A method for manufacturing a probe-type optical fiber gas pressure sensor

Abstract

The application belongs to the technical field of optical fiber sensors, and particularly relates to a preparation method of a probe type optical fiber gas pressure sensor, which comprises the following steps: step 1: mixing an elastomer with a curing agent thereof, and obtaining a mixed solution after treatment; step 2: placing magnetic Fe3O4 particles into the mixed solution obtained in step 1, and obtaining a Fe3O4-elastomer mixed solution after treatment; step 3: filling the Fe3O4-elastomer mixed solution obtained in step 2 into a first hollow core optical fiber, and performing a curing operation; forming a Fe3O4-elastomer magnetorheological elastomer; and step 4: finally, cutting and fusion splicing are performed to obtain the hollow core optical fiber as a pressure sensing hole structure of the probe type optical fiber pressure sensor. The application improves the applicability of the optical fiber gas pressure sensor, improves the sensing sensitivity, and prepares a high-performance optical fiber sensor on the basis of a magnetorheological elastomer diaphragm material; and can be used in the field of optical fiber sensing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical fiber sensors, and particularly relates to a preparation method of a probe type optical fiber gas pressure sensor. BACKGROUND

[0002] Pitot pressure fluctuation testing is a key experimental technique used to simulate various aerodynamic conditions encountered by aircraft in actual flight, helping researchers evaluate and optimize aircraft design to ensure performance and structural stability at high speeds and under different airflow conditions; traditional pressure measurement often relies on mechanical sensors, but these devices have dynamic response limitations in high-frequency fluctuation measurements; optical fiber sensors can accurately capture rapidly changing pressure data in complex flow states, providing more detailed pressure distribution maps, which are crucial for analyzing the aerodynamic loads, vibration characteristics of aircraft, and their response to sudden airflow changes.

[0003] Optical fiber sensors detect various physical and chemical changes by utilizing the characteristics of light transmission through optical fibers. Such sensors have the advantages of small size, light weight, strong anti-electromagnetic interference ability, and can work in extreme environmental conditions such as high temperature, high pressure, or corrosive environments. The core principle of optical fiber sensors is to perceive external environmental changes by monitoring the changes in intensity, phase, polarization, or wavelength of light passing through the optical fiber. Optical fiber sensors based on the Fabry-Perot interference principle (F-P) consist of two parallel reflecting surfaces forming an optical resonant cavity, one of which is fixed, while the other moves with the change of gas pressure, thereby changing the optical path length of the cavity. When gas pressure acts on the sensor probe, the movable reflecting surface produces displacement, causing changes in interference fringes. This change is transmitted through the optical fiber to the optical signal demodulation device, realizing quantitative detection of gas pressure. The sensitivity, measurement range, response frequency, and other characteristics of the current optical fiber pressure sensor based on the F-P principle are closely related to the material properties of the diaphragm. Once the material of the diaphragm is fixed, the sensing characteristics of the sensor cannot be adjusted by other methods, which to some extent limits the application range of the pressure sensor.

[0004] Magnetorheological elastomers are a kind of smart materials composed of tiny magnetic particles suspended in a polymer matrix. The characteristic of this material is that its mechanical properties such as stiffness and damping performance can be rapidly and reversibly changed under the action of an external magnetic field. Due to these characteristics, magnetorheological elastomers show great application potential in the fields of vibration control, impact absorption, and dynamic load regulation. Using magnetorheological elastomers as the diaphragm material of optical fiber pressure sensors based on the F-P principle, the sensitivity, measurement range, response frequency, and other characteristics of the sensor can be changed in real time and non-contact by changing the magnetic field applied to the outside of the sensor, improving the performance and adaptability of the sensor. SUMMARY

[0005] The purpose of this invention is to provide a method for fabricating a probe-type fiber optic gas pressure sensor, resulting in a small-sized, high-frequency-response, simple-to-fabricate, and tunable-sensitivity pulsating wind pressure sensor. Since this patent proposes a fiber optic gas pressure sensor based on the Fabry-Perot (FP) interferometry principle, its diaphragm material is a high-reflectivity magnetorheological elastomer. Under non-contact conditions, the Young's modulus of the diaphragm can be adjusted by changing the strength of an external magnetic field, thereby regulating the sensor's performance. It offers advantages over ordinary FP fiber optic pressure sensors in terms of environmental adaptability and sensitivity.

[0006] The specific technical solution adopted by this invention is as follows:

[0007] A method for fabricating a probe-type fiber optic gas pressure sensor includes the following steps:

[0008] Step 1: Mix the elastomer and its curing agent according to the specified ratio and stir until they are evenly mixed. Place the mixture under vacuum for a certain period of time to obtain a mixed solution of the elastomer and its curing agent.

[0009] Step 2: Add magnetic Fe3O4 particles with a particle size of 20nm into the mixed solution obtained in Step 1, and stir until the magnetic particles are dispersed in the mixed solution. After oscillation, a Fe3O4-elastomer mixed solution with uniformly dispersed nanoparticles is obtained.

[0010] Step 3: Fill the first hollow fiber with the Fe3O4-elastomer mixed solution obtained in Step 2 and perform a curing operation; the Fe3O4-elastomer solution in the first hollow fiber is cured to form a Fe3O4-elastomer magnetorheological elastomer;

[0011] Step 4: Use a fiber optic fusion splicer to splice the second hollow fiber with the single-mode fiber; simultaneously, fusion splice the first hollow fiber (filled with Fe3O4-elastomer magnetorheological elastomer) obtained in Step 3 with the second hollow fiber; then place the spliced ​​fiber structure in... Figure 2 The fiber precision cutting platform shown has fiber optic clamps fixing both ends of the fiber. The fusion point between the hollow fiber and the fiber filled with filler material is found using a microscope camera. Then, by adjusting the translation distance L2 = 5 μm of the three-dimensional displacement stage, the excess part of the fiber filled with filler material is cut off by the fiber optic cutter. The length of the fiber filled with filler material is L2, which is used as the thickness of the Fe3O4-elastomer magnetorheological elastomer film. Finally, the first hollow fiber structure is spliced ​​with a section of the third hollow fiber to obtain this section of hollow fiber as the pressure-sensing hole structure of the probe-type fiber optic pressure sensor.

[0012] Preferably, in step 1, the elastomer is dimethylsiloxane, and the curing agent for dimethylsiloxane is PDMS polydimethylsiloxane high transparency curing agent or dibutyl phthalate; the mass ratio of dimethylsiloxane to its curing agent is 10:1.

[0013] Preferably, in step 1, the elastomer is made of rubber, and the curing agent for the rubber is a yellowing-resistant curing agent or di-o-tolueneguanidine, and the mass ratio of the rubber to its curing agent is 10:0.2-0.5.

[0014] Preferably, in step 1, the mixture of the elastomer and its curing agent is placed under vacuum for 10 minutes.

[0015] Preferably, in both step 1 and step 2, a glass rod is used to mix and stir the solution.

[0016] In step 2, the oscillation method involves placing the solution containing magnetic particles into an ultrasonic oscillator and oscillating for 5 minutes to achieve uniform dispersion of the magnetic particles. In this invention, the dispersion speed of the magnetic solution in the solution is accelerated by using an ultrasonic oscillator.

[0017] Preferably, in step 3, the filling length is 1 mm; the curing operation is: the hollow optical fiber filled with Fe3O4-elastomer mixed solution is placed in a drying oven for curing, the temperature is set to 100℃, and the curing time is set to 1 h.

[0018] Preferably, in step 4, the length of the second hollow fiber is L1 = 50 μm; the outer diameter of the first hollow fiber, the second hollow fiber, and the third hollow fiber is 125 μm and the inner diameter is 75 μm.

[0019] The technical effects achieved by this invention are as follows:

[0020] This invention uses magnetorheological elastomer as the diaphragm of an FP fiber optic pressure sensor. Compared with other types of FP fiber optic pressure sensors, the Young's modulus of the sensor diaphragm can be changed in real time and non-contactly by changing the external magnetic field, thereby adjusting the performance of the sensor and providing greater flexibility.

[0021] Simultaneously, by utilizing a fiber optic precision cutting platform, the reflective cavity length and magnetorheological elastomer diaphragm thickness of the FP fiber optic pressure sensor can be precisely controlled, enabling the sensor to achieve high sensitivity. By changing the external environmental magnetic field, the sensor's sensitivity and measurement range can be adjusted to match different pulsating pressure measurement environments.

[0022] This invention improves the applicability and sensing sensitivity of fiber optic gas pressure sensors, and fabricates high-performance fiber optic sensors based on magnetorheological elastomer diaphragm materials; it can be used in the field of fiber optic sensing. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the probe-type fiber optic gas pressure sensor structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the high-precision fiber optic cutting platform of the present invention.

[0025] The attached diagram lists the components represented by each number as follows:

[0026] 1. Single-mode optical fiber; 2. Optical fiber fusion splice; 3. Second hollow optical fiber; 4. Fe3O4-elastomer magnetorheological elastomer film; 5. First hollow optical fiber; 6. Optical fiber clamp; 7. Optical fiber cleaver; 8. Microscope; 9. Adjustable three-dimensional displacement stage; 10. Third hollow optical fiber. Detailed Implementation

[0027] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0028] Example 1:

[0029] like Figure 1 As shown, a method for fabricating a probe-type fiber optic gas pressure sensor includes the following steps:

[0030] Step 1: Mix dimethylsiloxane (PDMS) as the elastomer with its curing agent. The curing agent for dimethylsiloxane is either PDMS polydimethylsiloxane high-transparency curing agent or dibutyl phthalate. The mass ratio of dimethylsiloxane to its curing agent is 10:1. Stir with a glass rod until the two are evenly mixed. Place the mixture under vacuum for a certain period of time, specifically 10 minutes, to obtain a mixed solution of the elastomer and its curing agent.

[0031] Step 2: Add 20nm magnetic Fe3O4 particles to the mixed solution obtained in Step 1, and stir with a glass rod until the magnetic particles are dispersed in the mixed solution. The oscillation method is to place the solution containing the magnetic particles into an ultrasonic oscillator and oscillate for 5 minutes to complete the uniform dispersion of the magnetic particles. In this invention, the dispersion speed of the magnetic solution in the solution is accelerated by using an ultrasonic oscillator, and a Fe3O4-PDMS mixed solution with uniformly dispersed nanoparticles is obtained after oscillation.

[0032] Step 3: Fill the first hollow fiber 5 with the Fe3O4-PDMS mixed solution obtained in Step 2, with a filling length of 1 mm; and perform a curing operation; the curing operation is as follows: place the hollow fiber filled with Fe3O4-elastomer mixed solution in a drying oven for curing, set the temperature to 100℃, and set the curing time to 1 h; the Fe3O4-PDMS solution in the first hollow fiber 5 is cured to form Fe3O4-PDMS magnetorheological elastomer;

[0033] Step 4: Use a fiber optic fusion splicer to splice the second hollow fiber 3 with the single-mode fiber 1; simultaneously, fusion splice the first hollow fiber 5, which is internally filled with Fe3O4-PDMS magnetorheological elastomer obtained in Step 3, with the second hollow fiber 3; then place the spliced ​​fiber structure in... Figure 2 The fiber precision cutting platform shown has fiber optic clamps 6 fixing both ends of the fiber. The fusion point between the hollow fiber and the fiber filled with filling material is found by the microscope camera 8. Then, by adjusting the translation distance L2 = 5μm of the three-dimensional displacement stage 9, the excess part of the fiber filled with filling material is cut off by the fiber optic cutter 7. The length of the fiber filled with filling material is L2, which is used as the thickness of the Fe3O4-elastomer magnetorheological elastomer film 4. In this embodiment, the Fe3O4-elastomer magnetorheological elastomer film 4 is a Fe3O4-PDMS magnetorheological elastomer film. Finally, the first hollow fiber 5 structure is spliced ​​with a section of the third hollow fiber 10 to obtain this section of hollow fiber as the pressure-sensing hole structure of the probe-type fiber optic pressure sensor.

[0034] In step 4, the length of the second hollow fiber 3 is L1 = 50 μm; the outer diameter of the first hollow fiber 5, the second hollow fiber 3, and the third hollow fiber 10 is 125 μm and the inner diameter is 75 μm.

[0035] Example 2:

[0036] The difference between this embodiment and Embodiment 1 is that:

[0037] In step 1, the elastomer is rubber, and the curing agent for the rubber is a yellowing-resistant curing agent or di-o-tolueneguanidine. The mass ratio of rubber to its curing agent is 10:0.2-0.5.

[0038] It should be noted that, as Figure 1 As shown, a fiber fusion splice 2 is obtained by fusion splicing single-mode fiber 1 and second hollow fiber 3.

[0039] This invention uses magnetorheological elastomer as the diaphragm of an FP fiber optic pressure sensor. Compared with other types of FP fiber optic pressure sensors, the Young's modulus of the sensor diaphragm can be changed in real time and non-contactly by changing the external magnetic field, thereby adjusting the performance of the sensor and providing greater flexibility.

[0040] Simultaneously, by utilizing a fiber optic precision cutting platform, the reflective cavity length and magnetorheological elastomer diaphragm thickness of the FP fiber optic pressure sensor can be precisely controlled, resulting in high sensor sensitivity. By altering the external environmental magnetic field, the sensor's sensitivity and measurement range can be adjusted to match different pulsating pressure measurement environments.

[0041] This invention improves the applicability and sensing sensitivity of fiber optic gas pressure sensors, and fabricates high-performance fiber optic sensors based on magnetorheological elastomer diaphragm materials; it can be used in the field of fiber optic sensing.

[0042] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A method of making a probe-style optical fiber gas pressure sensor, the method comprising: The method comprises the following steps: ​ Step 1: mixing the elastomer with its curing agent, stirring until the two are uniformly mixed, and placing the mixture under vacuum for a certain period of time to obtain a mixed solution of the elastomer and its curing agent; Step 2: placing 20 nm magnetic Fe3O4 particles into the mixed solution obtained in Step 1 and stirring until the magnetic particles are dispersed in the mixed solution, and then oscillating to obtain a Fe3O4-elastomer mixed solution with uniformly dispersed nanoparticles; Step 3: filling the Fe3O4-elastomer mixed solution obtained in Step 2 into a first hollow core optical fiber (5) and performing a curing operation; the Fe3O4-elastomer solution in the first hollow core optical fiber (5) is cured to form a Fe3O4-elastomer magneto-rheological elastomer; Step 4: using a fiber fusion machine to splice a second hollow core optical fiber (3) with a single-mode optical fiber (1); at the same time, the first hollow core optical fiber (5) filled with the Fe3O4-elastomer magneto-rheological elastomer obtained in Step 3 is fused with the second hollow core optical fiber (3); then the spliced optical fiber structure is placed on an optical fiber precision cutting platform, the two ends of the optical fiber are fixed by optical fiber clamps (6), the fusion point between the hollow core optical fiber and the filling material optical fiber is found by a microscope camera (8), then the three-dimensional displacement table (9) is adjusted to translate a distance L2=5 μm, and the excess part of the filling material optical fiber is cut off by an optical fiber cutting knife (7), the length of the filling material optical fiber is L2, and serves as the thickness of the Fe3O4-elastomer magneto-rheological elastomer film (4); finally, the first hollow core optical fiber (5) structure is spliced with a third hollow core optical fiber (10) again, and the hollow core optical fiber obtained serves as a pressure sensing hole structure of a probe type optical fiber pressure sensor.

2. The method of claim 1, wherein the method further comprises: In Step 1, the elastomer uses dimethylsiloxane, the curing agent of dimethylsiloxane uses PDMS polydimethylsiloxane high-transparency curing agent or dibutyl phthalate; the mass ratio of dimethylsiloxane and its curing agent is 10:

1. ​ 3. The method of claim 1, wherein the method further comprises: In Step 1, the elastomer uses rubber, the curing agent of rubber uses yellow-resistant curing agent or di-o-tolyl guanidine, and the mass ratio of rubber and its curing agent is 10:0.2-0.

5. ​ 4. A method of manufacturing a probe-type optical fiber gas pressure sensor according to claim 3 or 2, characterized in that: In Step 1, the mixture of the elastomer and its curing agent is placed under vacuum for 10 min.

5. The method of claim 4, wherein the method further comprises: In Step 1 and Step 2, a glass rod is used to mix and stir the solution. ​ 6. The preparation method of the probe type optical fiber gas pressure sensor according to claim 5, wherein in Step 2, the oscillation mode is to place the solution mixed with the magnetic particles into an ultrasonic oscillation instrument and oscillate for 5 min to complete the uniform dispersion of the magnetic particles.

7. The method of claim 6, wherein the method further comprises: In Step 3, the filling length is 1 mm; the curing operation is to place the hollow core optical fiber filled with the Fe3O4-elastomer mixed solution into a drying oven for curing, the temperature is set to 100℃, and the curing time is set to 1 h. ​ 8. The method of claim 7, wherein the method further comprises: In Step 4, the length of the second hollow core optical fiber (3) is L1=50 μm; the outer diameter of the first hollow core optical fiber (5), the second hollow core optical fiber (3) and the third hollow core optical fiber (10) is 125 μm, and the inner diameter is 75 μm.

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