CN118730330A - High-sensitivity temperature sensor based on liquid metal filling and its injection packaging process - Google Patents

Abstract

The present invention belongs to the technical field of temperature sensors, and specifically relates to a high-sensitivity temperature sensor based on liquid metal filling and its injection packaging process, the sensor comprises a single-mode optical fiber, a first hollow-core optical fiber and a second hollow-core optical fiber; one end of the single-mode optical fiber is connected to one end of the first hollow-core optical fiber, and the other end of the first hollow-core optical fiber and the inner wall of the second hollow-core optical fiber are filled with an indium gallium tin alloy; the diameter of the single-mode optical fiber is 10 μm; the outer diameter of the single-mode optical fiber is 125 μm, the inner diameter of the first hollow-core optical fiber is 20 μm, and the outer diameter of the first hollow-core optical fiber is 125 μm; the inner diameter of the second hollow-core optical fiber is 135 μm, and the outer diameter of the second hollow-core optical fiber is 200 μm; one end of the single-mode optical fiber, the first hollow-core optical fiber and the indium gallium tin alloy are all located inside one end of the second hollow-core optical fiber, and the side of the indium gallium tin alloy away from the first hollow-core optical fiber and the inner wall of the second hollow-core optical fiber are filled with UV curing glue. The present invention is applied to temperature measurement in complex environments, and has the advantages of ultra-high sensitivity, small size and high resolution.

Description

High-sensitivity temperature sensor based on liquid metal filling and its injection packaging process

Technical Field

The invention belongs to the technical field of temperature sensors, and in particular relates to a high-sensitivity temperature sensor based on liquid metal filling and an injection packaging process thereof.

Background Art

The accuracy of temperature changes plays a vital role in manufacturing, food processing, pharmaceuticals and other fields; the current traditional temperature measurement methods usually involve the use of thermocouples, resistance temperature detectors or infrared radiation temperature measurement; however, in the heat treatment process, it is unavoidable to have the influence of electromagnetic radiation, chemical corrosion, etc. on microwave ripples. Therefore, in many cases, due to the advantages of anti-electromagnetic interference, compact structure, low cost and high sensitivity, the use of optical fiber sensors as the measurement of temperature parameters has become the best choice. According to the sensing principle, optical fiber temperature sensors can be divided into: fiber Bragg grating (FBG) type, long period fiber grating (LPFG) type and interference type. Usually, LPFG and FBG require the use of large instruments, such as high-frequency CO2 lasers, ultraviolet lasers and even femtosecond lasers for point-by-point writing. These methods increase complexity and cost.

In contrast, interferometric sensors, especially Fabry-Perot (F-P) sensors, have become a hot topic of research due to their small size, high sensitivity, and fast response speed. Generally, F-P interferometric (FPI) sensors are divided into two categories: intrinsic and extrinsic. For extrinsic F-P sensors, the Fabry-Perot cavity consists of the fiber end face and the external reflective surface, with air in the middle as the medium. Different preparation processes can be used.

In the prior art, an EFPI sensor is prepared by combining Al ₂ O ₃ ceramic tube with single-mode optical fiber (SMF); the proposed sensor can realize high-temperature measurement, and the maximum sensitivity between 25℃ and 1000℃ is 0.0113nm/℃; in the prior art, an EFPI is prepared by embedding two sections of SMFs coated with different reflectivity materials on the end faces into a glass capillary; between 25℃ and 55℃, the sensitivity of the sensor reaches 0.093nm/℃. In the prior art, an EFPI is prepared by forming a cavity using SMF and sapphire-derived fibers; however, the medium of the above cavity structure is air with a low thermal expansion coefficient, resulting in low sensitivity; therefore, to improve the sensitivity, an attempt can be made to introduce a reflective material with a high thermal expansion coefficient; in the prior art, an EFPI is formed by splicing SMF and cedar oil sprayed hollow fiber (HCF); the temperature sensitivity of the sensor is demodulated by OPD, reaching 50.93μm/℃ in the range of 25-70℃. However, the 3mm cedar oil length exceeds the size of the sensor and limits the application range of the sensor.

Typically, most EFPI sensors used for temperature measurement utilize the thermal expansion of the cavity medium, which results in a change in the optical path difference (OPD); however, the medium in the cavity is usually air with a low thermal expansion coefficient, resulting in low sensitivity. Therefore, to improve the sensitivity, one can try to introduce reflective materials with a high thermal expansion coefficient; in summary, the sensitivity of existing fiber optic temperature sensors cannot meet the needs of some high-precision temperature detection fields; therefore, it is necessary to design a compact and sensitive fiber optic sensor.

Summary of the invention

The purpose of the present invention is to provide a high-sensitivity temperature sensor based on liquid metal filling and its injection packaging process. The sensor is formed by splicing a single-mode optical fiber (SMF) and a hollow-core optical fiber (HCF), and an indium gallium tin alloy is injected into the hollow-core optical fiber (HCF). The basic principle is that the indium gallium tin alloy has good fluidity and thermal conductivity. During the temperature change process, the high thermal expansion coefficient of the indium gallium tin alloy causes the optical path difference to change dramatically, so this sensor has ultra-high temperature sensitivity. At the same time, through structural design, the operating temperature of the measuring device of the present invention can be 30-40°C, and the sensitivity reaches 11.3nm/°C. This technology can be applied to temperature measurement in complex environments, and has the advantages of ultra-high sensitivity, small size and high resolution.

The technical solution adopted by the present invention is as follows:

A high-sensitivity temperature sensor based on liquid metal filling, comprising a single-mode optical fiber, a first hollow-core optical fiber and a second hollow-core optical fiber;

One end of the single-mode optical fiber is connected to one end of the first hollow-core optical fiber, and the other end of the first hollow-core optical fiber is provided with an indium gallium tin alloy;

One end of the single-mode optical fiber, the first hollow optical fiber and the InGaSn alloy are all located inside one end of the second hollow optical fiber, and UV curing glue is filled between a side of the InGaSn alloy away from the first hollow optical fiber and an inner wall of the second hollow optical fiber.

Preferably, the diameter of the single-mode optical fiber is 10 μm; the outer diameter of the single-mode optical fiber is 125 μm, the inner diameter of the first hollow-core optical fiber is 20 μm, and the outer diameter of the first hollow-core optical fiber is 125 μm; the inner diameter of the second hollow-core optical fiber is 135 μm, and the outer diameter of the second hollow-core optical fiber is 200 μm.

Preferably, the length of the first hollow-core optical fiber is 80 μm; the length of the second hollow-core optical fiber is 1000 μm.

The injection packaging process of the high-sensitivity temperature sensor based on liquid metal filling includes the following steps:

Step 1: Firstly, the single-mode optical fiber and the first hollow-core optical fiber are welded;

Step 2: Take out the welded optical fiber, put the first hollow-core optical fiber into the optical fiber cutting table, cut off 80 μm of the first hollow-core optical fiber at the right end of the welding point, and then put it into one of the fixtures of the fusion splicer again;

Step 3: Cut the second hollow-core optical fiber flat with a fiber cleaver, burn off the coating with fire, and put it into the fixture on the other side of the fusion splicer;

Step 4: Set the fusion splicer to manual mode, align the x and y axes of the optical fibers on both sides, insert the first hollow-core fiber into the second hollow-core fiber by 100 μm, and weld it 2-3 times to make the second hollow-core fiber collapse and wrap around the first hollow-core fiber;

Step 5: Remove the optical fiber and place the second hollow-core optical fiber side into the optical fiber cleaver. After cutting 1000 μm, place it into the optical fiber alignment table and insert the hollow-core optical fiber injector containing the InGaSn alloy needle into the second hollow-core optical fiber. Inject the InGaSn alloy into the second hollow-core optical fiber along the leftmost solder joint for 500 μm.

Step 6: Insert the hollow fiber syringe containing the UV curing glue needle into the second hollow fiber, inject the UV curing glue into the right end of the InGaSn alloy, and irradiate the sealed end with a UV lamp.

Preferably, the specific welding steps in step 1 are as follows:

First, take a single-mode optical fiber, strip the coating on one end, cut it flat with a fiber optic cutter, and place it in a fixture of the fusion splicer; then, take the first hollow optical fiber, burn off the coating with fire, wipe off the excess coating on the optical fiber with a cleaning cloth, cut it flat with a fiber optic cutter, place it in another fixture of the fusion splicer and perform discharge welding.

Preferably, in step 5, a hollow optical fiber syringe containing an indium gallium tin alloy needle needs to be prepared first. First, a hollow optical fiber with a diameter of 100 μm is stripped of the coating, and the two ends are cut flat with a cutting knife, and then one end is inserted into the needle end of the syringe. Then, the needle mouth of the syringe is sealed with UV curing glue, and then the UV curing glue is cured with an ultraviolet lamp; finally, indium gallium tin alloy is injected into the other side of the needle end of the syringe to complete the packaging.

Preferably, in step 6, it is necessary to first prepare a hollow optical fiber syringe containing a UV curing glue needle. First, take a hollow optical fiber with a diameter of 100 μm, strip off the coating, cut both ends flat with a cutting knife, and then insert one end into the needle end of the syringe. Then, seal the needle of the syringe with UV curing glue, and then use an ultraviolet lamp to cure the UV curing glue; finally, inject UV curing glue into the other side of the needle end of the syringe to complete the packaging.

The technical effects achieved by the present invention are:

The high-sensitivity temperature sensor based on liquid metal filling of the present invention is formed by splicing a single-mode optical fiber (SMF) and a hollow-core optical fiber (HCF), and an indium gallium tin alloy is injected into the hollow-core optical fiber (HCF). The basic principle is that the indium gallium tin alloy has good fluidity and thermal conductivity. During the temperature change process, the high thermal expansion coefficient of the indium gallium tin alloy causes the optical path difference of the dual optical paths to change dramatically, so this sensor has ultra-high temperature sensitivity. At the same time, through structural design, the operating temperature of the measuring device of the present invention can be 30-40°C, and the sensitivity reaches 11.3nm/°C. This technology can be applied to temperature measurement in complex environments, and has the advantages of ultra-high sensitivity, small size and high resolution.

The high-sensitivity temperature sensor based on liquid metal filling of the present invention comprises a single-mode optical fiber, a first hollow-core optical fiber and a second hollow-core optical fiber; one end of the single-mode optical fiber is connected to one end of the first hollow-core optical fiber, and an indium gallium tin alloy is filled between the other end of the first hollow-core optical fiber and the inner wall of the second hollow-core optical fiber; the inner diameter of the single-mode optical fiber is 10 μm; the outer diameter of the single-mode optical fiber is 125 μm, the inner diameter of the first hollow-core optical fiber is 20 μm, and the outer diameter of the first hollow-core optical fiber is 125 μm; the inner diameter of the second hollow-core optical fiber is 135 μm, and the outer diameter of the second hollow-core optical fiber is 200 μm; one end of the single-mode optical fiber, the first hollow-core optical fiber and the indium gallium tin alloy are all located inside one end of the second hollow-core optical fiber, and a UV curing glue is filled between the side of the indium gallium tin alloy away from the first hollow-core optical fiber and the inner wall of the second hollow-core optical fiber; the length of the first hollow-core optical fiber is 80 μm; the length of the second hollow-core optical fiber is 1000 μm, so that the temperature sensor of the present invention has a compact structure and high sensitivity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the overall transparent structure of a high-sensitivity temperature sensor based on liquid metal filling in Example 1 of the present invention;

FIG2 is a transparent structural schematic diagram of a hollow optical fiber injector containing an indium gallium tin alloy needle in Example 2 of the present invention;

FIG3 is a transparent structural schematic diagram of a hollow optical fiber injector containing a UV curing adhesive needle in Example 2 of the present invention;

FIG. 4 is a schematic diagram of dual-beam interference based on Fabry-Perot liquid metal in Embodiment 2 of the present invention.

In the accompanying drawings, the components represented by the reference numerals are listed as follows:

1. Single-mode optical fiber; 2. First hollow optical fiber; 3. Second hollow optical fiber; 4. Indium gallium tin alloy; 5. Hollow optical fiber injector containing Indium gallium tin alloy needle; 6. Hollow optical fiber injector containing UV curing glue needle; 7. UV curing glue.

DETAILED DESCRIPTION

In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

Embodiment 1:

As shown in FIG1 , a high-sensitivity temperature sensor based on liquid metal filling includes a single-mode optical fiber 1, a first hollow-core optical fiber 2, and a second hollow-core optical fiber 3;

One end of the single-mode optical fiber 1 is connected to one end of the first hollow-core optical fiber 2 , and an indium gallium tin alloy 4 is filled between the other end of the first hollow-core optical fiber 2 and the inner wall of the second hollow-core optical fiber 3 .

The diameter of the single-mode optical fiber 1 is 10 μm; the outer diameter of the single-mode optical fiber 1 is 125 μm, the inner diameter of the first hollow-core optical fiber 2 is 20 μm, and the outer diameter of the first hollow-core optical fiber 2 is 125 μm; the inner diameter of the second hollow-core optical fiber 3 is 135 μm, and the outer diameter of the second hollow-core optical fiber 3 is 200 μm.

One end of the single-mode optical fiber 1, the first hollow-core optical fiber 2 and the InGaSn alloy 4 are all located inside one end of the second hollow-core optical fiber 3, and UV curing glue 7 is filled between the side of the InGaSn alloy 4 away from the first hollow-core optical fiber 2 and the inner wall of the second hollow-core optical fiber 3.

The length of the first hollow-core optical fiber 2 is 80 μm; the length of the second hollow-core optical fiber 3 is 1000 μm.

The high-sensitivity temperature sensor based on liquid metal filling disclosed in this embodiment has been experimentally measured to have an operating temperature of 30-40°C and a sensitivity of 11.3nm/°C. This technology can be applied to temperature measurement in complex environments and has the advantages of ultra-high sensitivity, small size and high resolution.

Embodiment 2:

The injection packaging process of the high-sensitivity temperature sensor based on liquid metal filling includes the following steps:

Step 1: First, take a single-mode optical fiber 1, strip off the coating at one end, cut it flat with a fiber cleaver, and place it in a fixture of the fusion splicer; then, take a first hollow-core optical fiber 2, burn off the coating with fire, wipe off the excess coating on the optical fiber with a cleaning cloth, cut it flat with a fiber cleaver, place it in another fixture of the fusion splicer and perform discharge welding, thus completing the welding of the single-mode optical fiber 1 and the first hollow-core optical fiber 2;

Step 2: Take out the welded optical fiber, put the first hollow-core optical fiber 2 into the optical fiber cutting table, cut off 80 μm of the first hollow-core optical fiber 2 at the right end of the welding point, and then put it into one of the clamps of the fusion splicer again;

Step 3: Cut the second hollow-core optical fiber 3 flat with an optical fiber cutter, burn off the coating with fire, and then put it into the fixture on the other side of the fusion splicer;

Step 4: Set the fusion splicer to manual mode, align the x and y axes of the optical fibers on both sides, insert the first hollow-core optical fiber 2 into the second hollow-core optical fiber 3 by 100 μm, and then weld it 2-3 times to make the second hollow-core optical fiber 3 collapse and wrap the first hollow-core optical fiber 2;

Step 5: First, make a hollow fiber injector 5 containing an indium gallium tin alloy needle. First, take a hollow fiber with a diameter of 100 μm, strip off the coating, cut both ends flat with a cutting knife, and then insert one end into the needle end of the syringe. Then, seal the needle of the syringe with UV curing glue, and then use an ultraviolet lamp to cure the UV curing glue; finally, inject indium gallium tin alloy 4 into the other side of the syringe needle end to complete the packaging; then remove the optical fiber and put the side of the second hollow fiber 3 into the optical fiber cutting knife, cut 1000 μm, put it into the optical fiber alignment table, and insert the hollow fiber injector 5 containing the indium gallium tin alloy needle into the second hollow fiber 3, and inject the indium gallium tin alloy 4 into the second hollow fiber 3 along the leftmost solder joint 3500 μm;

Step 6: First make a hollow optical fiber syringe 6 containing a UV curing glue needle. First, take a hollow optical fiber with a diameter of 100 μm, strip off the coating, cut both ends flat with a cutting knife, and then insert one end into the needle end of the syringe. Then, seal the needle mouth of the syringe with UV curing glue, and then use an ultraviolet lamp to cure the UV curing glue; finally, inject UV curing glue into the other side of the syringe needle end to complete the packaging, and then insert the hollow optical fiber syringe 6 containing the UV curing glue needle into the second hollow optical fiber 3, inject UV curing glue 7 into the right end of the indium gallium tin alloy 4, and irradiate the sealed end with an ultraviolet lamp.

The working principle of the present invention is as follows: the sensor of the present invention is spliced by a single-mode optical fiber SMF and a hollow-core optical fiber HCF and embedded with an indium gallium tin alloy into a hollow-core optical fiber with a larger diameter; the two reflection surfaces of EFPI (Fabry-Perot) are the end faces of the single-mode optical fiber and the alloy, forming a cavity with air as the medium; the indium gallium tin alloy is conducive to temperature measurement due to its liquid state at room temperature and high thermal expansion coefficient; the proposed EFPI (Fabry-Perot) sensor has ultra-high sensitivity within a small range of 30-40°C; the sensor of the present invention has the advantages of extremely high sensitivity, small size and high resolution, and can be applied to the field of high-precision temperature detection;

On the one hand, the present invention comprises a single-mode optical fiber 1, a first hollow-core optical fiber 2 with an inner diameter of 20 μm and an outer diameter of 125 μm, a second hollow-core optical fiber 3 with an inner diameter of 135 μm and an outer diameter of 200 μm, and an indium gallium tin alloy 4; on the other hand, a hollow-core optical fiber injector 5 containing an indium gallium tin alloy needle and a hollow-core optical fiber injector 6 containing a UV curing glue needle are used to inject the indium gallium tin alloy 4 and the UV curing glue 7 respectively;

In actual use, as shown in FIG4 , the sensor of the present invention has three reflection areas, namely, the reflection area at the welding point between the single-mode optical fiber 1 and the first hollow-core optical fiber 2, the reflection area between the first hollow-core optical fiber 2 and the indium gallium tin alloy 4, and the reflection area at the welding point between the first hollow-core optical fiber 2 and the single-mode optical fiber 1;

It should be added that part of the light spectrum transmitted from the core of the single-mode optical fiber is first reflected for the first time from the reflection area at the welding point between the single-mode optical fiber 1 and the first hollow-core optical fiber 2, and the other part enters the first hollow-core optical fiber 2, is completely reflected by the reflection area at the connection point between the other end of the first hollow-core optical fiber 2 and the indium gallium tin alloy 4, remains in the first hollow-core optical fiber 2, and then is reflected to the welding point between one end of the first hollow-core optical fiber 2 and the single-mode optical fiber 1, and is reflected again, as shown in FIG. 4 .

In summary, the spectrum of the spectrum transmitted from the core of the single-mode fiber is reflected into three parts: I ₁ , I ₂ , and I ₃ . Since the reflectivity of the interface air/SMF is much lower than that of air/LM, I ₃ will decay rapidly. Therefore, unlike the typical FPI,

In this structure, the interface between multiple beams is simplified to two beam cross sections, and the output light intensity can be expressed as:

in, is the initial phase, is the phase change of light when it passes through the cavity, which can be given by:

Where n represents the refractive index of the medium in the cavity, L is the refractive index of the F-P cavity, and λ represents the wavelength of the incident light. According to formula (1) and formula (2), the phase difference between the two reflected light beams satisfies the following conditions:

Here, is the wavelength of the m-order interference dip; therefore, it can be expressed as:

Formula (4) indicates that the interference inclination angle varies linearly with the cavity length; therefore, in this case, by using the material of high thermal expansion coefficient of indium gallium tin alloy (4), and adopting a clever design to associate the temperature with the cavity length L, the sensor of the present invention has a very high sensitivity to temperature and a linear relationship; it has been experimentally proved that the sensor is formed by splicing a single-mode optical fiber (SMF) and a hollow-core optical fiber (HCF), and indium gallium tin alloy is injected into the hollow-core optical fiber (HCF). The basic principle is that indium gallium tin alloy has good fluidity and thermal conductivity. During the temperature change process, the high thermal expansion coefficient of indium gallium tin alloy causes the optical path difference to change dramatically, so this sensor has ultra-high temperature sensitivity. At the same time, through structural design, the operating temperature of the measuring device of the present invention can be 30-40°C, and the sensitivity reaches 11.3nm/°C. This technology can be applied to temperature measurement in complex environments, and has the advantages of ultra-high sensitivity, small size and high resolution.

The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims (8)

1. High sensitivity temperature sensor based on liquid metal fills, its characterized in that: comprises a single-mode optical fiber (1), a first hollow optical fiber (2) and a second hollow optical fiber (3);

One end of the single-mode optical fiber (1) is connected with one end of the first hollow optical fiber (2), and the other end of the first hollow optical fiber (2) is provided with indium gallium tin alloy (4);

The single-mode optical fiber (1) one end, the first hollow optical fiber (2) and the indium gallium tin alloy (4) are all located inside one end of the second hollow optical fiber (3), and UV curing glue (7) is filled between one side, away from the first hollow optical fiber (2), of the indium gallium tin alloy (4) and the inner wall of the second hollow optical fiber (3).

2. The liquid metal fill-based high sensitivity temperature sensor of claim 1, wherein: the diameter of the single-mode optical fiber (1) is 10 mu m; the outer diameter of the single-mode optical fiber (1) is 125 mu m, the inner diameter of the first hollow optical fiber (2) is 20 mu m, and the outer diameter of the first hollow optical fiber (2) is 125 mu m.

3. The liquid metal fill-based high sensitivity temperature sensor of claim 1, wherein: the second hollow fiber (3) has an inner diameter of 135 μm and the second hollow fiber (3) has an outer diameter of 200 μm.

4. The liquid metal fill-based high sensitivity temperature sensor of claim 1, wherein: the length of the first hollow optical fiber (2) is 80 μm; the second hollow fiber (3) has a length of 1000 μm.

5. The injection packaging process of the high-sensitivity temperature sensor based on liquid metal filling is characterized by comprising the following steps of: the injection packaging process is applied to injection packaging the high-sensitivity temperature sensor according to any one of claims 1 to 4, and comprises the following steps:

step 1: firstly, welding the single-mode optical fiber (1) and the first hollow optical fiber (2) and cutting off redundant hollow optical fibers (2), wherein the remained hollow optical fibers (2) are 80 mu m;

Step 2: placing the structure obtained in the step 1 into a clamp at one side of an optical fiber fusion splicer;

Step 3: cutting the second hollow optical fiber (3) by an optical fiber cutting knife, burning off the cut second hollow optical fiber with fire, and putting the cut second hollow optical fiber into a clamp at the other side of the fusion splicer;

Step 4: the fusion splicer is adjusted to a manual mode, the x axis and the y axis of the two side optical fibers are aligned, and the first hollow optical fiber (2) is inserted into the second hollow optical fiber (3) for 100 mu m and then welded for 2-3 times, so that the second hollow optical fiber (3) collapses and wraps the first hollow optical fiber (2);

Step 5: taking down the optical fiber, putting the side of the second hollow optical fiber (3) into an optical fiber cutting knife, cutting 1000 mu m, putting into an optical fiber alignment table, inserting a hollow optical fiber injector (5) containing an indium gallium tin alloy needle into the second hollow optical fiber (3), and injecting the indium gallium tin alloy (4) into the second hollow optical fiber (3) along the leftmost welding point;

Step 6: a hollow optical fiber injector (6) containing a UV curing glue needle is inserted into the second hollow optical fiber (3), UV curing glue (7) is injected into the right end of the indium gallium tin alloy (4), and the sealing tail end is irradiated by an ultraviolet lamp.

6. The liquid metal fill-based high sensitivity temperature sensor of claim 5, wherein: the specific welding step in the step 1 is as follows:

Firstly, a single-mode fiber (1) is taken, one end of the single-mode fiber is stripped and coated, and is placed in a clamp of a fusion splicer after being cut flat by a fiber cutting knife; then, the first hollow optical fiber (2) is taken, after the coating is burned off by fire, the excessive coating on the optical fiber is wiped off by a cleaning cloth, and after the coating is cut flat by an optical fiber cutting knife, the optical fiber is placed in another clamp of a fusion splicer and is subjected to discharge welding.

7. The liquid metal fill-based high sensitivity temperature sensor of claim 6, wherein: in the step 5, a hollow optical fiber injector (5) containing an indium gallium tin alloy needle head is required to be manufactured, a hollow optical fiber with the diameter of 100 mu m is firstly taken for stripping and coating, two ends of a cutting knife are cut flat, one end of the cutting knife stretches into the needle head end of the injector, then a needle head opening of the injector is sealed by UV curing glue, and then the UV curing glue is cured by an ultraviolet lamp; and finally, injecting indium gallium tin alloy (4) at the other side of the needle end of the injector to finish packaging.

8. The liquid metal fill-based high sensitivity temperature sensor of claim 7, wherein: in the step 6, a hollow optical fiber injector (6) containing a UV curing glue needle head is required to be manufactured, hollow optical fibers with the diameter of 100 mu m are firstly taken for stripping and coating, two ends of each of the hollow optical fibers are cut flat by a cutting knife, one end of each of the hollow optical fibers extends into the needle head end of the injector, then a needle head opening of the injector is sealed by the UV curing glue, and then the UV curing glue is cured by an ultraviolet lamp; and finally, injecting UV curing adhesive at the other side of the needle end of the injector to complete packaging.