High-temperature and high-pressure fiber bragg grating temperature sensor system

Abstract

The utility model discloses a high-temperature and high-pressure fiber grating temperature sensor system, which comprises a sweep frequency light source, the sweep frequency light source is connected with a high-temperature and high-pressure fiber grating temperature sensor through a circulator, the circulator is connected with a spectrum unit through an optical fiber coupler, and the spectrum unit is connected with a spectrum driving circuit through an optical fiber coupler. The spectrum driving circuit is connected with an AD conversion circuit through a PCI bus, the AD conversion circuit is connected with a control system through a PCI bus, and the control system is connected with an industrial control system through an RJ45 network cable. And the high-temperature and high-pressure fiber grating temperature sensor is connected with the circulator through the optical fiber coupler. The high-temperature and high-pressure fiber bragg grating temperature sensor system disclosed by the utility model solves the problem that the temperature field distribution of a storage tank cannot be measured in the pressurizing process of a propellant in the storage tank of a spacecraft at present.

Description

Technical Field

[0001] This utility model belongs to the field of fiber optic grating sensor technology, specifically relating to a high-temperature and high-pressure fiber optic grating temperature sensor system. Background Technology

[0002] The pressurization capacity of rocket and other spacecraft propellant tanks is a key parameter that affects the success or failure of rocket launches, influencing whether the propellant temperature changes with pressure during the pressurization process of HAN-based and other new propellant satellites. Therefore, to obtain the propellant temperature field distribution within the spacecraft tank, establish the coupling relationship covering the fluid and solid regions, and realize the propellant temperature field distribution during the pre-pressurization process, it is of great significance for improving propellant temperature quality and increasing thrust-to-weight ratio. Currently, measuring the temperature field within the spacecraft tank requires accurate measurement of the temperature field at multiple points above 800°C within a short distance of 200 mm and a high-pressure environment of 20 MPa.

[0003] Currently, temperature measurement generally employs electrical temperature measurement methods such as thermocouples or platinum resistance thermometers. Thermocouples refer to the use of welding or bonding to directly fix a sheathed thin-wire thermocouple to the surface being measured. However, traditional electrical temperature measurement methods have significant problems when measuring temperature field distribution inside spacecraft tanks. First, multiple sensors cannot be installed on the same cross-section, leading to large errors in the measured temperature field distribution. Second, the problem of numerous leads due to the difficulty in reuse still exists, and a large number of leads extending from inside the tank can easily cause leaks in the high-pressure seal. Third, simultaneous measurements by multiple sensors can result in synchronization errors. Fourth, traditional electrical temperature measurement methods cannot achieve high-frequency rapid measurements above 5kHz during the pressurization process. Utility Model Content

[0004] The purpose of this invention is to provide a high-temperature and high-pressure fiber optic grating temperature sensor system, which solves the problem that the temperature field distribution of propellant in spacecraft tanks cannot be measured during the pressurization process.

[0005] The technical solution adopted in this utility model is a high-temperature and high-pressure fiber Bragg grating temperature sensor system, including a swept-frequency light source. The swept-frequency light source is connected to a high-temperature and high-pressure fiber Bragg grating temperature sensor through a circulator. The circulator is connected to a spectral unit through an optical fiber coupler. The spectral unit is connected to a spectral driving circuit through an optical fiber coupler. The spectral driving circuit is connected to an AD conversion circuit through a PCI bus. The AD conversion circuit is connected to a control system through a PCI bus. The control system is connected to an industrial control system through an RJ45 network cable. The high-temperature and high-pressure fiber Bragg grating temperature sensor is connected to the circulator through an optical fiber coupler.

[0006] The features of this utility model also include:

[0007] The high-temperature and high-pressure fiber Bragg grating temperature sensor includes a sensor mounting outer tube, a sensor mounting inner tube fixedly installed inside the sensor mounting outer tube, and a fiber Bragg grating temperature measuring point fixedly installed inside the sensor mounting inner tube. The fiber optic cable at the lead end of the fiber Bragg grating temperature measuring point is connected to an armored optical cable, and the other end of the armored optical cable is connected to a circulator. A ball-head plug is provided on the outer side of the sensor mounting outer tube near the armored optical cable. The end of the ball-head plug near the sensor mounting outer tube is fixed to the sensor mounting outer tube by an outer nut. The sensor also includes a wire locking kit, which is used to fix the end of the ball-head plug near the sensor mounting outer tube to the armored optical cable.

[0008] The substrate of the fiber optic temperature measuring point is made of silicon dioxide optical fiber. The temperature resistance of the fiber optic temperature measuring point is 1700℃. The fiber optic temperature measuring point generates short pulse laser through a femtosecond laser with a laser pulse energy of not less than 300μJ. The diameter of the short pulse laser spot is not greater than 1μm. The position platform for controlling the movement of the femtosecond laser at the fiber optic temperature measuring point has a motion error of less than 1mm. Eight grating regions are uniformly engraved on the fiber optic temperature measuring point, and the surface of each of the eight grating regions is coated with a gold-plated coating.

[0009] The sensor mounting inner tube is made of stainless steel capillary tube, and its length is greater than the length of the fiber optic grating temperature measuring point; the sensor mounting outer tube is made of stainless steel.

[0010] Armored optical cables consist of an inner armored stainless steel tube, an outer armored stainless steel tube, and a rubber tubing.

[0011] Both the ball head plug and the outer nut are standard 60° ball head type parts, and the ball head plug is made of steel.

[0012] The ball head plug and the sensor mounting tube are laser welded together using laser welding points.

[0013] The inner diameter of one side of the locking kit is the same as the outer diameter of the armored optical cable, and the locking kit and the armored optical cable are sealed with high-temperature ceramic adhesive.

[0014] The beneficial effects of the utility model are:

[0015] The high-temperature and high-pressure fiber Bragg grating temperature sensor system provided by this utility model adopts femtosecond laser writing grating technology and gold plating coating technology to achieve accurate measurement of the temperature field of more than 800°C at 8 temperature points within a short distance range of 200mm and a high-pressure environment of 20MPa. The structural strength problem of the fiber Bragg grating sensor during long-term high-temperature measurement is solved by using humidity control technology and inert reaction technology, and the sealing under high pressure environment is achieved by using ball head sealing and laser welding. Attached Figure Description

[0016] Figure 1This is a schematic diagram of the structure of the high temperature and high pressure fiber optic grating temperature sensor system of this utility model;

[0017] Figure 2 This is a schematic diagram of the high-temperature and high-pressure fiber optic sensor structure of this utility model.

[0018] In the diagram, 1. Inner tube for sensor mounting, 2. Outer tube for sensor mounting, 3. Temperature measuring point of fiber optic grating, 4. Ball plug, 5. Outer nut, 6. Wire locking kit, 7. Armored optical cable, 8. Laser solder joint, 9. High temperature and high pressure fiber optic grating temperature sensor, 10. Sweep frequency light source, 11. Circulator, 12. Spectral unit, 13. Spectral drive circuit, 14. AD conversion circuit, 15. Industrial control system, 16. Control system. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] The high-temperature and high-pressure fiber Bragg grating temperature sensor system provided by this utility model, such as Figure 1 As shown, the system includes a swept-frequency light source 10, which is connected to a high-temperature, high-pressure fiber Bragg grating temperature sensor 9 via a circulator 11. The center wavelength of the swept-frequency light source 10 is 1550nm, the laser power is not less than 10mW, and the bandwidth is 80nm. The circulator 11 is connected to a spectral unit 12 via an optical fiber coupler. The spectral unit 12 has a single-channel maximum measurement frequency of 20kHz, a 16-channel maximum measurement frequency of 5kHz, a measurement range of 1500nm~1580nm, and a repeatability of less than 2pm. The spectral unit 12 is connected to a spectral driving circuit 13 via an optical fiber coupler. The spectral driving circuit 13 is connected to an AD conversion circuit 14 via a PCI bus. The AD conversion circuit 14 is connected to a control system 16 via a PCI bus. The control system 16 uses high-speed FPGA control, with a maximum operating frequency of not less than 500MHz. The control system 16 is connected to an industrial control system 15 via an RJ45 network cable. The high-temperature, high-pressure fiber Bragg grating temperature sensor 9 is connected to the circulator 11 via an optical fiber coupler. Figure 2As shown, the high-temperature and high-pressure fiber Bragg grating temperature sensor 9 includes a sensor mounting outer tube 2, a sensor mounting inner tube 1 fixedly installed inside the sensor mounting outer tube 2, and a fiber Bragg grating temperature measuring point 3 fixedly installed inside the sensor mounting inner tube 1. An armored optical cable 7 is connected to the lead end of the fiber Bragg grating temperature measuring point 3. The other end of the armored optical cable 7 is connected to a circulator 11. A ball-head plug 4 is provided on the outer side of the sensor mounting outer tube 2 near the armored optical cable 7. The end of the ball-head plug 4 near the sensor mounting outer tube 2 is fixed to the sensor mounting outer tube 2 by an outer nut 5. The sensor also includes a locking assembly 6, whereby the end of the ball-head plug 4 near the sensor mounting outer tube 2 is locked to the armored optical cable 7 by a locking assembly 6. The wire assembly 6 is used for fixation; the substrate of the fiber optic temperature measuring point 3 is made of silicon dioxide optical fiber. Silicon dioxide is the most stable optical fiber material and can work for a long time in high temperature and high pressure environments. The temperature resistance of the fiber optic temperature measuring point 3 is 1700℃. The fiber optic temperature measuring point 3 generates short pulse laser through a femtosecond laser with a laser pulse energy of not less than 300μJ. The diameter of the short pulse laser spot is not greater than 1μm. The position platform for controlling the movement of the femtosecond laser at the fiber optic temperature measuring point 3 has a motion error of less than 1mm. Eight grating regions are uniformly engraved on the 200mm fiber optic temperature measuring point 3 at a spacing of 25mm, and each grating region corresponds to an independent center wavelength. Different fiber Bragg grating temperature sensors can be distinguished based on their wavelength. The fiber Bragg gratings are formed by high-energy laser pulse density writing on the grating regions, using side-writing technology to create permanent physical damage to the fiber core. These gratings only degrade at temperatures above 800°C. Each of the eight grating regions is coated with a gold-plated layer with a thickness controlled to within 100µm to prevent degradation at 800°C. The sensor mounting inner tube 1 is made of stainless steel capillary tube with a diameter of 0.3mm and a length of 210mm. The length of the inner tube 1 is greater than the length of the fiber Bragg grating temperature measuring point 3, ensuring that the bottom of the grating region does not touch the bottom of the steel tube, thus providing good performance. The sensor mounting tube 2 is made of stainless steel to ensure that changes in external temperature can be transmitted to the fiber optic grating temperature measuring point 3 in a timely manner. The armored optical cable 7 includes an inner armored stainless steel tube, an outer armored stainless steel tube, and a rubber tube. The ball head plug 4 and the outer nut 5 are both 60° ball head type standard parts. The ball head plug 4 is made of steel and can withstand pressure up to 35MPa. The ball head plug 4 and the sensor mounting tube 2 are laser welded through laser welding points 8 to ensure that the pressure resistance of the entire sensor can reach more than 15MPa. The inner diameter of one side of the wire locking kit 6 is the same as the outer diameter of the armored optical cable 7. The wire locking kit 6 and the armored optical cable 7 are sealed with high-temperature ceramic glue.When the high-temperature, high-pressure fiber Bragg grating temperature sensor is placed in the rocket's propellant tank, changes in external temperature are transmitted through the outer sensor mounting tube 2 and the inner sensor mounting tube 1 to the eight temperature measuring points on the fiber Bragg grating temperature measuring point 3. This causes a change in the wavelength of the grating region at these eight points. The change in external temperature corresponds to a change in the center wavelength of the light returned by the fiber Bragg grating temperature sensor. By measuring the reflected wavelength and demodulating it, the magnitude of the wavelength change can be obtained, and thus the temperature value can be derived. The wavelength change at the fiber Bragg grating temperature measuring point 3 is transmitted via the emitted light through the armored optical cable 7 to the high-temperature, high-pressure fiber Bragg grating temperature sensing system for demodulation.

[0021] The high-temperature and high-pressure fiber Bragg grating temperature sensor system provided by this utility model works as follows: A swept-frequency light source emits pulsed laser light, which is transmitted to the high-temperature and high-pressure fiber Bragg grating temperature sensor. After receiving the pulsed laser light, the high-temperature and high-pressure fiber Bragg grating temperature sensor reflects the pulsed laser light that meets the wavelength requirement back to the spectral unit at the temperature measurement points of the fiber Bragg grating in eight grating regions. The spectral unit transmits the reflected light to the spectral driving circuit. The spectral driving circuit converts the reflected light collected in the spectral unit into a photocurrent signal and transmits it to the AD conversion circuit. The AD conversion circuit converts the collected photocurrent signal into a digital signal and transmits it to the control system. The control system filters the received digital signal to obtain a wavelength digital signal, and converts the wavelength digital signal of each measurement point into temperature data according to the internal processing algorithm, which is then transmitted to the industrial control system. The industrial control system displays the received temperature data.

[0022] Example 1

[0023] The high-temperature and high-pressure fiber Bragg grating temperature sensor system proposed in this embodiment, such as Figure 1 As shown, the system includes a swept frequency light source 10, which is connected to a high-temperature and high-pressure fiber optic grating temperature sensor 9 via a circulator 11. The circulator 11 is connected to a spectral unit 12 via an optical fiber coupler. The spectral unit 12 is connected to a spectral driving circuit 13 via an optical fiber coupler. The spectral driving circuit 13 is connected to an AD conversion circuit 14 via a PCI bus. The AD conversion circuit 14 is connected to a control system 16 via a PCI bus. The control system 16 is connected to an industrial control system 15 via an RJ45 network cable.

[0024] Example 2

[0025] The high-temperature and high-pressure fiber Bragg grating temperature sensor system proposed in this embodiment, such as Figure 1As shown, the system includes a swept frequency light source 10, which is connected to a high-temperature and high-pressure fiber Bragg grating temperature sensor 9 via a circulator 11. The circulator 11 is connected to a spectral unit 12 via an optical fiber coupler. The spectral unit 12 is connected to a spectral driving circuit 13 via an optical fiber coupler. The spectral driving circuit 13 is connected to an AD conversion circuit 14 via a PCI bus. The AD conversion circuit 14 is connected to a control system 16 via a PCI bus. The control system 16 is connected to an industrial control system 15 via an RJ45 network cable. The high-temperature and high-pressure fiber Bragg grating temperature sensor 9 is connected to the circulator 11 via an optical fiber coupler.

[0026] Example 3

[0027] The high-temperature and high-pressure fiber Bragg grating temperature sensor system proposed in this embodiment, such as Figure 1 As shown, the system includes a swept-frequency light source 10, which is connected to a high-temperature, high-pressure fiber Bragg grating temperature sensor 9 via a circulator 11. The circulator 11 is connected to a spectral unit 12 via an optical fiber coupler. The spectral unit 12 is connected to a spectral driving circuit 13 via an optical fiber coupler. The spectral driving circuit 13 is connected to an AD conversion circuit 14 via a PCI bus. The AD conversion circuit 14 is connected to a control system 16 via a PCI bus. The control system 16 is connected to an industrial control system 15 via an RJ45 network cable. The high-temperature, high-pressure fiber Bragg grating temperature sensor 9 is connected to the circulator 11 via an optical fiber coupler. Figure 2 As shown, the high-temperature and high-pressure fiber Bragg grating temperature sensor 9 includes a sensor mounting outer tube 2, a sensor mounting inner tube 1 fixedly installed inside the sensor mounting outer tube 2, a fiber Bragg grating temperature measuring point 3 fixedly installed inside the sensor mounting inner tube 1, an armored optical cable 7 connected to the lead end of the fiber Bragg grating temperature measuring point 3, and the other end of the armored optical cable 7 connected to a circulator 11. A ball-head plug 4 is provided on the outer side of the sensor mounting outer tube 2 near the armored optical cable 7. The ball-head plug 4 near the sensor mounting outer tube 2 is fixed to the sensor mounting outer tube 2 by an outer nut 5. It also includes a wire locking kit 6, and the ball-head plug 4 near the sensor mounting outer tube 2 is fixed to the armored optical cable 7 by the wire locking kit 6.

[0028] Example 4

[0029] The high-temperature and high-pressure fiber Bragg grating temperature sensor system proposed in this embodiment, such as Figure 1As shown, the system includes a swept-frequency light source 10, which is connected to a high-temperature, high-pressure fiber Bragg grating temperature sensor 9 via a circulator 11. The circulator 11 is connected to a spectral unit 12 via an optical fiber coupler. The spectral unit 12 is connected to a spectral driving circuit 13 via an optical fiber coupler. The spectral driving circuit 13 is connected to an AD conversion circuit 14 via a PCI bus. The AD conversion circuit 14 is connected to a control system 16 via a PCI bus. The control system 16 is connected to an industrial control system 15 via an RJ45 network cable. The high-temperature, high-pressure fiber Bragg grating temperature sensor 9 is connected to the circulator 11 via an optical fiber coupler. Figure 2 As shown, the high-temperature and high-pressure fiber Bragg grating temperature sensor 9 includes a sensor mounting outer tube 2, a sensor mounting inner tube 1 fixedly installed inside the sensor mounting outer tube 2, a fiber Bragg grating temperature measuring point 3 fixedly installed inside the sensor mounting inner tube 1, an armored optical cable 7 connected to the lead end of the fiber Bragg grating temperature measuring point 3, and the other end of the armored optical cable 7 connected to a circulator 11. A ball-head plug 4 is provided on the outer side of the sensor mounting outer tube 2 near the armored optical cable 7. The end of the ball-head plug 4 near the sensor mounting outer tube 2 is fixed to the sensor mounting outer tube 2 by an outer nut 5. It also includes a wire locking kit 6. The ball-head plug 4 is located near the outer tube 2. One end of the proximity sensor mounting tube 2 is fixed to the armored optical cable 7 by the locking kit 6; the substrate of the fiber optic grating temperature measuring point 3 is made of silicon dioxide optical fiber, the temperature resistance of the fiber optic grating temperature measuring point 3 is 1700℃, the fiber optic grating temperature measuring point 3 generates short pulse laser by a femtosecond laser with a laser pulse energy of not less than 300μJ, the diameter of the short pulse laser spot is not greater than 1μm, the position platform of the fiber optic grating temperature measuring point 3 controlling the movement of the femtosecond laser has a motion error of less than 1mm, and 8 grating areas are uniformly engraved on the fiber optic grating temperature measuring point 3, and the surface of each of the 8 grating areas is coated with a gold-plated coating.

[0030] Example 5

[0031] The high-temperature and high-pressure fiber Bragg grating temperature sensor system proposed in this embodiment, such as Figure 1 As shown, the system includes a swept-frequency light source 10, which is connected to a high-temperature, high-pressure fiber Bragg grating temperature sensor 9 via a circulator 11. The circulator 11 is connected to a spectral unit 12 via an optical fiber coupler. The spectral unit 12 is connected to a spectral driving circuit 13 via an optical fiber coupler. The spectral driving circuit 13 is connected to an AD conversion circuit 14 via a PCI bus. The AD conversion circuit 14 is connected to a control system 16 via a PCI bus. The control system 16 is connected to an industrial control system 15 via an RJ45 network cable. The high-temperature, high-pressure fiber Bragg grating temperature sensor 9 is connected to the circulator 11 via an optical fiber coupler. Figure 2As shown, the high-temperature and high-pressure fiber Bragg grating temperature sensor 9 includes a sensor mounting outer tube 2, a sensor mounting inner tube 1 fixedly installed inside the sensor mounting outer tube 2, and a fiber Bragg grating temperature measuring point 3 fixedly installed inside the sensor mounting inner tube 1. The fiber optic cable 7 is connected to the lead end of the fiber Bragg grating temperature measuring point 3, and the other end of the armored optical cable 7 is connected to a circulator 11. A ball-head plug 4 is provided on the outer side of the sensor mounting outer tube 2 near the armored optical cable 7. The end of the ball-head plug 4 near the sensor mounting outer tube 2 is fixed to the sensor mounting outer tube 2 by an outer nut 5. It also includes a wire-locking kit 6, which fixes the end of the ball-head plug 4 near the sensor mounting outer tube 2 to the armored optical cable 7. The substrate of the fiber Bragg grating temperature measuring point 3 is made of a two-dimensional... Made of silicon dioxide optical fiber, the fiber optic grating temperature measuring point 3 has a temperature resistance of 1700℃. The fiber optic grating temperature measuring point 3 generates short-pulse laser through a femtosecond laser with a laser pulse energy of not less than 300μJ. The diameter of the short-pulse laser spot is not greater than 1μm. The position platform controlling the movement of the femtosecond laser at the fiber optic grating temperature measuring point 3 has a motion error of less than 1mm. Eight grating areas are uniformly engraved on the fiber optic grating temperature measuring point 3, and the surface of each of the eight grating areas is coated with a gold-plated coating. The sensor mounting inner tube 1 is made of stainless steel capillary tube, and the length of the sensor mounting inner tube 1 is greater than the length of the fiber optic grating temperature measuring point 3. The sensor mounting outer tube 2 is made of stainless steel. The armored optical cable 7 includes an armored stainless steel inner tube, an armored stainless steel outer tube, and a rubber tube.

[0032] Example 6

[0033] The high-temperature and high-pressure fiber Bragg grating temperature sensor system proposed in this embodiment, such as Figure 1 As shown, the system includes a swept-frequency light source 10, which is connected to a high-temperature, high-pressure fiber Bragg grating temperature sensor 9 via a circulator 11. The circulator 11 is connected to a spectral unit 12 via an optical fiber coupler. The spectral unit 12 is connected to a spectral driving circuit 13 via an optical fiber coupler. The spectral driving circuit 13 is connected to an AD conversion circuit 14 via a PCI bus. The AD conversion circuit 14 is connected to a control system 16 via a PCI bus. The control system 16 is connected to an industrial control system 15 via an RJ45 network cable. The high-temperature, high-pressure fiber Bragg grating temperature sensor 9 is connected to the circulator 11 via an optical fiber coupler. Figure 2As shown, the high-temperature and high-pressure fiber Bragg grating temperature sensor 9 includes a sensor mounting outer tube 2, a sensor mounting inner tube 1 fixedly installed inside the sensor mounting outer tube 2, and a fiber Bragg grating temperature measuring point 3 fixedly installed inside the sensor mounting inner tube 1. An armored optical cable 7 is connected to the lead end of the fiber Bragg grating temperature measuring point 3, and the other end of the armored optical cable 7 is connected to a circulator 11. A ball-head plug 4 is provided on the outer side of the sensor mounting outer tube 2 near the armored optical cable 7. The end of the ball-head plug 4 near the sensor mounting outer tube 2 is fixed to the sensor mounting outer tube 2 by an outer nut 5. It also includes a wire-locking kit 6, which fixes the end of the ball-head plug 4 near the sensor mounting outer tube 2 to the armored optical cable 7. The substrate of the fiber Bragg grating temperature measuring point 3 is made of silicon dioxide optical fiber, the temperature resistance of the fiber Bragg grating temperature measuring point 3 is 1700℃, and the laser pulse energy of the fiber Bragg grating temperature measuring point 3 is not less than 300μJ. The femtosecond laser generates short-pulse lasers with a spot diameter of no more than 1 μm. The position platform controlling the movement of the femtosecond laser at the fiber optic grating temperature measuring point 3 has a motion error of less than 1 mm. The fiber optic grating temperature measuring point 3 has 8 uniformly engraved grating regions, and each of the 8 grating regions is coated with a gold-plated coating. The sensor mounting inner tube 1 is made of stainless steel capillary tube, and its length is greater than that of the fiber optic grating temperature measuring point 3. The sensor mounting outer tube 2 is made of stainless steel. The armored optical cable 7 includes an armored stainless steel inner tube, an armored stainless steel outer tube, and a rubber tube. The ball head plug 4 and the outer nut 5 are both 60° ball head type standard parts. The ball head plug 4 is made of steel, and it is laser-welded to the sensor mounting outer tube 2 through laser welding point 8. The inner diameter of one side of the locking kit 6 is the same as the outer diameter of the armored optical cable 7, and the locking kit 6 and the armored optical cable 7 are sealed with high-temperature ceramic glue.

Claims

1. A high-temperature, high-pressure fiber Bragg grating temperature sensor system, characterized in that, The system includes a swept frequency light source (10), which is connected to a high-temperature and high-pressure fiber Bragg grating temperature sensor (9) via a circulator (11). The circulator (11) is connected to a spectral unit (12) via an optical fiber coupler. The spectral unit (12) is connected to a spectral driving circuit (13) via an optical fiber coupler. The spectral driving circuit (13) is connected to an AD conversion circuit (14) via a PCI bus. The AD conversion circuit (14) is connected to a control system (16) via a PCI bus. The control system (16) is connected to an industrial control system (15) via an RJ45 network cable. The high-temperature and high-pressure fiber Bragg grating temperature sensor (9) is connected to the circulator (11) via an optical fiber coupler.

2. The high-temperature and high-pressure fiber Bragg grating temperature sensor system according to claim 1, characterized in that, The high-temperature and high-pressure fiber Bragg grating temperature sensor (9) includes a sensor mounting outer tube (2), a sensor mounting inner tube (1) is fixedly installed inside the sensor mounting outer tube (2), a fiber Bragg grating temperature measuring point (3) is fixedly installed inside the sensor mounting inner tube (1), an armored optical cable (7) is connected to the lead end of the fiber Bragg grating temperature measuring point (3), and the other end of the armored optical cable (7) is connected to the circulator (11). A ball-head plug (4) is provided on the outer side of the sensor mounting outer tube (2) near the armored optical cable (7). The ball-head plug (4) near the sensor mounting outer tube (2) is fixed to the sensor mounting outer tube (2) by an outer nut (5). It also includes a wire locking kit (6). The ball-head plug (4) near the sensor mounting outer tube (2) is fixed to the armored optical cable (7) by the wire locking kit (6).

3. The high-temperature and high-pressure fiber Bragg grating temperature sensor system according to claim 2, characterized in that, The substrate of the fiber optic temperature measuring point (3) is made of silicon dioxide optical fiber. The temperature resistance of the fiber optic temperature measuring point (3) is 1700℃. The fiber optic temperature measuring point (3) generates short pulse laser through a femtosecond laser with a laser pulse energy of not less than 300μJ. The diameter of the short pulse laser spot is not greater than 1μm. The position platform of the fiber optic temperature measuring point (3) controlling the movement of the femtosecond laser has a motion error of less than 1mm. Eight grating regions are uniformly engraved on the fiber optic temperature measuring point (3), and the surfaces of the eight grating regions are all coated with a gold-plated coating.

4. The high-temperature and high-pressure fiber Bragg grating temperature sensor system according to claim 2, characterized in that, The sensor mounting inner tube (1) is made of stainless steel capillary tube, and the length of the sensor mounting inner tube (1) is greater than the length of the fiber optic grating temperature measuring point (3); the sensor mounting outer tube (2) is made of stainless steel.

5. The high-temperature and high-pressure fiber Bragg grating temperature sensor system according to claim 2, characterized in that, The armored optical cable (7) includes an armored stainless steel inner tube, an armored stainless steel outer tube, and a rubber tube.

6. The high-temperature and high-pressure fiber Bragg grating temperature sensor system according to claim 2, characterized in that, Both the ball head plug (4) and the outer nut (5) are standard 60° ball head type parts, and the ball head plug (4) is made of steel.

7. The high-temperature and high-pressure fiber Bragg grating temperature sensor system according to claim 2, characterized in that, The ball-head plug (4) and the sensor mounting tube (2) are laser welded together via laser welding points (8).

8. The high-temperature and high-pressure fiber Bragg grating temperature sensor system according to claim 2, characterized in that, The inner diameter of one side of the locking kit (6) is the same as the outer diameter of the armored optical cable (7), and the locking kit (6) and the armored optical cable (7) are sealed with high-temperature ceramic glue.

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