Extensible and easy-to-implement high-sensitivity strain sensor and method of making the same

Abstract

The application belongs to the technical field of optical fiber sensing application, and particularly relates to a high-sensitivity strain sensor which is expandable and easy to implement and a manufacturing method thereof. The sensor is composed of a high-sensitivity strain Fabry-Perot interferometer and a low-sensitivity strain Fabry-Perot interferometer in parallel. The high-sensitivity interferometer is composed of a first single-mode optical fiber, a first hollow capillary and a first tapered single-mode optical fiber, forming an interferometer with an interference cavity and a long cantilever beam structure, the cavity length of the interference cavity is 86.28 microns, and the length of the long cantilever beam L is 1882.2 microns. The low-sensitivity interferometer is composed of a second single-mode optical fiber, a second hollow capillary and a second tapered single-mode optical fiber, the cavity composed of the end face of the second single-mode optical fiber and the end face of the second tapered single-mode optical fiber is a reference cavity, and the cavity length of the reference cavity is 93.38 microns. The strain sensor has high strain measurement sensitivity and low temperature cross talk characteristics, and is low in cost and easy to implement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical fiber sensing application, and particularly relates to a scalable and easily implemented high-sensitivity strain sensor and a manufacturing method thereof. BACKGROUND

[0002] As a core means of material performance evaluation and structure health monitoring, strain sensing technology plays an irreplaceable role in intelligent medical treatment, infrastructure safety, aerospace and other high-precision fields. Compared with traditional electrical strain sensors that rely on resistance changes, optical fiber strain sensors have become a research hotspot for the next generation of sensing technology due to their advantages of resistance to electromagnetic interference, distributed measurement, resistance to harsh environments, and miniaturization and integration. Among them, the optical fiber sensor based on Fabry-Perot interferometer (FPI) has a unique application value in complex working condition monitoring due to its compact structure, low manufacturing cost and low temperature sensitivity.

[0003] In the field of strain sensing, the key to the engineering implementation of the vernier effect lies in the accurate control of the cavity length difference of the double Fabry-Perot interferometer. The traditional method usually relies on high-precision nanoscale etching process or complex photolithography technology, which makes it difficult to ensure the uniformity of the cavity length, the consistency of the sensor is poor and the manufacturing cost is high. In addition, the open cavity is easily contaminated by environmental dust, and the difference in thermal expansion coefficient of the double cavity will introduce temperature crosstalk problem, which further limits the practical application of the sensor. At present, the application of the vernier effect in the Fabry-Perot interferometric strain sensor faces two major technical bottlenecks: one is the accurate matching of the free spectral range of the double cavity, which needs to break through the sub-micron cavity length control precision, and the other is the non-uniform influence of environmental parameters (temperature, humidity) on the double cavity, which leads to cross-sensitivity problem. SUMMARY

[0004] In order to solve the above technical problems, the application provides a scalable and easily implemented high-sensitivity strain sensor and a manufacturing method thereof. The strain sensor has high sensitivity for strain measurement and low temperature crosstalk, and is low in cost and easy to implement.

[0005] The technical scheme adopted by the application is: a scalable and easily implemented high-sensitivity strain sensor, which is composed of a high-sensitivity strain Fabry-Perot interferometer and a low-sensitivity strain Fabry-Perot interferometer connected in parallel by a two-way two-coupler.

[0006] The high-sensitivity strain fiber Bragg grating interferometer is composed of a first single-mode optical fiber, a first hollow capillary and a first tapered single-mode optical fiber. One end of the first hollow capillary is fused to one end of the first single-mode optical fiber, and the other end is fused to the end of the tapered section of the first tapered single-mode optical fiber. The part of the tapered section of the first tapered single-mode optical fiber after fusion is located inside the first hollow capillary, forming a high-sensitivity strain fiber Bragg grating interferometer with a long cantilever beam structure. The cavity formed by the end faces of the first hollow capillary, the first single-mode optical fiber and the first tapered single-mode optical fiber is the interference cavity.

[0007] The cavity length of the interference cavity is 86.18-86.38 μm, which is the distance between the end face of the first single-mode optical fiber and the end face of the first tapered single-mode optical fiber. The length of the long cantilever beam L is 1881.2-1883.2 μm (the length of the long cantilever beam L is the distance from the end face of the left first single-mode optical fiber to the fusion point, i.e. the length of the first hollow capillary after welding).

[0008] The low-sensitivity strain fiber Bragg grating interferometer is composed of a second single-mode optical fiber, a second hollow capillary and a second tapered single-mode optical fiber. One end of the second hollow capillary is fused to one end of the second single-mode optical fiber, and the other end is fused to the end face of the tapered section of the second tapered single-mode optical fiber. The end face of the second single-mode optical fiber and the end face of the tapered section of the second tapered single-mode optical fiber form a reference cavity. The cavity length of the reference cavity is 93.28-93.48 μm.

[0009] Further, the cavity length of the interference cavity is 86.18 μm, and the length of the long cantilever beam L is 1881.2 μm; the cavity length of the reference cavity is 93.28 μm.

[0010] Further, the cavity length of the interference cavity is 86.28 μm, and the length of the long cantilever beam L is 1882.2 μm; the cavity length of the reference cavity is 93.38 μm.

[0011] Further, the cavity length of the interference cavity is 86.38 μm, and the length of the long cantilever beam L is 1883.2 μm; the cavity length of the reference cavity is 93.48 μm.

[0012] Further, the inner diameter of the first hollow capillary and the second hollow capillary is preferably 100 nm.

[0013] A method for manufacturing a high-sensitivity strain sensor that is scalable and easy to implement, the manufacturing method comprising the following steps:

[0014] Step one, build experimental equipment, introduce the light signal from the super-continuous light source into the output end of the first single-mode optical fiber through an optical fiber ring, and connect the reflected light into a spectrum analyzer to monitor and record the interference spectrum.

[0015] Step two, place the first single mode optical fiber with flat end face into the optical fiber fusion splicer; take another first hollow capillary with flat end face into the optical fiber fusion splicer, observe the interface of the optical fiber fusion splicer, and control the driving motor to make the two end faces of the first single mode optical fiber and the first hollow capillary close to the discharge center of the fusion splicer, set the discharge power to -10, the discharge time to 300 ms, discharge, and fuse the first single mode optical fiber and the first hollow capillary together to make a first hollow single mode optical fiber.

[0016] Step three, take out the first hollow single mode optical fiber in the optical fiber fusion splicer, and cut off the excess first hollow capillary with a fiber cutting knife.

[0017] Step four, fix the single mode optical fiber with stripped coating layer in the commercial optical fiber fusion tapering system (Ideal photonics, IPCS-5000-SMT), set the fiber clamp pulling distance to 0-4 mm and 4-15 mm, the pulling speed to 0.07 mm / s and 1 mm / s, the hydrogen flow rate to 147 sccm, the hydrogen torch heating width to 8 mm, and the torch scanning distance to 2.4 mm, start the commercial optical fiber fusion tapering system after setting the parameters, fuse and taper the single mode optical fiber into a tapered single mode optical fiber, and cut the tapered single mode optical fiber in the middle into two segments with a fiber cutter, one segment being a first tapered single mode optical fiber and the other segment being a second tapered single mode optical fiber.

[0018] Step five, insert the tapered segment of the first tapered single mode optical fiber in step four into the first hollow capillary of the first hollow single mode optical fiber in step three, adjust the first tapered single mode optical fiber with the left and right motors of the optical fiber fusion splicer so that it forms an interference cavity with the end face of the first single mode optical fiber and the first hollow capillary; align the discharge electrode of the optical fiber fusion splicer with the end face of the first hollow capillary, set the welding time to 1000 ms and the welding power to -10 bit, fuse the end of the first hollow capillary with the tapered segment of the first tapered single mode optical fiber, and cut down the interference cavity (5) with a length of 15 cm on both sides to make a high-sensitivity strain Fabry-Perot interferometer with an interference cavity and a long cantilever beam structure.

[0019] Step six, replace the optical fiber circulator with a two-to-two coupler, connect the super-continuous light source and the optical spectrum analyzer to one end of the two-to-two coupler respectively, and connect the high-sensitivity strain Fabry-Perot interferometer in step five and the output end of a second single mode optical fiber with flat end face to the other end of the two-to-two coupler respectively.

[0020] Step seven, place the second single-mode optical fiber in the optical fiber fusion machine; take another second hollow capillary with flat end faces and place it in the optical fiber fusion machine, observe the interface of the optical fiber fusion machine, and control the driving motor to make the two end faces of the second single-mode optical fiber and the second hollow capillary close to the discharge center of the fusion machine, set the discharge power to -10, the discharge time to 300 ms, and discharge to fuse the second single-mode optical fiber and the second hollow capillary together to make a second hollow single-mode optical fiber.

[0021] Step eight, take out the second hollow single-mode optical fiber in the optical fiber fusion machine, and cut off the excess second hollow capillary with a fiber cutting knife.

[0022] Step nine, insert the tapered section of the second tapered single-mode optical fiber in step four into the second hollow capillary of the second hollow single-mode optical fiber in step eight, adjust the distance between the end face of the second tapered single-mode optical fiber and the end face of the second hollow single-mode optical fiber through the left and right motors of the optical fiber fusion machine, and observe the optical spectrum analyzer at the same time until the vernier envelope spectrum appears, at this time, the end face of the second single-mode optical fiber and the end face of the tapered section of the second tapered single-mode optical fiber form a reference cavity; then, the end face of the second tapered single-mode optical fiber is subjected to the discharge electrode of the optical fiber fusion machine, the welding time is set to 1000 ms, the welding power is set to -10 bit, and the second hollow single-mode optical fiber and the second tapered single-mode optical fiber are fused together; a low-sensitivity strain Fabry-Perot sensor interferometer with a reference cavity is prepared.

[0023] The high-sensitivity strain sensor which is expandable and easy to implement is composed of a high-sensitivity strain Fabry-Perot interferometer and a low-sensitivity strain Fabry-Perot interferometer connected in parallel by a two-way two-coupler.

[0024] The application has the beneficial effects that a low-cost and high-effect strain sensor and a manufacturing method based on the vernier effect are designed, high-sensitivity strain measurement is realized, and temperature interference is effectively suppressed. When the high-sensitivity strain Fabry-Perot interferometer and the low-sensitivity strain Fabry-Perot interferometer are connected in parallel, the sensor exhibits an ultra-high strain sensitivity of 631.12 pm / με, which is 11.96 times higher than that of a single high-sensitivity strain Fabry-Perot interferometer; in the temperature range of 25-150 °C, the temperature sensitivity is 9.39 pm / °C, and the temperature cross-sensitivity is as low as 0.015 µε / °C, which significantly reduces the measurement error caused by temperature changes. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Fig. 1 is a structural schematic diagram of the expandable and easy-to-implement high-sensitivity strain sensor in Example One.

[0026] Figure 2 Fig. 2 is a structural schematic diagram of the high-sensitivity strain Fabry-Perot sensor interferometer in Example One.

[0027] Figure 3 is a structural schematic diagram of the low-sensitivity strain fiber Bragg grating sensor interferometer in embodiment one.

[0028] Figure 4 is a schematic diagram of step one of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four.

[0029] Figure 5 is a schematic diagram of step two of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four.

[0030] Figure 6 is a schematic diagram of step three of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four.

[0031] Figure 7 is a schematic diagram of step four of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four.

[0032] Figure 8 is a schematic diagram of step five of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four.

[0033] Figure 9 is a schematic diagram of step six of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four.

[0034] Figure 10 is a schematic diagram of step seven of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four.

[0035] Figure 11 is a schematic diagram of step nine of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four before fusion.

[0036] Figure 12 is a schematic diagram of step nine of the scalable and easy-to-implement high-sensitivity strain sensor fabrication method in embodiment four after fusion.

[0037] Figure 13 is an interference curve spectral diagram of the scalable and easy-to-implement high-sensitivity strain sensor after the sensor is subjected to an axial stress of 0-200 με in steps of 25 με.

[0038] Figure 14 is an interference curve spectral diagram of the scalable and easy-to-implement high-sensitivity strain sensor when the temperature is raised from 25 ℃ to 150 ℃ in steps of 25 ℃.

[0039] Figure reference numerals: 1. High-sensitivity strain Fabry-Perot interferometer; 2. Low-sensitivity strain Fabry-Perot interferometer; 3. Two-to-two coupler; 4. Fiber circulator; 5. Spectrometer; 6. Fiber fusion splicer; 7. Single-mode fiber; 8. Commercial fiber fusion tapering system; 11. First single-mode fiber; 12. Interference cavity; 13. First hollow capillary; 14. First tapered single-mode fiber; 21. Second single-mode fiber; 22. Reference cavity; 23. Second hollow capillary; 24. Second tapered single-mode fiber. Detailed Implementation

[0040] Example 1

[0041] like Figures 1-3 As shown, a scalable and easily implemented high-sensitivity strain sensor is provided, which consists of a high-sensitivity strain Fabry-Perot interferometer 1 and a low-sensitivity strain Fabry-Perot interferometer 2 connected in parallel by a two-to-two coupler 3.

[0042] The high-sensitivity strain Fabry-Perot interferometer consists of a first single-mode fiber 11, a first hollow capillary tube 13, and a first tapered single-mode fiber 14. One end of the first hollow capillary tube is fused to one end of the first single-mode fiber, and its other end is fused to the end of the tapered section of the first tapered single-mode fiber. The tapered section of the first tapered single-mode fiber is located inside the first hollow capillary tube, forming a high-sensitivity strain Fabry-Perot interferometer with a long cantilever beam structure. The cavity formed by the end faces of the first hollow capillary tube, the first single-mode fiber, and the first tapered single-mode fiber is the interference cavity 12. The cavity length of the interference cavity is 86.28 μm, and the length of the long cantilever beam L is 1882.2 μm.

[0043] The low-sensitivity strain Fabry-Perot interferometer consists of a second single-mode fiber 21, a second hollow capillary tube 23, and a second tapered single-mode fiber 24. One end of the second hollow capillary tube is fused to one end of the second single-mode fiber, and the other end is fused to the end face of the tapered section of the second tapered single-mode fiber. The end face of the second single-mode fiber and the end face of the tapered section of the second tapered single-mode fiber form a reference cavity 22 with a cavity length of 93.38 μm.

[0044] Example 2

[0045] Based on the technical solution of Embodiment 1, the lengths of the dry cavity and the long cantilever beam of the high-sensitivity strain Fabry-Perot interferometer are changed, with the dry cavity length being 86.18 μm and the long cantilever beam L being 1881.2 μm. The length of the reference cavity of the low-sensitivity strain Fabry-Perot interferometer is also changed, with the reference cavity length being 93.28 μm.

[0046] Example 3

[0047] On the basis of the technical scheme of the embodiment, the length of the dry cavity of the high-sensitivity strain Fabry-Perot interferometer and the length of the long cantilever beam are changed, the length of the long cantilever beam L is 1883.2 μm, and the length of the reference cavity of the low-sensitivity strain Fabry-Perot interferometer is changed, the length of the reference cavity is 93.48 μm.

[0048] Embodiment four

[0049] As Figures 4-12 shown, the manufacturing method of the expandable and easy-to-implement high-sensitivity strain sensor includes the following steps:

[0050] Step one, build the experimental equipment, introduce the light signal from the super-continuous light source into the output end of the first single-mode optical fiber through an optical fiber ring 4, and connect the reflected light into a spectrum analyzer 5 to monitor and record the interference spectrum.

[0051] Step two, place the end face cut flat first single-mode optical fiber in the optical fiber fusion splicer 6; take another end face cut flat first hollow capillary and place it in the optical fiber fusion splicer, observe the interface of the optical fiber fusion splicer, and control the driving motor to make the two end faces of the first single-mode optical fiber and the first hollow capillary close to the discharge center of the fusion splicer, set the discharge power to -10, and the discharge time to 300 ms, discharge, and fuse the first single-mode optical fiber and the first hollow capillary together to make the first hollow single-mode optical fiber.

[0052] Step three, take out the first hollow single-mode optical fiber in the optical fiber fusion splicer, and cut off the excess first hollow capillary with a fiber cutting knife.

[0053] Step four, fix the single-mode optical fiber 7 with stripped coating in a commercial optical fiber fusion tapering system 8 (Ideal photonics, IPCS-5000-SMT), set the fiber clamping pulling distance to 0-4 mm and 4-15 mm, the pulling speed to 0.07 mm / s and 1 mm / s, the hydrogen flow rate to 147 sccm, the hydrogen torch heating width to 8 mm, and the torch scanning distance to 2.4 mm, start the commercial optical fiber fusion tapering system after setting the parameters, fuse and pull the single-mode optical fiber into a tapered single-mode optical fiber, and cut the tapered single-mode optical fiber in the middle into two segments with an optical fiber cutter, one segment is the first tapered single-mode optical fiber, and the other segment is the second tapered single-mode optical fiber.

[0054] Step five, insert the tapered section of the first tapered single mode fiber in step four into the first hollow capillary of the first hollow core single mode fiber in step three, adjust the first tapered single mode fiber to form an interference cavity with the end face of the first single mode fiber and the first hollow capillary by the left and right motors of the fiber fusion splicer; align the discharge electrode of the fiber fusion splicer with the end face of the first hollow capillary, set the welding time to 1000 ms, the welding power to -10 bit, fuse the end of the first hollow capillary with the tapered section of the first tapered single mode fiber together, cut down the 15 cm length region on both sides of the interference cavity, and prepare a high-sensitivity strain Fabry-Perot interferometer with an interference cavity and a long cantilever beam structure.

[0055] Step six, replace the fiber circulator with a two-to-two coupler, connect the super-continuum light source and the optical spectrum analyzer to one end of the two-to-two coupler respectively, and connect the high-sensitivity strain Fabry-Perot interferometer in step five and the output end of a second single mode fiber with a cut flat end face to the other end of the two-to-two coupler respectively.

[0056] Step seven, place the second single mode fiber in the fiber fusion splicer; place another second hollow capillary with a cut flat end face in the fiber fusion splicer, observe the interface of the fiber fusion splicer, and control the driving motor to make the two end faces of the second single mode fiber and the second hollow capillary close to the discharge center of the fiber fusion splicer, set the discharge power to -10 and the discharge time to 300 ms, and discharge to fuse the second single mode fiber and the second hollow capillary together to prepare a second hollow core single mode fiber.

[0057] Step eight, take out the second hollow core single mode fiber from the fiber fusion splicer and cut off the excess second hollow capillary with a fiber cutting knife.

[0058] Step nine, insert the tapered section of the second tapered single mode fiber in step four into the second hollow capillary of the second hollow core single mode fiber in step eight, adjust the distance between the end face of the second tapered single mode fiber and the end face of the second hollow core single mode fiber by the left and right motors of the fiber fusion splicer, and observe the optical spectrum analyzer at the same time until the Vernier envelope spectrum appears, at this time, the end face of the second single mode fiber and the end face of the tapered section of the second tapered single mode fiber form a reference cavity; then align the discharge electrode of the fiber fusion splicer with the end face of the tapered section of the second tapered single mode fiber, set the welding time to 1000 ms and the welding power to -10 bit, fuse the second hollow core single mode fiber and the second tapered single mode fiber together; and prepare a low-sensitivity strain Fabry-Perot sensor interferometer with a reference cavity.

[0059] A high-sensitivity strain sensor is composed of a high-sensitivity strain Fabry-Perot interferometer and a low-sensitivity strain Fabry-Perot interferometer connected in parallel by a two-way coupler. The high-sensitivity strain Fabry-Perot interferometer is formed by arc discharge welding a single-mode optical fiber, a hollow capillary and a tapered single-mode optical fiber to form a Fabry-Perot interferometer with a long cantilever beam structure. The low-sensitivity strain Fabry-Perot interferometer precisely matches the cavity length of the high-sensitivity strain Fabry-Perot interferometer to excite the vernier effect by a fusion splicer. Applying optical simulation of the vernier effect to fiber interferometers is an effective means to improve the sensitivity and resolution of optical sensors. The vernier effect is achieved by obtaining two slightly detuned interference signals and overlapping them to produce a vernier envelope, which shows amplified sensitivity compared to a single interferometer of the constituent structure. Due to the proximity of the cavity lengths of the sensing cavity and the reference cavity, the interference frequencies produced by the two interferometers are slightly offset. When the sensing cavity and the reference cavity are connected in parallel, the signals of the two are overlapped, thereby producing an envelope modulation effect. Compared with the use of the sensing cavity alone, this structure can significantly amplify the sensitivity and improve the sensing performance of the sensor.

[0060] As shown in Figure 13 , the change of the interference spectrum of the high-sensitivity strain sensor based on the vernier effect gas cavity after applying an axial stress of 0-200 με with a step of 25 με. Through the linear relationship between different stress levels and wavelengths and the fitting based on the wavelength shift and stress, the strain sensitivity of the prepared sensor is 631.12 pm / με.

[0061] As shown in Figure 14 , the temperature was increased from 25 ℃ to 150 ℃ with a step of 25 ℃, and the interference spectrum at each temperature was collected. The temperature sensitivity of the high-sensitivity strain sensor based on the vernier effect gas cavity is 631.12 pm / με, and the temperature cross-sensitivity is 0.015 µε / °C με / ℃, which has a lower temperature sensitivity, thereby reducing the measurement error caused by temperature changes, making the strain measurement in complex environments less affected by temperature and the data more accurate.

[0062] To solve the problem of complex production process and high cost of vernier effect fiber sensor, a low-cost strain sensor based on parallel Fabry-Perot interferometer is designed. The sensor adopts a simple structure design, which is composed of single-mode fiber and hollow capillary to form two parallel Fabry-Perot interferometers. The vernier effect is realized by matching the cavity length through a fusion splicer. The sensor shows an ultra-high strain sensitivity of 631.12 pm / με and an ultra-low cross-sensitivity of 0.015 µε / °C, which greatly reduces the measurement error caused by temperature changes. The high-sensitivity strain sensor combined with the optical vernier effect can significantly improve the sensitivity of stress measurement. Compared with the existing technology, the sensor only needs single-mode fiber, hollow capillary and commercial fusion splicer to produce high-sensitivity strain sensor, which is simple to make, easy to operate and low in cost.

Claims

1. A scalable and easy to implement high sensitivity strain sensor, characterized in that: The high-sensitivity strain sensor is composed of a high-sensitivity strain Fabry-Perot interferometer and a low-sensitivity strain Fabry-Perot interferometer connected in parallel by a two-branch two-coupler; The high-sensitivity strain Fabry-Perot interferometer is composed of a first single-mode optical fiber, a first hollow capillary and a first tapered single-mode optical fiber, one end of the first hollow capillary is fused to one end of the first single-mode optical fiber, the other end of the first hollow capillary is fused to the end of the tapered section of the first tapered single-mode optical fiber, part of the tapered section of the first tapered single-mode optical fiber after fusion is located inside the first hollow capillary, forming a high-sensitivity strain Fabry-Perot interferometer with a long cantilever beam structure, and the cavity composed of the end faces of the first hollow capillary, the first single-mode optical fiber and the first tapered single-mode optical fiber is the interference cavity; The cavity length of the interference cavity is 86.18-86.38 μm, and the length of the long cantilever beam L is 1881.2-1883.2 μm. The low-sensitivity strain Fabry-Perot interferometer is composed of a second single-mode optical fiber, a second hollow capillary and a second tapered single-mode optical fiber, one end of the second hollow capillary is fused to one end of the second single-mode optical fiber, the other end of the second hollow capillary is fused to the end face of the tapered section of the second tapered single-mode optical fiber, and the end face of the second single-mode optical fiber and the end face of the tapered section of the second tapered single-mode optical fiber form a reference cavity, and the cavity length of the reference cavity is 93.28-93.48 μm.

2. The scalable and easy-to-implement high-sensitivity strain sensor of claim 1, wherein: The cavity length of the interference cavity is 86.18 μm, the length of the long cantilever beam L is 1881.2 μm, and the cavity length of the reference cavity is 93.28 μm.

3. The scalable and easy-to-implement high-sensitivity strain sensor of claim 1, wherein: The cavity length of the interference cavity is 86.28 μm, the length of the long cantilever beam L is 1882.2 μm, and the cavity length of the reference cavity is 93.38 μm.

4. The scalable and easy-to-implement high-sensitivity strain sensor of claim 1, wherein: The cavity length of the interference cavity is 86.38 μm, the length of the long cantilever beam L is 1883.2 μm, and the cavity length of the reference cavity is 93.48 μm.

5. A method of fabricating the scalable and easy-to-implement high-sensitivity strain sensor of claim 1, comprising: The manufacturing method comprises the following steps: Step one, build the experimental equipment, introduce the light signal from the super-continuous light source into the output end of the first single-mode optical fiber through a fiber ring, and connect the reflected light into a spectrum analyzer to monitor and record the interference spectrum; Step two, place the first single-mode optical fiber with a flat end face in the fiber fusion machine, and place another first hollow capillary with a flat end face in the fiber fusion machine, observe the interface of the fiber fusion machine, control the driving motor to make the two end faces of the first single-mode optical fiber and the first hollow capillary close to the discharge center of the fusion machine, set the discharge power to -10 bit, and the discharge time to 300 ms, and then discharge to fuse the first single-mode optical fiber and the first hollow capillary together to form a first hollow single-mode optical fiber; Step three, take out the first hollow single-mode optical fiber in the fiber fusion machine, and cut off the excess first hollow capillary with a fiber cutting knife. Step four, fix the single mode optical fiber with stripping coating layer in the commercial optical fiber fusion tapering system, set the pulling distance of the optical fiber clamp to be 0-4 mm and 4-15 mm, the pulling speed to be 0.07 mm / s and 1 mm / s, the hydrogen flow rate to be 147 sccm, the hydrogen torch heating width to be 8 mm, and the torch scanning distance to be 2.4 mm, start the commercial optical fiber fusion tapering system after setting the parameters, and then melt and draw the single mode optical fiber into a tapered single mode optical fiber, cut the tapered single mode optical fiber in the middle into two segments by using an optical fiber cutter, one segment is a first tapered single mode optical fiber, and the other segment is a second tapered single mode optical fiber; Step five, insert the tapered segment of the first tapered single mode optical fiber in step four into the first hollow capillary of the first hollow core single mode optical fiber in step three, adjust the first tapered single mode optical fiber by using the left and right motors of the optical fiber fusion splicer, so that the first tapered single mode optical fiber forms an interference cavity with the end face of the first single mode optical fiber and the first hollow capillary, align the discharge electrode of the optical fiber fusion splicer with the end face of the first hollow capillary, set the welding time to be 1000 ms and the welding power to be -10 bit, fuse the end of the first hollow capillary with the tapered segment of the first tapered single mode optical fiber, and thus a high-sensitivity strain Fabry-Perot interferometer with an interference cavity and a long cantilever beam structure is prepared; Step six, replace the optical fiber circulator with a two-to-two coupler, connect the super-continuous light source and the optical spectrum analyzer to one end of the two-to-two coupler respectively, and connect the high-sensitivity strain Fabry-Perot interferometer in step five and the output end of a second single mode optical fiber with a flattened end face to the other end of the two-to-two coupler respectively; Step seven, place the second single mode optical fiber in the optical fiber fusion splicer, and place another second hollow capillary with a flattened end face in the optical fiber fusion splicer, observe the interface of the optical fiber fusion splicer, and control the driving motor to make the two end faces of the second single mode optical fiber and the second hollow capillary close to the discharge center of the optical fiber fusion splicer, set the discharge power to be -10 bit and the discharge time to be 300 ms, and then discharge to fuse the second single mode optical fiber and the second hollow capillary together to prepare a second hollow core single mode optical fiber; Step eight, take out the second hollow core single mode optical fiber in the optical fiber fusion splicer, and cut off the excess second hollow capillary by using a fiber cutter; Step nine, insert the tapered segment of the second tapered single mode optical fiber in step four into the second hollow capillary of the second hollow core single mode optical fiber in step eight, adjust the distance between the end face of the second tapered single mode optical fiber and the end face of the second hollow core single mode optical fiber by using the left and right motors of the optical fiber fusion splicer, and observe the optical spectrum analyzer at the same time, until a clear vernier envelope spectrum appears, at this time, the end face of the second single mode optical fiber and the end face of the tapered segment of the second tapered single mode optical fiber form a reference cavity, then align the discharge electrode of the optical fiber fusion splicer with the end face of the tapered segment of the second tapered single mode optical fiber, set the welding time to be 1000 ms and the welding power to be -10 bit, and then fuse the second hollow core single mode optical fiber and the second tapered single mode optical fiber together, and thus a low-sensitivity strain Fabry-Perot sensor interferometer with a reference cavity is prepared; A high-sensitivity strain sensor consisting of a high-sensitivity strain Fabry-Perot interferometer and a low-sensitivity strain Fabry-Perot interferometer connected in parallel by a two-way coupler. A high-sensitivity strain sensor consisting of a high-sensitivity strain Fabry-Perot interferometer and a low-sensitivity strain Fabry-Perot interferometer connected in parallel by a two-way coupler.

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