Inverse piezoelectric optical voltage-temperature two-parameter measurement method

Abstract

The invention relates to the technical field of electric power detection, in particular to an inverse piezoelectric optical voltage-temperature two-parameter measurement method. S1, obtaining a spectrum provided by a broadband laser source through a Gaussian equation; s2, receiving the spectrum of the broadband laser source through a voltage sensor; and S3, setting an FBG1 and an FBG2, simplifying the reflectivity of the FBG through a Gaussian equation, and calculating the reflectivity of the FBG in the FBG1 and the FBG2. According to the inverse piezoelectric optical voltage-temperature two-parameter measurement method provided by the invention, the voltage parameter and the temperature parameter are respectively obtained based on a double-grating demodulation and edge filtering mode of an inverse piezoelectric optical effect, so that simultaneous measurement of the voltage-temperature parameter is realized; the sensor has the characteristics of simple operation, strong passive anti-electromagnetic interference capability, guarantee of the working stability of the sensor, and no need of adding extra equipment or cost.

Description

Technical Field

[0001] The present invention relates to the technical field of power detection, and particularly to a method for measuring inverse piezoelectric optical voltage-temperature dual parameters. Background Art

[0002] Monitoring the voltages of each node in the power grid can help understand the operating state of the power grid, promptly give early warnings of power grid faults or obtain power grid fault information in a timely and accurate manner, ensuring the safe and efficient operation of the power system. Temperature monitoring can prevent fires and protect power equipment. Due to its good electromagnetic shielding, high compatibility with optical fibers, high fidelity of data transmission and other advantages, optical sensors are gradually becoming a research hotspot in power grid monitoring. Finding a highly accurate optical voltage-temperature method is bound to be one of the essential conditions for power grid voltage-temperature monitoring.

[0003] Therefore, a method for measuring inverse piezoelectric optical voltage-temperature dual parameters is designed to provide a technical solution for the above technical problems. Summary of the Invention

[0004] Based on this, it is necessary to provide a method for measuring inverse piezoelectric optical voltage-temperature dual parameters to solve the technical problems proposed in the above background art.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for measuring inverse piezoelectric optical voltage-temperature dual parameters is as follows:

[0007] S1: Obtain the spectrum provided by the broadband laser source through the Gaussian equation;

[0008] S2: Receive the spectrum of the broadband laser source through the voltage sensor;

[0009] S3: Set FBG1 and FBG2, simplify the reflectivity of the FBG through the Gaussian equation, and calculate the reflectivity of the FBG in FBG1 and FBG2.

[0010] As a preferred embodiment of the method for measuring inverse piezoelectric optical voltage-temperature dual parameters provided by the present invention, in step S1, the spectrum provided by the broadband laser source is obtained through the Gaussian equation, and the expression is as follows:

[0011]

[0012] Wherein, I peak is the peak power, λ0 is the central wavelength, and Δλ0 is the full width at half maximum.

[0013] As a preferred embodiment of the method for measuring inverse piezoelectric optical voltage-temperature dual parameters provided by the present invention, in step S2, the voltage sensor is composed of a voltage measurement unit and a temperature measurement unit, and both the voltage measurement unit and the temperature measurement unit are composed of piezoelectric ceramics and fiber Bragg gratings.

[0014] As a preferred embodiment of the method for measuring inverse piezoelectric optical voltage-temperature dual parameters provided by the present invention, the grating is a C-band reflective Bragg grating, adhered to the piezoelectric ceramic, and silver electrode layers serving as voltage input ports are plated on both sides of the piezoelectric ceramic.

[0015] As a preferred embodiment of the method for measuring inverse piezoelectric optical voltage-temperature dual parameters provided by the present invention, in step S3, FBG1 and FBG2 are set, temperature is measured through FBG1, and voltage is measured jointly through FBG1 and FBG2.

[0016] As a preferred embodiment of the method for measuring inverse piezoelectric optical voltage-temperature dual parameters provided by the present invention, in step S3, the reflectivity of the FBG is simplified by the Gaussian equation, and the reflectivities of the FBGs in FBG1 and FBG2 are calculated. The expressions are as follows:

[0017]

[0018]

[0019] In the formula, represents the reflection spectrum of the temperature measurement unit, represents the reflection spectrum of the voltage measurement unit; and represent the central wavelengths of the fiber Bragg gratings, and represent the FWHM of the fiber Bragg grating spectra, and R0 represents the maximum reflectivity of the fiber Bragg grating.

[0020] As a preferred embodiment of the method for measuring inverse piezoelectric optical voltage-temperature dual parameters provided by the present invention, for the fiber Bragg grating in the temperature measurement unit, the reflected light I1(λ) should be the product of the incident broadband light source spectrum and the reflection spectrum of the reference grating. The expression is as follows:

[0021] I1(λ) = S(λ B )F R2 (λ);

[0022] The reflected light of FBG2 is the product of the transmitted light of FBG1 and the reflectivity of FBG2. The expression is as follows:

[0023] I2(λ) = [S(λ B)-S(λ B )F R1 (λ)]F S2 (λ);

[0024] Since I PD = I2(λ), after optimization, we get:

[0025] I PD = [S(λ B )-S(λ B )F R2 (λ)]F S2 (λ);

[0026] The optical signal received by the photodetector has the following expression:

[0027]

[0028] After optimization, we get:

[0029]

[0030] Among them, S(λ B ) is the spectrum provided by the broadband laser source, are the reflectivities of the FBGs in FBG1 and FBG2 respectively, and represent their central wavelengths respectively, and represent their full width at half maximum respectively, and R0 is their maximum refractive index.

[0031] It can be clearly seen that through the above technical solution of this application, the technical problems to be solved by this application can surely be solved.

[0032] Meanwhile, through the above technical solution, the present invention has at least the following beneficial effects:

[0033] 1. A method for measuring inverse piezoelectric optical voltage - temperature dual parameters provided by the present invention obtains voltage parameters and temperature parameters respectively through the dual - grating demodulation and edge filtering methods based on the inverse piezoelectric optical effect, realizes the simultaneous measurement of voltage - temperature parameters, promotes the application research and development of optical sensors in the power system, and has the characteristics of simple operation, strong passive anti - electromagnetic interference ability, ensuring the working stability of the sensor, and not requiring additional equipment or cost, further improving the application possibility of inverse piezoelectric optical voltage sensors.

[0034] 2. The present invention can realize the simultaneous measurement of voltage - temperature dual parameters under a relatively simple optical path structure and does not require the use of relatively expensive equipment such as a spectrum analyzer.

[0035] 3. The calculation process of the present invention is simple and it has strong practicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 is the optical path schematic diagram of the present invention;

[0038] Figure 2 is the input-output response schematic diagram of different waveforms of the present invention;

[0039] Figure 3 is the schematic diagram of the input-output linear fitting result of the sine wave voltage at 50 Hz of the present invention;

[0040] Figure 4 is the schematic diagram of the frequency response test result of the present invention;

[0041] Figure 5 is the schematic diagram of the temperature characteristic test of the LPG edge filtering demodulation method of the present invention;

[0042] Figure 6 is the schematic diagram of the relationship between the resonant wavelength of LPG and temperature of the present invention;

[0043] Figure 7 is the schematic diagram of the temperature characteristic test of the non-negative temperature packaged FBG edge filtering demodulation method of the present invention;

[0044] Figure 8 is the schematic diagram of the relationship between the resonant wavelength of the non-negative temperature packaged FBG and temperature of the present invention;

[0045] Figure 9 is the schematic diagram of the temperature characteristic test of the negative temperature packaged FBG edge filtering demodulation method of the present invention;

[0046] Figure 10 is the schematic diagram of the relationship between the central wavelength of the negative temperature compensated packaged FBG and temperature of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following will further elaborate on the present invention in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0048] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0049] It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments can be combined with each other.

[0050] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0051] Embodiment 1

[0052] Referring to Figure 1 , a method for measuring inverse piezoelectric optical voltage-temperature dual parameters.

[0053] (1) The spectrum provided by the broadband light source can be approximately obtained by the Gaussian equation:

[0054]

[0055] where I peak is the peak power, λ0 is the central wavelength, and Δλ0 is the full width at half maximum (FWHM).

[0056] I peak is defined as:

[0057]

[0058] In the formula, P0 represents the incident power provided by the broadband source for the system.

[0059] Considering the central wavelength of the FBG, the reflectivity of the FBG is simplified by the Gaussian equation. Then, the reflectivities of the FBGs in FBG1 and FBG2 can be expressed as:

[0060]

[0061] In the formula, represents the reflection spectrum of the temperature measurement unit, represents the reflection spectrum of the voltage measurement unit. and represent the central wavelengths of the fiber Bragg gratings, and represent the FWHM of the fiber Bragg grating spectra, and R0 represents the maximum reflectivity of the fiber Bragg grating. Therefore, for the fiber Bragg grating in the temperature measurement unit, the reflected light I1(λ) should be the product of the incident broadband light source spectrum and the reflection spectrum of the reference grating:

[0062] I1(λ) = S(λ B )FR2 (λ) (5);

[0063] The reflected light of FBG2 is the product of the transmitted light of FBG1 and the reflectivity of FBG2:

[0064] I2(λ) = [S(λ B ) - S(λ B )F R1 (λ)]F S2 (λ) (6);

[0065] I PD = I2(λ) (7);

[0066] I PD = [S(λ B ) - S(λ B )F R2 (λ)]F S2 (λ) (8);

[0067] The signal received by the photodetector can be expressed in the form shown in Equation (2). It should be noted that the signal received by the photodetector is closely related to the central wavelength of the FBG, especially FBG2. Any change in its central wavelength will directly affect the change in the output light intensity. Considering the possible light intensity loss k when the light enters the grating and the fact that the photodetector provided by the manufacturer has a light responsivity of 0.95 A / W near 1550 nm (wavelength range from 1400 nm to 1650 nm), the expression of the received optical signal by the photodetector is as follows:

[0068]

[0069] where S(λ B ) is the spectrum provided by the broadband laser source, are the reflectivities of the FBGs in FBG1 and FBG2 respectively, and the upper and lower bounds of this integral are determined by the light range provided by the broadband laser source. and represent their central wavelengths respectively, and represent their full width at half maximum respectively, and R0 is their maximum refractive index;

[0070] Temperature measurement uses the functional relationship between the output light intensity and the wavelength to obtain the optical power signal of the reflected spectrum of the temperature measurement unit passing through this filter:

[0071]

[0072] If H(λ) can be approximately regarded as a linear function within a specific range, then:

[0073]

[0074] In the formula, represents the total reflected power of the FBG, denoted by I(λ). Therefore, the information of wavelength drift can be obtained by detecting I(λ) / I1(λ), that is:

[0075] H(λ) = Aλ + B = I(λ) / I I (λ) (13);

[0076] In the formula: A is the proportionality coefficient of the linear filter; B is the intercept.

[0077] After transformation, it can be obtained:

[0078]

[0079] Therefore, the wavelength drift amount can be obtained by detecting the optical power transmitted through the edge filter and the reflected optical power of the FBG.

[0080] (2) The expression of the optical signal received by the optical power meter is as follows:

[0081]

[0082] where S(λ - λ′) is the total reflected power of FBG1, and the optical power signal after the reflected spectrum of the FBG passes through the filter is I( λ ), H(λ) is the spectral transmittance curve, and the upper and lower bounds of this integral are determined by the optical range provided by the broadband laser source.

[0083] (3) Set Fiber Bragg Grating 1 and Fiber Bragg Grating 2. The spectral shapes of the two gratings satisfy the theoretical expression of the grating transmission spectrum in Equation (10). The central wavelength difference between the two gratings should make the spectra 1 and 2 have an overlapping part. Fiber Bragg Grating 1 is used for temperature measurement, and Fiber Bragg Grating 1 and Fiber Bragg Grating 2 work together for voltage measurement.

[0084] Preferably, the voltage sensor is mainly divided into two units, a voltage measurement unit and a temperature measurement unit, both of which are composed of piezoelectric ceramics and fiber gratings. The parameters of the piezoelectric ceramics are the same, and the other parameters of the fiber gratings in the two units are the same, and the central wavelengths are different but close.

[0085] Preferably, the grating is a C-band reflective Bragg grating, which is directly adhered to the piezoelectric ceramic; silver electrode layers serving as voltage input ports are plated on both sides of the piezoelectric ceramic.

[0086] (4) The spectrum of the light incident from the broadband laser source will change in the optical path. After passing through the circulator 1, the light enters the fiber Bragg grating 1. The transmitted light passing through the fiber Bragg grating 1 then enters the optical circulator 2 and the fiber Bragg grating 2 in sequence. Finally, the light reflected by the fiber Bragg grating 1 and the fiber Bragg grating 2 enters the optical detector, and the light reflected by the fiber Bragg grating 1 enters the edge filter. The transmission spectrum of the edge filter enters the optical power meter. Since the two FBGs made of the same material are placed in the same environment and have the same thermal expansion coefficient α and thermo-optic coefficient η, when the temperature changes, the two FBGs will undergo the same deformation. Therefore, the temperature influence during voltage measurement can be eliminated. Since the fiber Bragg grating 1 is only affected by temperature, the spectrum reflected by the fiber Bragg grating 1 shifts with the change of temperature. The temperature can be measured through the change of the optical power after passing through the edge filter. The light in the optical detector of the voltage sensing part depends on the overlapping area of the spectra of the two FBGs, and its value is only related to the relative central wavelength positions of the two FBGs and has nothing to do with their absolute central wavelength positions, thus realizing the dual-parameter measurement of voltage and temperature.

[0087] Embodiment 2

[0088] Reference Figures 1 - 4 , which is disclosed on the basis of the above Embodiment 1.

[0089] As shown in the attached Figure 1 The optical path structure connected as shown consists of two fiber Bragg gratings with a grating area length of 10 mm directly adhered to the piezoelectric ceramic, having all other parameters identical except for the central wavelength, a freely placed long-period fiber grating, and two optical circulators.

[0090] According to this optical path connection and using sine waves, square waves, and triangular waves for verification, the results are as shown in Figure 2 , where (a) 50 Hz sine wave input-output response; (b) 1 kHz sine wave input-output response; (c) 50 Hz rectangular wave input-output response; (d) 1 kHz rectangular wave input-output response; (e) 50 Hz triangular wave input-output response; (f) 1 kHz triangular wave input-output response. The test signal used for sensor testing is an AC voltage signal, and its frequency varies between 50 Hz and 20 kHz. Figure 2 The input voltage signal passing through the high-voltage amplifier in Figure 2 is 1 kV. 50 Hz is the operating frequency of the power grid. Therefore, as shown in Figure 2 (a), 2(c), and 2(e), the responses of the sensor at 50 Hz are presented. To compare the sensor responses, the response characteristics of the sensor at 1 kHz are listed as shown in Figure 4It can be seen that the output voltage waveforms and sensor responses at two different frequency points have strong consistency. The existence of distortion is because the piezoelectric ceramic requires a process before the signal stabilizes, that is, the hysteresis effect. When the piezoelectric ceramic encounters the turning point of the square wave, it is like the piezoelectric ceramic is at a higher frequency point. When the frequency is high, the small fluctuations can more clearly show the process before the piezoelectric ceramic reaches the stable state.

[0091] The waveform distortion is more obvious because when the piezoelectric ceramic encounters the turning point of the square wave, the signal changes violently in a short time, which requires the piezoelectric ceramic to respond quickly, but in fact the piezoelectric ceramic may not be able to respond immediately.

[0092] The linearity test results of the sensor under the sine waveform of 50 Hz are as Figure 3 shown. The black dots represent the data detected by the sensor under the sine wave. The red straight line corresponds to the straight line after fitting the scattered point data, and the straight line R2 is 0.989.

[0093] The frequency response test results of the sensor with optimized optical path connection processing in the frequency range of 50 Hz to 20 kHz are presented. This test was carried out on a unified test platform, and the voltage value applied during the test was 1 kV. Generally speaking, the sensor exhibits quite stable frequency response characteristics, which ensures its effective application in the measurement frequency band of 50 Hz to 20 kHz.

[0094] Next, experiments are carried out using LPG (long period fiber grating), FBG with a larger bandwidth, and FBG with a larger bandwidth with negative temperature compensation packaging as edge filters respectively. In the present invention, long period fiber grating (LPG), ordinary FBG with a wider bandwidth, and broadband FBG with negative temperature compensation packaging are selected as edge filters respectively for the following reasons:

[0095] Long period fiber grating (LPG): LPG has a relatively wide attenuation bandwidth and unidirectional filtering characteristics. Its transmission spectrum responds significantly to wavelength changes, can effectively amplify the drift effect of the FBG reflection spectrum, and improve the detection sensitivity to temperature changes.

[0096] FBG with a wider bandwidth: Compared with narrowband FBG, the change of the reflection spectrum of broadband FBG is more likely to fall into the slope area of the edge filter, making the output optical intensity more sensitive to wavelength changes, thereby improving the accuracy of edge filter demodulation.

[0097] Broadband FBG with negative temperature compensation packaging: When the environmental temperature changes, this type of grating can suppress the drift of its own central wavelength, ensure the stability of the response curve when it is used as an edge filter, and contribute to improving the anti-interference ability and reliability of the system.

[0098] Embodiment III

[0099] Reference Figure 1 、 Figures 5 - 6 Based on the above-mentioned First Embodiment and Second Embodiment, a method of using LPG for filtering is disclosed.

[0100] According to the optical path structure shown in the appendix Figure 1 Connect as shown. Replace the edge filter in the figure with an LPG with a loss peak depth of approximately 28 dB and a resonant wavelength of 1548.6 nm. Place the FBG sensor in a temperature control box and heat it to 62 °C and maintain this temperature for two hours to achieve the consistency between the FBG temperature and the temperature set in the temperature control box. Control the temperature to gradually decrease from 62 °C to 23 °C, and record data every 3 °C. The experimental results are as Figure 5 shown, where (a) shows the relationship between temperature and the LPG transmission spectrum; (b) shows the relationship between temperature and the peak power of the LPG transmission spectrum; (c) shows the relationship between temperature and the power of the LPG transmission spectrum. As the temperature increases, the central wavelength of the FBG drifts towards the long-wavelength direction, and the peak of the optical power also increases as the central wavelength increases, as shown in Figure 5 (a). A linear function is used for fitting, with a fitting slope of 0.45238 nW / °C and a fitting degree of 0.9948, indicating that within this measurement range, the peak optical power of the FBG reflection spectrum is approximately linearly related to the temperature, as shown in Figure 5 (b). The relationship between the optical power of the LPG transmitted light directly measured by the optical power meter and the temperature is as shown in Figure 5 (c). A linear function is used for fitting, with a fitting slope of 2.12594 nw / °C and a fitting degree of 0.99998. However, as the temperature increases, the resonant wavelength of the LPG used as the edge filter will drift, as shown in Figure 6 shown. To achieve the above experimental results, the LPG used in this experiment needs to be placed in a constant temperature box. LPG is very sensitive to temperature, so when using LPG as an edge filter, the experimental environment temperature is quite demanding. Therefore, this demodulation method requires the LPG to be strictly placed in a constant temperature environment while avoiding strain on the LPG.

[0101] Fourth Embodiment

[0102] Reference Figure 1 、 Figures 7 - 8 Based on the above-mentioned First Embodiment, Second Embodiment and Third Embodiment, a method of using an FBG with a larger bandwidth as an edge filter is disclosed.

[0103] Similarly, according to the optical path structure shown in the appendix Figure 1 Connect as shown. Replace the edge filter in the figure with an FBG with a bandwidth of 1.507 nm, and set other conditions the same as above. Set the temperature to gradually decrease from 65 °C to 15 °C, and record data every 5 °C. The experimental results are as Figure 7As shown, where (a) shows the relationship between temperature and the transmission spectrum of the edge-filtered FBG; (b) shows the relationship between the resonant wavelength of the edge-filtered FBG and temperature; (c) shows the relationship between temperature and the power of the transmission spectrum of the edge-filtered FBG. As the temperature increases, the central wavelength of the FBG drifts towards the long-wavelength direction, and the peak value of the optical power also increases as the central wavelength increases, as Figure 7 (a), the resonant wavelength of the FBG acting as an edge filter increases from 1549.816 nm to 1550.276 nm, as Figure 7 (b). The relationship between the transmitted optical power of the unpackaged FBG directly measured by an optical power meter and temperature is as Figure 7 (c), and an exponential function is used for fitting, with a fitting degree of 0.99824. Figure 7 The reason for the exponential change in the optical power value is that when using the FBG as an edge filter, the shape and bandwidth of its spectrum determine the overlapping wavelength range of the reflection spectra of the FBGs in the temperature measurement unit. When the temperature of the environment where the FBG in the temperature measurement part is located rises, the overlapping part of the FBG acting as an edge filter shows an exponential increase. And when using the FBG as an edge filter, since the temperature sensitivity of the FBG is significantly lower, as Figure 8 when the temperature rises from 15 °C to 65 °C, the central wavelength rises from 1550.115 nm to 1550.617 nm. For every 1 °C change in temperature on average, the central wavelength rises by about 0.01 nm. Compared with the LPG, its applicability to the external environment is greatly increased.

[0104] Example Five

[0105] Reference Figure 1 、 Figures 9 - 10 , based on the above Examples One, Two, Three, and Four, a method of filtering using a larger-bandwidth FBG with negative temperature compensation packaging is disclosed.

[0106] Similarly, connect according to the optical path structure shown in the appendix Figure 1 , replace the edge filter in the figure with an FBG with negative temperature compensation packaging having a bandwidth of 1.955 nm and a central wavelength of 1550 nm, and place the FBG with negative temperature compensation packaging and the FBG sensor together in a temperature control box. Other measurement conditions are set the same as in Examples Two and Three before. Set the temperature to 65 °C and gradually decrease it to 20 °C, and record the data every 5 °C. The experimental results are as Figure 9 shown, where (a) shows the relationship between temperature and the transmission spectrum of the edge-filtered FBG with negative temperature compensation; (b) shows the relationship between the resonant wavelength of the edge-filtered FBG with negative temperature compensation and temperature; (c) shows the relationship between temperature and the power of the transmission spectrum of the edge-filtered FBG with negative temperature compensation. As the temperature increases, the central wavelength of the FBG drifts towards the long-wavelength direction, and the peak value of the optical power also increases as the central wavelength increases, as Figure 9(a), the resonant wavelength of the negative temperature compensated FBG as an edge filter increases from 1550.204 nm to 1550.632 nm as Figure 9 (b). The relationship between the transmitted optical power of the FBG with a negative temperature packaging bandwidth of 1.96 nm directly measured by an optical power meter and temperature is as Figure 9 (c) is fitted with an exponential function, and the goodness of fit is 0.99566. When the FBG with negative temperature compensation packaging is used, the central wavelength remains quite stable when the external temperature changes drastically. During the process of temperature changing from 20 °C to 65 °C, the maximum deviation of the central wavelength is only 0.017 nm as Figure 10 shown. The measurement results show that the FBG with a large bandwidth using negative temperature compensation packaging as an edge filter can be directly used in a temperature measurement environment without being placed in a constant temperature environment separately.

[0107] When using an LPG with a loss peak depth of about 28 dB as an edge filter, the temperature measurement range is from 23 °C to 62 °C, and the temperature and transmitted light show a linear change, with a goodness of fit of 0.99998. When using an FBG with a bandwidth of 1.507 nm as an edge filter, the temperature measurement range is from 15 °C to 65 °C, and the temperature and transmitted light show an exponential change, with a goodness of fit of 0.99824. When using an FBG with a negative temperature compensation packaging with a bandwidth of 1.96 nm as an edge filter, the temperature measurement range is from 20 °C to 65 °C, and the temperature and transmitted light show an exponential change, with a goodness of fit of 0.99566. There is a matching problem that the temperature measurement range when using an FBG with a negative temperature compensation packaging with a bandwidth of 1.96 nm as an edge filter is smaller than that when using an FBG with a bandwidth of 1.507 nm as an edge filter. Similarly, the magnitude of the reflectivity of the central wavelength of the FBG as an edge filter also affects the measurement results. The LPG has a relatively wide bandwidth, and within a certain temperature range, the change in light intensity shows a good linear relationship. However, the LPG is very sensitive to temperature changes, which limits its stability in practical applications. To avoid the influence of temperature, the LPG usually needs to be placed in a constant temperature environment, increasing the usage cost and complexity. The FBG with a wider bandwidth has a wider reflection bandwidth compared to the traditional narrowband FBG, and can more effectively match the FBG reflection spectrum, improving the sensitivity and accuracy of the measurement. However, since the FBG itself is still sensitive to external temperature changes, when using an FBG with a wider bandwidth as an edge filter, it still cannot be directly placed in the temperature environment to be measured. The broadband FBG with negative temperature compensation packaging combines the advantages of the broadband FBG and improves its resistance to temperature changes through negative temperature compensation packaging. This enables it to maintain good measurement accuracy within a relatively wide temperature range and is suitable for temperature measurement scenarios.

[0108] The preferred embodiments of the present invention disclosed above are only used to assist in the description of the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for measuring dual parameters of voltage and temperature by inverse piezoelectric optics, characterized in that, The steps are as follows: S1: Obtain the spectrum provided by the broadband laser source through the Gaussian equation; S2: Receive the spectrum of the broadband laser source through a voltage sensor; S3: Set FBG1 and FBG2, simplify the reflectivity of the FBG through the Gaussian equation, and calculate the reflectivities of the FBGs in FBG1 and FBG2.

2. The method for measuring inverse piezoelectric optical voltage and temperature dual-parameters according to claim 1, characterized in that, In step S1, the spectrum provided by the broadband laser source is obtained through the Gaussian equation, and the expression is as follows: Among them, I peak is the peak power, λ0 is the central wavelength, and Δλ0 is the full width at half maximum.

3. A method for measuring dual parameters of inverse piezoelectric optical voltage and temperature according to claim 1, characterized in that, In step S2, the voltage sensor is composed of a voltage measurement unit and a temperature measurement unit, and both the voltage measurement unit and the temperature measurement unit are composed of piezoelectric ceramics and fiber Bragg gratings.

4. A method for measuring inverse piezoelectric optical voltage and temperature dual parameters according to claim 3, characterized in that, The grating is a C-band reflective Bragg grating, adhered to the piezoelectric ceramic, and silver electrode layers serving as voltage input ports are plated on both sides of the piezoelectric ceramic.

5. A method for measuring dual parameters of inverse piezoelectric optical voltage and temperature according to claim 1, characterized in that In step S3, FBG1 and FBG2 are set, temperature measurement is performed through FBG1, and voltage measurement is jointly performed through FBG1 and FBG2.

6. The method for measuring inverse piezoelectric optical voltage-temperature dual parameters according to claim 2, characterized in that, In step S3, the reflectivity of the FBG is simplified through the Gaussian equation, and the reflectivities of the FBGs in FBG1 and FBG2 are calculated, and the expression is as follows: In the formula, represents the reflection spectrum of the temperature measurement unit, represents the reflection spectrum of the voltage measurement unit; and represent the central wavelength of the fiber Bragg grating, and represent the FWHM of the fiber Bragg grating spectrum, and R0 represents the maximum reflectivity of the fiber Bragg grating.

7. A method for measuring inverse piezoelectric optical voltage-temperature dual parameters according to claim 6, characterized in that For the fiber Bragg grating in the temperature measurement unit, the reflected light I1(λ) should be the product of the incident broadband light source spectrum and the reflected spectrum of the reference grating, and the expression is as follows: I1(λ) = S(λ B )F R2 (λ); The reflected light of FBG2 is the product of the transmitted light of FBG1 and the reflectivity of FBG2, and the expression is as follows: I2(λ) = [S(λ B ) - S(λ B )F R1 (λ)]F S2 (λ); Since I PD = I2(λ), after optimization, we get: I PD = [S(λ B ) - S(λ B )F R2 (λ)]F S2 (λ); The optical signal received by the photodetector, and the expression is as follows: After optimization, it is obtained that: Among them, S(λ B ) is the spectrum provided by the broadband laser source, are the reflectivities of the FBGs in FBG1 and FBG2 respectively, and represent their central wavelengths respectively, and represent their full-width at half maximum respectively, and R0 is their maximum refractive index.

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