Method, system and apparatus for demodulating a fabry-perot cavity micromachined pressure

Abstract

The application provides a Fabry-Perot cavity micrometer pressure demodulation method, system and device, comprising: setting a reference pressure; obtaining a first frequency spectrum corresponding to the Fabry-Perot cavity under the reference pressure; obtaining a first eigenvalue, selecting a first new metric in the sequence of the first eigenvalue; constructing a function relationship according to the first new metric and the reference pressure; obtaining a second frequency spectrum corresponding to the Fabry-Perot cavity when measuring pressure; obtaining a second eigenvalue, selecting the second eigenvalue as a second new metric which is the same as the sequence of the first new metric; obtaining a demodulated pressure measurement value according to the second new metric and the function relationship. The application can avoid the problems of demodulation error, demodulation error increase and demodulation speed reduction; at the same time, the method can directly obtain the pressure measurement value, without demodulating the cavity length and then converting it into pressure, thereby avoiding the demodulation error caused by the fact that the pressure and the cavity length are not strictly linearly related.

Description

Technical Field

[0001] This invention relates to a demodulation method, system, device, electronic device, and storage medium for measuring micropressure in a Fabry-Perot cavity, belonging to the field of micropressure sensors. Background Technology

[0002] In the medical field, monitoring internal pressure is crucial for assessing organ and tissue damage. Fiber optic Fabry-Perot micropressure sensors offer advantages such as high sensitivity, resistance to electromagnetic interference, and small size, enabling precision medicine in multiple medical fields, including cardiovascular blood supply capacity assessment. The performance of fiber optic Fabry-Perot micropressure sensors depends on the application scenario. According to the "Medical Pressure Analysis Demonstration Standard Collection Standard," in the field of cardiovascular blood supply capacity assessment, the sensor reading error must be within ±3% in the range of 6.7 kPa to 40 kPa. Therefore, high demodulation accuracy is required for micropressure sensors. Interferometric fiber optic Fabry-Perot micropressure sensors utilize the characteristic of carrying a larger amount of information across a wide spectrum, thus offering advantages such as high measurement accuracy and a large dynamic range, making them one of the ideal methods for micropressure monitoring.

[0003] The key to interferometric demodulation is to use its broadband interference signal to solve for the cavity length of the fiber Fabry-Perot cavity. Based on the processing of the equivalent initial phase, it can be divided into two demodulation types: TYPE I and TYPE II demodulation. Fast Fourier Transform (FFT) is a commonly used method for TYPE I demodulation, which determines the optical path difference by calculating the number of fringes using FFT. This demodulation method based on direct frequency estimation is called TYPE I demodulation. Based on this, methods such as Buneman frequency estimation and fast all-phase method have been developed. These require large amounts of data calculation to achieve high accuracy, but the improvement is limited, with accuracy and resolution limited to hundreds of nanometers, also restricting the demodulation speed. TYPE II demodulation utilizes the known equivalent initial phase, offering advantages such as high resolution, large dynamic range, and strong robustness. However, the low quality of the fiber Fabry-Perot cavity causes the equivalent initial phase to change with the cavity length, and estimating the equivalent initial phase requires strict experimental control (stable control, a defined initial stage). This makes the equivalent initial phase estimation inaccurate, leading to pressure measurement errors. This technical limitation has consistently hampered the demodulation accuracy of fiber optic Fabry-Perot micro-pressure sensors. Therefore, it is essential to provide a high-precision micro-pressure demodulation method to overcome the aforementioned shortcomings.

[0004] Existing technologies, exemplified by Chinese patent CN109520429, first employ FFT to derive a coarse cavity length estimate L. Then, a range of simulated cavity length values ​​is defined before and after the coarse estimate. A stepping cavity length ΔL is set to generate a sequence {Li} of simulated cavity lengths with a total number of K values. These are then substituted into the maximum likelihood formula, and the simulated cavity length Li corresponding to the maximum value is the demodulation cavity length. This method, by selecting an appropriate stepping cavity length ΔL, allows for fine estimation within a very small cavity length range, thus significantly improving the speed of maximum likelihood estimation in the fine estimation process, thereby achieving high-speed and high-precision demodulation.

[0005] However, due to the asynchronous sampling of the above methods, spectral leakage and the picket fence effect can occur, so only spectral lines near the true spectral lines can be observed. Using these spectral lines for coarse cavity length estimation will result in significant estimation errors, greatly affecting demodulation accuracy and time. Furthermore, the above methods do not consider the impact of the Fabry-Perot cavity's equivalent initial phase on demodulation accuracy. For an ideal Fabry-Perot cavity, the equivalent initial phase is a fixed value. However, in multimode fiber, multimode transmission or poor Fabry-Perot cavity quality leading to beam divergence or non-parallelism will cause the equivalent initial phase to vary with the cavity length. An inaccurate Fabry-Perot cavity equivalent initial phase value will result in a large deviation between the simulated cavity length corresponding to the maximum likelihood estimate and the actual cavity length, reducing demodulation accuracy. In practice, estimating the initial phase requires a strict experimental environment with stable control and a defined initial stage, making accurate estimation of the equivalent initial phase very difficult. Moreover, FFT is strictly applicable to stationary processes, while pressure changes and environmental interference during spectral acquisition cause variations in the Fabry-Perot cavity length, leading to large measurement errors. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a demodulation method, system and apparatus for Fabry-Perot cavity micropressure measurement, which is used to solve at least one of the aforementioned technical problems.

[0007] Specifically, the technical solution is as follows:

[0008] A demodulation method for micropressure measurement in a Fabry-Perot cavity includes:

[0009] Set a reference pressure;

[0010] Obtain the first spectrum corresponding to the Fabry-Perot cavity under the reference pressure;

[0011] Obtain the first feature value, and select the first new metric from the sequence of the first feature values;

[0012] A functional relationship is constructed based on the first new metric and the reference pressure;

[0013] Obtain the second spectrum corresponding to the Fabry-Perot cavity when measuring pressure;

[0014] Obtain the second feature value, and select the second feature value that is the same as the first new metric sequence as the second new metric;

[0015] The demodulated pressure measurement value is obtained based on the relationship between the second new metric and the function.

[0016] The phrase "obtaining the first spectrum corresponding to the Fabry-Perot cavity under the reference pressure" includes:

[0017] The interference spectrum of the Fabry-Perot cavity in the wavenumber domain can be obtained using the following formula:

[0018]

[0019] Where I0 is the power of the light source, γ is the edge visibility, and L is the optical path length of the Fabry-Perot cavity. Equivalent initial phase, k-wave number; It is the AC component after removing the mean and normalizing.

[0020] The phrase "obtaining the first feature value and selecting the first new metric" includes:

[0021] Under different reference pressures, a discrete signal with at least one sampling point in the wavelength domain of the interference spectrum is obtained;

[0022] The interference spectrum is converted from the wavelength domain to the wavenumber domain and solved using the fast Fourier transform.

[0023] Select the spectrum corresponding to the Fabry-Perot cavity and convert it into a Toeplitz matrix;

[0024] The eigenvalue decomposition of the Toeplitz matrix yields the first eigenvalue sequence, which is then arranged in descending order.

[0025] We selected higher-order eigenvalues ​​to measure the Fabry-Perot cavity length as the first new metric.

[0026] The phrase "obtaining the second feature value and selecting the second new metric" includes:

[0027] Acquire the second spectrum corresponding to the measured pressure;

[0028] Obtain the discrete signal of at least one sampling point in the wavelength domain of the interference spectrum corresponding to the second spectrum;

[0029] The interference spectrum is converted from the wavelength domain to the wavenumber domain and solved using the fast Fourier transform.

[0030] Select the spectrum corresponding to the Fabry-Perot cavity and convert it into a Toeplitz matrix;

[0031] The eigenvalue decomposition of the Toeplitz matrix yields a sequence of second eigenvalues, which are then arranged in descending order.

[0032] We selected higher-order eigenvalues ​​to measure the Fabry-Perot cavity length as a second new metric.

[0033] A demodulation system for Fabry-Perot cavity micropressure measurement includes:

[0034] The data acquisition module is used to collect external reference pressure.

[0035] The processing module interacts with the acquisition module to obtain the reference pressure and use the reference pressure to obtain a first new metric, so as to construct a functional relationship between the reference pressure and the first new metric.

[0036] The demodulation module interacts with the processing module to obtain the functional relationship of the first new metric;

[0037] The processing module interacts with the acquisition module to obtain a second new metric corresponding to the measured pressure.

[0038] The demodulation module interacts with the processing module to obtain the second new metric and, based on the functional relationship between the reference pressure and the first new metric, obtains the value of the measured pressure.

[0039] The processing module acquires the reference pressure, obtains the first spectrum corresponding to the Fabry-Perot cavity based on the reference pressure, obtains the first feature value based on the first spectrum, and then selects the i-th feature value as the first new metric after arranging the first feature values ​​in descending order.

[0040] The processing module acquires the second spectrum corresponding to the measured pressure, obtains the second feature value based on the second spectrum, sorts the second feature value in descending order, and selects the i-th feature value as the second new metric.

[0041] A pressure measuring device, comprising:

[0042] Broadband light source;

[0043] An optical splitter is disposed at the output end of the broadband light source;

[0044] A pressure sensor interacts with the optical splitter to sense external pressure and generate an interference signal from the pressure via the optical splitter.

[0045] A data acquisition unit is provided at one output end of the optical splitter for acquiring the interference signal emitted by the optical splitter.

[0046] The demodulation unit interacts with the data acquisition unit to obtain the external pressure value based on the interference signal using the Fabry-Perot cavity micro-pressure demodulation method described above.

[0047] An electronic device based on Fabry-Perot cavity micro-pressure measurement includes:

[0048] Storage media, used to store computer programs

[0049] The processing unit exchanges data with the storage medium and executes the computer program during measurement to perform the demodulation method of Fabry-Perot cavity micropressure as described above.

[0050] A computer-readable storage medium having a computer program stored therein;

[0051] When the computer program is running, it executes the steps of the demodulation method for Fabry-Perot cavity micro-pressure measurement as described above.

[0052] The present invention has at least the following beneficial effects:

[0053] The demodulation method for Fabry-Perot cavity micro-pressure measurement described in this invention uses a reference pressure to obtain its corresponding spectral data. The spectrum is transformed to obtain eigenvalues ​​and eigenvectors. The eigenvalues ​​are arranged in descending order, and a specific eigenvalue is selected as the first new metric. A function relating the reference pressure and the first new metric is constructed. When measuring pressure, the spectrum formed by the external pressure is transformed to obtain eigenvalues, which are then arranged in descending order. A specific eigenvalue is selected as the second new metric. The second new metric is then substituted into the function constructed from the reference pressure and the first new metric to obtain the measured pressure value. This invention does not need to consider the problem of low Fabry-Perot cavity quality, avoiding demodulation errors caused by difficulty in accurately estimating the equivalent initial phase. Moreover, this invention can achieve accurate demodulation even with a small number of spectral data points, avoiding the increased demodulation error and reduced demodulation speed caused by large errors in coarsely estimating the cavity length using FFT due to limited spectral data. Furthermore, the method described in this invention can directly obtain the pressure measurement value without first demodulating the cavity length and then converting it to pressure, avoiding demodulation errors caused by the non-strict linear relationship between pressure and cavity length.

[0054] The measuring device of this invention acquires external pressure through a demodulation unit, and then passes it through an optical path splitter into a pressure sensor (fiber optic Fabry-Perot cavity micro-pressure sensor) to cause interference. The external pressure value is then obtained through the demodulation method described above for Fabry-Perot cavity micro-pressure measurement. This measuring device has the advantages of simple structure, high demodulation accuracy, and high resolution. Attached Figure Description

[0055] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 This is a schematic diagram of the demodulation method for Fabry-Perot cavity micro-pressure measurement according to the present invention;

[0057] Figure 2 This is a flowchart of the demodulation method for Fabry-Perot cavity micropressure measurement according to the present invention;

[0058] Figure 3 This is a structural block diagram of the pressure measuring device described in this invention;

[0059] Figure 4 for Figure 3 Interference signal diagram obtained by the data acquisition unit in the middle;

[0060] Figure 5 for Figure 3 Spectrum diagram of the Fabry-Perot cavity inside the medium pressure sensor;

[0061] Figure 6 A sequence of eigenvalues ​​for the spectrum;

[0062] Figure 7 The graph shows the relationship between the first new metric x1 and the reference pressure y.

[0063] Figure 8 The demodulation results are shown in the graph for the measured pressure interval of 1 kPa.

[0064] Figure 9 The demodulation results are shown for a pressure interval of 0.1 kPa.

[0065] Figure 10 for Figure 8 Graph of demodulated pressure reading error;

[0066] Among them, 1. Broadband light source; 2. Data acquisition unit; 3. Optical splitter; 4. Demodulation unit; 5. Pressure sensor; 100. Acquisition module; 200. Processing module; 300. Demodulation module. Detailed Implementation

[0067] Those skilled in the art will understand that the modules in the apparatus of the implementation scenario can be distributed within the apparatus of the implementation scenario as described, or they can be located in one or more apparatuses different from this implementation scenario, with corresponding changes. The modules of the above-described implementation scenario can be combined into one module, or they can be further divided into multiple sub-modules.

[0068] Figure 1 The working principle of the demodulation method described in this invention is as follows: The spectrum of the interference signal is transformed to obtain the first eigenvalue and eigenvector of the spectrum; the first eigenvalues ​​are arranged in descending order; the i-th eigenvalue x is selected. i As the first new metric, the reference pressure value y is substituted with the first new metric x. i The function y = f(x) i In the demodulation process, the demodulation pressure y is obtained; the demodulation steps are as follows: Figure 2 As shown, it includes:

[0069] 1) Using a pressure controller as the reference pressure y, obtain its corresponding spectral data. Transform the spectrum to obtain the first eigenvalue and eigenvector of the spectrum. Sort the first eigenvalues ​​in descending order and select the i-th first eigenvalue x. i As the first new metric; constructing a reference pressure y and the first new metric x i The function y = f(x) i ), i = 1, 2, 3, ...

[0070] 2) Measure pressure y m When the spectrum is transformed, the second eigenvalue of the spectrum is obtained, and the second eigenvalues ​​are sorted in descending order. The i-th second eigenvalue x is selected. i As the second new metric; the second new metric x i Substitute into the function y = f(x) i In the calculation, the current measured pressure value y is obtained. m .

[0071] The interference spectrum of a typical Fabry-Perot cavity in the wavenumber domain is expressed as: Equation 1:

[0072] [Formula 1] Where I0 is the power of the light source, γ is the edge visibility, and L is the optical path length of the Fabry-Perot cavity. Equivalent initial phase, k-wave number It is the AC component after removing the mean and normalizing.

[0073] Changes in pressure cause changes in L, which are reflected in the frequency corresponding to the Fabry-Perot cavity length in the spectrum. Therefore, by analyzing the spectral shift information in the interference spectrum, the pressure measurement value can be obtained, and pressure demodulation can be achieved, specifically as follows:

[0074] The first step is to use the pressure set by the pressure controller as the reference pressure y, and select the eigenvalue sensitive to the change in Fabry-Perot cavity length as the first new metric. Under different reference pressures y, discrete signals of N sampling points in the wavelength domain of the interference spectrum are obtained from the spectrometer. The discrete signals of N sampling points in the wavelength domain of the interference spectrum are obtained from the spectrometer. Let λ be the N wavelength samples, and I(λ) be the amplitude of the corresponding interference spectrum. The wavelength domain of the interference spectrum is converted to the wavenumber domain to obtain I(k). FFT is applied to I(k) to obtain G, and the expression of G is: Equation 2. Select the spectrum G2 corresponding to the Fabry-Perot cavity, and then convert G2 into a Toeplitz matrix M. The eigenvalues ​​of matrix M are decomposed to obtain the first eigenvalue sequence x and arranged in descending order, as shown in Equation 3. The eigenvectors of low-order eigenvalues ​​are affected by noise, while high-order eigenvalues ​​limit most of the signal energy and are the dominant eigenvalues ​​of the signal. Because the key information of the cavity length frequency domain spectrum is encoded in the above steps and placed in the high-order eigenvalue x. i Therefore, the higher-order eigenvalues ​​are sensitive to changes in the Fabry-Perot cavity length, which in turn is sensitive to changes in pressure, and are thus identified as the first new metric.

[0075] [Formula 2] G = FFT(I(k)) = [G1, G2, ..., G N ]

[0076] [Formula 3] x = [x1>x2>…>x] i >…>x n ]

[0077] Where n is the number of G2 data points;

[0078] The second step involves repeating the above steps to obtain the first new metric x corresponding to several specific reference pressures. i Thus, the first new metric x is constructed. i The functional relationship between y and the reference pressure y is y = f(x) i ).

[0079] The third step is to obtain the measured pressure y. m The spectrum corresponding to the Fabry-Perot cavity; calculate the second eigenvalue using the same method as in the first step and arrange them in descending order; select the second eigenvalue x with the same order as the first eigenvalue. i As a second new metric, substituting it into the function yields the current measured pressure y. m =f(x) i ).

[0080] This embodiment describes the use of calculated spectral characteristic values ​​as a new metric for interferometric fiber Fabry-Perot micro-pressure demodulation, thereby directly establishing the relationship between the new metric and pressure, avoiding the influence of factors such as insufficient data acquisition points and low Fabry-Perot cavity quality; it also has high measurement accuracy and resolution when the amount of interferometric spectral data acquired is low; therefore, the pressure demodulation method provided by this invention has accurate measurement, high resolution, good stability, and strong applicability.

[0081] The present invention also provides an embodiment:

[0082] like Figure 3 A pressure measuring device includes: a broadband light source 1, a data acquisition unit 2, an optical splitter 3, a demodulation unit 4, and a pressure sensor 5; wherein, the optical splitter 3 is disposed at the output end of the broadband light source 1; the pressure sensor 5 interacts with the optical splitter 3 to sense external pressure and form an interference signal from the pressure via the optical splitter 3; the data acquisition unit 2 is disposed at one output end of the optical splitter 3 to acquire the interference signal emitted by the optical splitter 3; the demodulation unit 4 interacts with the data acquisition unit 2 to obtain the external pressure value based on the interference signal using the demodulation method of Fabry-Perot cavity micro-pressure measurement described above; the pressure sensor 5 is preferably a fiber optic Fabry-Perot cavity micro-pressure sensor.

[0083] In this embodiment, the broadband light source 1 emits light, which enters the fiber optic Fabry-Perot cavity micro-pressure sensor through the optical splitter 3 and interferes. The interference signal enters the data acquisition unit 2, obtaining an interference signal with 1566 data points, such as... Figure 4 Finally, demodulation is performed in demodulation unit 4, and the demodulation steps are as follows: Figures 1-2 Finally, the measured pressure is demodulated.

[0084] The present invention also provides an embodiment:

[0085] An electronic device based on Fabry-Perot cavity micro-pressure measurement includes: a storage medium and a processing unit; wherein the storage medium is used to store a computer program; the processing unit exchanges data with the storage medium and, during measurement, executes the computer program through the processing unit to perform the steps of the Fabry-Perot cavity micro-pressure measurement demodulation method as described above.

[0086] In the aforementioned electronic device, the storage medium is preferably a portable hard drive, a solid-state drive, or a USB flash drive; the processing unit, preferably a CPU, exchanges data with the storage medium and executes the computer program during measurement to perform the demodulation steps of the Fabry-Perot cavity micro-pressure measurement method as described above.

[0087] The aforementioned CPU can execute various appropriate actions and processes according to the program stored in the storage medium. The electronic device also includes peripherals such as input sections including a keyboard, mouse, etc., and may also include output sections such as a cathode ray tube (CRT), liquid crystal display (LCD), and speakers; particularly, according to the embodiments disclosed in this invention, such as... Figures 1-2 Any of the processes described herein can be implemented as computer software programs.

[0088] One embodiment of the present invention includes a computer program product comprising a computer program carried on a computer-readable medium, the computer program including functions for performing... Figures 1-2 The flowchart illustrates the program code for the method. This computer program can be downloaded and installed from a network. When executed by the CPU, the computer program performs the functions defined in the system of this invention.

[0089] The present invention also provides an embodiment:

[0090] A computer-readable storage medium storing a computer program; when the computer program is run, it executes the steps of the demodulation method for Fabry-Perot cavity micropressure as described above.

[0091] In this invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wireline, optical fiber, RF, etc., or any suitable combination thereof.

[0092] Verification process:

[0093] The specific measurement is performed using the pressure measuring device described above, and the process is as follows:

[0094] First, a reference pressure y and eigenvalue x are constructed under several specific reference pressures. i The function y = f(x) i The collected spectral data is converted to obtain the spectrum corresponding to the Fabry-Perot cavity, such as... Figure 5 As shown; calculate the first eigenvalue sequence x of the spectrum, as follows. Figure 6 As shown; then, the first eigenvalue x1, i.e., i=1, is selected as the first new metric to construct the functional relationship y=f(x1) between the first new metric x1 and the reference pressure y, as follows. Figure 7 As shown, the relationship is represented as x1 = f -1 (y), thus constructing a functional relationship represented as y=f(x1); finally, using the constructed first new metric and pressure functional relationship for demodulation, the pressure demodulation results at measured pressure intervals of 1 kPa and 0.1 kPa are obtained respectively, as follows. Figure 8 and Figure 9 As shown, the reading error of the demodulated pressure is as follows: Figure 10 As shown.

[0095] The present invention has been experimentally verified, and the demodulation results show that when there are few spectral data points, the demodulation method provided by the present invention has the advantages of high demodulation accuracy and high resolution.

[0096] The above descriptions only cover a few specific embodiments of the present invention. However, the present invention is not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention. The above-mentioned serial numbers are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

Claims

1. A demodulation method for micropressure measurement in a Fabry-Perot cavity, characterized in that, include: Set a reference pressure; Obtain the first spectrum corresponding to the Fabry-Perot cavity under the reference pressure; Obtaining a first eigenvalue and selecting a first new metric from the sequence of the first eigenvalues ​​includes: obtaining discrete signals at least one sampling point in the wavelength domain of the interference spectrum under different reference pressures; converting the wavelength domain of the interference spectrum to the wavenumber domain and solving it using a fast Fourier transform; selecting the spectrum corresponding to the Fabry-Perot cavity and converting it into a Toeplitz matrix; decomposing the eigenvalues ​​of the Toeplitz matrix to obtain a first eigenvalue sequence and arranging it in descending order; and selecting a higher-order eigenvalue of the Fabry-Perot cavity length as the first new metric. A functional relationship is constructed based on the first new metric and the reference pressure; Obtain the second spectrum corresponding to the Fabry-Perot cavity when measuring pressure; Obtaining a second eigenvalue, and selecting the second eigenvalue that is identical to the first new metric sequence as the second new metric, includes: acquiring the second spectrum corresponding to the measured pressure; obtaining the discrete signal of at least one sampling point in the wavelength domain of the interference spectrum corresponding to the second spectrum; converting the wavelength domain of the interference spectrum to the wavenumber domain and solving it using fast Fourier transform; selecting the spectrum corresponding to the Fabry-Perot cavity and converting it into a Toeplitz matrix; decomposing the eigenvalues ​​of the Toeplitz matrix to obtain a second eigenvalue sequence and arranging them in descending order; and selecting the higher-order eigenvalue of the Fabry-Perot cavity length as the second new metric. The demodulated pressure measurement value is obtained based on the relationship between the second new metric and the function.

2. The demodulation method for Fabry-Perot cavity micropressure measurement according to claim 1, characterized in that, The step of obtaining the first spectrum corresponding to the Fabry-Perot cavity under the reference pressure includes: The interference spectrum of the Fabry-Perot cavity in the wavenumber domain can be obtained using the following formula: I(k)= I0{1+γ cos(2Lk+ 0)}; Where I0 is the power of the light source, γ is the edge visibility, and L is the optical path length of the Fabry-Perot cavity. 0 is the equivalent initial phase, k is the wave number; cos(2Lk+ 0) is the AC component after removing the mean and normalizing.

3. A demodulation system for Fabry-Perot cavity micro-pressure measurement, characterized in that, For implementing the demodulation method of Fabry-Perot cavity micro-pressure measurement as described in claim 1 or 2, the system comprises: The data acquisition module is used to collect external reference pressure. The processing module interacts with the acquisition module to obtain the reference pressure and use the reference pressure to obtain a first new metric, so as to construct a functional relationship between the reference pressure and the first new metric. The demodulation module interacts with the processing module to obtain the functional relationship of the first new metric; The processing module interacts with the acquisition module to obtain a second new metric corresponding to the measured pressure. The demodulation module interacts with the processing module to obtain the second new metric and, based on the functional relationship between the reference pressure and the first new metric, obtains the value of the measured pressure.

4. The demodulation system for Fabry-Perot cavity micro-pressure measurement according to claim 3, characterized in that, The processing module acquires the reference pressure, obtains the first spectrum corresponding to the Fabry-Perot cavity based on the reference pressure, obtains the first feature value based on the first spectrum, and then selects the i-th feature value as the first new metric after arranging the first feature values ​​in descending order.

5. The demodulation system for Fabry-Perot cavity micro-pressure measurement according to claim 3, characterized in that, The processing module acquires the second spectrum corresponding to the measured pressure, obtains the second feature value based on the second spectrum, sorts the second feature value in descending order, and selects the i-th feature value as the second new metric.

6. A pressure measuring device, characterized in that, include: Broadband light source; An optical splitter is disposed at the output end of the broadband light source; A pressure sensor interacts with the optical splitter to sense external pressure and generate an interference signal from the pressure via the optical splitter. A data acquisition unit is provided at one output end of the optical splitter for acquiring the interference signal emitted by the optical splitter. The demodulation unit interacts with the data acquisition unit to obtain the external pressure value based on the interference signal using the demodulation method for Fabry-Perot cavity micro-pressure measurement as described in claim 1 or 2.

7. An electronic device based on Fabry-Perot cavity micro-pressure measurement, characterized in that, include: Storage media, used to store computer programs The processing unit exchanges data with the storage medium and, during measurement, executes the computer program through the processing unit to perform the demodulation method of Fabry-Perot cavity micropressure measurement as described in claim 1 or 2.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program. When the computer program is run, it executes the steps of the demodulation method for Fabry-Perot cavity micro-pressure measurement as described in claim 1 or 2.

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