A radiation-resistant fiber Bragg grating strain sensor and fiber Bragg grating packaging structure

Abstract

The present invention relates to the technical field of fiber Bragg grating strain sensors, and specifically to a radiation-resistant fiber Bragg grating strain sensor and a fiber Bragg grating packaging structure. In order to solve the problems of relatively low control accuracy, low yield rate and poor flexibility in adjusting the measurement range in the traditional fiber Bragg grating pre-stretching method, a new radiation-resistant fiber Bragg grating strain sensor is provided, including a fiber Bragg grating and a fiber Bragg grating packaging structure. The fiber Bragg grating packaging structure includes a base plate, a slide rail is fixed to the left end of the base plate, a slide plate is arranged on the slide rail for sliding left and right, and a positioning fixture is provided on the slide plate and the slide rail for positioning and fixing the slide plate after sliding relative to the slide rail. A fixing block is fixed to the right end of the slide rail, and the fixing block is located on the right side of the slide plate. The fixing block is provided with a threaded through hole whose axial direction is arranged in the left and right directions, and an adjusting bolt is provided in the threaded through hole. A fixing plate is fixed to the right end of the base plate. The structure of the sensor is simple and the strain measurement range can be adjusted flexibly.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber Bragg grating strain sensors, in particular to a radiation-resistant fiber Bragg grating strain sensor and a fiber Bragg grating packaging structure. Background Art

[0002] In harsh radiation environments such as space, the nuclear industry, and nuclear power plants, online monitoring of strain parameters using sensing technologies that guarantee long-term stability is often required to improve the safety and reliability of equipment operation. Traditional electronic sensors are susceptible to electromagnetic fields, high temperatures, and ionizing radiation, which can lead to failures during operation. Compared to traditional sensors, fiber Bragg grating (FBG) sensors offer advantages such as immunity to electromagnetic interference, high temperature resistance, high sensitivity, and fast response, making them considered potential candidates for use in radiation environments.

[0003] Fiber Bragg grating is a method of achieving periodic changes in the refractive index along the axial direction in the fiber core through specific technical means, thereby forming a diffraction grating that can reflect light that meets the condition λ. B = 2n eff • λ is a specific wavelength of light, where λ B represents the central wavelength of the grating, n eff is the effective refractive index of the fiber core, and Λ is the grating period. Any change in the effective refractive index of the fiber core and the grating period will result in a corresponding change in the grating's central wavelength. When external strain acts on a fiber Bragg grating, it causes stretching or compression of the fiber Bragg grating region, which in turn changes the grating's central wavelength. This change can be precisely monitored, enabling effective strain monitoring.

[0004] Fiber Bragg grating (FBG) strain sensors are widely used in numerous industrial fields due to their precision and stability. The accuracy and reliability of FBG sensors depend largely on the design and implementation of their packaging technology. If the FBG is not properly pre-stretched during the packaging process, the grating region will remain relaxed. When the FBG strain sensor is subjected to an inward compressive force, the FBG itself will not experience the corresponding force, resulting in an ineffective transmission of the external force to the FBG, making it impossible for the FBG strain sensor to detect negative strain. In applications requiring large-scale negative strain detection, if the FBG is not pre-stretched enough, once a certain measurement range is reached, the FBG will no longer be subjected to force and will transition to a relaxed state, limiting its ability to monitor even larger negative strains. To meet the requirements for negative strain measurement, it is necessary to apply an appropriate amount of pre-stretch to the FBG within the FBG during the manufacturing process. Furthermore, FBGs are inherently fragile and can easily break when subjected to excessive tension, thus losing their monitoring function. Therefore, controlling the pre-stretch of the FBG is crucial when measuring strain.

[0005] The traditional pre-stretching method of fiber Bragg grating is mainly manual stretching, and then the stretched fiber Bragg grating is glued and heated to cure. However, the control accuracy of the pre-stretching amount of the fiber Bragg grating by manual stretching is relatively low. At the same time, the glue-dispensing and heating curing after stretching also increases the difficulty of glue-dispensing and heating curing, and the yield rate is low. In addition, this method cannot adapt to the measurement of different strain ranges of the test piece, that is, if the strain range is different and the pre-stretching amount of the fiber Bragg grating is different, the fiber Bragg grating needs to be stretched, glued and heated to cure again, which is cumbersome to operate and has poor flexibility in adjusting the measurement range. Summary of the Invention

[0006] In order to solve the problems of relatively low control accuracy, low yield and poor flexibility in adjusting the measurement range in traditional fiber Bragg grating pre-stretching methods, the present invention provides a new radiation-resistant fiber Bragg grating strain sensor and a fiber Bragg grating packaging structure.

[0007] The present invention is achieved by adopting the following technical solutions:

[0008] A radiation-resistant fiber Bragg grating strain sensor includes a fiber Bragg grating and a fiber Bragg grating packaging structure. The fiber Bragg grating packaging structure includes a base plate, a slide rail is fixed to the left end of the base plate, a slide plate is arranged on the slide rail for sliding left and right, and the slide plate and the slide rail are provided with positioning fixing parts for positioning and fixing the slide plate after sliding relative to the slide rail. The slide plate and the base plate are arranged parallel to each other, a fixing block is fixed to the right end of the slide rail, the fixing block is located on the right side of the slide plate, a threaded through hole is provided on the fixing block, and an adjustment bolt for pushing the slide plate to move left is provided in the threaded through hole. A fixing plate arranged parallel to the base plate is fixed to the right end of the base plate.

[0009] During use, the two ends of the fiber Bragg grating (FBG) are first fixed to the slide and fixed plate respectively by dispensing glue. The fiber Bragg grating is then naturally straightened through the slide and fixed plate, and the slide is pre-tightened using the positioning fixture (pre-tightening means that after tightening, the slide can still move slightly relative to the slide rail when subjected to thrust). The adjustment bolt is then turned according to the strain range to be tested, and the adjustment bolt pushes the slide leftward. Finally, the slide is positioned and fixed again using the positioning fixture to complete the pre-stretching of the fiber Bragg grating. During measurement, the strain measurement of the measured component can be achieved by simply fixing the base plate to the measured component. In addition, when adjusting the strain measurement range, the positioning fixture is released so that the slide is in a state where it can slide freely relative to the slide rail. The adjusting bolt is then loosened and the slide is manually pushed to the right until it contacts the left end face of the fixed block. The slide is pre-tightened again using the positioning fixture, and the adjustment bolt is then turned according to the strain range to be tested, thereby adjusting the pre-stretching range of the fiber Bragg grating and adjusting the strain measurement range.

[0010] Furthermore, the optical fiber used in the fiber Bragg grating is a single-mode pure quartz core optical fiber and is inscribed using a femtosecond laser, which has better radiation resistance.

[0011] A fiber grating packaging structure includes a base plate, a slide rail is fixed to the left end of the base plate, a slide plate is arranged on the slide rail for sliding left and right, the slide plate and the slide rail are equipped with positioning and fixing parts for positioning and fixing the slide plate after sliding relative to the slide rail, the slide plate and the base plate are arranged parallel to the base plate, a fixed block is fixed to the right end of the slide rail, the fixed block is located on the right side of the slide plate, a threaded through hole is provided on the fixed block whose axial direction is arranged in the left and right directions, an adjustment bolt for pushing the slide plate to move left is provided in the threaded through hole, and a fixing plate arranged parallel to the base plate is fixed to the right end of the base plate.

[0012] During use, the two ends of the fiber Bragg grating (FBG) are first fixed to the slide and fixed plate respectively by dispensing glue. The fiber Bragg grating is then naturally straightened through the slide and fixed plate, and the slide is pre-tightened using the positioning fixture (pre-tightening means that after tightening, the slide can still move slightly relative to the slide rail when subjected to thrust). The adjustment bolt is then turned according to the strain range to be tested, and the adjustment bolt pushes the slide leftward. Finally, the slide is positioned and fixed again using the positioning fixture to complete the pre-stretching of the fiber Bragg grating. During measurement, the strain measurement of the measured component can be achieved by simply fixing the base plate to the measured component. In addition, when adjusting the strain measurement range, the positioning fixture is released so that the slide is in a state where it can slide freely relative to the slide rail. The adjusting bolt is then loosened and the slide is manually pushed to the right until it contacts the left end face of the fixed block. The slide is pre-tightened again using the positioning fixture, and the adjustment bolt is then turned according to the strain range to be tested, thereby adjusting the pre-stretching range of the fiber Bragg grating and adjusting the strain measurement range.

[0013] Furthermore, the slide rail includes an upper strip plate and a lower strip plate. The upper strip plate has an inverted L-shaped cross section, and the lower strip plate has an L-shaped cross section. The upper strip plate and the lower strip plate are arranged vertically and facing each other. The upper strip plate and the lower strip plate are fixed to the left end plate and form an upper slide groove and a lower slide groove with the left end plate, respectively. The slide plate is adapted to the upper slide groove and the lower slide groove. The slide rail structure is simple and easy to implement.

[0014] Furthermore, the positioning fixture includes upper and lower fastening bolts. The top surface of the upper strip plate is provided with a vertically arranged upper fastening threaded hole that is compatible with the upper fastening bolt, and the top surface of the lower strip plate is provided with a vertically arranged lower fastening threaded hole that is compatible with the lower fastening bolt. After the slide slides to the designated position, the upper and lower fastening bolts are simply tightened to achieve positioning and fixation of the slide slide, thus concretizing and standardizing the structure of the positioning fixture.

[0015] Furthermore, the bottom plate includes a left end plate and a right end plate, and the left end plate and the right end plate are connected and fixed by an H-shaped plate, so that the fiber Bragg grating responds promptly when strain occurs in the measured component and ensures its sensitivity.

[0016] Furthermore, a plurality of fixing holes are distributed on the bottom plate, which facilitates spot welding or bolt fixation with different parts of the measured component, thereby facilitating strain measurement of different parts of the measured component, comprehensively capturing the strain conditions of the measured component in different areas, and thus providing more comprehensive data support for the analysis of the measured component.

[0017] Furthermore, both the slide plate and the fixed plate are provided with slots for placing the fiber optic Bragg grating, which facilitates the positioning of the fiber optic Bragg grating.

[0018] Furthermore, both the slide plate and the fixing plate are provided with glue dispensing grooves for facilitating the dispensing of the optical fiber Bragg grating, thereby facilitating the glue dispensing and fixing of the optical fiber Bragg grating.

[0019] The beneficial effects of the present invention are as follows: the present invention cleverly realizes the pre-stretching of the fiber Bragg grating by controlling the adjustment bolt, thereby achieving the effect of the fiber Bragg grating realizing negative strain measurement; at the same time, it also enables the strain measurement range of the sensor to be flexibly adjusted according to actual needs, the overall structure is simple, the yield rate is high, and the finished product can adjust the negative strain range, the manufacturing cost is low, the applicability is strong, and the control accuracy is high; in addition, the sensor has good radiation resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 A schematic diagram of the three-dimensional effect of the fiber Bragg grating packaging structure described in the present invention;

[0023] Figure 2 This is a front view of the fiber Bragg grating packaging structure described in the present invention;

[0024] Figure 3 Schematic diagram of the relationship between the radiation-induced Bragg wavelength shift (BWS) and irradiation dose of FBGs inscribed in germanium (Ge)-doped fiber and pure silica core (PSC) fiber;

[0025] Figure 4 Schematic diagram of the dose dependence of radiation-induced BWS on FBGs in Ge-doped fibers and PSC fibers written using ultraviolet (UV) and femtosecond (FS) lasers.

[0026] In the figure: 1-left end plate, 2-right end plate, 3-slide plate, 4-fixing block, 5-adjusting bolt, 6-fixing plate, 7-slot, 8-glue dispensing slot, 9-fixing hole, 10-upper strip plate, 11-lower strip plate, 12-upper fastening bolt, 13-lower fastening bolt. DETAILED DESCRIPTION

[0027] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0028] In the description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance. It should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, removable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms based on specific circumstances.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0031] like Figure 1 and Figure 2 As shown, a radiation-resistant fiber Bragg grating strain sensor includes a fiber Bragg grating and a fiber Bragg grating packaging structure. The fiber Bragg grating packaging structure includes a base plate, a slide rail is fixed to the left end of the base plate, and a slide plate 3 is arranged on the slide rail for sliding left and right. The slide plate 3 and the slide rail are provided with positioning and fixing parts for positioning and fixing the slide plate 3 after sliding relative to the slide rail. The slide plate 3 is arranged parallel to the base plate, and a fixing block 4 is fixed to the right end of the slide rail. The fixing block 4 is located on the right side of the slide plate 3. The fixing block is provided with a threaded through hole whose axial direction is arranged in the left and right directions. An adjusting bolt 5 for pushing the slide plate 3 to move left is provided in the threaded through hole. A fixing plate 6 arranged parallel to the base plate is fixed to the right end of the base plate.

[0032] During use, the two ends of the fiber Bragg grating are first fixed to the slide 3 and the fixed plate 6 respectively by dispensing glue. Then, the fiber Bragg grating is naturally straightened through the slide 3 and the fixed plate 6, and then the slide 3 is pre-tightened using the positioning fixture (pre-tightening means that after tightening, the slide 3 can still move slightly relative to the slide rail when subjected to thrust). Then, the adjusting bolt 5 is turned according to the strain range to be tested, and the adjusting bolt 5 pushes the slide 3 to the left. Finally, the slide 3 is positioned and fixed again using the positioning fixture to complete the pre-stretching of the fiber Bragg grating. During measurement, the strain measurement of the measured component can be achieved by simply fixing the base plate to the measured component. In addition, when the strain measurement range is adjusted, the positioning fixture is released so that the slide 3 is in a state where it can slide freely relative to the slide rail. The adjusting bolt 5 is then loosened and the slide 3 is manually pushed to the right until it contacts the left end face of the fixed block. The slide 3 is pre-tightened again using the positioning fixture. Then, the adjusting bolt 5 is turned according to the strain range to be tested, thereby adjusting the pre-stretching range of the fiber Bragg grating and adjusting the strain measurement range.

[0033] In specific implementation, the optical fiber used in the fiber grating is a single-mode pure quartz core optical fiber and is inscribed by a femtosecond laser, which has better radiation resistance.

[0034] Principle: Radiation affects different doped fibers differently depending on their composition. Studies have shown that fibers with fluorine-doped or single-mode pure silica cores exhibit better radiation resistance than fibers with germanium (Ge)-doped or phosphorus-doped cores.

[0035] Furthermore, the radiation resistance of fiber Bragg gratings (FBGs) is also related to the FBG writing technique. Traditional FBG writing methods typically utilize ultraviolet (UV) laser sources. Due to the linear absorption mechanism, high concentrations of Ge or fiber-loaded hydrogen are often used in the fiber core region to enhance the material's photosensitivity. Exposing Ge-doped silica fibers to high-photon-energy UV laser sources improves the grating's radiation resistance by eliminating color center precursors due to the refractive index change induced by color center defects. However, the presence of Ge or the additional hydrogen loading makes the fiber more susceptible to high-energy ionizing radiation. Single-mode pure silica core fiber Bragg gratings (FBGs) are insensitive to conventional UV laser writing techniques. Therefore, femtosecond laser direct writing techniques, based on non-photosensitive FBG inscription, are employed to inscribe FBGs in fibers doped to enhance their radiation sensitivity. Femtosecond laser direct writing densifies the fiber, creates internal stress fields, and locally increases material density or even permanent mechanical damage, thereby improving radiation resistance. The writing parameters of femtosecond laser direct writing technology affect the spectral performance of FBG, as well as the material modification and the interaction between radiation and laser-modified materials.

[0036] In order to further confirm the irradiation response of FBG, the following experiments are conducted:

[0037] Experiment 1: Using ultrafast femtosecond laser direct writing technology, FBGs were written in two different single-mode optical fibers: germanium-doped (Ge) fiber and pure silica core (PSC) fiber at different femtosecond laser powers. The FBGs were exposed to gamma radiation with a cumulative dose of up to 100 kGy (dose rate 3.835 kGy / h) and the radiation-induced Bragg wavelength shift (BWS) was measured. Figure 3 As shown in the figure, at room temperature, the FBG undergoes a redshift due to radiation and exhibits saturation behavior with cumulative irradiation dose. In the low-dose region (below 10 kGy), the Bragg wavelength increases rapidly and varies almost linearly with dose. The slope of the curve for the FBG inscribed in PSC fiber (FS-PSC-FBG) using femtosecond laser direct writing is smaller than that for the FBG inscribed in Ge-doped fiber (FS-Ge-FBG). The Ge-doped fiber core contains GeO2, which has higher radiation sensitivity (BWS variation). With increasing irradiation dose, the BWS increases continuously, but the slope is smaller. When the radiation dose reaches approximately 20 kGy, the BWS changes slowly and gradually approaches saturation. The Bragg wavelength stops increasing with increasing radiation dose, but there is a slight fluctuation until the end of irradiation. These results indicate that the FBG inscribed in PSC fiber has a low Bragg wavelength shift. Therefore, a single-mode pure silica core fiber Bragg grating is used to improve its radiation resistance.

[0038] Experiment 2: Analyze and compare the relationship between radiation-induced BWS and dose on FBG in Ge-doped fiber and PSC fiber written by UV and Fs, such as Figure 4 As shown in the figure, the radiation-induced BWS in the FBG inscribed using a UV laser phase mask (UV-FBG-Ge) is larger than that in the FBG inscribed using femtosecond laser direct writing (FS-FBG-Ge). The maximum wavelength shift of the FBG inscribed in pure silica core fiber using femtosecond laser direct writing (FS-FBG-PSC) is approximately 8.964 pm, the lowest among PSC / Ge-doped FBGs inscribed using FS or UV lasers. The UV-FBG-Ge exhibits high radiation sensitivity, primarily due to H₂ loading prior to grating inscription, which enhances the fiber's photosensitivity to UV light. The refractive index change induced by femtosecond lasers is a multiphoton absorption process via defect states or interband absorption, which is associated with fiber densification, internal stress fields, and defect-related formation. The different responses to irradiation may be attributed to the different physical modifications of the fiber material by the different writing techniques, which induce refractive index modulation. Therefore, FBGs inscribed in pure silica core fiber using femtosecond laser writing are used to improve their irradiation performance.

[0039] A fiber Bragg grating packaging structure includes a base plate, a slide rail is fixed to the left end of the base plate, a slide plate 3 is arranged on the slide rail for sliding left and right, the slide plate 3 and the slide rail are equipped with positioning and fixing parts for positioning and fixing the slide plate 3 after sliding relative to the slide rail, the slide plate 3 is arranged parallel to the base plate, a fixing block 4 is fixed to the right end of the slide rail, the fixing block 4 is located on the right side of the slide plate 3, a threaded through hole is provided on the fixing block 4 whose axial direction is arranged in the left and right directions, an adjusting bolt 5 for pushing the slide plate 3 to move left is provided in the threaded through hole (in specific implementation, the end of the adjusting bolt 5 is provided with a cross slot for easy twisting), and a fixing plate 6 arranged parallel to the base plate is fixed to the right end of the base plate.

[0040] During use, the two ends of the fiber Bragg grating are first fixed to the slide 3 and the fixed plate 6 respectively by dispensing glue. Then, the fiber Bragg grating is naturally straightened through the slide 3 and the fixed plate 6, and then the slide 3 is pre-tightened using the positioning fixture (pre-tightening means that after tightening, the slide 3 can still move slightly relative to the slide rail when subjected to thrust). Then, the adjusting bolt 5 is turned according to the strain range to be tested, and the adjusting bolt 5 pushes the slide 3 to the left. Finally, the slide 3 is positioned and fixed again using the positioning fixture to complete the pre-stretching of the fiber Bragg grating. During measurement, the strain measurement of the measured component can be achieved by simply fixing the base plate to the measured component. In addition, when the strain measurement range is adjusted, the positioning fixture is released so that the slide 3 is in a state where it can slide freely relative to the slide rail. The adjusting bolt 5 is then loosened and the slide 3 is manually pushed to the right until it contacts the left end face of the fixed block. The slide 3 is pre-tightened again using the positioning fixture. Then, the adjusting bolt 5 is turned according to the strain range to be tested, thereby adjusting the pre-stretching range of the fiber Bragg grating and adjusting the strain measurement range.

[0041] In a specific implementation, the slide rail includes an upper strip plate 10 and a lower strip plate 11. The cross-section of the upper strip plate 10 is inverted L-shaped, and the cross-section of the lower strip plate 11 is L-shaped. The upper strip plate 10 and the lower strip plate 11 are distributed vertically and arranged facing each other. The upper strip plate 10 and the lower strip plate 11 are fixed to the left end plate 1 and form an upper slide groove and a lower slide groove with the left end plate 1, respectively. The slide plate 3 is adapted to the upper and lower slide grooves. The slide rail structure is simple and easy to implement.

[0042] In practice, the positioning fixtures include upper and lower fastening bolts 12 and 13. The top surface of the upper strip plate 10 is provided with vertically arranged upper fastening threaded holes that mate with the upper fastening bolts 12, while the top surface of the lower strip plate 11 is provided with vertically arranged lower fastening threaded holes that mate with the lower fastening bolts 13. Once the slide plate 3 has slid to the designated position, the upper and lower fastening bolts 12 and 13 simply need to be tightened to secure the slide plate 3 in place. This clarifies and standardizes the structure of the positioning fixtures.

[0043] In specific implementation, the bottom plate includes a left end plate 1 and a right end plate 2, which are connected and fixed by an H-shaped plate, so that the fiber Bragg grating responds promptly when strain occurs in the measured component and ensures its sensitivity.

[0044] In specific implementation, a plurality of fixing holes 9 are distributed on the bottom plate, which facilitates spot welding or bolt fixation with different parts of the measured component, thereby facilitating strain measurement of different parts of the measured component, and comprehensively capturing the strain conditions of the measured component in different areas, thereby providing more comprehensive data support for the analysis of the measured component.

[0045] In this specific embodiment, both the slide plate 3 and the fixing plate 6 are provided with a slot 7 for placing the fiber Bragg grating, so as to facilitate the positioning of the fiber Bragg grating.

[0046] In this specific embodiment, both the slide plate 3 and the fixing plate 6 are provided with glue dispensing grooves 8 for facilitating glue dispensing of the optical fiber Bragg grating, thereby facilitating glue dispensing and fixing of the optical fiber Bragg grating.

[0047] The above description is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be included in the scope of protection of the claims.

Claims

1. A radiation-resistant fiber Bragg grating strain sensor, characterized in that: The invention comprises a fiber Bragg grating (FBG) and a fiber Bragg grating (FBG) packaging structure, wherein the fiber Bragg grating (FBG) packaging structure comprises a bottom plate, a slide rail is fixed on the left end of the bottom plate, a slide plate (3) is arranged on the slide rail for sliding left and right, a positioning fixing member is provided on the slide plate (3) and the slide rail for positioning and fixing the slide plate (3) after sliding relative to the slide rail, the slide plate (3) is arranged in parallel with the bottom plate, a fixing block (4) is fixed on the right end of the slide rail, the fixing block (4) is located on the right side of the slide plate (3), a threaded through hole is provided on the fixing block, the threaded through hole is provided with an adjusting bolt (5) for pushing the slide plate (3) to move leftward, and a fixing plate (6) arranged in parallel with the bottom plate is fixed on the right end of the bottom plate, wherein the bottom plate comprises a left end plate (1) and a right end plate (2), and the left end plate (1) and the right end plate (2) are connected by an H-shaped The plates are connected and fixed, and the slide rail includes an upper strip plate (10) and a lower strip plate (11). The cross section of the upper strip plate (10) is inverted L-shaped, and the cross section of the lower strip plate (11) is L-shaped. The upper strip plate (10) and the lower strip plate (11) are distributed up and down and arranged facing each other. The upper strip plate (10) and the lower strip plate (11) are fixed to the left end plate (1) and form an upper slide groove and a lower slide groove with the left end plate (1) respectively. The slide plate (3) is adapted to the upper slide groove and the lower slide groove. The positioning fixing member includes an upper fastening bolt (12) and a lower fastening bolt (13). The top surface of the upper strip plate (10) is provided with an upper fastening threaded hole arranged vertically and adapted to the upper fastening bolt (12), and the top surface of the lower strip plate (11) is provided with a lower fastening threaded hole arranged vertically and adapted to the lower fastening bolt (13).

2. The radiation-resistant fiber Bragg grating strain sensor according to claim 1, characterized in that: The optical fiber used in the fiber grating is a single-mode pure quartz core optical fiber and is inscribed by a femtosecond laser.

3. The radiation-resistant fiber Bragg grating strain sensor according to claim 2, characterized in that: A plurality of fixing holes (9) are distributed on the bottom plate.

4. The radiation-resistant fiber Bragg grating strain sensor according to claim 3, characterized in that: Both the slide plate (3) and the fixed plate (6) are provided with a slot (7) for placing the optical fiber grating.

5. The radiation-resistant fiber Bragg grating strain sensor according to claim 4, characterized in that: The slide plate (3) and the fixed plate (6) are both provided with glue dispensing grooves (8) for facilitating the dispensing of the optical fiber Bragg grating.

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