A Distributed Optical Fiber Rapid Monitoring Superconductor Temperature System

Abstract

The present invention discloses a distributed optical fiber rapid monitoring system for superconductor temperature, comprising a distributed single-mode optical fiber Raman temperature measurement device, a superconductor, a polyimide single-mode optical fiber, a liquid nitrogen tank, a function generator and an oscilloscope. The surface of the superconductor is grooved, and the polyimide single-mode optical fiber is installed in the surface groove of the superconductor. The beneficial effects of the present invention are: 1. The distributed optical fiber rapid detection system for superconductor temperature can realize state monitoring of superconductors in a liquid nitrogen environment. 2. The distributed optical fiber rapid detection system for superconductor temperature can measure the temperature of superconductors with high spatial resolution and high precision. In a liquid nitrogen environment, the temperature measurement accuracy is ±2°C. 3. The distributed optical fiber rapid detection system for superconductor temperature can respond to temperature changes ultra-fast, with a response speed of 0.1s. 4. The distributed single-mode optical fiber Raman temperature measurement device is stable and easy to carry.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fibers, in particular to a distributed optical fiber fast monitoring system for superconductor temperature. Background Art

[0002] Special metals exhibit a superconducting state in liquid nitrogen. Under ideal conditions, the conductors remain cool and can carry large currents. However, if the superconductor's material fails, it loses its superconducting state in liquid nitrogen, resulting in high resistance and causing the conductor to heat up or even burn out. If the superconductor's temperature could be measured, the current could be cut off at the initial stage of heating, protecting the superconductor from burning out. Therefore, real-time temperature measurement at various points on the superconductor is essential.

[0003] At one atmosphere of pressure, the temperature of liquid nitrogen is -196°C. Monitoring the temperature of a superconductor requires a temperature sensor capable of operating in liquid nitrogen environments. Because optical fibers are optical fibers, they have a wide operating temperature range. Therefore, only a single-mode fiber is required as the sensing medium. Using distributed single-mode fiber Raman temperature sensing technology, continuous monitoring of various superconductor temperature points is possible.

[0004] Currently, patents for measuring physical quantities in liquid nitrogen environments include: Chinese Patent No. 201710182354.6, filed on March 24, 2017, for "A Method for Measuring Material Strain at Ultra-Low Temperatures Using Fiber Bragg Gratings," and Chinese Patent No. 201710043179.2, filed on January 19, 2017, for "An Embedded Low-Temperature Fiber Temperature Sensor and Its Preparation Method." However, these systems currently only provide strain and temperature information at a specific point on the object being measured at ultra-low temperatures and are unable to achieve continuous spatial temperature monitoring of superconductors. Measuring the overcurrent temperature changes of superconductors requires a very fast temperature response system. Summary of the Invention

[0005] The object of the present invention is to provide a distributed optical fiber fast superconductor temperature monitoring system to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A distributed optical fiber rapid superconductor temperature monitoring system includes a distributed single-mode optical fiber Raman temperature measurement device, a superconductor, a polyimide single-mode optical fiber, a liquid nitrogen tank, a function generator, and an oscilloscope. The surface of the superconductor is grooved, the polyimide single-mode optical fiber is installed in the surface groove of the superconductor, the polyimide single-mode optical fiber is connected to the distributed single-mode optical fiber Raman temperature measurement device, the superconductor is placed in the liquid nitrogen tank, the function generator is connected to one end of the superconductor, and the oscilloscope is connected to the other end of the superconductor.

[0008] As a further solution of the present invention: the polyimide single-mode optical fiber is sealed into the surface groove of the superconductor 2 through a glue-filling and packaging process.

[0009] As a further solution of the present invention: the distributed single-mode fiber Raman temperature measurement equipment includes a narrow linewidth laser LD, an acousto-optic modulator AOM, an acousto-optic modulator driver, an arbitrary waveform generator AWG, an erbium-doped fiber amplifier EDFA, a fiber grating filter, a Raman second-order amplifier, a wavelength division multiplexer WDM1, a circulator, a wavelength division multiplexer WDM2, a wavelength division multiplexer WDM3, a detector APD, a dual-channel amplifier circuit, a two-channel acquisition card, and a computer.

[0010] As a further solution of the present invention, the output end of the narrow linewidth laser LD is connected to the input end of the acousto-optic modulator AOM, and the continuous laser output by the narrow linewidth laser enters the acousto-optic modulator AOM. The arbitrary waveform generator AWG is located above the acousto-optic modulator driver, and the electrical pulse signal output by the arbitrary waveform generator AWG is loaded onto the acousto-optic modulator driver. The acousto-optic modulator driver loads the pulsed radio frequency signal onto the acousto-optic modulator AOM, and is used to modulate the continuous laser into pulsed light. The output end of the acousto-optic modulator AOM is connected to the input end of the erbium-doped fiber amplifier EDFA, and is used to amplify the pulsed light power. The output end of A is connected to the input end of the fiber Bragg grating filter to filter out noise outside the filter bandwidth to improve the signal-to-noise ratio. The output end of the fiber Bragg grating filter is connected to the input port 1 of the wavelength division multiplexer WDM1. The output of the Raman second-order amplifier is connected to the input port 2 of the wavelength division multiplexer WDM1. The output end of the wavelength division multiplexer WDM1 is connected to the circulator 1 port. The pulse light is injected into the single-mode optical fiber through the circulator 2 port output. The back Raman scattered light is input through the circulator 2 port. The circulator 3 output port is connected to the input port of the wavelength division multiplexer WDM2. The output 1 port of the wavelength division multiplexer WDM2 is connected to the 1 channel of the detector APD. The output port 2 of the wavelength division multiplexer WDM2 is connected to the input port of the wavelength division multiplexer WDM3, which is used to pass the remaining light after removing the wavelength. The output port 2 of the wavelength division multiplexer WDM3 is connected to the channel 2 of the detector APD, which is used to remove the light with a wavelength of . The remaining light is converted into photoelectricity by the detector. The output port 1 of the wavelength division multiplexer WDM3 is tied. The two output ports of the detector APD are respectively connected to the dual-channel amplifier circuit for amplifying weak electrical signals. The output end of the dual-channel amplifier circuit is connected to the input end of the two-channel acquisition card for collecting two-channel electrical signals. The two-channel acquisition card is connected to the computer through a network cable for For data transmission, the arbitrary waveform generator (AWG) generates pulses to trigger the acquisition card, synchronizing signal acquisition. The polyimide optical fiber can be replaced with a polyimide small-bend-radius optical fiber to enhance its strength in liquid nitrogen. The optical fiber can be fixed to the superconductor by glue encapsulation or welding. The two channels of the arbitrary waveform generator (AWG) generate two synchronized electrical pulse signals. The trigger signal is generated by the acquisition card, which can also control the arbitrary waveform generator (AWG). The wavelength division multiplexer (WDM) and the subsequent stage of the WDM can be equipped with optical fiber filters to improve the signal-to-noise ratio.

[0011] As a further solution of the present invention: the wavelength division multiplexer WDM1 is a 1380nm wavelength division multiplexer.

[0012] As a further solution of the present invention: the wavelength division multiplexer WDM2 is a 1450nm wavelength division multiplexer.

[0013] As a further solution of the present invention: the wavelength division multiplexer WDM3 is a 1663nm wavelength division multiplexer.

[0014] A temperature measurement method for a distributed optical fiber rapid superconductor temperature detection system includes the following steps: Step 1: Encapsulating a polyimide optical fiber into a superconductor, which is then placed in a liquid nitrogen tank. Step 2: Connecting one end of the polyimide optical fiber to a distributed single-mode optical fiber Raman temperature measurement device to monitor the temperature. Step 3: Generating pulses using a function generator while simultaneously monitoring the temperature using the distributed single-mode optical fiber Raman temperature measurement device, and monitoring the pulse signals generated by the function generator using an oscilloscope.

[0015] A temperature measurement method for a distributed single-mode fiber Raman temperature measurement device includes the following steps: Step 1: Light from a narrow-linewidth laser enters an acousto-optic modulator (AOM) and is modulated into pulsed light with a high extinction ratio. Step 2: The pulsed light is amplified by an erbium-doped fiber amplifier (EDFA). Step 3: The amplified pulsed light is filtered for out-of-band noise by a fiber Bragg grating filter (FBG). Step 4: Light from a 1380nm Raman second-order amplifier is injected into the optical fiber via WDM1 to amplify the 1450nm wavelength light in the optical fiber. Step 5: The light then enters the single-mode sensing fiber through the first output port of the circulator. Step 6: The reverse Raman scattered signal is input through the second port of the circulator and output through the third port. Step 7: The Rayleigh scattered light and anti-Stokes light are separated by using optical fiber wavelength division multiplexers (WDM1) and optical fiber wavelength division multiplexers (WDM2). Step 8: The optical signal is converted into an electrical signal using two channels of the detector (APD). Step 9: The Raman electrical signal is amplified by a dual-channel amplifier circuit. Step 10: Use a dual-channel acquisition card to acquire signals. Step 11: Transmit the data collected by the acquisition card to a computer via a network cable for data processing. Step 12: Provide a trigger signal to the acquisition card via an arbitrary function generator (AWG).

[0016] Compared with existing technologies, the present invention offers the following advantages: 1. The distributed optical fiber rapid superconductor temperature detection system enables superconductor status monitoring in liquid nitrogen environments. 2. The distributed optical fiber rapid superconductor temperature detection system measures superconductor temperature with high spatial resolution and precision. In liquid nitrogen environments, the temperature measurement accuracy is ±2°C. 3. The distributed optical fiber rapid superconductor temperature detection system responds to temperature changes extremely quickly, with a response speed of 0.1 seconds. 4. The distributed single-mode optical fiber Raman temperature measurement device is stable and portable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of an embodiment of the present invention;

[0018] Figure 2 This is a structural diagram of a distributed single-mode optical fiber Raman temperature measurement device.

[0019] Figure 1 Middle: Distributed single-mode fiber Raman temperature measurement equipment-1, polyimide single-mode fiber-2, liquid nitrogen tank-3, superconductor-4, function generator-5, oscilloscope-6. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1: Please refer to Figure 1 In an embodiment of the present invention, a distributed optical fiber rapid monitoring superconductor temperature system includes a distributed single-mode optical fiber Raman temperature measurement device 1, a polyimide single-mode optical fiber 2, a liquid nitrogen tank 3, a superconductor 4, a function generator 5, an oscilloscope 6, etc.

[0022] The surface of the superconductor 4 is grooved, and the polyimide single-mode 2 optical fiber is sealed into the surface groove of the superconductor through a glue potting process.

[0023] The polyimide single-mode optical fiber 2 is connected to the distributed single-mode optical fiber Raman temperature measurement device 1 .

[0024] The superconductor 4 is placed into the liquid nitrogen tank 3 .

[0025] The function generator 5 is connected to one end of the superconductor 4, and the oscilloscope 6 is connected to the other end of the superconductor 4. The oscilloscope 6 is used to observe the waveform of the function generator 5 after passing through the superconductor 4.

[0026] The distributed single-mode fiber Raman temperature measurement equipment includes a narrow linewidth laser LD, an acousto-optic modulator AOM, an acousto-optic modulator driver, an arbitrary waveform generator AWG, an erbium-doped fiber amplifier EDFA, a fiber grating filter, a 1380nm Raman second-order amplifier, a 1380nm wavelength division multiplexer WDM1, a circulator, a 1450nm wavelength division multiplexer WDM2, a 1663nm wavelength division multiplexer WDM3, a detector APD, a dual-channel amplifier circuit, a two-channel acquisition card, and a computer.

[0027] The output end of the narrow linewidth laser LD is connected to the input end of the acousto-optic modulator AOM, so that the continuous laser light output by the narrow linewidth laser enters the acousto-optic modulator AOM.

[0028] The arbitrary waveform generator AWG is located above the AOM driver and is used to load the electrical pulse signal output by the arbitrary waveform generator AWG onto the AOM driver.

[0029] The acousto-optic modulator drives the pulsed radio frequency signal to be loaded on the acousto-optic modulator AOM, so as to modulate the continuous laser into pulsed light.

[0030] The output end of the acousto-optic modulator AOM is connected to the input end of the erbium-doped fiber amplifier EDFA for amplifying the pulse light power.

[0031] The output end of the erbium-doped fiber amplifier EDFA is connected to the input end of the fiber grating filter, and is used to filter out noise outside the filter bandwidth to improve the signal-to-noise ratio.

[0032] The output end of the fiber Bragg grating filter is connected to the input port 1 of the 1380nm wavelength division multiplexing WDM1, and the output of the 1380nm Raman second-order amplifier is connected to the input port 2 of the 1380nm wavelength division multiplexing WDM1. The light with a wavelength of 1380nm is injected into the optical fiber to amplify the optical signal with a wavelength of 1450nm transmitted in the optical fiber.

[0033] The 1380nm wavelength division multiplexing WDM1 output end is connected to the circulator first port and outputted through the circulator second port, the pulse light is injected into the single mode optical fiber, and the back Raman scattered light is inputted through the circulator second port.

[0034] The circulator's output port 3 is connected to the input port of the 1450nm wavelength division multiplexer WDM2. The output port 1 of the 1450nm wavelength division multiplexer WDM2 is connected to channel 1 of the detector APD, for separating light with a wavelength of 1450nm and performing photoelectric conversion through the detector.

[0035] The output port 2 of the 1450nm wavelength division multiplexer WDM2 is connected to the input port of the 1663nm wavelength division multiplexer WDM3, and is used to pass the remaining light after removing the 1450nm wavelength.

[0036] The output port 2 of the 1663nm wavelength division multiplexer WDM3 is connected to the channel 2 of the detector APD to remove the light with a wavelength of 1663nm and allow the remaining light to be photoelectrically converted by the detector. The output port 1 of the 1663nm wavelength division multiplexer WDM3 is tied into a knot.

[0037] The two output ports of the detector APD are respectively connected to the dual-channel amplifier circuit for amplifying weak electrical signals.

[0038] The output end of the dual-channel amplifier circuit is connected to the input end of the two-channel acquisition card for collecting two-channel electrical signals. The two-channel acquisition card is connected to the computer via a network cable for data transmission.

[0039] The arbitrary waveform generator (AWG) generates pulses to trigger the acquisition card to synchronize signal acquisition.

[0040] Specifically, the polyimide optical fiber can be replaced with a polyimide small bend radius optical fiber to enhance the strength of the optical fiber in liquid nitrogen.

[0041] Specifically, the optical fiber can be fixed to the superconductor by glue potting or welding.

[0042] Specifically, the two channels of the arbitrary waveform generator AWG generate two synchronous electrical pulse signals, and the acquisition card generates a trigger signal, which can also control the arbitrary waveform generator AWG.

[0043] Specifically, a 1450nm optical fiber filter and a 1663nm optical fiber filter can be added to the subsequent stages of the 1450nm wavelength division multiplexer WDM-10 and the 1663nm wavelength division multiplexer WDM-11, which can improve the signal-to-noise ratio.

[0044] Example 2: Based on Example 1,

[0045] The temperature calculation algorithm of the distributed single-mode optical fiber Raman temperature measurement device is as follows:

[0046] Anti-Stokes Raman backscattered photon number:

[0047]

[0048] Rayleigh backscattered photon number:

[0049]

[0050] In the above formulas, N e is the number of photons contained in each laser pulse incident into the optical fiber; K S ,K AS ,K R are coefficients related to the fiber Stokes and Anti-Stokes Raman scattering cross sections, Rayleigh scattering cross sections, etc.; S is the backscattering factor of the fiber; v S ,v aS ,v0 are the frequencies of Stokes and Anti-Stokes Raman photons, and the frequency of the incident photon. S ,α AS, α0 is the average transmission loss of Stokes and Anti-Stokes Raman scattered photons and incident photons in the optical fiber; L is the length of the optical fiber; R S (T),R AS (T) is related to the population of the upper and lower energy levels of the molecule related to Raman scattering of the optical fiber molecules. The population of the molecular energy level is related to the temperature. They are

[0051] R s (T) = [1-exp(-hΔv / kT)] -1

[0052] R AS (T) = [exp(hΔv / kT)-1] -1

[0053] Where Δv is the Raman phonon frequency, h is Planck's constant, and k is the Boltzmann constant. When the temperature at a local location in the fiber changes, the number of photons scattered by the fiber Raman backscattering is modulated, which is the temperature modulation mechanism of fiber Raman backscattering.

[0054] The ratio of the number of Anti-Stokes Raman scattering to Rayleigh scattering photons is

[0055]

[0056] In actual measurement, the temperature of each point of the optical fiber is determined by the above formula when the starting temperature T=T0 is known, that is,

[0057]

[0058] In actual measurements, the ratio of photon numbers is not measured directly, but rather the ratio of signal levels after photoelectric conversion. The ratio of signal levels corresponding to the photon number ratio in the above formula can be measured experimentally. If the starting temperature T0 is known, the temperature T at each point on the optical fiber can be determined from the above formula.

[0059] Temperature calibration method for distributed single-mode optical fiber Raman temperature measurement equipment

[0060] Only an ideal distributed fiber optic temperature sensor's Anti-Stokes and Rayleigh optical signal channels have identical scattering coefficients, responsivities, and filter factors. Therefore, by establishing a calibration zone on the optical fiber, we can eliminate temperature measurement errors caused by differences in scattering coefficients, responsivities, and optical filter factors between the Anti-Stokes and Rayleigh signal processing channels. This resolves the temperature benchmark issue for temperature sensing and lays a solid foundation for standardized measurements with distributed fiber optic temperature sensors.

[0061] (1) Place a 350m reference optical fiber in the chassis. Assuming the temperature is constant, set this section of optical fiber as the calibration area. The temperature of the calibration area is a constant value T c .

[0062] (2) Eliminating the influence of different sensitivity of the two channels on temperature measurement

[0063] The laser emits a rectangular pulse light with a peak power of P0 and a duration of ΔT, and couples it into the optical fiber. According to the derivation, the Rayleigh / Anti-Stokes photocurrents generated in the APD detector are:

[0064] Rayleigh Light:

[0065] Anti-Stokes Light:

[0066] Where K R ,K as ---Responsivity of Rayleigh and Anti-Stokes optical signals

[0067] S-----------Backscattering factor of optical fiber

[0068] n 01 ---------Coupling coefficient between light source and optical fiber

[0069] n 02 ----------The product of the coupler's reverse splitting ratio and the fiber-optic detection coupling factor

[0070] f R ,f as -----------Rayleigh and Anti-Stokes optical filter factors

[0071] α 0R ,α 0as -------Backscattering coefficients of Rayleigh and Anti-Stokes optical signals

[0072] α R ,α as ----------Loss coefficients of Rayleigh and Anti-Stokes optical signals

[0073] The ratio is

[0074]

[0075] The ratio of the Anti-Stokes and Rayleigh backscattered signals measured in the temperature calibration region is

[0076]

[0077] Since the scattering coefficient and sensor response of any two points on the optical fiber will not change at room temperature, the above two equations are compared to obtain the temperature of the spatial point on the optical fiber in the temperature measurement area.

[0078]

[0079] It can be seen that this ratio eliminates the influence of different sensitivities in the Anti-Stokes and Rayleigh signal channels on the temperature measurement results. The temperature measurement formula is obtained from the above formula

[0080]

[0081] The method of setting the calibration area can eliminate the influence of the differences in scattering coefficient, optical filtering factor and APD responsivity on the measurement results during the transmission of Rayleigh and Anti-Stokes optical signals.

[0082] (3) Eliminating the influence of Rayleigh and Anti-Stokes loss coefficients on temperature measurement results

[0083] The loss coefficient of the Raman signal is related to the temperature of the corresponding spatial point along the fiber. Assuming the temperature of the entire fiber is constant, select two spatial points, L1 and L2. The amplitudes of the Raman backscattered light are I(L1) and I(L2).

[0084]

[0085] According to the above formula, the Rayleigh and Anti-Stokes signal loss coefficient α can be obtained R (T),α as (T):

[0086]

[0087]

[0088] The temperature-related Raman scattering signal loss coefficient difference on the optical fiber is α d (T) Yes

[0089] α d (T)=2α as (T)-2α R (T)

[0090] In this way, it can be concluded that the light intensity of the Rayleigh and Anti-Stokes signals at L on the optical fiber detected by the APD is expressed by the following two equations:

[0091]

[0092]

[0093] Comparing the two equations, we can get the signal ratio R of Anti-Stokes and Rayleigh without the loss coefficient difference. c

[0094]

[0095] R c Substituting (T) into the above formula, we can get the temperature T at L on the optical fiber (the temperature of the calibration area of the sensing optical fiber is T c The temperature T(L) of the measurement area on the optical fiber can be expressed as follows:

[0096]

[0097] This formula contains the integral of the loss coefficient difference of the Raman signal on the optical fiber that is related to temperature. Because both sides of this formula include unknown temperature distribution, this formula is unsolvable. To solve this equation, you can use the continuous summation or iterative convergence method to obtain T(L). The continuous summation method is to use the integral of the above formula to calculate the temperature of the Nth point by the loss coefficient difference α of the Raman signal from point 0 to point N-1. d (T) and is expressed as a sum, which is easy to process by software programming. The formula is

[0098]

[0099] The continuous summation method can better solve the problem of difference in Raman signal loss coefficient in optical fiber.

[0100] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0101] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A distributed optical fiber rapid monitoring superconductor temperature system, comprising a distributed single-mode optical fiber Raman temperature measurement device (1), a superconductor (4), a polyimide single-mode optical fiber (2), a liquid nitrogen tank (3), a function generator (5) and an oscilloscope (6), characterized in that: The surface of the superconductor (4) is grooved, the polyimide single-mode optical fiber (2) is installed in the surface groove of the superconductor (4), the polyimide single-mode optical fiber (2) is connected to the distributed single-mode optical fiber Raman temperature measurement device (1), the superconductor (4) is placed in the liquid nitrogen tank (3), the function generator (5) is connected to one end of the superconductor (4) connected to the distributed single-mode optical fiber Raman temperature measurement device (1), and the oscilloscope (6) is connected to the other end of the superconductor (4); The distributed single-mode fiber Raman temperature measurement device includes a narrow linewidth laser LD, an acousto-optic modulator AOM, an acousto-optic modulator driver, an arbitrary waveform generator AWG, an erbium-doped fiber amplifier EDFA, a fiber grating filter, a Raman second-order amplifier, a wavelength division multiplexer WDM1, a circulator, a wavelength division multiplexer WDM2, a wavelength division multiplexer WDM3, a detector APD, a dual-channel amplifier circuit, a two-channel acquisition card, and a computer; The output end of the narrow linewidth laser LD is connected to the input end of the acousto-optic modulator AOM, so that the continuous laser output by the narrow linewidth laser LD enters the acousto-optic modulator AOM; the arbitrary waveform generator AWG is configured to be connected to the acousto-optic modulator driver, so as to load the electrical pulse signal output by the arbitrary waveform generator AWG onto the acousto-optic modulator driver; The acousto-optic modulator drives the pulsed radio frequency signal to be loaded onto the acousto-optic modulator AOM, so as to modulate the continuous laser into pulsed light; the output end of the acousto-optic modulator AOM is connected to the input end of the erbium-doped fiber amplifier EDFA, so as to amplify the power of the pulsed light; the output end of the erbium-doped fiber amplifier EDFA is connected to the input end of the fiber grating filter, so as to filter out noise outside the filter bandwidth to improve the signal-to-noise ratio; the output end of the fiber grating filter is connected to the first input port of the wavelength division multiplexer WDM1, and the output end of the second-order Raman amplifier is connected to the second input port of the wavelength division multiplexer WDM1, so that light of a first wavelength is injected into the optical fiber to amplify the optical signal of a second wavelength transmitted in the optical fiber; the output end of the wavelength division multiplexer WDM1 is connected to the first port of the circulator, so as to inject the pulsed light into the single-mode optical fiber, and the back Raman scattered light is input through the second port of the circulator and output through the third port of the circulator; the third output port of the circulator is connected to the input port of the wavelength division multiplexer WDM2; the first output port of the wavelength division multiplexer WDM2 is connected to the probe The first channel of the detector APD is connected to separate the light of the second wavelength; the second output port of the wavelength division multiplexer WDM2 is connected to the input port of the wavelength division multiplexer WDM3, and is used to remove the light of the second wavelength and pass the light of the remaining wavelengths, wherein the wavelength division multiplexer WDM2 is a wavelength division multiplexer for the second wavelength; the second output port of the wavelength division multiplexer WDM3 is connected to the second channel of the detector APD, and is used to remove the light of the third wavelength, and the light of the remaining wavelengths is photoelectrically converted by the detector APD, wherein the wavelength division multiplexer W DM3 is a wavelength division multiplexer for the third wavelength; the first output port of the wavelength division multiplexer WDM3 is knotted; the two output ports of the detector APD are respectively connected to the dual-channel amplifier circuit for amplifying weak electrical signals; the output end of the dual-channel amplifier circuit is connected to the input end of the two-channel acquisition card for collecting two electrical signals; the two-channel acquisition card is connected to the computer via a network cable for data transmission; the arbitrary waveform generator AWG is configured to generate pulses to trigger the two-channel acquisition cards to synchronize signal acquisition.

2. A distributed optical fiber rapid monitoring superconductor temperature system according to claim 1, characterized in that: The polyimide single-mode optical fiber (2) is sealed into the surface groove of the superconductor (4) through a glue-filling packaging process; or, The polyimide single-mode optical fiber (2) is fixed in the surface groove of the superconductor (4) by welding.

3. The distributed optical fiber rapid superconductor temperature monitoring system according to claim 1, characterized in that: The polyimide optical fiber is configured as a polyimide small bend radius optical fiber, so as to enhance the strength of the optical fiber in liquid nitrogen; or Generate two synchronous electrical pulse signals according to the two channels of the arbitrary waveform generator AWG, and generate a trigger signal through the two-channel acquisition card to control the arbitrary waveform generator AWG; or Optical fiber filters are added to the subsequent stages of the wavelength division multiplexer WDM2 and the wavelength division multiplexer WDM3 accordingly.

4. The distributed optical fiber fast monitoring superconductor temperature system according to claim 1, characterized in that: The wavelength division multiplexer WDM1 is a 1380nm wavelength division multiplexer.

5. The distributed optical fiber fast monitoring superconductor temperature system according to claim 1, characterized in that: The wavelength division multiplexer WDM2 is a 1450nm wavelength division multiplexer.

6. The distributed optical fiber fast monitoring superconductor temperature system according to claim 1, characterized in that: The wavelength division multiplexer WDM3 is a 1663nm wavelength division multiplexer.

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