High-temperature sensor based on FBG (fiber Bragg Grating) and working and manufacturing method thereof
阅读说明：本技术 一种基于fbg的高温传感器及其工作、制作方法 (High-temperature sensor based on FBG (fiber Bragg Grating) and working and manufacturing method thereof ) 是由 杨才千 李帅 杨国玉 杨宁 张立业 范丽 张旭辉 许福 于 2020-05-18 设计创作，主要内容包括：本发明提供了一种基于FBG的高温传感器及其工作、制作方法,高温传感器包含功能不同的两个FBG通道,一个FBG通道作为传感器的温度补偿通道,另一个FBG通道作为传感器的间接测温通道,两个通道各含一个FBG,并且具有相同的封装结构；FBG封装片,封装保护含FBG的裸光纤；顶推结构,作为传感器的动力来源作用于FBG封装片。该传感器具有体型小,高温灵敏度高,测温精度高等特点,并且在高温工况下的集成组网方面具有较好的便利性。该发明的特点决定其特别适用于航空航天,热井油田以及土建消防等涉及高温传感的领域。(The invention provides a high-temperature sensor based on FBG (fiber Bragg Grating) and a working and manufacturing method thereof, wherein the high-temperature sensor comprises two FBG channels with different functions, one FBG channel is used as a temperature compensation channel of the sensor, the other FBG channel is used as an indirect temperature measurement channel of the sensor, and the two channels respectively contain one FBG and have the same packaging structure; the FBG packaging sheet is used for packaging and protecting the bare fiber containing the FBG; and the pushing structure is used as a power source of the sensor and acts on the FBG packaging sheet. The sensor has the characteristics of small size, high-temperature sensitivity, high temperature measurement precision and the like, and has better convenience in the aspect of integrated networking under the high-temperature working condition. The invention is particularly suitable for the fields of aerospace, hot well oil fields, civil engineering fire protection and the like, which relate to high-temperature sensing.)
1. A FBG-based high temperature sensor, comprising:
the sensor comprises a sensor body, wherein a hollow cavity is arranged on the sensor body along the axis direction of the sensor body and is provided with a closed end and an open end;
the two connecting arms are symmetrically arranged on the left side and the right side of the open end of the hollow cavity;
the two ends of the first sensitization FBG packaging sheet are respectively and fixedly connected with one connecting arm, the middle part of the first sensitization FBG packaging sheet is butted with the open end of the hollow cavity, and a first sensitization FBG for temperature measurement is packaged in the first sensitization FBG packaging sheet;
the fixed base is positioned at the bottommost part of the whole sensor body and used for fixing the sensor body and the sensing substrate;
the second sensitization FBG packaging piece is arranged at the other end of the hollow cavity to form the closed end on the hollow cavity, and the second sensitization FBG packaging piece has the same packaging structure as the first sensitization FBG packaging piece;
the high-temperature-resistant rubber is arranged in the hollow cavity chamber and close to one side of the closed end;
one end of the piston is in close contact with the high-temperature-resistant rubber and is subjected to the direct action of thermal expansion of the high-temperature-resistant rubber;
and the ejector rod is positioned in the hollow cavity chamber and close to one side of the first sensitization FBG packaging sheet, and is driven by the piston to provide a vertical action for the first sensitization FBG packaging sheet so as to deflect the first sensitization FBG packaging sheet.
2. The FBG-based high-temperature sensor as claimed in claim 1, wherein both ends of the first sensitization FBG packaging piece are respectively fixed with the connecting arm through fasteners, so that the first sensitization FBG packaging piece does not generate axial displacement along the FBG.
3. The FBG-based high-temperature sensor according to claim 1, wherein the first and second sensitized FBG packaging sheets are identical in structure and each comprise a packaging metal sheet for packaging, a polyimide resin thin tape cured in the packaging metal sheet, and FBGs cured in the polyimide resin thin tape after PI rubber is cured;
the polyimide resin thin belt is arranged in the packaging metal sheet close to the bending outer side of the packaging metal sheet.
4. The FBG-based high-temperature sensor as claimed in claim 3, wherein the thin polyimide resin strip is doped with high-temperature resistant ceramic powder and high-temperature resistant metal powder for increasing the vitrification threshold temperature of the epoxy resin.
5. The FBG-based high temperature sensor as claimed in claim 4, wherein the ratio of polyimide resin to refractory ceramic powder to refractory metal powder is 1: 2.75: 7.08.
6. The FBG-based high temperature sensor as claimed in claim 1, wherein the bottom of the fixed base has a horizontal basal plane.
7. A working method of the high temperature sensor using the FBG-based high temperature sensor as claimed in any one of claims 1 to 6,
when the high-temperature-resistant rubber is heated and thermally expands, the high-temperature-resistant rubber acts on the piston in the hollow cavity to enable the piston to generate an acting force along the axial direction of the hollow cavity, the acting force pushes the first sensitivity enhancing FBG packaging sheet through the ejector rod to enable the first sensitivity enhancing FBG packaging sheet to be bent, and the first sensitivity enhancing FBG can accurately identify the acting force;
the second sensitization FBG located at the other end of the hollow cavity can decouple the temperature and the strain, and the specific decoupling formula is as follows:
temperature difference calculation formula:
temperature calculation formula:
in the formula: t-temperature value (DEG C) of the measuring point,
T0-measuring the initial temperature value (. degree. C.),
λmeasuringThe wavelength value (nm) measured by the first sensitized FBG,
λ0first sensitized FBG at T0A value of wavelength (nm) at temperature,
λt test-the wavelength value (nm) measured by the second sensitized FBG,
λT0second sensitized FBG at T0A value of wavelength (nm) at temperature,
KT1-the temperature coefficient of the first sensitized FBG,
KT2-temperature coefficient of the second sensitized FBG.
8. A method for manufacturing a high temperature sensor based on FBG as claimed in any of claims 1 to 6, which includes the following steps:
s1, stripping of a coating layer: carefully stripping off the coating layers in the two sensitivity-enhanced FBG polyimide curing sections by using optical fiber pliers, and cleaning the coating layers by using alcohol;
s2, annealing: putting the two optical fibers stripped of the coating layer and sensitized FBGs into a tube furnace for annealing treatment; firstly, placing the fiber bragg grating part in the middle of a tube furnace, fixing two ends of the fiber bragg grating part to enable the fiber bragg grating part to be suspended in the tube furnace, plugging furnace mouths at the two ends of the tube furnace with high-temperature cotton, heating the tube furnace to 500 ℃, keeping the constant temperature for 24 hours after the temperature is stable, and taking out the fiber to be cooled to the room temperature;
s3, PI solidification of optical fiber: vertically fixing two ends of a processed first sensitization FBG on two sides of a mould provided with a packaging metal sheet, enabling an optical fiber to pass through the center of the packaging metal sheet, then preparing a PI doping solution, heating the PI solution in a water bath, slowly and uniformly adding high-temperature-resistant ceramic powder and metal powder which are mixed according to a ratio when no obvious bubbles emerge, stirring until the mixture is uniformly mixed, cooling to room temperature after no bubbles emerge, adding a curing agent into the prepared PI doping solution, stirring, slowly pouring the mixture into the packaging metal sheet, placing the mixture in a muffle furnace for curing and forming, and operating a second sensitization FBG as the first sensitization FBG;
s4, packaging: and (2) pouring a proper amount of high-temperature-resistant rubber into the hollow cavity, filling the piston with the ejector rod after the high-temperature-resistant rubber is compacted, aligning the top of the ejector rod with the opening of the high-temperature-resistant rubber cylinder, fixing the first sensitization FBG packaging piece with the connecting arm of the hollow cavity through a screw, and finally sleeving armored optical cables at two ends of the sensor to complete the packaging and manufacturing of the sensor.
Technical Field
The invention relates to the field of high-temperature monitoring equipment, in particular to a high-temperature sensor based on FBG (fiber Bragg Grating) and a working and manufacturing method thereof.
Background
An optical fiber sensor is a sensor that converts the state of an object to be measured into a measurable optical signal. Since the birth of the optical fiber sensor, the optical fiber sensor is widely applied to a plurality of traditional sensing fields because of the advantages of electromagnetic interference resistance, intrinsic safety, small volume, light weight, easiness in embedding into materials and the like.
The severe environments such as deep space high temperature and strong electromagnetic interference cause immeasurable damage to the aircraft during service. Therefore, reliability research on aircraft in such harsh environments has become a major issue. With the revolution of fuels containing space flight, the working process of an aircraft fuel tank is in a high-temperature state, and the whole structural component is in a high-temperature working process.
Petrochemical industry is the leading force of energy industry, and in its production process, general operation is all under the high temperature environment to the petroleum product all is flammable explosive, in case the conflagration explosion accident takes place, will cause big loss. With the rapid development of the petrochemical industry, the safety and health monitoring of the petrochemical industry are very important.
The working principle of the traditional FBG temperature sensor is that when the external temperature changes, the Bragg grating can change sensitively, so that light different from the calibration wavelength is reflected. However, the FBG degradation phenomenon in which the reflected light power becomes smaller becomes more and more significant at higher temperatures. During the fabrication of FBGs, the carrier transitions are distributed to energy levels with different energies, the higher the energy level the higher the energy required for the decay to occur. The higher the temperature, the fewer the number of carriers that will sustain the transition state and the more severe the degradation, and when the temperature is too high above a threshold, the reflected light power will go to zero.
The existing FBG temperature sensor technology is relatively mature, but in the high-temperature field, the FBG temperature sensor has the defects of low sensitivity, low reliability, low precision and the like. Particularly in the high and new technical fields such as aerospace and the like, the traditional sensor cannot meet the industrial requirements due to the non-functional defects such as overlarge function and body size, and therefore a sensor with high sensitivity is urgently required to be developed. Aiming at high-temperature working conditions in the fields of aerospace, hot well oil fields and the like, the inherent advantages of the FBG enable the FBG to have the high-sensitivity sensing capability under the working conditions.
Disclosure of Invention
Aiming at the defects of the existing FBG temperature sensor, the invention provides the high-temperature sensor based on the FBG and the working and manufacturing method thereof.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
an FBG-based high temperature sensor comprising:
the sensor comprises a sensor body, wherein a hollow cavity is arranged on the sensor body along the axis direction of the sensor body and is provided with a closed end and an open end;
the two connecting arms are symmetrically arranged on the left side and the right side of the open end of the hollow cavity;
the two ends of the first sensitization FBG packaging sheet are respectively and fixedly connected with one connecting arm, the middle part of the first sensitization FBG packaging sheet is butted with the open end of the hollow cavity, and a first sensitization FBG for temperature measurement is packaged in the first sensitization FBG packaging sheet;
the fixed base is positioned at the bottommost part of the whole sensor body and used for fixing the sensor body and the sensing substrate;
the second sensitization FBG packaging piece is arranged at the other end of the hollow cavity to form the closed end on the hollow cavity, and the second sensitization FBG packaging piece has the same packaging structure as the first sensitization FBG packaging piece;
the high-temperature-resistant rubber is arranged in the hollow cavity chamber and close to one side of the closed end;
one end of the piston is in close contact with the high-temperature-resistant rubber and is subjected to the direct action of thermal expansion of the high-temperature-resistant rubber;
and the ejector rod is positioned in the hollow cavity chamber and close to one side of the first sensitization FBG packaging sheet, and is driven by the piston to provide a vertical action for the first sensitization FBG packaging sheet so as to deflect the first sensitization FBG packaging sheet.
The two ends of the first sensitivity enhancing FBG packaging piece are respectively fixed with the connecting arm through fasteners, so that the first sensitivity enhancing FBG packaging piece does not generate axial displacement along the FBG.
The first sensitization FBG packaging sheet and the second sensitization FBG packaging sheet have the same structure and respectively comprise a packaging metal sheet for packaging, a polyimide resin thin belt solidified in the packaging metal sheet and FBGs solidified in the polyimide resin thin belt after PI rubber solidification;
the polyimide resin thin belt is arranged in the packaging metal sheet close to the bending outer side of the packaging metal sheet.
The polyimide resin thin belt is doped with high-temperature resistant ceramic powder and high-temperature resistant metal powder for improving the vitrification threshold temperature of the epoxy resin.
Polyimide resin, high-temperature resistant ceramic powder and high-temperature resistant metal powder are 1: 2.75: 7.08.
The bottom of the fixed base is provided with a horizontal base surface.
The invention further discloses a working method of the high-temperature sensor, which utilizes the high-temperature sensor based on the FBG,
when the high-temperature-resistant rubber is heated and thermally expands, the high-temperature-resistant rubber acts on the piston in the hollow cavity to enable the piston to generate an acting force along the axial direction of the hollow cavity, the acting force pushes the first sensitivity enhancing FBG packaging sheet through the ejector rod to enable the first sensitivity enhancing FBG packaging sheet to be bent, and the first sensitivity enhancing FBG can accurately identify the acting force;
the second sensitization FBG located at the other end of the hollow cavity can decouple the temperature and the strain, and the specific decoupling formula is as follows:
temperature difference calculation formula:temperature calculation formula:in the formula: t-temperature value (DEG C) of the measuring point,
T0-measuring the initial temperature value (. degree. C.),
λmeasuringThe wavelength value (nm) measured by the first sensitized FBG,
λ0first sensitized FBG at T0A value of wavelength (nm) at temperature,
λt test-the wavelength value (nm) measured by the second sensitized FBG,
λT0second sensitized FBG at T0A value of wavelength (nm) at temperature,
KT1-the temperature coefficient of the first sensitized FBG,
KT2-temperature coefficient of the second sensitized FBG.
The manufacturing method of the FBG-based high-temperature sensor comprises the following steps:
s1, stripping of a coating layer: carefully stripping off the coating layers in the two sensitivity-enhanced FBG polyimide curing sections by using optical fiber pliers, and cleaning the coating layers by using alcohol;
s2, annealing: putting the two optical fibers stripped of the coating layer and sensitized FBGs into a tube furnace for annealing treatment; firstly, placing the fiber bragg grating part in the middle of a tube furnace, fixing two ends of the fiber bragg grating part to enable the fiber bragg grating part to be suspended in the tube furnace, plugging furnace mouths at the two ends of the tube furnace with high-temperature cotton, heating the tube furnace to 500 ℃, keeping the constant temperature for 24 hours after the temperature is stable, and taking out the fiber to be cooled to the room temperature;
s3, PI solidification of optical fiber: vertically fixing two ends of a processed first sensitization FBG on two sides of a mould provided with a packaging metal sheet, enabling an optical fiber to pass through the center of the packaging metal sheet, then preparing a PI doping solution, heating the PI solution in a water bath, slowly and uniformly adding high-temperature-resistant ceramic powder and metal powder which are mixed according to a ratio when no obvious bubbles emerge, stirring until the mixture is uniformly mixed, cooling to room temperature after no bubbles emerge, adding a curing agent into the prepared PI doping solution, stirring, slowly pouring the mixture into the packaging metal sheet, placing the mixture in a muffle furnace for curing and forming, and operating a second sensitization FBG as the first sensitization FBG;
s4, packaging: and (2) pouring a proper amount of high-temperature-resistant rubber into the hollow cavity, filling the piston with the ejector rod after the high-temperature-resistant rubber is compacted, aligning the top of the ejector rod with the opening of the high-temperature-resistant rubber cylinder, fixing the first sensitization FBG packaging piece with the connecting arm of the hollow cavity through a screw, and finally sleeving armored optical cables at two ends of the sensor to complete the packaging and manufacturing of the sensor.
Compared with the existing FBG temperature sensor, the FBG temperature sensor has the beneficial effects that:
1. the sensor adopts the design of temperature compensation and temperature measurement double FBGs, and the temperature compensation FBGs can obviously eliminate the wavelength nonlinear drift caused by the temperature of the temperature measurement FBGs in a high-temperature environment.
2. The sensor has small overall dimension and small occupied space, and can be integrated with a plurality of sensors to realize a networking high-temperature sensing system.
3. The sensor grating is packaged by a material with excellent heat insulation effect, and has higher reflected light power in a higher temperature field.
4. The thermal bimetal adopted by the sensor has stable high-temperature performance and can play a role in thermal deflection deformation at a higher temperature.
5. The sensor base adopts the design of flat basal plane, and laminating that can be better is surveyed the thing surface, so the installation is more stable, and the temperature sensing area is closely contacted with the thing surface to be surveyed, so the result that obtains is closer to the thing surface actual temperature that awaits measuring.
6. The sensor is suitable for various high-temperature working conditions such as a hot well oil field, aerospace and the like, and has wide application range and high temperature measurement sensitivity.
Drawings
FIG. 1 is a schematic structural diagram of a FBG-based high-temperature sensor according to the present invention;
wherein, 1, optical fiber; 101. a first optical fiber; 102. a second optical fiber; 2. a first sensitized FBG packaging sheet; 301. a connecting arm; 302. a sensor body; 303. a fixed base; 304. a second sensitivity enhanced FBG packaging sheet; 305. a top rod; 306. a piston; 4. a nut; 501. a first sensitivity-enhanced FBG polyimide solidified thin strip; 502. a second sensitization FBG polyimide solidified thin belt; 6. high temperature resistant rubber;
fig. 2 is a schematic diagram of the first sensitized FBG package piece flexing;
FIG. 3 is a side view of a high temperature sensor of the present invention;
FIG. 4 is a schematic diagram of an FBG-based high temperature sensor sensing system according to the present invention;
100, the high-temperature sensor based on the FBG; 200. an armored optical cable; 300. a data processing terminal; 400. FBG demodulator.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the drawings and the specific embodiments in the specification.
The optical fiber has good tensile property which can reach 8000 mu at most, so that the high-temperature monitoring threshold of the sensor can be obviously improved by stretching the optical fiber by means of thermal expansion of silicon rubber. Meanwhile, the sensor has better temperature linearity thanks to the good thermal effect of the expansion material.
FBG has obvious advantages in terms of integration and networking. Due to the characteristic of very small volume of the fiber grating, each probe point only uses a relatively small light source component, and most of light can be transmitted and continuously transmitted. The maximum number of 30 gratings can be simultaneously used on one optical fiber, and the transmission distance exceeds 45km, which brings great convenience to networking. Meanwhile, the feasibility of the technology is improved by using technologies such as wavelength division multiplexing and the like. In general, FBGs have great advantages in a wide range of multi-node measurements.
According to the technical characteristics, the invention provides the high-temperature sensor based on the FBG.
The utility model provides a high temperature sensor based on FBG, this sensor includes bare fiber 1, first sensitization FBG encapsulates
And the sensitized FBG and the PI solution are solidified in the polyimide thin belt, wherein two ends of the first sensitized FBG packaging sheet are fixed with the connecting arm by bolts.
The temperature compensation FBG is positioned in the second sensitization FBG packaging sheet, and the temperature measurement FBG is positioned in the first sensitization FBG packaging sheet.
Preferably, the armored optical cable is led out from the temperature compensation end of the sensor and can be directly connected with the demodulation equipment and the data analysis processing terminal.
In the invention, the PI solution is doped with high-temperature resistant ceramic powder and high-temperature resistant metal powder, so that the threshold temperature of polyimide vitrification is obviously improved.
Preferably, the high-temperature resistant metal powder is high-fineness high-temperature resistant nickel powder.
In the invention, one side of the sensor is provided with a first sensitization
Preferably, the thin PI band in the sensor is tightly combined with the inner walls of the first and second sensitized FBG packaging sheets.
Preferably, the inner cavity of the first sensitivity enhanced FBG packaging piece in the sensor adopts eccentric processing, specifically: the polyimide resin thin belt is arranged in the packaging metal sheet close to the bending outer side of the packaging metal sheet, and the arrangement can reduce the problem of low sensitivity of the sensor caused by the minimum strain of the neutral axis position.
Preferably, the sensor comprises PI rubber. The PI rubber is solidified to protect the FBG, has excellent high-temperature resistance and can keep good working elasticity of the FBG under the action of high-temperature fatigue.
In the present invention, the device has a length of 10 to 80mm, preferably 20 to 70mm, more preferably 30 to 60mm, for example 50 mm. The width is 10-80mm, preferably 20-70mm, more preferably 30-60mm, e.g. 50 mm. The height is 2-20mm, preferably 4-16mm, more preferably 5-12mm, e.g. 10 mm.
In the invention, the temperature sensitivity of the sensing part for temperature compensation is 10.5 pm/DEG C, the strain sensitivity is 1.2 pm/mu, and the sensitivity of the whole sensor can reach (20-27) multiplied by 1.2 pm/DEG C.
A method for manufacturing a FBG-based high temperature sensor, the method comprising the steps of:
1) stripping of the coating layer: carefully stripping off the coating layers in the two sensitivity-enhanced FBG polyimide curing sections by using optical fiber pliers, and cleaning the coating layers by using alcohol;
2) annealing: putting the two optical fibers stripped of the coating layer and sensitized FBGs into a tube furnace for annealing treatment; firstly, placing the fiber bragg grating part in the middle of a tube furnace, fixing two ends of the fiber bragg grating part to enable the fiber bragg grating part to be suspended in the tube furnace, plugging furnace mouths at the two ends of the tube furnace with high-temperature cotton, heating the tube furnace to 500 ℃, keeping the constant temperature for 24 hours after the temperature is stable, and taking out the fiber to be cooled to the room temperature;
3) PI curing of the optical fiber: the two ends of the processed first sensitization FBG are vertically fixed on the two sides of the mould provided with the packaging metal sheet, so that the optical fiber penetrates through the center of the packaging metal sheet. And then preparing a PI doping solution, heating the PI solution in a water bath, slowly and uniformly adding high-temperature-resistant ceramic powder and metal powder which are mixed according to the proportion when no obvious bubbles emerge, stirring until the mixture is uniformly mixed, cooling to room temperature after no bubbles emerge, adding a curing agent into the prepared PI doping solution, stirring, slowly pouring the mixture into a packaging metal sheet, and placing the packaging metal sheet in a muffle furnace for curing and forming. The second sensitization FBG operates the same as the first sensitization FBG;
4) and pouring a proper amount of high-temperature-resistant rubber into the hollow cavity, and filling the hollow cavity with a piston with an ejector rod after the hollow cavity is compacted so that the top of the ejector rod is aligned with the opening of the high-temperature-resistant rubber cylinder. And then, fixing the first sensitivity-enhanced FBG packaging piece with a connecting arm of the hollow cavity by using a screw, and finally sleeving armored optical cables at two ends of the sensor to finish the packaging and manufacturing of the sensor.
In the invention, step 1) is to peel off the coating layer on the surface of the optical fiber (including the grating) by using an optical fiber clamp, so as to prevent the phenomenon that the interface slips when the sensor works, thereby causing the sudden change of the wavelength.
In the invention, the step 2) is to place the grating part of the FBG treated in the step 1) at the central position of the tubular furnace, keep the constant temperature for 24 hours, and then carry out the subsequent steps after the temperature field is stable (the reflection wavelength tends to be stable).
Preferably, the temperature of the tube furnace is measured directly by a thermocouple located in the vicinity of the grating, so that the temperature obtained is closer to the actual temperature.
Preferably, the temperature compensated FBG is very close to the temperature FBG, preferably 1mm, to ensure that they have the same annealing process at the ambient temperature.
In the invention, the step 3) is to solidify and mold the annealed bare fiber and PI rubber in a mold, so that the FBG is in a uniform stress field, and the PI rubber can well ensure the working performance of the FBG at high temperature.
In the invention, in the step 4), the high-temperature-resistant rubber is utilized to generate thermal expansion in the cylinder chamber, the ejector rod acts on the first sensitization FBG packaging sheet, and the temperature measurement FBG in the cylinder chamber recognizes the bending tension of the first sensitization FBG packaging sheet, so that the wavelength drift of the temperature measurement FBG is caused.
In the present invention, the high temperature resistant rubber used is not subjected to a special process, and is a currently known technology.
In the invention, the selection of the high-temperature resistant rubber can be comprehensively selected according to the actual working condition requirement and the FBG sensitivity.
In the invention, the temperature measurement FBG is in the working condition of coupling the temperature field and the strain field, and the temperature compensation FBG positioned on the second sensitivity enhancing FBG packaging sheet can better decouple the temperature and the strain.
In the invention, because the sensor is very small in size, the integrated networking of the sensor becomes very feasible, and the sensor is particularly suitable for the field requiring high-temperature sensing.
In the invention, the metal composite polyimide rubber package can well reduce the mechanical abrasion of the sensor.
In the invention, the FBG cured by the PI rubber is adopted, and the PI rubber can better reduce the high-temperature damage of the FBG.
In the invention, the high-temperature-resistant rubber in the hollow cavity is a main power source of the sensor, so that the FBG in a high-temperature environment can sense with high precision and high sensitivity.
In the invention, the high-temperature resistant rubber has a better linear thermal expansion coefficient in a high-temperature environment, and can keep good working performance in the high-temperature environment. When the high-temperature-resistant rubber is subjected to thermal expansion, the temperature measurement FBG in the first sensitivity-enhancing FBG packaging sheet can identify the bending tension of the temperature measurement FBG, so that corresponding wavelength drift occurs.
In the invention, the FBG high-temperature sensor further improves the FBG temperature measurement threshold value and has better feasibility.