Hollow-core optical fiber temperature cross sensitivity suppression method and system

Abstract

The invention relates to the technical field of optical fiber sensing, in particular to a hollow-core optical fiber temperature cross sensitivity suppression method and system. The method comprises the following steps: constructing a frequency spectrum matrix during optical-acoustic coupling and an incidence matrix under the combined action of temperature and strain; inputting the optical-acoustic coupling time frequency spectrum matrix into the incidence matrix to decouple the temperature and the strain so as to respectively obtain an independent temperature distribution parameter and an independent strain distribution parameter; performing data fusion on the temperature distribution parameter, the strain distribution parameter and the optical-acoustic coupling time-frequency spectrum matrix to generate a multi-physical field distribution map in the axial direction of the hollow-core optical fiber; based on the generated multi-physical field distribution map, analyzing the axial temperature and strain distribution change of the hollow-core optical fiber; and iteratively generating and executing a compensation strategy based on the acquired positions and types of the abnormal points. According to the invention, the cross sensitivity influence of a temperature gradient field on strain measurement can be effectively suppressed, and the measurement precision and reliability of the hollow-core optical fiber in a complex environment are improved.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, and in particular to a method and system for suppressing temperature cross-sensitivity of hollow-core optical fibers. Background Art

[0002] As a unique fiber structure, hollow-core fiber (HCF) has been widely used in distributed fiber-optic sensing due to its low nonlinearity, low loss, and high sensitivity. However, in practical applications, the cross-sensitivity of HCF to temperature and strain seriously affects measurement accuracy. This is especially true in complex environments, where the coupling effect between the temperature gradient field and the strain field can cause mutual interference between the optical and acoustic signals, making it difficult to accurately decouple independent parameters. Traditional methods typically employ single-physics-field modeling or empirical formulas for compensation, but these methods cannot fundamentally address the cross-sensitivity between temperature and strain and lack the ability to efficiently process the combined effects of multiple physical fields. Furthermore, existing technologies are insufficient in identifying and correcting outliers, making it difficult to achieve real-time monitoring and adaptive adjustment in dynamic environments. Therefore, a method for suppressing HCF temperature cross-sensitivity based on a multi-physics-field coupling mechanism is urgently needed. Through the coordinated processing of optical-acoustic signals and high-precision decoupling, independent measurement and compensation of temperature and strain can be achieved, providing reliable technical support for distributed fiber-optic sensing in complex environments. Summary of the Invention

[0003] The present invention overcomes the deficiencies of the prior art and provides a method and system for suppressing temperature cross-sensitivity of a hollow-core optical fiber.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0005] A first aspect of the present invention discloses a method for suppressing temperature cross-sensitivity of a hollow-core optical fiber, comprising the following steps:

[0006] Collect the reflected light signal and scattered acoustic wave signal of the hollow-core optical fiber to construct the light-acoustic coupling time-frequency spectrum matrix; collect the temperature and strain distribution data of the hollow-core optical fiber axial direction to construct the correlation matrix under the combined action of temperature and strain;

[0007] Inputting the light-acoustic coupling time-frequency spectrum matrix into the correlation matrix to decouple temperature and strain, thereby obtaining independent temperature distribution parameters and strain distribution parameters respectively;

[0008] The temperature distribution parameters, strain distribution parameters and optical-acoustic coupling time-frequency spectrum matrix are fused to generate a multi-physical field distribution map along the hollow-core optical fiber axis.

[0009] Based on the generated multi-physics field distribution map, the temperature and strain distribution changes in the hollow-core optical fiber axis are analyzed to obtain the location and type of abnormal points;

[0010] Based on the acquired outlier locations and types, compensation strategies are iteratively generated and executed until temperature cross-sensitivity suppression is completed.

[0011] Preferably, the reflected light signal and scattered acoustic wave signal of the hollow core optical fiber are collected to construct a light-acoustic coupling time-frequency spectrum matrix, specifically:

[0012] The reflected light signal is received by the hollow-core fiber end reflector, and the wavelength of the light signal is scanned using a tunable laser and a photodetector to obtain the spectral intensity distribution;

[0013] According to the spectral intensity distribution, combined with fast Fourier transform, the Brillouin frequency shift characteristics in the spectrum are extracted, and a mapping table of temperature-sensitive frequency bands and strain-sensitive frequency bands is constructed through the linear relationship between frequency shift and temperature / strain;

[0014] The acoustic wave signal along the axis of the hollow-core optical fiber is collected by a distributed acoustic wave sensor, and the acoustic wave signal is decomposed in the time domain using wavelet transform to extract the acoustic wave attenuation coefficients of different frequency bands. The temperature-sensitive frequency band and the strain-sensitive frequency band are separated by combining the mapping table to obtain independent characteristics of temperature and strain;

[0015] The independent characteristics of temperature and strain and the acoustic wave attenuation coefficient are aligned in time series to construct a light-acoustic coupling time-frequency spectrum matrix; the matrix row vectors are the time sampling points, and the column vectors are the joint eigenvalues of the Brillouin frequency shift characteristics and the acoustic wave attenuation coefficient.

[0016] Preferably, the temperature and strain distribution data of the hollow-core optical fiber in the axial direction are collected to construct a correlation matrix under the combined action of temperature and strain, specifically:

[0017] The temperature and strain distribution data of the hollow-core optical fiber in the axial direction are collected in real time by a distributed optical fiber sensing system, and the temperature gradient field and strain field of the hollow-core optical fiber are obtained according to the temperature and strain distribution data;

[0018] Based on the acoustic wave modal distribution characteristics of the hollow-core fiber cross section, the finite element method is used to mesh the fiber cross section to obtain the acoustic wave propagation path and energy distribution of different acoustic wave modes.

[0019] The temperature gradient field is mapped into a non-uniform refractive index disturbance on the acoustic wave propagation path, and the acoustic wave attenuation coefficient is calculated based on the refractive index change on the acoustic wave propagation path;

[0020] The strain field is mapped to the effective refractive index change of the optical waveguide mode, and the optical wave phase delay distribution is calculated based on the linear relationship between the optical wave phase delay and the effective refractive index;

[0021] The acoustic wave attenuation coefficient and the optical wave phase delay are aligned according to spatial position to construct a correlation matrix under the combined action of temperature and strain; the matrix row vectors are the acoustic wave mode numbers, the column vectors are the optical waveguide mode numbers, and the matrix elements are the correlation coefficients between the acoustic wave attenuation coefficient and the optical wave phase delay.

[0022] Preferably, the light-acoustic coupling time-frequency spectrum matrix is input into the correlation matrix to decouple temperature and strain, thereby obtaining independent temperature distribution parameters and strain distribution parameters, specifically:

[0023] Aligning the optical-acoustic coupling time-frequency spectrum matrix in time sequence and spatial position and inputting it into the correlation matrix, extracting the correlation coefficient between the acoustic wave attenuation coefficient and the optical wave phase delay in the matrix as the initial input of the temperature and strain cross-sensitivity feature;

[0024] Define the objective functions of the temperature component and the strain component respectively. The objective function of the temperature component is the residual sum of squares of the acoustic wave attenuation coefficient and the temperature gradient field, and the objective function of the strain component is the residual sum of squares of the light wave phase delay and the strain field.

[0025] The cross-coupling terms of temperature and strain are introduced, and the weight coefficients of the mutual influence between the cross-coupling terms of temperature and strain are obtained. The cross-coupling terms are then added to the objective function to optimize the decoupling accuracy.

[0026] The objective function is smoothed using a regularization method to ensure the stability of the temperature and strain components during the iterative solution process. The objective function weight is dynamically adjusted using a gradient descent algorithm until the residuals of the temperature and strain components meet the preset convergence conditions.

[0027] Independent temperature distribution parameters and strain distribution parameters are output according to the optimized objective function.

[0028] Preferably, the temperature distribution parameters, strain distribution parameters and light-acoustic coupling time-frequency spectrum matrix are fused to generate a multi-physical field distribution map along the hollow-core optical fiber axis, specifically:

[0029] The temperature distribution parameters and the strain distribution parameters are aligned according to the spatial position of the hollow-core optical fiber axis to generate discrete data sequences of the temperature field and the strain field respectively;

[0030] The optical-acoustic coupling time-frequency spectrum matrix is decomposed according to time series and spatial position, and the characteristic values of the optical signal frequency shift and acoustic wave attenuation coefficient corresponding to each sampling point are extracted as auxiliary data for multi-physics field fusion;

[0031] Based on the discrete data sequences of temperature field and strain field, spatial distribution models of temperature gradient field and strain gradient field are constructed respectively. The discrete data are smoothed by interpolation algorithm to generate continuous temperature and strain distribution curves.

[0032] Correlate the eigenvalues of the light-acoustic coupling time-frequency spectrum matrix with the temperature and strain distribution curves to obtain the influence weights of temperature and strain on the light-acoustic coupling signal, and generate a multi-physics field joint distribution matrix based on the influence weights of temperature and strain on the light-acoustic coupling signal.

[0033] The multi-physics field joint distribution matrix is mapped into a three-dimensional visualization map to obtain the multi-physics field distribution map along the axial direction of the hollow-core optical fiber. The horizontal axis is the axial position of the hollow-core optical fiber, and the vertical axis is the distribution value of temperature and strain. The intensity changes of the light-acoustic coupling signal are marked by color gradients and contour lines to generate an intuitive multi-physics field distribution map.

[0034] Preferably, based on the generated multi-physics field distribution map, the temperature and strain distribution changes in the hollow-core optical fiber axis are analyzed to obtain the location and type of the abnormal point, specifically:

[0035] Based on the generated multi-physics field distribution map, the real-time distribution data of temperature and strain are extracted according to the spatial position of the hollow-core optical fiber axis, and the spatial change rate of the temperature gradient and strain gradient is calculated;

[0036] Set the threshold range of temperature and strain to determine whether the current distribution data exceeds the preset threshold. If so, use the sliding window algorithm to smooth the time series data of temperature and strain, calculate the mean and variance within the window, and determine whether there is abnormal fluctuation. If the variance exceeds the preset fluctuation range, it will be marked as an outlier.

[0037] Based on the eigenvalues of the optical-acoustic coupling time-frequency spectrum matrix, the optical signal frequency shift and acoustic wave attenuation coefficient corresponding to the abnormal point are analyzed to determine whether the abnormality is caused by temperature change or strain change. If the optical signal frequency shift is not within the preset frequency shift range, it is attributed to temperature fluctuation; if the acoustic wave attenuation coefficient is not within the preset attenuation coefficient range, it is attributed to strain fluctuation.

[0038] The location and type of the abnormal points are fed back to the database, and the distribution of the abnormal areas is displayed in real time through a visual interface.

[0039] Preferably, based on the acquired abnormal point location and type, a compensation strategy is iteratively generated and executed until temperature cross-sensitivity suppression is completed, specifically:

[0040] Based on the acquired abnormal point location and type, determine whether the abnormal point is a temperature-sensitive abnormality or a strain-sensitive abnormality;

[0041] If the abnormality is temperature-sensitive, the excitation frequency of the photoacoustic transducer in the temperature-sensitive frequency band is increased according to a first preset amplitude; if the abnormality is strain-sensitive, the excitation frequency of the photoacoustic transducer in the strain-sensitive frequency band is reduced according to a second preset amplitude;

[0042] Dynamically adjust the sampling interval of the hollow-core optical fiber according to the spatial distribution density of the abnormal points, shorten the sampling interval according to the first preset amplitude in the area with dense abnormal points, and extend the sampling interval according to the first preset amplitude in the area with sparse abnormal points;

[0043] Execute the adjusted photoacoustic transducer excitation frequency and sampling interval, re-collect the photoacoustic coupling signal and update the multi-physics field distribution map, calculate the residual change of temperature and strain, and if the residual reduction rate does not reach the preset reduction rate threshold, continue to iteratively execute the combined strategy of optimizing the excitation frequency and sampling interval until the residual reduction rate reaches the preset reduction rate threshold;

[0044] Based on the optimized light-acoustic coupling signal, the temperature compensation algorithm is used to correct the hollow-core fiber strain distribution data to eliminate the cross-sensitivity effect of the temperature gradient field on the strain measurement; and the temperature-compensated hollow-core fiber strain distribution data is output.

[0045] A second aspect of the present invention discloses a hollow-core optical fiber temperature cross-sensitivity suppression system, which includes a memory and a processor. The memory stores a hollow-core optical fiber temperature cross-sensitivity suppression method program. When the hollow-core optical fiber temperature cross-sensitivity suppression method program is executed by the processor, the steps of any one of the hollow-core optical fiber temperature cross-sensitivity suppression methods are implemented.

[0046] The present invention solves the technical defects existing in the background technology, and the present invention has the following beneficial effects: collecting the reflected light signal and scattered acoustic wave signal of the hollow-core optical fiber to construct a light-acoustic coupling time-frequency spectrum matrix; collecting the temperature and strain distribution data of the hollow-core optical fiber axial direction to construct a correlation matrix under the combined action of temperature and strain; inputting the light-acoustic coupling time-frequency spectrum matrix into the correlation matrix to decouple the temperature and strain, thereby obtaining independent temperature distribution parameters and strain distribution parameters respectively; performing data fusion on the temperature distribution parameters, strain distribution parameters and the light-acoustic coupling time-frequency spectrum matrix to generate a multi-physics field distribution map of the hollow-core optical fiber axial direction; based on the generated multi-physics field distribution map, analyzing the temperature and strain distribution changes of the hollow-core optical fiber axial direction to obtain the position and type of the abnormal point; based on the obtained abnormal point position and type, iteratively generating and executing a compensation strategy until temperature cross-sensitivity suppression is completed. The present invention can effectively suppress the cross-sensitivity effect of the temperature gradient field on strain measurement, and improve the measurement accuracy and reliability of the hollow-core optical fiber in a complex environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, they can also obtain drawings of other embodiments based on these drawings.

[0048] Figure 1 The overall method flow chart of a method for suppressing temperature cross-sensitivity of hollow-core optical fibers is as follows;

[0049] Figure 2 A partial flow chart of a method for suppressing temperature cross-sensitivity of hollow-core optical fibers;

[0050] Figure 3 This is a system block diagram of a hollow-core optical fiber temperature cross-sensitivity suppression system. DETAILED DESCRIPTION

[0051] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0052] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0053] like Figure 1 As shown, the first aspect of the present invention discloses a method for suppressing temperature cross-sensitivity of a hollow-core optical fiber, comprising the following steps:

[0054] S102, collecting reflected light signals and scattered acoustic wave signals of the hollow-core optical fiber to construct a light-acoustic coupling time-frequency spectrum matrix; collecting temperature and strain distribution data of the hollow-core optical fiber axial direction to construct a correlation matrix under the combined action of temperature and strain;

[0055] S104, inputting the light-acoustic coupling time-frequency spectrum matrix into the correlation matrix to decouple temperature and strain, thereby obtaining independent temperature distribution parameters and strain distribution parameters respectively;

[0056] S106, fusing the temperature distribution parameters, the strain distribution parameters, and the optical-acoustic coupling time-frequency spectrum matrix to generate a multi-physical field distribution map along the hollow-core optical fiber axis;

[0057] S108. Analyze the temperature and strain distribution changes in the hollow-core optical fiber axis based on the generated multi-physics field distribution map to obtain the location and type of the abnormal point;

[0058] S110 , based on the acquired abnormal point location and type, iteratively generate and execute compensation strategies until temperature cross-sensitivity suppression is completed.

[0059] It should be noted that the present invention realizes the precise decoupling of temperature and strain by combining the light-acoustic coupling time-frequency spectrum matrix with the temperature-strain correlation matrix, and generates a multi-physical field distribution map, which can efficiently identify the location and type of abnormal points; by dynamically adjusting the compensation strategy, it can effectively suppress the cross-sensitivity effect of the temperature gradient field on the strain measurement, improve the measurement accuracy and reliability of hollow-core optical fiber in complex environments, and provide an efficient and flexible technical solution for the optimization of distributed optical fiber sensing systems.

[0060] Preferably, the reflected light signal and scattered acoustic wave signal of the hollow core optical fiber are collected to construct a light-acoustic coupling time-frequency spectrum matrix, such as Figure 2 As shown, specifically:

[0061] S202, receiving a reflected light signal through a hollow-core optical fiber end face reflector, scanning the wavelength of the light signal using a tunable laser and a photodetector, and obtaining a spectral intensity distribution;

[0062] It should be noted that the reflected light signal is received by a hollow-core fiber end-face reflector and input into a tunable laser for wavelength scanning, covering the antiresonant transmission window of the hollow-core fiber. A photodetector detects the intensity of the light signal within the scanning range, recording the light intensity value corresponding to each wavelength to generate a spectral intensity distribution.

[0063] S204, extracting Brillouin frequency shift characteristics in the spectrum based on the spectral intensity distribution and in combination with fast Fourier transform, and constructing a mapping table of temperature-sensitive frequency bands and strain-sensitive frequency bands based on the linear relationship between frequency shift and temperature / strain;

[0064] It should be noted that a fast Fourier transform is performed on the spectral intensity distribution to extract the Brillouin scattering characteristic peak in the spectrum and obtain the frequency shift value of the characteristic peak. Based on the known linear relationship between the Brillouin frequency shift and temperature / strain, mapping models are established for the frequency shift value and the temperature gradient field and strain field, respectively. Then, the distribution range of the frequency shift value is used to divide the temperature-sensitive frequency band into the strain-sensitive frequency band, where the temperature-sensitive frequency band corresponds to the high-frequency Brillouin frequency shift, and the strain-sensitive frequency band corresponds to the low-frequency Brillouin frequency shift. Subsequently, based on the division results, a mapping table of the temperature-sensitive frequency band and the strain-sensitive frequency band is constructed, which contains the frequency band range, frequency shift value, and the corresponding temperature and strain influence weights.

[0065] S206. Collecting acoustic wave signals along the axis of the hollow-core optical fiber using a distributed acoustic wave sensor, performing time-domain decomposition of the acoustic wave signals using wavelet transform, extracting acoustic wave attenuation coefficients of different frequency bands, and separating temperature-sensitive frequency bands from strain-sensitive frequency bands using the mapping table to obtain independent features of temperature and strain;

[0066] It should be noted that a distributed acoustic sensor collects acoustic signals along the hollow-core optical fiber axis, recording the propagation time and intensity changes of the acoustic waves within the fiber. Wavelet transforms are used to decompose the acoustic signals in the time domain to extract acoustic attenuation coefficients in different frequency bands. High-frequency bands correspond to temperature-sensitive features, while low-frequency bands correspond to strain-sensitive features. The extracted acoustic attenuation coefficients are classified by frequency band based on the ranges of temperature-sensitive and strain-sensitive bands in the mapping table. Based on the frequency band classification results, the acoustic attenuation coefficients for the temperature-sensitive and strain-sensitive bands are separated, and their average values are calculated as representative eigenvalues to obtain independent features of temperature and strain.

[0067] S208. Align the independent characteristics of temperature and strain and the acoustic wave attenuation coefficient in time series to construct a light-acoustic coupling time-frequency spectrum matrix; the matrix row vectors are time sampling points, and the column vectors are the joint eigenvalues of the Brillouin frequency shift characteristics and the acoustic wave attenuation coefficient.

[0068] It should be noted that this method can effectively separate the temperature-sensitive frequency band from the strain-sensitive frequency band by collecting the reflected light signal and scattered acoustic wave signal of the hollow-core optical fiber and constructing a light-acoustic coupled time-frequency spectrum matrix, providing a high-dimensional data basis for the precise decoupling of temperature and strain.

[0069] Preferably, the temperature and strain distribution data of the hollow-core optical fiber in the axial direction are collected to construct a correlation matrix under the combined action of temperature and strain, specifically:

[0070] The temperature and strain distribution data of the hollow-core optical fiber in the axial direction are collected in real time by a distributed optical fiber sensing system, and the temperature gradient field and strain field of the hollow-core optical fiber are obtained according to the temperature and strain distribution data;

[0071] Based on the acoustic wave modal distribution characteristics of the hollow-core fiber cross section, the finite element method is used to mesh the fiber cross section to obtain the acoustic wave propagation path and energy distribution of different acoustic wave modes.

[0072] It should be noted that based on the acoustic wave modal distribution characteristics of the hollow-core optical fiber cross section, a geometric model of the optical fiber cross section is established, including the dimensions and material parameters of the core, cladding, and external structure. Then, the finite element method is used to mesh the geometric model, and the mesh density is determined according to the relationship between the acoustic wave wavelength and the optical fiber size to ensure that the mesh accuracy meets the requirements of acoustic wave propagation simulation. The acoustic wave excitation source is defined on the mesh model, and the acoustic wave frequency range is set to 1-10MHz to simulate the propagation paths of different acoustic wave modes; then, the energy distribution of the acoustic wave on the optical fiber cross section is calculated by the finite element solver, and the acoustic wave intensity and phase information of each mesh node are recorded; finally, based on the energy distribution results, the propagation paths and energy concentration areas of different acoustic wave modes are extracted to provide basic data for the subsequent mapping of temperature gradient field and strain field.

[0073] The temperature gradient field is mapped to the non-uniform refractive index disturbance on the acoustic wave propagation path. The acoustic wave attenuation coefficient is calculated by the refractive index change on the acoustic wave propagation path. The calculation formula is as follows:

[0074]

[0075] Where α(s) is the acoustic attenuation coefficient (unit: Np / m), which represents the energy attenuation per unit length; f is the acoustic frequency (unit: Hz), which is a specific modal frequency in the range of 1-10 MHz; Δn(s) is the refractive index change (dimensionless) along the acoustic wave propagation path, which is converted from the temperature gradient field through the thermo-optical effect; and c is the sound velocity in the optical fiber material (unit: m / s), which is related to the acoustic mode and material parameters of the hollow-core optical fiber.

[0076] The strain field is mapped to the effective refractive index change of the optical waveguide mode. The light wave phase delay distribution is calculated based on the linear relationship between the light wave phase delay and the effective refractive index. The calculation formula is:

[0077]

[0078] Where, is the phase delay of the light wave at the axial position z (unit: rad), which represents the cumulative phase change when the light wave propagates to this position; λ is the wavelength of the light wave (unit: m); Δn eff is the effective refractive index change caused by the strain field; L is the length of the light wave propagation path (unit: m), that is, the position coordinate of the optical fiber axial measurement point.

[0079] The acoustic wave attenuation coefficient and the optical wave phase delay are aligned according to spatial position to construct a correlation matrix under the combined action of temperature and strain; the matrix row vectors are the acoustic wave mode numbers, the column vectors are the optical waveguide mode numbers, and the matrix elements are the correlation coefficients between the acoustic wave attenuation coefficient and the optical wave phase delay.

[0080] It should be noted that this method can accurately quantify the influence of temperature gradient field and strain field on acoustic wave attenuation coefficient and light wave phase delay by collecting temperature and strain distribution data in the axial direction of hollow-core optical fiber and constructing the correlation matrix under the combined action of temperature and strain, thereby realizing efficient decoupling of multi-physical field coupling.

[0081] Preferably, the light-acoustic coupling time-frequency spectrum matrix is input into the correlation matrix to decouple temperature and strain, thereby obtaining independent temperature distribution parameters and strain distribution parameters, specifically:

[0082] Aligning the optical-acoustic coupling time-frequency spectrum matrix in time sequence and spatial position and inputting it into the correlation matrix, extracting the correlation coefficient between the acoustic wave attenuation coefficient and the optical wave phase delay in the matrix as the initial input of the temperature and strain cross-sensitivity feature;

[0083] It should be noted that the optical-acoustic coupling time-frequency spectrum matrix is aligned according to the time series and spatial position to ensure that the optical signal frequency shift and acoustic wave attenuation coefficient data of each sampling point are consistent with the corresponding position of the correlation matrix; the correlation coefficient between the acoustic wave attenuation coefficient and the optical wave phase delay is extracted from the correlation matrix as the initial input of the temperature and strain cross-sensitivity feature; then, the extracted correlation coefficient is normalized to eliminate the influence of dimensional differences on subsequent analysis; then, the correlation coefficient is smoothed by a sliding window algorithm to reduce noise interference; finally, the processed correlation coefficient is reorganized according to the time series and spatial position to generate an initial data set of the temperature and strain cross-sensitivity feature, providing accurate input for the definition and optimization of the subsequent objective function.

[0084] Define the objective functions of the temperature component and the strain component respectively. The objective function of the temperature component is the residual sum of squares of the acoustic wave attenuation coefficient and the temperature gradient field, and the objective function of the strain component is the residual sum of squares of the light wave phase delay and the strain field.

[0085] The cross-coupling terms of temperature and strain are introduced, and the weight coefficients of the mutual influence between the cross-coupling terms of temperature and strain are obtained. The cross-coupling terms are then added to the objective function to optimize the decoupling accuracy.

[0086] The objective function is smoothed using a regularization method to ensure the stability of the temperature and strain components during the iterative solution process. The objective function weight is dynamically adjusted using a gradient descent algorithm until the residuals of the temperature and strain components meet the preset convergence conditions.

[0087] It should be noted that the cross-coupling terms of temperature and strain are defined, where the weight of the influence of temperature on the acoustic wave attenuation coefficient is calculated by the refractive index change on the acoustic wave propagation path, and the weight of the influence of strain on the optical wave phase delay is calculated by the effective refractive index change of the optical waveguide mode; then, the finite element method is used to simulate the combined effect of the temperature gradient field and the strain field to obtain the weight coefficient of the mutual influence of temperature and strain; then, the cross-coupling terms are added to the objective functions of the temperature component and the strain component, and the contribution values of temperature and strain to the objective function are calculated respectively; subsequently, the gradient descent algorithm is used to dynamically adjust the weight coefficients of the cross-coupling terms to optimize the decoupling accuracy of the objective function; finally, the objective function residual is made to meet the preset convergence conditions through iterative solution to ensure that the decoupling result of temperature and strain is optimal.

[0088] Independent temperature distribution parameters and strain distribution parameters are output according to the optimized objective function.

[0089] Among them, the expression of the optimized objective function is:

[0090] J=‖δ-k T ΔT 2 ‖+‖Δψ-k ε ∈‖+γ<ω,T ∈ >+β T ‖T‖ 2 +β ∈ ‖∈‖ 2

[0091] Where J is the objective function itself, which represents the overall error that needs to be minimized; δ is the measured value of the acoustic attenuation coefficient; k T is the conversion coefficient between temperature and attenuation coefficient; ΔT is the temperature gradient; Δψ is the measured value of the light wave phase delay; k ε is the sensitivity coefficient between strain and phase delay; ∈ is the strain distribution parameter; γ is the global weight of the cross-coupling term; ω is the weight vector; T ∈ is the element-wise product of temperature and strain; β T For β ∈ are regularization coefficients to prevent overfitting and ensure the stability of the solution; T is the temperature distribution parameter.

[0092] It should be noted that by inputting the correlation matrix data into the optimized objective function, a gradient descent algorithm is used to iteratively adjust the values of the temperature and strain distribution parameters to minimize the temperature gradient residual, strain phase residual, and cross-coupling terms in the objective function. Under the constraints of the regularization term, by dynamically balancing the mutual influence weights of temperature and strain, the residuals of the temperature-related term (acoustic attenuation coefficient) and the strain-related term (optical wave phase delay) are ultimately converged to below the preset threshold. At this point, the output T and ∈ are the spatial distribution parameters of the physically independent and decoupled temperature and strain fields.

[0093] It should be noted that this method can accurately decouple the cross-sensitivity effects of temperature and strain by inputting the light-acoustic coupling time-frequency spectrum matrix into the correlation matrix and optimizing the difference terms of the objective functions of temperature and strain, thereby obtaining independent temperature distribution parameters and strain distribution parameters respectively.

[0094] Preferably, the temperature distribution parameters, strain distribution parameters and light-acoustic coupling time-frequency spectrum matrix are fused to generate a multi-physical field distribution map along the hollow-core optical fiber axis, specifically:

[0095] The temperature distribution parameters and the strain distribution parameters are aligned according to the spatial position of the hollow-core optical fiber axis to generate discrete data sequences of the temperature field and the strain field respectively;

[0096] The optical-acoustic coupling time-frequency spectrum matrix is decomposed according to time series and spatial position, and the characteristic values of the optical signal frequency shift and acoustic wave attenuation coefficient corresponding to each sampling point are extracted as auxiliary data for multi-physics field fusion;

[0097] Based on the discrete data sequences of temperature field and strain field, spatial distribution models of temperature gradient field and strain gradient field are constructed respectively. The discrete data are smoothed by interpolation algorithm to generate continuous temperature and strain distribution curves.

[0098] Correlate the eigenvalues of the light-acoustic coupling time-frequency spectrum matrix with the temperature and strain distribution curves to obtain the influence weights of temperature and strain on the light-acoustic coupling signal, and generate a multi-physics field joint distribution matrix based on the influence weights of temperature and strain on the light-acoustic coupling signal.

[0099] It should be noted that the eigenvalues of the optical-acoustic coupling time-frequency spectrum matrix are aligned according to the time series and spatial position, and the optical signal frequency shift and the acoustic wave attenuation coefficient are extracted as input data; then, based on the temperature and strain distribution curves, the influence weights of the temperature gradient field and the strain field on the optical signal frequency shift and the acoustic wave attenuation coefficient are obtained respectively, where the temperature gradient field is calculated by the refractive index perturbation of the acoustic wave propagation path, and the strain field is calculated by the effective refractive index change of the optical waveguide mode; then, the influence weights of temperature and strain on the optical-acoustic coupling signal are associated with the eigenvalues through the weighted fusion algorithm to generate a multi-physics field joint distribution matrix.

[0100] The multi-physical field joint distribution matrix is mapped into a three-dimensional visualization map to obtain the multi-physical field distribution map along the axial direction of the hollow-core optical fiber.

[0101] The horizontal axis of the map represents the axial position of the hollow-core optical fiber, and the vertical axis represents the distribution values of temperature and strain. The intensity changes of the light-acoustic coupling signal are marked by color gradients and contour lines to generate an intuitive multi-physical field distribution map.

[0102] It should be noted that this method generates a multi-physical field distribution map of the hollow-core optical fiber axis by fusing the temperature distribution parameters, strain distribution parameters and the light-acoustic coupling time-frequency matrix. It can intuitively display the spatial distribution and change trend of the temperature field, strain field and light-acoustic coupling signal, and provide an efficient and intuitive technical means for real-time monitoring of temperature and strain and identification of abnormal points, solving the technical problem that traditional methods are difficult to achieve multi-physical field joint analysis.

[0103] Preferably, based on the generated multi-physics field distribution map, the temperature and strain distribution changes in the hollow-core optical fiber axis are analyzed to obtain the location and type of the abnormal point, specifically:

[0104] Based on the generated multi-physics field distribution map, the real-time distribution data of temperature and strain are extracted according to the spatial position of the hollow-core optical fiber axis, and the spatial change rate of the temperature gradient and strain gradient is calculated;

[0105] Set the threshold range of temperature and strain to determine whether the current distribution data exceeds the preset threshold. If so, use the sliding window algorithm to smooth the time series data of temperature and strain, calculate the mean and variance within the window, and determine whether there is abnormal fluctuation. If the variance exceeds the preset fluctuation range, it will be marked as an outlier.

[0106] Based on the eigenvalues of the optical-acoustic coupling time-frequency spectrum matrix, the optical signal frequency shift and acoustic wave attenuation coefficient corresponding to the abnormal point are analyzed to determine whether the abnormality is caused by temperature change or strain change. If the optical signal frequency shift is not within the preset frequency shift range, it is attributed to temperature fluctuation; if the acoustic wave attenuation coefficient is not within the preset attenuation coefficient range, it is attributed to strain fluctuation.

[0107] The location and type of the abnormal points are fed back to the database, and the distribution of the abnormal areas is displayed in real time through a visual interface.

[0108] It should be noted that this method can accurately identify the location and type of abnormal points in the axial direction of the hollow-core optical fiber by analyzing the changes in temperature and strain distribution in the multi-physical field distribution map, and effectively distinguish abnormal phenomena caused by temperature fluctuations and strain fluctuations.

[0109] Preferably, based on the acquired abnormal point location and type, a compensation strategy is iteratively generated and executed until temperature cross-sensitivity suppression is completed, specifically:

[0110] Based on the acquired abnormal point location and type, determine whether the abnormal point is a temperature-sensitive abnormality or a strain-sensitive abnormality;

[0111] If the abnormality is temperature-sensitive, the excitation frequency of the photoacoustic transducer in the temperature-sensitive frequency band is increased according to a first preset amplitude; if the abnormality is strain-sensitive, the excitation frequency of the photoacoustic transducer in the strain-sensitive frequency band is reduced according to a second preset amplitude;

[0112] Exemplarily, when the system detects an abnormal point and determines its type, the excitation frequency of the photoacoustic transducer is dynamically adjusted according to the type of the abnormal point. If the abnormal point is a temperature-sensitive abnormality, the excitation frequency of the photoacoustic transducer in the temperature-sensitive frequency band (such as the high frequency band 1-5MHz) is increased according to a first preset amplitude (for example, an increase of 10%-20%) to enhance the acquisition intensity and signal-to-noise ratio of the temperature-sensitive signal, thereby more accurately capturing the changes in the temperature gradient field. If the abnormal point is a strain-sensitive abnormality, the excitation frequency of the photoacoustic transducer in the strain-sensitive frequency band (such as the low frequency band 0.5-1MHz) is reduced according to a second preset amplitude (for example, a decrease of 10%-20%) to reduce the noise interference of the strain-sensitive signal and ensure the measurement accuracy of the strain field.

[0113] Dynamically adjust the sampling interval of the hollow-core optical fiber according to the spatial distribution density of the abnormal points, shorten the sampling interval according to the first preset amplitude in the area with dense abnormal points, and extend the sampling interval according to the first preset amplitude in the area with sparse abnormal points;

[0114] For example, after an outlier is detected, the system dynamically adjusts the sampling interval of the hollow-core optical fiber based on the spatial distribution density of the outlier. For areas with dense outliers (e.g., more than 3 outliers per meter), the sampling interval is shortened by a first preset value (e.g., shortening the sampling interval to 1 cm) to improve spatial resolution and ensure that local feature changes of the outliers can be accurately captured. For areas with sparse outliers (e.g., less than 1 outlier per meter), the sampling interval is extended by a first preset value (e.g., extending the sampling interval to 10 cm) to improve sampling efficiency and reduce the system's computational load.

[0115] Execute the adjusted photoacoustic transducer excitation frequency and sampling interval, re-collect the photoacoustic coupling signal and update the multi-physics field distribution map, calculate the residual change of temperature and strain, and if the residual reduction rate does not reach the preset reduction rate threshold, continue to iteratively execute the combined strategy of optimizing the excitation frequency and sampling interval until the residual reduction rate reaches the preset reduction rate threshold;

[0116] Based on the optimized light-acoustic coupling signal, the temperature compensation algorithm is used to correct the hollow-core fiber strain distribution data to eliminate the cross-sensitivity effect of the temperature gradient field on the strain measurement; and the temperature-compensated hollow-core fiber strain distribution data is output.

[0117] The hollow-core optical fiber strain distribution data includes axial position, strain value and its time variation sequence, and strain gradient distribution.

[0118] It should be noted that this method can effectively suppress the cross-sensitivity of the temperature gradient field on strain measurement by dynamically adjusting the excitation frequency and sampling interval of the photoacoustic transducer based on the location and type of the abnormal point, and iteratively optimize the compensation strategy, thereby improving the measurement accuracy of the hollow-core optical fiber strain distribution data, and realizing real-time optimization and efficient correction of the hollow-core optical fiber sensing system in complex environments. It solves the technical problem that traditional methods are difficult to dynamically suppress temperature cross-sensitivity, and provides a reliable solution for high-precision distributed optical fiber sensing.

[0119] In this embodiment, the method for suppressing hollow-core optical fiber temperature cross-sensitivity further includes the following steps:

[0120] After temperature cross-sensitivity suppression is completed, the decoupled temperature distribution parameters and strain distribution parameters are cross-validated through independent calibration sensors, the measurement errors of temperature and strain are calculated, and it is determined whether the errors exceed the preset tolerance range;

[0121] If the error exceeds the tolerance range, local correction is performed on the area with the largest error based on the error distribution. The excitation frequency weight of the photoacoustic transducer in this area and the correlation coefficient of the correlation matrix are readjusted. The corrected photoacoustic coupling propagation path is simulated using a finite element model to calculate the correction effect.

[0122] The correction parameters are iteratively optimized using the gradient descent algorithm until the error is reduced to below the preset threshold;

[0123] If the number of iterations reaches the upper limit and still fails to meet the requirements, the global optimization mode is started, the temperature-strain correlation matrix is rebuilt, and the full-process suppression strategy is executed;

[0124] Update the optimized parameters to the model library of the temperature-strain correlation matrix to form a closed-loop self-learning mechanism to ensure the continuous optimization of the subsequent inhibition effect;

[0125] Generate a suppression effect verification report, record the error distribution, optimization parameters and number of iterations, and provide data support for system performance evaluation and further optimization.

[0126] It should be noted that this method can accurately identify and correct the error-exceeding area by performing independent calibration and error verification after temperature cross-sensitivity suppression, further improving the accuracy and stability of the suppression effect.

[0127] In this embodiment, the method for suppressing hollow-core optical fiber temperature cross-sensitivity further includes the following steps:

[0128] An asymmetric Bragg grating array is integrated at a preset axial position in the hollow-core optical fiber. The reflected light signal is collected through a tunable laser and a polarization analyzer to obtain the spatial gradient distribution data of the polarization state.

[0129] Based on the acoustic birefringence effect, a correlation model between sound pressure and polarization state is established. The sound pressure gradient field is mapped to the spatial rate of change of the polarization state. It is then determined whether the sound pressure exceeds a preset sound pressure threshold. If so, the grid of the local area of the grating array is refined.

[0130] Acoustic birefringence refers to the phenomenon in which sound waves cause anisotropic changes in the refractive index of a medium during propagation. When sound waves act on optical fiber materials, they generate periodic stress distribution within the material, causing the material's refractive index to differ in different directions, thereby changing the polarization state of light.

[0131] It should be noted that the physical relationship between sound pressure and polarization state is defined based on the acoustic-induced birefringence effect, mapping the sound pressure gradient field to the non-uniform variation of the refractive index of the optical fiber material. Using the finite element method, the hollow-core optical fiber cross section is meshed to simulate the propagation path of sound waves under different sound pressure gradients, and the polarization state changes caused by the sound waves are calculated. Based on the refractive index changes along the sound wave propagation path, a correlation model is established between the sound pressure gradient field and the spatial rate of change of the polarization state.

[0132] A tensor decomposition algorithm is used to reduce the dimensionality of the polarization state spatial gradient distribution data, extract the independent contributions of the temperature gradient and the acoustic pressure gradient to the polarization state, and eliminate the polarization distortion interference caused by the temperature gradient through an iterative optimization algorithm.

[0133] Based on the optimized polarization state data, the sound pressure gradient field distribution is recalculated, and the sound pressure gradient residual is judged to see whether it meets the convergence condition. If not, the parameter weights of the sound pressure-polarization correlation model are adjusted.

[0134] Finally, the sound pressure gradient field distribution data after eliminating polarization distortion is output.

[0135] It should be noted that the combination of an asymmetric Bragg grating array and a tensor decomposition algorithm effectively eliminates polarization distortion interference caused by temperature gradients, improving the measurement accuracy and reliability of the acoustic pressure gradient field. By dynamically adjusting the grating array grid density and the parameter weights of the acoustic pressure-polarization correlation model, accurate decoupling and real-time monitoring of the acoustic pressure gradient field in complex environments are ensured. This provides efficient technical support for the joint analysis of multiple physical fields and solves the technical problem of traditional methods that make it difficult to independently measure temperature and acoustic pressure gradients.

[0136] like Figure 3 As shown, the second aspect of the present invention discloses a hollow-core optical fiber temperature cross-sensitivity suppression system 6, which includes a memory 41 and a processor 52. The memory 41 stores a hollow-core optical fiber temperature cross-sensitivity suppression method program. When the hollow-core optical fiber temperature cross-sensitivity suppression method program is executed by the processor 52, the steps of any one of the hollow-core optical fiber temperature cross-sensitivity suppression methods are implemented.

[0137] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0138] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed across multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0139] In addition, all functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0140] Those skilled in the art will appreciate that all or part of the steps of the above-mentioned method embodiments may be implemented by hardware associated with program instructions, and the aforementioned program may be stored in a computer-readable storage medium. When the program is executed, the program executes the steps of the above-mentioned method embodiments. The aforementioned storage medium includes various media that can store program codes, such as mobile storage devices, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0141] Alternatively, if the above-mentioned integrated unit of the present invention is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the methods of each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROM, RAM, magnetic disks or optical disks.

[0142] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A method for suppressing temperature cross-sensitivity of hollow-core optical fibers, characterized in that: The following steps are involved: Collect the reflected light signal and scattered acoustic wave signal of the hollow-core optical fiber to construct the light-acoustic coupling time-frequency spectrum matrix; collect the temperature and strain distribution data of the hollow-core optical fiber axial direction to construct the correlation matrix under the combined action of temperature and strain; Inputting the light-acoustic coupling time-frequency spectrum matrix into the correlation matrix to decouple temperature and strain, thereby obtaining independent temperature distribution parameters and strain distribution parameters respectively; The temperature distribution parameters, strain distribution parameters and optical-acoustic coupling time-frequency spectrum matrix are fused to generate a multi-physical field distribution map along the hollow-core optical fiber axis. Based on the generated multi-physics field distribution map, the temperature and strain distribution changes in the hollow-core optical fiber axis are analyzed to obtain the location and type of abnormal points; Based on the acquired outlier locations and types, compensation strategies are iteratively generated and executed until temperature cross-sensitivity suppression is completed.

2. A method for suppressing temperature cross-sensitivity of hollow-core optical fibers according to claim 1, characterized in that: Collect the reflected light signal and scattered acoustic wave signal of the hollow core fiber and construct the optical-acoustic coupling time-frequency spectrum matrix, specifically: The reflected light signal is received by the hollow-core fiber end reflector, and the wavelength of the light signal is scanned using a tunable laser and a photodetector to obtain the spectral intensity distribution; According to the spectral intensity distribution, combined with fast Fourier transform, the Brillouin frequency shift characteristics in the spectrum are extracted, and a mapping table of temperature-sensitive frequency bands and strain-sensitive frequency bands is constructed through the linear relationship between frequency shift and temperature / strain; The acoustic wave signal along the axis of the hollow-core optical fiber is collected by a distributed acoustic wave sensor, and the acoustic wave signal is decomposed in the time domain using wavelet transform to extract the acoustic wave attenuation coefficients of different frequency bands. The temperature-sensitive frequency band and the strain-sensitive frequency band are separated by combining the mapping table to obtain independent characteristics of temperature and strain; The independent features of temperature and strain and the acoustic wave attenuation coefficient are aligned in time series to construct the optical-acoustic coupling time-spectral matrix.

3. The method for suppressing temperature cross-sensitivity of a hollow-core optical fiber according to claim 1, wherein: The temperature and strain distribution data of the hollow-core optical fiber axis are collected to construct the correlation matrix under the combined action of temperature and strain, specifically: The temperature and strain distribution data of the hollow-core optical fiber in the axial direction are collected in real time by a distributed optical fiber sensing system, and the temperature gradient field and strain field of the hollow-core optical fiber are obtained according to the temperature and strain distribution data; Based on the acoustic wave modal distribution characteristics of the hollow-core fiber cross section, the finite element method is used to mesh the fiber cross section to obtain the acoustic wave propagation path and energy distribution of different acoustic wave modes. The temperature gradient field is mapped into a non-uniform refractive index disturbance on the acoustic wave propagation path, and the acoustic wave attenuation coefficient is calculated based on the refractive index change on the acoustic wave propagation path; The strain field is mapped to the effective refractive index change of the optical waveguide mode, and the optical wave phase delay distribution is calculated based on the linear relationship between the optical wave phase delay and the effective refractive index; The acoustic wave attenuation coefficient and the light wave phase delay are aligned according to spatial position to construct the correlation matrix under the combined action of temperature and strain.

4. A method for suppressing temperature cross-sensitivity of hollow-core optical fibers according to claim 1, characterized in that: The light-acoustic coupling time-frequency spectrum matrix is input into the correlation matrix to decouple temperature and strain, thereby obtaining independent temperature distribution parameters and strain distribution parameters, specifically: Aligning the optical-acoustic coupling time-frequency spectrum matrix in time sequence and spatial position and inputting it into the correlation matrix, extracting the correlation coefficient between the acoustic wave attenuation coefficient and the optical wave phase delay in the matrix as the initial input of the temperature and strain cross-sensitivity feature; Define the objective functions of the temperature component and the strain component respectively. The objective function of the temperature component is the residual sum of squares of the acoustic wave attenuation coefficient and the temperature gradient field, and the objective function of the strain component is the residual sum of squares of the light wave phase delay and the strain field. The cross-coupling terms of temperature and strain are introduced, and the weight coefficients of the mutual influence between the cross-coupling terms of temperature and strain are obtained. The cross-coupling terms are then added to the objective function to optimize the decoupling accuracy. The objective function is smoothed using a regularization method to ensure the stability of the temperature and strain components during the iterative solution process. The objective function weight is dynamically adjusted using a gradient descent algorithm until the residuals of the temperature and strain components meet the preset convergence conditions. Independent temperature distribution parameters and strain distribution parameters are output according to the optimized objective function.

5. The method for suppressing temperature cross-sensitivity of a hollow-core optical fiber according to claim 1, wherein: The temperature distribution parameters, strain distribution parameters and optical-acoustic coupling time-frequency spectrum matrix are fused to generate a multi-physical field distribution map along the hollow-core optical fiber axis, specifically: The temperature distribution parameters and the strain distribution parameters are aligned according to the spatial position of the hollow-core optical fiber axis to generate discrete data sequences of the temperature field and the strain field respectively; The optical-acoustic coupling time-frequency spectrum matrix is decomposed according to time series and spatial position, and the characteristic values of the optical signal frequency shift and acoustic wave attenuation coefficient corresponding to each sampling point are extracted as auxiliary data for multi-physics field fusion; Based on the discrete data sequences of temperature field and strain field, spatial distribution models of temperature gradient field and strain gradient field are constructed respectively. The discrete data are smoothed by interpolation algorithm to generate continuous temperature and strain distribution curves. Correlate the eigenvalues of the light-acoustic coupling time-frequency spectrum matrix with the temperature and strain distribution curves to obtain the influence weights of temperature and strain on the light-acoustic coupling signal, and generate a multi-physics field joint distribution matrix based on the influence weights of temperature and strain on the light-acoustic coupling signal. The multi-physical field joint distribution matrix is mapped into a three-dimensional visualization map to obtain the multi-physical field distribution map along the axial direction of the hollow-core optical fiber.

6. A method for suppressing temperature cross-sensitivity of hollow-core optical fibers according to claim 1, characterized in that: Based on the generated multi-physics field distribution map, the temperature and strain distribution changes in the hollow-core optical fiber axis are analyzed to obtain the location and type of abnormal points, specifically: Based on the generated multi-physics field distribution map, the real-time distribution data of temperature and strain are extracted according to the spatial position of the hollow-core optical fiber axis, and the spatial change rate of the temperature gradient and strain gradient is calculated; Set the threshold range of temperature and strain to determine whether the current distribution data exceeds the preset threshold. If so, use the sliding window algorithm to smooth the time series data of temperature and strain, calculate the mean and variance within the window, and determine whether there is abnormal fluctuation. If the variance exceeds the preset fluctuation range, it will be marked as an outlier. Based on the eigenvalues of the optical-acoustic coupling time-frequency spectrum matrix, the optical signal frequency shift and acoustic wave attenuation coefficient corresponding to the abnormal point are analyzed to determine whether the abnormality is caused by temperature change or strain change. If the optical signal frequency shift is not within the preset frequency shift range, it is attributed to temperature fluctuation; if the acoustic wave attenuation coefficient is not within the preset attenuation coefficient range, it is attributed to strain fluctuation. The location and type of the abnormal points are fed back to the database, and the distribution of the abnormal areas is displayed in real time through a visual interface.

7. The method for suppressing temperature cross-sensitivity of a hollow-core optical fiber according to claim 1, wherein: Based on the acquired abnormal point location and type, the compensation strategy is iteratively generated and executed until temperature cross-sensitivity suppression is completed. Specifically: Based on the acquired abnormal point location and type, determine whether the abnormal point is a temperature-sensitive abnormality or a strain-sensitive abnormality; If the abnormality is temperature-sensitive, the excitation frequency of the photoacoustic transducer in the temperature-sensitive frequency band is increased according to a first preset amplitude; if the abnormality is strain-sensitive, the excitation frequency of the photoacoustic transducer in the strain-sensitive frequency band is reduced according to a second preset amplitude; Dynamically adjust the sampling interval of the hollow-core optical fiber according to the spatial distribution density of the abnormal points, shorten the sampling interval according to the first preset amplitude in the area with dense abnormal points, and extend the sampling interval according to the first preset amplitude in the area with sparse abnormal points; Execute the adjusted photoacoustic transducer excitation frequency and sampling interval, re-collect the photoacoustic coupling signal and update the multi-physics field distribution map, calculate the residual change of temperature and strain, and if the residual reduction rate does not reach the preset reduction rate threshold, continue to iteratively execute the combined strategy of optimizing the excitation frequency and sampling interval until the residual reduction rate reaches the preset reduction rate threshold; Based on the optimized optical-acoustic coupling signal, a temperature compensation algorithm is used to correct the hollow-core fiber strain distribution data to eliminate the cross-sensitivity effect of the temperature gradient field on the strain measurement. Output temperature-compensated hollow-core fiber strain distribution data.

8. A hollow-core optical fiber temperature cross-sensitivity suppression system, characterized in that: The hollow-core optical fiber temperature cross-sensitivity suppression system includes a memory and a processor, wherein the memory stores a hollow-core optical fiber temperature cross-sensitivity suppression method program. When the hollow-core optical fiber temperature cross-sensitivity suppression method program is executed by the processor, the steps of the hollow-core optical fiber temperature cross-sensitivity suppression method according to any one of claims 1 to 7 are implemented.

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