Double-parameter amplitude-phase fusion demodulation method based on optical fiber ring interference sensor

Abstract

The invention discloses a dual-parameter amplitude-phase fusion demodulation method based on an optical fiber ring interference sensor, and the method comprises the steps: obtaining the frequency response of a system through a vector network analyzer, and obtaining a dual-parameter amplitude-phase fusion demodulation signal through employing the frequency drift and fringe contrast of an interference amplitude spectrum of the frequency response, and the phase spectrum change under different modulation frequencies; therefore, double-parameter crosstalk-free amplitude-phase fusion demodulation of temperature and loss is realized based on combination of two kinds of information of the amplitude spectrum and the phase spectrum. The amplitude-phase fusion demodulation method has the characteristics of fast response of amplitude spectrum demodulation and high sensitivity and light source power fluctuation resistance of phase demodulation, the demodulation mode can be flexibly adjusted for different use scenes, and the amplitude demodulation result can be compensated and corrected based on the phase demodulation result; frequency response information is utilized, so that crosstalk-free measurement of the temperature and the loss by the radio frequency assisted FRIS can be realized independently based on the amplitude spectrum or the phase spectrum, and the amplitude spectrum and the phase spectrum can be fused to improve the demodulation performance.

Description

Technical Field

[0001] The invention relates to optical fiber sensing technology, and in particular to a dual-parameter amplitude-phase fusion demodulation method based on an optical fiber ring interference sensor. Background Art

[0002] With the continuous expansion of industrial production scale, the in-depth development of resource exploration technology and the growing demand for infrastructure monitoring, the demand for high-precision and high-stability measurement technology has become more urgent. Fiber interferometric sensors, with their high sensitivity, large measurement range and anti-electromagnetic interference ability, have shown great application potential and broad market prospects in many key fields such as precision measurement, environmental monitoring and industrial control. As a new type of fiber interferometric sensor, fiber ring interferometric sensor (FRIS) has excellent performance in enhancing the interaction between light and matter and improving sensing sensitivity due to its unique ring cavity ring-down structure and excellent characteristics of time-domain infinite impulse response. However, despite the significant technical progress of FRIS, its traditional demodulation methods, such as technical solutions based on time-domain pulse ring-down fitting or continuous random signal correlation demodulation, still face many challenges. These methods are easily affected by light source fluctuations in practical applications, resulting in unstable demodulation results; at the same time, the demodulation process takes a long time and it is difficult to meet real-time requirements; in addition, its anti-interference ability is limited, and it is difficult to maintain high-performance operation under complex and changing environmental conditions. These problems seriously restrict the application and development of FRIS in a wider range of fields.

[0003] In order to break through the above technical bottlenecks, RF-assisted sensing technology came into being. This technology cleverly combines the dual advantages of fiber optics and RF photonics, and opens up a new technical path for the field of fiber optic sensing by converting the external parameter change information carried by light waves into RF signals for processing. RF-assisted fiber optic sensing technology efficiently modulates RF signals onto optical carriers, and uses the low loss and high bandwidth characteristics of optical fibers for long-distance, high-fidelity signal transmission; then, the optical signals are accurately restored to RF signals through photoelectric conversion technology for subsequent processing and analysis, thereby achieving rapid and accurate measurement of environmental parameters. Combining this RF-assisted sensing technology with FRIS can not only significantly improve the demodulation speed and processing efficiency of the sensing system, but also greatly enhance the system's anti-interference ability and stability, providing a strong guarantee for high-precision measurements in complex environments.

[0004] In this RF-assisted FRIS, amplitude demodulation and phase demodulation methods each have their own advantages. The amplitude demodulation method has the advantages of simple operation and rapid response. However, its demodulation accuracy is easily affected by interference factors such as light source power fluctuations and electrical link noise, which increases the difficulty of peak finding and causes large demodulation errors. In addition, its demodulation sensitivity is closely related to the frequency resolution, and the system performance requirements are high. The phase demodulation method improves the loss sensing sensitivity through phase shift amplification technology based on the subtle changes in the phase spectrum, and can capture the weak information that is difficult to detect in the conventional amplitude spectrum from a unique phase perspective to further explore the sensing potential of FRIS. Although phase demodulation can still provide high demodulation sensitivity under limited equipment performance and is particularly suitable for RF-assisted optical fiber sensing systems, its demodulation process is relatively complex. In addition, the crosstalk between multiple parameters in the demodulation of FRIS is also an important factor that limits its multi-functional monitoring in complex scenarios. Therefore, there is an urgent need for a multi-parameter crosstalk-free demodulation method based on the frequency response of RF-assisted FRIS to achieve fast response, high sensitivity, and high precision. Summary of the invention

[0005] Purpose of the invention: In view of the above problems, the purpose of the present invention is to provide a dual-parameter amplitude-phase fusion demodulation method based on a fiber ring interferometer sensor, which can not only realize the crosstalk-free measurement of temperature and loss by RF-assisted FRIS based on amplitude spectrum or phase spectrum alone, but also can integrate the two to improve the demodulation performance.

[0006] Technical solution: A dual-parameter amplitude-phase fusion demodulation method based on an optical fiber ring interferometer sensor of the present invention comprises:

[0007] A swept frequency RF signal with a time-varying chirp is generated by a vector network analyzer. The swept frequency RF signal is injected into an electro-optical modulator after being power-amplified by an electrical amplifier and modulated and loaded onto the continuous incoherent light output by a broadband light source, so that the optical carrier carries the RF signal with a time-varying intensity.

[0008] The radio frequency modulated optical carrier is partially cross-coupled into the optical fiber ring interferometer sensor under the action of the optical fiber coupler, and the remaining part is directly self-coupled and output; the optical fiber ring interferometer sensor includes a loss sensing optical fiber and a temperature sensing optical fiber;

[0009] The optical carrier propagates in a loop in the optical fiber ring interferometer sensor, and each time it passes through the optical fiber coupler, part of the optical wave is cross-coupled to the outside of the ring and superimposed with the optical carrier output by the first self-coupling;

[0010] In the fiber ring interferometer sensor, by applying temperature change to the temperature sensing fiber or applying loss change to the loss sensing fiber, the optical carrier circulating in the fiber ring interferometer sensor generates a fixed optical path difference and time delay difference;

[0011] The superimposed optical carrier is received by the photodetector and converted into a radio frequency electrical signal carrying the information of the parameter to be measured. Interference occurs in the electrical frequency domain, and the frequency response of the fiber ring interferometer sensor is obtained through a vector network analyzer. Dual parameter demodulation of temperature and loss is achieved based on the fusion of amplitude spectrum and phase shift spectrum.

[0012] Furthermore, dual parameter demodulation of temperature and loss based on the fusion of amplitude spectrum and phase shift spectrum includes:

[0013] Obtain the frequency corresponding to the interference peak or interference valley in the amplitude spectrum, calculate the first temperature according to the frequency, and use the first temperature to determine the integer digits of the demodulation temperature; obtain the frequency corresponding to the zero phase shift point of the phase shift spectrum, calculate the second temperature according to the frequency, and use the second temperature to determine the decimal digits of the demodulation temperature.

[0014] Furthermore, dual parameter demodulation of temperature and loss based on the fusion of amplitude spectrum and phase shift spectrum also includes:

[0015] Selecting an amplitude spectrum containing at least three cycles, extracting the maximum and minimum values ​​of the spectrum line, calculating the average value of the interference fringe contrast, and determining the percentile of the demodulation loss according to the average value of the fringe contrast;

[0016] A phase shift spectrum within a range of 0 to 50 MHz is obtained, the loss is demodulated according to the phase shift amount of the phase shift spectrum, and the thousandth of the demodulation loss is determined according to the demodulation result.

[0017] Furthermore, the broadband light source outputs a broad spectrum of light with a wavelength of 1530 nm to 1565 nm.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0019] 1. The present invention utilizes the frequency drift of the interference amplitude spectrum, the change of the fringe contrast, and the frequency drift and the change of the phase shift amount of the phase shift spectrum in the frequency response to realize the dual-parameter crosstalk-free demodulation of temperature and loss;

[0020] 2. The present invention combines the amplitude and phase information of the FRIS frequency response, and has the advantages of rapid response of amplitude demodulation and high sensitivity and high precision of phase demodulation;

[0021] 3. The present invention greatly improves the information utilization rate of the frequency response, and improves the accuracy of the demodulation result by mutual compensation and correction from the two dimensions of amplitude and phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the structural diagram of the demodulation system of the fiber ring interferometer sensor;

[0023] Figure 2 Interference amplitude spectrum and phase shift spectrum at different temperatures and different losses. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0025] The present embodiment describes a dual-parameter amplitude-phase fusion demodulation method based on an optical fiber ring interferometer sensor, which is applied to Figure 1 In the fiber ring interferometer sensor demodulation system shown, the method includes:

[0026] A swept frequency RF signal with a time-varying chirp is generated by a vector network analyzer. The swept frequency RF signal is injected into an electro-optical modulator after being power-amplified by an electrical amplifier and modulated and loaded onto the continuous incoherent light output by a broadband light source, so that the optical carrier carries the RF signal with a time-varying intensity.

[0027] The radio frequency modulated optical carrier is partially cross-coupled into the optical fiber ring interferometer sensor under the action of the optical fiber coupler, and the remaining part is directly self-coupled and output; the optical fiber ring interferometer sensor includes a loss sensing optical fiber and a temperature sensing optical fiber;

[0028] The optical carrier propagates in a loop in the optical fiber ring interferometer sensor, and each time it passes through the optical fiber coupler, part of the optical wave is cross-coupled to the outside of the ring and superimposed with the optical carrier output by the first self-coupling;

[0029] In the fiber ring interferometer sensor, by applying temperature change to the temperature sensing fiber or applying loss change to the loss sensing fiber, the optical carrier circulating in the fiber ring interferometer sensor generates a fixed optical path difference and time delay difference;

[0030] The superimposed optical carrier is received by the photodetector and converted into a radio frequency electrical signal carrying the information of the parameter to be measured. Interference occurs in the electrical frequency domain, and the frequency response of the fiber ring interferometer sensor is obtained through a vector network analyzer. Dual parameter demodulation of temperature and loss is achieved based on the fusion of amplitude spectrum and phase shift spectrum.

[0031] Furthermore, dual parameter demodulation of temperature and loss based on the fusion of amplitude spectrum and phase shift spectrum includes:

[0032] Obtain the frequency corresponding to the interference peak or interference valley in the amplitude spectrum, calculate the first temperature according to the frequency, and use the first temperature to determine the integer digits of the demodulation temperature; obtain the frequency corresponding to the zero phase shift point of the phase shift spectrum, calculate the second temperature according to the frequency, and use the second temperature to determine the decimal digits of the demodulation temperature.

[0033] In an example such as Figure 1As shown, the demodulation system of the fiber ring interferometer sensor includes a broadband light source 101, an electro-optic modulator 103, a fiber coupler 106, a photodetector 110, a vector network analyzer 108 and an amplifier 107 connected in sequence, and the input end and the output end of the fiber coupler 106 are respectively connected to the two ends of the fiber ring interferometer sensor. The fiber ring interferometer sensor includes a loss sensing fiber 104 and a temperature sensing fiber 105, wherein the loss sensing fiber 104 is an intensity modulated fiber loss sensor, and the temperature sensing fiber 105 is a fiber coil. The broadband light source 101 is connected to the electro-optic modulator 103 through a single-mode optical fiber 102, and the photodetector 110 is connected to the vector network analyzer 108 through a coaxial cable.

[0034] In this example, a broadband light source 101 is used to output C-band, that is, a wide-spectrum light with a wavelength of 1530 to 1565 nm, to provide sufficient optical power while avoiding optical interference and reducing the impact of optical jitter on the RF signal. During operation, the swept RF signal generated by the vector network analyzer 108 is injected into the electro-optical modulator 103, and the continuous optical carrier is intensity modulated so that the optical carrier carries the RF signal that changes with time in intensity. The RF modulated optical carrier is coupled into the FRIS through the optical fiber coupler 106, and is partially coupled out of the FRIS in each cyclic propagation, and then converted into a RF electrical signal carrying the parameter information to be measured by the photodetector 110. The converted RF signals with different amplitudes of delay will interfere in the frequency domain and form an amplitude spectrum and a phase spectrum related to the fiber ring length. The frequency response of the system is obtained using the vector network analyzer 108. Most of the optical fibers in the FRIS are coiled into optical coils for temperature sensing, and the remaining optical fibers are used to sense changes related to loss such as bending and attenuation.

[0035] The broadband light source 101 outputs broadband light with a wavelength of 1530nm to 1565nm. The single-mode optical fiber 102 is an ordinary standard single-mode optical fiber, and the bandwidth of the electro-optic modulator 103 should be greater than the maximum frequency required for demodulation. For this embodiment, its bandwidth should be no less than 4.1GHz. The coupling ratio of the fiber coupler 106 is 50:50 in this embodiment, and can be adjusted according to the size of the initial total loss of FRIS in practice. The electrical amplifier 107 is 3dB in this embodiment, and can be adjusted according to the output power of the vector network analyzer 108 and the rated power of the electro-optic modulator 103. The response wavelength range of the photodetector 110 should cover the wavelength range of the light source, and the bandwidth should be greater than the maximum frequency required for demodulation. For this patent embodiment, its bandwidth should be no less than 4.1GHz.

[0036] The total length of the fiber loop in the fiber ring interferometer sensor is 16m, corresponding to a free spectrum range of about 12.5MHz. The fiber coil is 12m long and is used for temperature sensing, and the remaining fiber is used to sense changes related to loss such as bending and attenuation. A vector network analyzer is used to obtain the frequency response of the system, in which the frequency response in the range of 4 to 4.01GHz is obtained for amplitude and phase demodulation of temperature to achieve temperature sensing; the frequency response in the range of 0 to 50MHz is obtained, which can cover about four cycles of interference patterns and is used for amplitude and phase demodulation of loss.

[0037] For ease of implementation, temperature demodulation is performed in the range of 4 to 4.01 GHz. As the temperature increases, the refractive index of the optical fiber increases, causing the effective refractive index of the fundamental mode to increase accordingly, thereby increasing the time delay between the RF signals involved in the interference, and ultimately reducing the free spectral range, i.e., the period of the interference spectrum, causing the interference spectrum to drift toward the low frequency direction. Figure 2 The middle figure (a) shows the interference amplitude spectrum at different temperatures. The interference peak in the interference amplitude spectrum is tracked to obtain the change in the interference peak frequency as the interference spectrum drift.

[0038] When the length of the fiber ring and the fiber coil for temperature measurement are constant, the drift of the interference amplitude spectrum accumulates with the increase of frequency, thus forming a cumulative amplification effect in which the sensitivity increases with the frequency. The temperature sensing sensitivity is proportional to the modulated RF frequency. The temperature information of the external environment is obtained by demodulating the amplitude spectrum and phase spectrum. The former has a fast response speed and the latter has a high sensitivity, so as to realize temperature sensing.

[0039] When performing temperature sensing, increasing the length of the optical fiber coil can increase the effect of parameters such as temperature on the mode propagation in the optical fiber, thereby achieving the effect of improving the sensing sensitivity. Without considering the transmission loss of 0.2dB / km in the optical fiber, the temperature sensing sensitivity is proportional to the length of the optical fiber coil. Taking into account the actual propagation loss, the loss caused by the increase in the optical fiber length has little effect on the temperature sensing sensitivity, but the free spectrum range will also be reduced accordingly, which will bring difficulty to the demodulation. At the same time, the increase in loss caused by the increase in the length of the optical fiber coil will reduce the dynamic range of the intensity modulated optical fiber loss sensor. Therefore, considering the temperature and loss dual parameter demodulation characteristics of this embodiment, as well as the demodulation difficulty and dynamic range, the total length of the optical fiber should not exceed 100m.

[0040] like Figure 2 Figure (c) shows the phase shift spectra at different temperatures. Different from the demodulation temperature based on tracking the amplitude interference peak frequency drift, the method used for demodulation temperature based on phase shift spectrum drift is to track the drift of the zero phase shift point to avoid the influence of loss-induced phase shift on temperature-induced phase shift; at the same time, fitting in the high-slope linear region near the zero phase shift point can improve the demodulation frequency resolution, thereby improving the accuracy.

[0041] When performing temperature sensing, the standard deviation of the demodulation result based on the amplitude is generally 10 to 20 kHz, which is equivalent to an error of about 0.6 to 1.1°C. Therefore, the temperature obtained by demodulation is usually rounded to an integer, such as Figure 2 In the middle figure (a), the interference peak in the interference amplitude spectrum is tracked to obtain the interference peak frequency change as the interference spectrum drift. The temperature is obtained by demodulation and the integer digit of the temperature is taken. As shown in Figure (c), the drift of the zero phase shift point is tracked. The standard deviation of the phase-based demodulation result is generally less than 5kHz, which is equivalent to a temperature error of less than 0.3℃. At this time, the temperature demodulation result can be taken to one decimal place, which improves the temperature demodulation accuracy. The final demodulated temperature is composed of integer digits and decimal digits.

[0042] Amplitude demodulation temperature is fast, but the demodulation of amplitude spectrum drift depends on the tracking accuracy and frequency resolution of the interference peak. When the half-height full width of the interference peak is large, it will introduce large errors; phase demodulation temperature requires further data processing, resulting in a slower demodulation speed, but the zero phase shift point effectively avoids the errors that may be caused by peak search, and fitting in the linear region with a large slope can break through the frequency resolution limit, while suppressing the crosstalk caused by loss and improving the sensing accuracy. In this example, the amplitude demodulation result is used as the initial value, and the phase demodulation result is used to perform delay correction, which can have the advantages of fast response and high precision.

[0043] Furthermore, dual parameter demodulation of temperature and loss based on the fusion of amplitude spectrum and phase shift spectrum also includes:

[0044] Selecting an amplitude spectrum containing at least three cycles, extracting the maximum and minimum values ​​of the spectrum line, calculating the average value of the interference fringe contrast, and determining the percentile of the demodulation loss according to the average value of the fringe contrast;

[0045] A phase shift spectrum within a range of 0 to 50 MHz is obtained, the loss is demodulated according to the phase shift amount of the phase shift spectrum, and the thousandth of the demodulation loss is determined according to the demodulation result.

[0046] In a specific example, the frequency response in the range of 4 to 4.04 GHz is obtained, which can cover about three cycles of interference patterns for amplitude-based loss demodulation; the frequency response in the range of 0 to 50 MHz is obtained for phase-based loss demodulation. This further illustrates the characteristics of independent demodulation of temperature and loss without crosstalk in the case of amplitude and phase demodulation respectively.

[0047] For ease of implementation, loss demodulation should be performed in the range of 0 to 50 MHz. As the propagation loss in the FRIS increases, the intensity of the RF modulated optical carrier cross-coupled from the fiber ring to the outside of the ring decreases, causing a decrease in the contrast of the interference amplitude spectrum fringes and a change in the phase at some RF frequencies. In this embodiment, Figure 2Figure (b) shows the interference amplitude spectrum under different losses. The frequency response in the range of 4 to 4.04 GHz, which is similar to that in Figure (a), is directly used to illustrate the crosstalk-free characteristics of amplitude-based demodulation of temperature and loss, that is, at the same frequency, the amplitude-based demodulation method can still obtain temperature and loss information without crosstalk. There are about three periods in this frequency range. The maximum and minimum values ​​of these periodic interference patterns are extracted, and the average value of their fringe contrast is obtained, which can suppress the error caused by frequency factors and realize the demodulation of loss. Since the fringe contrast of the interference amplitude spectrum is independent of frequency, loss demodulation can also be performed in the range of 0 to 50 MHz.

[0048] In this embodiment, if Figure 2 Figure (d) shows the phase shift spectrum under different losses at temperatures of 10, 30, and 50°C. In the range of 0 to 50 MHz, the zero-loss phase spectrum is used as the initial phase, and the phase spectrum is differentially processed to obtain the phase shift spectrum. Different RF frequencies correspond to different loss-related phase shift sensitivities. By demodulating the phase shift at this frequency, the sensing sensitivity can be greatly improved. However, for the frequency response in the high-frequency range, the phase shift changes caused by temperature and loss in the phase shift spectrum will interfere with each other, so loss demodulation is required at a low frequency of 0 to 50 MHz to avoid crosstalk from temperature changes.

[0049] When performing loss sensing, the standard deviation of the demodulation result based on amplitude is generally 0.05-0.10dB, which is equivalent to a transmittance error of about 0.98%-1.97% (transmittance is used to characterize loss). Therefore, the transmittance obtained by demodulation is usually taken to the percentile. The standard deviation of the demodulation result based on phase is generally less than 0.0005rad, which is equivalent to a transmittance error of less than 0.18%. At this time, the transmittance obtained by demodulation can be taken to the thousandth, which improves the accuracy of the transmittance, that is, the loss demodulation. The final demodulation loss is composed of percentiles and thousandths. The method of amplitude demodulation loss is relatively simple and fast, but it is easily interfered by RF signal power fluctuations and electrical noise, thereby introducing errors; similar to temperature demodulation, phase demodulation loss requires a more complex data processing process, but phase shift amplification technology can significantly improve the demodulation sensitivity. Based on the integration of amplitude demodulation and phase demodulation of temperature and loss by FRIS, it can quickly obtain results based on amplitude demodulation, and then make high-sensitivity and high-precision corrections based on the phase demodulation results, thereby combining the advantages of amplitude demodulation and phase demodulation.

[0050] In this embodiment, a fiber ring interference sensor is used to sense changes in temperature and loss. When the temperature change changes the refractive index of the optical fiber through the thermo-optical effect, thereby affecting the propagation delay of the light wave, it will cause the drift of the frequency domain amplitude interference spectrum and the phase shift spectrum; when the optical fiber is bent or damaged, thereby generating propagation loss, it will reduce the power of the optical carrier and the modulated RF signal, resulting in changes in the contrast of the frequency domain amplitude interference spectrum and the phase shift amount. Therefore, when the temperature and loss change, a large dynamic range and high sensitivity temperature demodulation can be achieved based on the frequency drift of the amplitude spectrum and the phase shift spectrum, that is, the frequency corresponding to the interference peak or interference valley in the amplitude spectrum is tracked to obtain the corresponding temperature. At this time, the temperature sensor has a fast demodulation characteristic; the frequency corresponding to the zero phase shift point of the phase shift spectrum is tracked to obtain the corresponding temperature. At this time, the temperature sensor has high precision and anti-power fluctuation characteristics. At the same time, based on the amplitude spectrum fringe contrast and the phase shift change of the phase shift spectrum, a large dynamic range and high sensitivity loss demodulation is achieved, that is, the magnitude of the interference fringe contrast of the interference amplitude spectrum is calculated to demodulate the loss. At this time, the loss sensor has a fast demodulation characteristic; the magnitude of the phase shift of the phase shift spectrum is calculated to demodulate the loss. At this time, the loss sensor has high precision and anti-power fluctuation characteristics. Based on this amplitude-phase fusion demodulation method, fast response, high sensitivity, and high precision temperature and loss dual parameter demodulation can be achieved.

[0051] In the present invention, a vector network analyzer is used to obtain the frequency response of the system, and the frequency drift and fringe contrast of the interference amplitude spectrum of the frequency response and the change of the phase spectrum under different modulation frequencies are used to realize the dual-parameter crosstalk-free amplitude-phase fusion demodulation of temperature and loss based on the combination of the two information of amplitude spectrum and phase spectrum. The dual-parameter amplitude-phase fusion demodulation method described in the present invention has the characteristics of rapid response of amplitude spectrum demodulation, high sensitivity of phase demodulation and resistance to light source power fluctuation. The demodulation mode can be flexibly adjusted for different usage scenarios, and the amplitude demodulation result can be compensated and corrected based on the phase demodulation result. The dual-parameter amplitude-phase fusion demodulation method described in the present invention makes full use of the frequency response information, not only can the RF-assisted FRIS realize crosstalk-free measurement of temperature and loss based on the amplitude spectrum or phase spectrum alone, but also can integrate the two to improve the demodulation performance, which is an effective solution to realize a multifunctional RF-assisted optical fiber sensing system with rapid response, high sensitivity and high precision.

Claims

1. A dual-parameter amplitude-phase fusion demodulation method based on a fiber ring interferometer sensor, characterized in that: include: A swept frequency RF signal with a time-varying chirp is generated by a vector network analyzer. The swept frequency RF signal is injected into an electro-optical modulator after being power-amplified by an electrical amplifier and modulated and loaded onto the continuous incoherent light output by a broadband light source, so that the optical carrier carries the RF signal with a time-varying intensity. The radio frequency modulated optical carrier is partially cross-coupled into the optical fiber ring interferometer sensor under the action of the optical fiber coupler, and the remaining part is directly self-coupled and output; the optical fiber ring interferometer sensor includes a loss sensing optical fiber and a temperature sensing optical fiber; The optical carrier propagates in a loop in the optical fiber ring interferometer sensor, and each time it passes through the optical fiber coupler, part of the optical wave is cross-coupled to the outside of the ring and superimposed with the optical carrier output by the first self-coupling; In the fiber ring interferometer sensor, by applying temperature change to the temperature sensing fiber or applying loss change to the loss sensing fiber, the optical carrier circulating in the fiber ring interferometer sensor generates a fixed optical path difference and time delay difference; The superimposed optical carrier is received by the photodetector and converted into a radio frequency electrical signal carrying the information of the parameter to be measured. Interference occurs in the electrical frequency domain, and the frequency response of the fiber ring interferometer sensor is obtained through a vector network analyzer. Dual parameter demodulation of temperature and loss is achieved based on the fusion of amplitude spectrum and phase shift spectrum.

2. A dual-parameter amplitude-phase fusion demodulation method based on an optical fiber ring interferometer sensor according to claim 1, characterized in that: Dual parameter demodulation of temperature and loss based on the fusion of amplitude spectrum and phase shift spectrum includes: Obtain the frequency corresponding to the interference peak or interference valley in the amplitude spectrum, calculate the first temperature according to the frequency, and use the first temperature to determine the integer digits of the demodulation temperature; obtain the frequency corresponding to the zero phase shift point of the phase shift spectrum, calculate the second temperature according to the frequency, and use the second temperature to determine the decimal digits of the demodulation temperature.

3. A dual-parameter amplitude-phase fusion demodulation method based on an optical fiber ring interferometer sensor according to claim 2, characterized in that: Dual parameter demodulation of temperature and loss based on the fusion of amplitude spectrum and phase shift spectrum also includes: Selecting an amplitude spectrum containing at least three cycles, extracting the maximum and minimum values ​​of the spectrum line, calculating the average value of the interference fringe contrast, and determining the percentile of the demodulation loss according to the average value of the fringe contrast; A phase shift spectrum within a range of 0 to 50 MHz is obtained, the loss is demodulated according to the phase shift amount of the phase shift spectrum, and the thousandth of the demodulation loss is determined according to the demodulation result.

4. A dual-parameter amplitude-phase fusion demodulation method based on an optical fiber ring interferometer sensor according to claim 1, characterized in that: The broadband light source outputs a wide spectrum of light with a wavelength of 1530nm to 1565nm.

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