscattered Rayleigh light is divided into X and Y polarization state lights in the coherent detection module 6, and is marked as S-X and S-Y light respectively; similarly, the local light is also divided into L-X and L-Y state light; the two state lights of the backscattered Rayleigh light and the two state lights of the corresponding local light are beat respectively, and then are photoelectrically converted into I-X and I-Y state electrical signals and 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.

[0050] The vibration detection method of the high-frequency-response distributed optical fiber acoustic wave sensor further comprises the following steps:

[0051] Step 1: after the data acquisition card 7 collects the electrical signals, a time-frequency analysis method is used to form a two-dimensional array, and the array is marked in the order of transmission time; the time-frequency analysis method comprises a short-time Fourier transform and a wavelet transform.

[0052] Step 2: after the time-frequency analysis is used on the electrical signals, a beat frequency-optical frequency domain fingerprint image of the backscattered Rayleigh light of each position of the sensing optical fiber 5 at the nthprobing is obtained.

[0053] Step 3: an image matching method is used to detect the translation amount of the backscattered Rayleigh light of the to-be-detected position of the sensing optical fiber 5 in the beat frequency-optical frequency domain fingerprint image, so that the position of the backscattered Rayleigh light of the to-be-detected position in the entire beat frequency-optical frequency domain fingerprint image is obtained.

[0054] Step 4: according to the position of the backscattered Rayleigh light of the to-be-detected position in the entire beat frequency-optical frequency domain fingerprint image, the corresponding instantaneous optical frequency shift of the to-be-detected position is obtained, so that the strain size at the to-be-detected position of the sensing optical fiber 5 is calculated.

[0055] The step 3 comprises the following steps:

[0056] Step 3.1: Using an image matching method, the image matching method includes: taking a subregion corresponding to a certain position L to be measured in the sensing optical fiber 5 in space and at a certain time point t on the beat frequency-optical frequency domain fingerprint image of the backscattered light obtained by the first detection, defining it as a reference subregion; performing image matching near the reference subregion on the beat frequency-optical frequency domain fingerprint image of the backscattered light obtained by the nth detection to find the subregion to be measured that best matches the reference subregion; and obtaining the translation amount of the backscattered light in the beat frequency-optical frequency domain fingerprint image corresponding to the temporal and spatial position L to be measured on the sensing optical fiber 5;

[0057] like Figure 3 As shown, where:

[0058] (a): The white dotted box is the beat frequency of the Rayleigh scattered light obtained in the first detection - the sub-region on the optical frequency domain fingerprint image corresponding to a certain position L to be measured on the sensing optical fiber 5 in space and a certain time point t in time;

[0059] (b): The white dotted box is the beat frequency of the Rayleigh backscattered light obtained by the nth detection - the sub-region to be tested that best matches the reference sub-region is found by image matching near the reference sub-region on the optical frequency domain fingerprint image;

[0060] Step 3.2: Repeat step 3.1 by changing the time point t until the position of the backscattered Rayleigh light corresponding to the position L to be measured in the space within the entire beat frequency-optical frequency domain fingerprint image is obtained.

[0061] The step 4 comprises the following steps:

[0062] Step 4.1: Based on the position of the backscattered Rayleigh light corresponding to the spatial position L to be measured obtained by the nth detection within the entire beat frequency-optical frequency domain fingerprint image, obtain the instantaneous optical frequency shift corresponding to the position to be measured L;

[0063] Step 4.2: According to the instantaneous optical frequency shift, the spectrum or phase change information of the backscattered Rayleigh light corresponding to the position to be measured L obtained by the n-th detection is obtained, thereby calculating the strain magnitude.

[0064] In step 4.2, the frequency shift Δν of the spectrum of the Rayleigh scattered light at the position to be measured is obtained according to the instantaneous optical frequency shift corresponding to the position to be measured L. The strain is Among them, K ε-ν is the strain-frequency shift coefficient, and ν0 is the center frequency.

[0065] In step 4.2, according to the instantaneous optical frequency shift corresponding to the position to be measured L, the differential phase change Δφ of the Rayleigh scattered light at the position to be measured is obtained, and the strain is Among them, K ε-φwhere is the strain-phase coefficient, and AL is the differential distance.

[0066] Further comprising step 5: changing n and L, repeating steps 3-4, as shown, until the strain distribution on the whole sensing optical fiber 5 over time is obtained, so as to realize strain detection without crosstalk on the whole optical fiber, and improve the response bandwidth of the sensing system. Figure 4

[0067] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0068] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the specific embodiments described above, and various changes or modifications can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other without conflict.​

Claims

1. A vibration detection method for a high-frequency response distributed optical fiber acoustic wave sensor, characterized in that: The high-frequency response distributed optical fiber acoustic wave sensor comprises a laser module, an optical fiber coupler (2), an optical fiber circulator (4), a sensing optical fiber (5), a coherent detection module (6), a data acquisition card (7), and a data processor (8); The laser light output by the laser module is divided into detection light and local light through an optical fiber coupler (2); the detection light is input into a sensing optical fiber (5) through an optical fiber circulator (4) to form backward Rayleigh scattered light; the backward Rayleigh scattered light is input into a coherent detection module (6) as signal light through the optical fiber circulator (4); the local light is input into the coherent detection module (6); the coherent detection module (6) can beat the backward Rayleigh scattered light and the local light and form an electrical signal output; the data acquisition card (7) can acquire the electrical signal; and the data processor (8) can process the electrical signal; The detection light input to the optical fiber circulator (4) is a frequency-sweep optical pulse train; The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor further comprises 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 backscattered Rayleigh light; Step 3: using an image matching method to detect the translation of the backscattered Rayleigh light at the position to be measured of the sensing optical fiber (5) in the beat frequency-optical frequency domain fingerprint image, thereby obtaining the position of the backscattered Rayleigh light at the position to be measured in the entire beat frequency-optical frequency domain fingerprint image; Step 4: According to the position of the backscattered Rayleigh light at the position to be measured in the entire beat frequency-optical frequency domain fingerprint image, the instantaneous optical frequency shift corresponding to the position to be measured is obtained, thereby calculating the strain magnitude at the position to be measured of the sensing optical fiber (5).

2. The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor according to claim 1, characterized in that: In step 1, after the data acquisition card (7) collects the electrical signal, it uses the time-frequency analysis method to form a two-dimensional array and marks it in the order of the emission time; The time-frequency analysis method includes short-time Fourier transform and wavelet transform.

3. The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor according to claim 1, characterized in that: In step 2, after performing time-frequency analysis on the electrical signal, a beat frequency-optical frequency domain fingerprint image of the backward Rayleigh scattered light at each position of the sensing optical fiber (5) during the nth detection is obtained.

4. The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor according to claim 3, characterized in that: The step 3 comprises the following steps: Step 3.1: using an image matching method, the image matching method comprising: taking a subregion corresponding to a certain position L of the sensing optical fiber (5) to be measured in space and a certain time point t in time on the beat frequency-optical frequency domain fingerprint image of the backscattered light obtained by the first detection, defining it as a reference subregion, using image matching near the reference subregion on the beat frequency-optical frequency domain fingerprint image of the backscattered light obtained by the nth detection, finding a subregion to be measured that best matches the reference subregion, and obtaining a translation amount of the backscattered light corresponding to the temporal and spatial position L of the sensing optical fiber (5) in the beat frequency-optical frequency domain fingerprint image; Step 3.2: Repeat step 3.1 by changing the time point t until the position of the backscattered Rayleigh light corresponding to the position L to be measured in the space within the entire beat frequency-optical frequency domain fingerprint image is obtained.

5. The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor according to claim 3, characterized in that: The step 4 comprises the following steps: Step 4.1: Based on the position of the backscattered Rayleigh light corresponding to the spatial position L to be measured obtained by the nth detection within the entire beat frequency-optical frequency domain fingerprint image, obtain the instantaneous optical frequency shift corresponding to the position to be measured L; Step 4.2: According to the instantaneous optical frequency shift, the spectrum or phase change information of the backscattered Rayleigh light corresponding to the position to be measured L obtained by the n-th detection is obtained, thereby calculating the strain magnitude.

6. The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor according to claims 4 and 5, characterized in that: The method further includes step 5: changing n and L, and repeating steps 3-4 until the time-varying strain distribution on the entire sensing optical fiber (5) is obtained.

7. The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor according to claim 5, characterized in that: In step 4.2, the frequency shift Δν of the spectrum of the Rayleigh scattered light at the position to be measured is obtained according to the instantaneous optical frequency shift corresponding to the position to be measured L. The strain is Among them, K ε-ν is the strain-frequency shift coefficient, and ν0 is the center frequency.

8. The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor according to claim 5, characterized in that: In step 4.2, according to the instantaneous optical frequency shift corresponding to the position to be measured L, the differential phase change Δφ of the Rayleigh scattered light at the position to be measured is obtained, and 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 optical fiber acoustic wave sensor according to claim 1, characterized in that: The laser module adopts a frequency-sweeping laser (1), and the frequency-sweeping laser (1) is capable of outputting a frequency-sweeping optical pulse train.

10. The vibration detection method of the high-frequency response distributed optical fiber acoustic wave sensor according to claim 1, characterized in that: The laser module adopts a narrow linewidth laser, and the high-frequency response distributed optical fiber acoustic wave sensor further comprises 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 swept frequency radio frequency pulse train signal to the optical modulator, and the detection light can form a swept frequency optical pulse train through the optical modulator.

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