Radiation-resistant fiber bragg grating strain sensor and fiber bragg grating packaging structure

Abstract

The invention relates to the technical field of fiber bragg grating strain sensors, in particular to an irradiation-resistant fiber bragg grating strain sensor and a fiber bragg grating packaging structure. In order to solve the problems of relatively low control precision, low yield and poor measurement range adjustment flexibility of a traditional fiber grating prestretching mode, the invention provides a novel radiation-resistant fiber grating strain sensor, which comprises a fiber grating and a fiber grating packaging structure, and the fiber grating packaging structure comprises a bottom plate, a sliding rail is fixed to the left end of the bottom plate, a sliding plate is arranged on the sliding rail in a left-right sliding mode, positioning fixing pieces used for positioning and fixing the sliding plate after the sliding plate slides relative to the sliding rail are arranged on the sliding plate and the sliding rail in a matched mode, a fixing block is fixed to the right end of the sliding rail and located on the right side of the sliding plate, and a threaded through hole with the axial direction arranged in the left-right direction is formed in the fixing block. Adjusting bolts are arranged in the threaded through holes in a matched mode, and a fixing plate is fixed to the right end of the bottom plate. The sensor is simple in structure and flexible in strain measurement range adjustment.

Description

Technical Field

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

[0002] In harsh radiation environments such as space, nuclear industry, and nuclear power plants, it is often necessary to use sensing technology that can operate stably for a long time to monitor strain parameters online in order to improve the safety and reliability of equipment operation. Traditional electronic sensors are easily affected by electromagnetic fields, high temperatures, ionizing radiation, etc., which can cause failures during operation. Compared with traditional sensors, fiber Bragg grating (FBG) sensors have the advantages of anti-electromagnetic interference, high temperature resistance, high sensitivity, and fast response, and are considered to be 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 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 central wavelength of the grating. When external strain acts on the fiber grating, it will cause the fiber grating area to stretch or compress, thereby changing the central wavelength of the grating. This change can be accurately monitored, thereby achieving effective monitoring of the strain.

[0004] Fiber Bragg grating strain sensors have been widely used in many industrial fields due to their accuracy and stability. The accuracy and reliability of fiber Bragg grating sensors depend largely on the design and implementation of their packaging technology. During the packaging process of fiber Bragg grating strain sensors, if the fiber Bragg grating is not properly pre-stretched, the grating area will remain in a relaxed state. When the fiber Bragg grating strain sensor is subjected to an inward squeezing force, the fiber Bragg grating itself will not be subjected to the corresponding force, resulting in the external force being unable to be effectively transmitted to the fiber Bragg grating, so that the fiber Bragg grating strain sensor cannot monitor negative strain. In an application environment that requires large-scale negative strain detection, if the pre-stretching amount of the fiber Bragg grating is insufficient, once a certain measurement range is reached, the fiber Bragg grating will no longer be subjected to force and will be transformed into a relaxed state, which will limit its ability to monitor larger negative strains. In order to meet the demand for negative strain measurement, it is necessary to apply an appropriate amount of pre-stretching to the internal fiber Bragg grating when manufacturing the fiber Bragg grating strain sensor. In addition, the fiber Bragg grating itself is relatively fragile. When the applied tension is too large, it is easy to cause it to break, thereby losing its monitoring function. Therefore, when performing strain measurement, it is crucial to control the pre-stretching amount of the fiber Bragg grating.

[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 for curing. 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-pointing and heating curing after stretching also increases the difficulty of glue-pointing and heating curing, and the yield rate is low. In addition, this method cannot adapt to the measurement of different strain ranges of the measured part, 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 for curing again, the operation is cumbersome, and the flexibility of adjusting the measurement range is poor. Summary of the invention

[0006] In order to solve the problems of relatively low control accuracy, low yield rate and poor flexibility in adjusting the measuring range in the traditional fiber Bragg grating pre-stretching method, 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: A radiation-resistant fiber Bragg grating strain sensor comprises a fiber Bragg grating and a fiber Bragg grating packaging structure. The fiber Bragg grating packaging structure comprises 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 provided 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 in parallel, 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, the axial direction of the threaded through hole is arranged in the left and right directions, an adjusting bolt for pushing the slide plate to move leftward 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.

[0008] When in use, first fix the two ends of the fiber Bragg grating to the slide plate and the fixed plate respectively by dispensing glue, then naturally straighten the fiber Bragg grating through the slide plate and the fixed plate, and then pre-tighten the slide plate through the positioning fixture (pre-tightening means that after tightening, the slide plate can still move slightly relative to the slide rail when subjected to thrust), then turn the adjustment bolt according to the strain range to be tested, and the adjustment bolt pushes the slide plate to move to the left, and finally the slide plate is positioned and fixed by the positioning fixture to complete the pre-stretching of the fiber Bragg grating. When measuring, it is only necessary to fix the bottom plate on the measured component to achieve the strain measurement of the measured component. In addition, when the strain measurement range is adjusted, release the positioning fixture, so that the slide plate is in a state where it can slide freely relative to the slide rail, loosen the adjustment bolt, manually push the slide plate to slide to the right until it contacts the left end face of the fixed block, and pre-tighten the slide plate again through the positioning fixture, and then turn the adjustment bolt according to the strain range to be tested, so as to adjust the pre-stretching range of the fiber Bragg grating and adjust the strain measurement range.

[0009] Furthermore, the optical fiber used in the fiber grating is a single-mode pure quartz core optical fiber and is inscribed by a femtosecond laser, so it has better radiation resistance.

[0010] 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 provided 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 in parallel, 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, the axial direction of which is arranged in the left and right directions, an adjusting bolt for pushing the slide plate to move leftward 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.

[0011] When in use, first fix the two ends of the fiber Bragg grating to the slide plate and the fixed plate respectively by dispensing glue, then naturally straighten the fiber Bragg grating through the slide plate and the fixed plate, and then pre-tighten the slide plate through the positioning fixture (pre-tightening means that after tightening, the slide plate can still move slightly relative to the slide rail when subjected to thrust), then turn the adjustment bolt according to the strain range to be tested, and the adjustment bolt pushes the slide plate to move to the left, and finally the slide plate is positioned and fixed by the positioning fixture to complete the pre-stretching of the fiber Bragg grating. When measuring, it is only necessary to fix the bottom plate on the measured component to achieve the strain measurement of the measured component. In addition, when the strain measurement range is adjusted, release the positioning fixture, so that the slide plate is in a state where it can slide freely relative to the slide rail, loosen the adjustment bolt, manually push the slide plate to slide to the right until it contacts the left end face of the fixed block, and pre-tighten the slide plate again through the positioning fixture, and then turn the adjustment bolt according to the strain range to be tested, so as to adjust the pre-stretching range of the fiber Bragg grating and adjust the strain measurement range.

[0012] Furthermore, the slide rail includes an upper strip plate and a lower strip plate, the cross section of the upper strip plate is an inverted L-shape, the cross section of the lower strip plate is an L-shape, the upper strip plate and the lower strip plate are distributed up and down and arranged 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, and 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.

[0013] Furthermore, the positioning fixing member includes an upper fastening bolt and a lower fastening bolt, the top surface of the upper strip plate is provided with an upper fastening threaded hole arranged vertically and matched with the upper fastening bolt, and the top surface of the lower strip plate is provided with a lower fastening threaded hole arranged vertically and matched with the lower fastening bolt. After the slide plate slides to the specified position, it only needs to tighten the upper fastening bolt and the lower fastening bolt to realize the positioning and fixing of the slide plate, and the structure of the positioning fixing member is concretized and standardized.

[0014] 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 grating responds promptly when strain occurs in the measured component and ensures its sensitivity.

[0015] Furthermore, a plurality of fixing holes are distributed on the bottom plate, which facilitates spot welding or bolt fixing 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.

[0016] Furthermore, both the sliding plate and the fixing plate are provided with slots for placing the fiber grating, so as to facilitate the positioning of the fiber grating.

[0017] Furthermore, both the slide plate and the fixing plate are provided with glue dispensing grooves for conveniently dispensing glue on the optical fiber Bragg grating, so as to facilitate the glue dispensing and fixing of the optical fiber Bragg grating.

[0018] The beneficial effects of the present invention are as follows: the present invention ingeniously realizes the pre-stretching of the fiber Bragg grating by controlling the adjusting bolt, thereby achieving the effect of the fiber Bragg grating realizing negative strain measurement; at the same time, the strain measurement range of the sensor can 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

[0019] 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.

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Figure 1 It is a three-dimensional effect schematic diagram of the fiber Bragg grating packaging structure described in the present invention; Figure 2 It is a front view of the fiber Bragg grating packaging structure described in the present invention; Figure 3 Schematic diagram of the relationship between the radiation-induced Bragg wavelength shift (BWS) and irradiation dose of FBGs written in germanium (Ge)-doped fiber and pure silica core (PSC) fiber; 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.

[0022] 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

[0023] 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 the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0024] In the description, it should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be understood as indicating or implying relative importance. It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0025] 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 of the embodiments.

[0026] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0027] 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, a slide plate 3 is arranged on the slide rail for sliding left and right, and 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, and an adjusting bolt 5 for pushing the slide plate 3 to move leftward 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.

[0028] When in use, firstly, the two ends of the fiber Bragg grating are fixed to the slide plate 3 and the fixed plate 6 respectively by dispensing glue, and then the fiber Bragg grating is naturally straightened through the slide plate 3 and the fixed plate 6, and then the slide plate 3 is pre-tightened by the positioning fixture (pre-tightening means that the slide plate 3 can still move slightly relative to the slide rail when subjected to thrust after tightening), and then the adjusting bolt 5 is screwed according to the strain range to be tested, and the adjusting bolt 5 pushes the slide plate 3 to move to the left, and finally the slide plate 3 is positioned and fixed by the positioning fixture to complete the pre-stretching of the fiber Bragg grating. When measuring, it is only necessary to fix the bottom plate on the measured component to achieve the strain measurement of the measured component. In addition, when the strain measurement range is adjusted, the positioning fixture is released, so that the slide plate 3 is in a state of free sliding relative to the slide rail, the adjusting bolt 5 is loosened, and the slide plate 3 is manually pushed to slide to the right until it contacts the left end face of the fixed block, and the slide plate 3 is pre-tightened again by the positioning fixture, and then the adjusting bolt 5 is screwed according to the strain range to be tested, thereby achieving the adjustment of the pre-stretching range of the fiber Bragg grating and the adjustment of the strain measurement range.

[0029] In specific implementation, the optical fiber used for the fiber grating is a single-mode pure quartz core optical fiber and is inscribed by a femtosecond laser, so it has better radiation resistance.

[0030] Principle explanation: Radiation affects differently doped fibers differently in terms of fiber composition. Studies have shown that fibers with fluorine-doped or single-mode pure silica cores exhibit better radiation resistance than germanium (Ge)-doped or phosphorus-doped core fibers.

[0031] In addition, the radiation resistance of fiber Bragg gratings is also related to the writing technology of fiber Bragg gratings. The traditional writing method of fiber Bragg gratings usually uses ultraviolet (UV) laser light sources. Due to the influence of linear absorption mechanism, high concentrations of Ge or fiber-loaded hydrogen are usually doped in the core region to improve the photosensitivity of the material. When Ge-doped silica fiber is exposed to a high-photon energy ultraviolet laser light source, the refractive index changes caused by color center defects, and high-energy ultraviolet radiation improves the radiation resistance of the grating by eliminating the precursors of the color center. However, the presence of Ge content or additional hydrogen loading makes the fiber more susceptible to high-energy ionizing radiation. For single-mode pure quartz core fiber Bragg gratings are insensitive to the UV laser light source of traditional FBG writing, so it is necessary to use non-photosensitive femtosecond laser direct writing technology to write FBG in optical fibers doped to improve their radiation sensitivity. Femtosecond laser direct writing technology makes the fiber densified and the stress field inside the fiber, locally increases the material density or increases 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.

[0032] In order to further confirm the irradiation response of FBG, the following experiments are performed: Experiment 1: Using ultrafast femtosecond laser direct writing technology, FBGs were written in two different single-mode optical fibers, germanium (Ge) doped fiber and pure silica core (PSC) fiber, with 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, such as Figure 3 As shown, it can be seen that at room temperature, FBG is affected by radiation and produces red shift, and shows saturation behavior of cumulative irradiation dose. For the low-dose region (less than 10kGy), the Bragg wavelength increases rapidly and changes almost linearly with the dose. The slope of the curve of FBG written in PSC fiber by femtosecond laser direct writing technology (FS-PSC-FBG) is smaller than the slope of the curve of FBG written in Ge-doped fiber by femtosecond laser direct writing technology (FS-Ge-FBG), in which the germanium-doped fiber core contains GeO2, and the radiation sensitivity (BWS change) is high. With the increase of irradiation dose, BWS continues to rise, but the slope is small. When the radiation dose reaches about 20kGy, BWS changes slowly and gradually tends to saturation. The Bragg wavelength stops rising with the increase of radiation dose, but there is a little fluctuation until the radiation ends. The results show that the FBG written in PSC fiber has a lower Bragg wavelength shift, so the fiber grating adopts a single-mode pure quartz core fiber grating to improve its radiation resistance.

[0033] 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, it can be seen that the radiation-induced BWS in the FBG written by the UV laser phase mask (UV-FBG- Ge) is larger than that in the FBG written by the femtosecond laser direct writing technique (FS-FBG-Ge). The maximum wavelength shift of the FBG written by the femtosecond laser direct writing technique in pure silica core fiber (FS-FBG-PSC) is about 8.964pm, which is the lowest among the PSC / Ge doped FBG written by FS or UV. UV-FBG-Ge shows higher radiation sensitivity, which is mainly related to the H2 loading before grating writing, which enhances the photosensitivity of the fiber to UV light. FS-FBG-PSC. The refractive index change induced by femtosecond laser is a multiphoton absorption process through defect states or interband absorption, which is related to fiber densification, stress field in the fiber and defect-related formation. The different responses to irradiation may be attributed to the different physical modifications of the fiber material by different writing techniques to induce the refractive index modulation of the fiber. Therefore, the FBG written in pure silica core fiber by femtosecond laser writing technique is used to improve its irradiation performance.

[0034] 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 3 is slidably arranged on the slide rail, 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, 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, the axial direction of the threaded through hole is arranged in the left and right directions, an adjusting bolt 5 for pushing the slide plate 3 to move leftward 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.

[0035] When in use, firstly, the two ends of the fiber Bragg grating are fixed to the slide plate 3 and the fixed plate 6 respectively by dispensing glue, and then the fiber Bragg grating is naturally straightened through the slide plate 3 and the fixed plate 6, and then the slide plate 3 is pre-tightened by the positioning fixture (pre-tightening means that the slide plate 3 can still move slightly relative to the slide rail when subjected to thrust after tightening), and then the adjusting bolt 5 is screwed according to the strain range to be tested, and the adjusting bolt 5 pushes the slide plate 3 to move to the left, and finally the slide plate 3 is positioned and fixed by the positioning fixture to complete the pre-stretching of the fiber Bragg grating. When measuring, it is only necessary to fix the bottom plate on the measured component to achieve the strain measurement of the measured component. In addition, when the strain measurement range is adjusted, the positioning fixture is released, so that the slide plate 3 is in a state of free sliding relative to the slide rail, the adjusting bolt 5 is loosened, and the slide plate 3 is manually pushed to slide to the right until it contacts the left end face of the fixed block, and the slide plate 3 is pre-tightened again by the positioning fixture, and then the adjusting bolt 5 is screwed according to the strain range to be tested, thereby achieving the adjustment of the pre-stretching range of the fiber Bragg grating and the adjustment of the strain measurement range.

[0036] In 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 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 slide rail structure is simple and easy to implement.

[0037] In specific implementation, 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 matched with 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 matched with the lower fastening bolt 13. After the slide plate 3 slides to the specified position, it only needs to tighten the upper fastening bolt 12 and the lower fastening bolt 13 to realize the positioning and fixing of the slide plate 3, and the structure of the positioning fixing member is concretized and standardized.

[0038] 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 grating responds promptly when strain occurs in the measured component and ensures its sensitivity.

[0039] In specific implementation, a plurality of fixing holes 9 are distributed on the bottom plate, which are convenient for spot welding or bolt fixing with different parts of the measured component, and then convenient for strain measurement of different parts of the measured component, and comprehensively capture the strain conditions of the measured component in different areas, thereby providing more comprehensive data support for the analysis of the measured component.

[0040] In this specific embodiment, both the sliding plate 3 and the fixing plate 6 are provided with a slot 7 for placing the fiber grating, so as to facilitate the positioning of the fiber grating.

[0041] In this specific embodiment, both the slide plate 3 and the fixing plate 6 are provided with glue dispensing grooves 8 for conveniently dispensing glue on the fiber grating, so as to facilitate the glue dispensing and fixing of the fiber grating.

[0042] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope 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 packaging structure. The fiber Bragg grating packaging structure comprises a bottom plate. A slide rail is fixed to the left end of the bottom plate. A slide plate (3) is arranged on the slide rail for sliding left and right. Positioning fixing parts are 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 parallel to the bottom 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. The threaded through hole is provided with an adjusting bolt (5) for pushing the slide plate (3) to move leftward. A fixing plate (6) arranged parallel to the bottom plate is fixed to the right end of the bottom plate.

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. A fiber grating packaging structure, characterized in that: The invention comprises a bottom plate, a slide rail is fixed to the left end of the bottom 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 provided with positioning fixing parts for positioning and fixing the slide plate (3) after sliding relative to the slide rail, the slide plate (3) and the bottom plate are arranged in parallel, 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 leftward is provided in the threaded through hole, and a fixing plate (6) arranged in parallel with the bottom plate is fixed to the right end of the bottom plate.

4. The fiber grating packaging structure according to claim 3, characterized in that: The slide rail comprises an upper strip plate (10) and a lower strip plate (11); the cross section of the upper strip plate (10) is in an inverted L shape, and the cross section of the lower strip plate (11) is in an L shape; 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; and the slide plate (3) is adapted to the upper slide groove and the lower slide groove.

5. The fiber grating packaging structure according to claim 4, characterized in that: The positioning fixing member comprises 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 matched with the upper fastening bolt (12); the top surface of the lower strip plate (11) is provided with a lower fastening threaded hole arranged vertically and matched with the lower fastening bolt (13).

6. The fiber Bragg grating packaging structure according to claim 5, characterized in that: 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 and fixed by an H-shaped plate.

7. The fiber Bragg grating packaging structure according to claim 6, characterized in that: A plurality of fixing holes (9) are distributed on the bottom plate.

8. The fiber Bragg grating packaging structure according to claim 7, characterized in that: The slide plate (3) and the fixing plate (6) are both provided with a slot (7) for placing the optical fiber grating.

9. The fiber Bragg grating packaging structure according to claim 8, 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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