Method for manufacturing parallel MZI (Mach Zehnder Interferometer) intrafiber microflow sensor based on vernier effect
By introducing the parallel MZI optical path difference of cursor effect in the in-fiber microfluidic sensor, the problem of limited sensitivity of the in-fiber microfluidic sensor is solved, and high-precision detection of changes in the characteristics of microfluidic fluids is achieved, especially suitable for biomedical and environmental monitoring. field.
Patent Information
- Application Number
- CN202411233870.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-04
- Publication Date
- 2024-12-31
AI Technical Summary
The sensitivity and detection limit of the microfluidic sensor in the fiber are easily limited by the refractive index and optical waveguide mode of the optical fiber material, making it difficult to effectively detect tiny changes in fluid characteristics.
The microfluidic sensor production method in the parallel MZI fiber based on the cursor effect is adopted. By designing the path difference between the parallel sensor MZI and the reference MZI optical path, the phase difference caused by the change in the refractive index of the fluid is amplified and the sensitivity of the sensor is improved. Specific steps include multi-mode fiber grinding and polishing, ultrasonic cutting, dual-hole microstructure fiber fusion and single-mode fiber alignment and welding to form a liquid inlet and outlet port to ensure that the end surface of the fiber is flat and the air hole channel is independent.
It significantly improves the detection limit and sensitivity of the sensor, and is especially suitable for biomedical testing and environmental monitoring, and can clearly detect small concentration changes and weak environmental disturbances, providing higher detection accuracy.
Smart Images
Figure CN119224932A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on a vernier effect. Background Art
[0002] Intrafiber microfluidic sensors combine the advantages of microfluidics and fiber optic sensing technologies to achieve efficient coupling between fluid samples and optical waveguides. They have high integration, low loss, and strong anti-interference capabilities, and therefore show great application potential in the fields of biosensing, chemical analysis, and environmental monitoring. Intrafiber microfluidic sensors interact with the flowing sample medium through light waves in the optical fiber, and can detect the refractive index, chemical composition, or temperature changes of the medium in real time, providing a highly integrated and miniaturized detection solution. However, intrafiber microfluidic sensors still face several technical challenges and limitations in practical applications. For example, the sensitivity and detection limit of intrafiber microfluidic sensors are easily limited by the refractive index of the optical fiber material and the optical waveguide mode.
[0003] The vernier effect sensitization scheme is considered to be a powerful tool to improve the sensitivity of fiber optic sensors. The vernier effect uses the tiny path difference between the two optical paths to amplify tiny phase changes through the slight movement of the interference fringes. This effect is similar to the reading principle in a vernier caliper. In the optical interference process, a tiny auxiliary phase difference can be introduced to make tiny changes that are originally difficult to detect more obvious. Therefore, the introduction of the vernier effect in the parallel MZI intrafiber microfluidic sensor can effectively improve the sensitivity of the sensor.
[0004] Therefore, it is necessary to develop a method for fabricating a parallel MZI intrafiber microfluidic sensor based on the vernier effect. Summary of the invention
[0005] The purpose of the present invention is to overcome the shortcomings of the background technology and creatively propose a method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on the vernier effect, comprising the following steps:
[0006] 1) Strip off the coating of the middle section of about 3 cm of the multimode optical fiber, wipe it clean with alcohol, and then place it on a high-precision optical fiber grinder for grinding and polishing;
[0007] 2) The ground and polished multimode optical fiber is placed on the LDS 2.5 optical fiber micromachining platform, and the ground and polished areas at both ends are accurately cut using ultrasonic assisted cutting technology to ensure that the end faces are cut smoothly and the length of the ground and polished areas at both ends is controlled within 30 μm. After cutting, two multimode optical fiber units are obtained, namely, multimode optical fiber unit 1 (2) and multimode optical fiber unit 2 (6);
[0008] 3) Take a section of double-hole microstructured optical fiber (4), remove the coating layer about 2 cm from both ends, and cut the end surface flat with an optical fiber cutter;
[0009] 4) Aligning and fusing the multimode optical fiber unit 1 (2) and the multimode optical fiber unit 2 (6) cut in step 2) with the two ends of the dual-hole microstructure optical fiber (4) respectively, and fusing them on an optical fiber fusion splicer in an arc discharge manner, to obtain a sensing structure of a ground and polished multimode optical fiber unit 1-dual-hole microstructure optical fiber-ground and polished multimode optical fiber unit 2, and constructing a liquid inlet (3) and a liquid outlet (5);
[0010] 5) The two ends of the sensing structure of the ground and polished multimode optical fiber unit-dual-hole microstructure optical fiber-ground and polished multimode optical fiber unit obtained by the process in step 4) are aligned and fused with the input single-mode optical fiber (1) and the output single-mode optical fiber (7) respectively on an optical fiber fusion splicer in an automatic fusion splicing manner.
[0011] In the above-mentioned method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on the vernier effect, the input and output single-mode optical fiber cladding diameter is 125 μm, and the core diameter is 9 μm; the multi-mode optical fiber cladding diameter is 125 μm, and the core diameter is 62.5 μm; the double-hole microstructure optical fiber cladding diameter is 125 μm, and the core diameter is 6 μm.
[0012] In the above-mentioned method for manufacturing a parallel MZI intrafiber microfluidic sensor based on the vernier effect, the grinding and polishing process of the multimode optical fiber in step 1 needs to be carried out in a clean room or a clean workbench to avoid dust and pollutants affecting the optical fiber end face, and the grinding and polishing time is set to 60s.
[0013] In the above-mentioned method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on the vernier effect, in step 2, the ground and polished multimode optical fiber is cut to obtain two multimode optical fiber units, and the cut end faces thereof are characterized by being D-shaped.
[0014] In the above-mentioned method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on the vernier effect, when the double-hole microstructure optical fiber is fused with the multimode optical fiber unit in step 4, the double-hole microstructure optical fiber needs to be away from the discharge electrode to avoid air hole collapse during discharge. The discharge current is set to 37 mA and the number of discharges is 15 times.
[0015] In the above-mentioned method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on the vernier effect, after the dual-hole microstructure optical fiber and the multimode optical fiber unit are fused in step 4, the two air hole channels of the dual-hole microstructure optical fiber are independent of each other, the lower air hole is a closed air hole channel, and only the upper air hole channel is left to communicate with the external environment, and the two ends serve as the inlet and outlet of the microfluid.
[0016] The advantages and positive effects of the present invention are:
[0017] In the parallel MZI intrafiber microfluidic sensor, the path difference between the parallel sensing MZI and reference MZI optical paths is designed to produce a vernier effect, thereby amplifying the phase difference caused by the change in the refractive index of the fluid. This allows even tiny changes in fluid properties to be clearly detected, greatly improving the sensitivity of the sensor.
[0018] Compared with the traditional intra-fiber microfluidic sensor, the parallel MZI intra-fiber microfluidic sensor based on the vernier effect proposed in this invention has significantly improved detection limit and sensitivity, especially when detecting small concentration changes or weak environmental disturbances, showing higher detection accuracy. This sensitivity advantage makes it particularly suitable for the fields of biomedical detection, chemical analysis and environmental monitoring that require high precision, and provides a more powerful tool for the detection and analysis of fluid media at the microscale. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0020] Figure 1 A schematic diagram of the structure of a parallel MZI intra-fiber microfluidic sensor based on the vernier effect provided by the present invention.
[0021] Figure 2 This is a schematic diagram of the end face structure after the dual-hole microstructure optical fiber and the multimode optical fiber unit are fused together provided by the present invention.
[0022] Figure 3 The present invention provides a production flow chart of a parallel MZI intra-fiber microfluidic sensor based on the vernier effect.
[0023] In the figure: 1 is the input single-mode optical fiber, 2 is the multi-mode optical fiber unit 1, 3 is the liquid inlet, 4 is the double-hole microstructure optical fiber, 5 is the liquid outlet, 6 is the multi-mode optical fiber unit 2, and 7 is the output single-mode optical fiber. DETAILED DESCRIPTION
[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.
[0025] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0026] Throughout the description and claims of this specification, the words "comprise" and "include" and their variations mean "including but not limited to", and they are not intended to (and do not) exclude other ingredients, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context requires otherwise. In particular, where the indefinite article is used, the specification should be understood to contemplate the plural as well as the singular, unless the context requires otherwise.
[0027] First embodiment
[0028] Working principle of the present invention:
[0029] The incident light enters from the input single-mode optical fiber and is transmitted to the first section of the multimode optical fiber unit after grinding and polishing. The multimode optical fiber unit 1 is equivalent to a beam coupler, which guides the light to the air and the silica and closed air hole parts of the double-hole microstructure optical fiber. The light transmitted in the circulating air holes and the closed air holes of the double-hole microstructure optical fiber interferes with the light propagating along the fiber core respectively. Since the circulating air hole channel allows different microfluids to flow through, the interference may change. It is a sensing MZI, and the one below is a reference MZI, thus forming two parallel MZIs.
[0030] After grinding and polishing, a part of the multimode fiber is removed, and after LDS 2.5 cutting, the sensing interferometer and the reference interferometer have a micron-level length difference. The free spectral range (FSR) of the two interferometers is close but not equal, so the vernier effect can be obtained, amplifying the phase difference caused by the change in the refractive index of the fluid, thereby achieving the effect of improving sensitivity. The multimode fiber unit 2 recouples the light beam for interference transmission to the output single-mode fiber.
[0031] The interference spectra of the sensing interferometer and the reference interferometer are:
[0032]
[0033]
[0034] Combined with Figure 1 , 2 3. A method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on a vernier effect, comprising the following steps:
[0035] S1. Strip off the coating of about 3cm in the middle of the multimode optical fiber, wipe it clean with alcohol, and then place it on a high-precision optical fiber grinder for grinding and polishing.
[0036] Specifically, the grinding and polishing process of the multimode optical fiber needs to be carried out in a clean room or a clean workbench to prevent dust and pollutants from affecting the optical fiber end face, and the grinding and polishing time is set to 60s.
[0037] S2. The ground and polished multimode optical fiber is placed on the LDS 2.5 optical fiber micromachining platform. The ground and polished areas at both ends are precisely cut using ultrasonic assisted cutting technology to ensure that the end faces are cut smoothly. The length of the ground and polished areas at both ends is controlled within 30 μm. After cutting, two multimode optical fiber units are obtained, multimode optical fiber unit one (2) and multimode optical fiber unit two (6).
[0038] Specifically, the end faces of the two multimode optical fiber units obtained after cutting are characterized by being D-shaped.
[0039] S3, take a section of double-hole microstructure optical fiber (4), strip off the coating layer at about 2 cm at both ends, and cut the end face flat with a fiber cleaver, align and fuse the multimode optical fiber unit 1 (2) and multimode optical fiber unit 2 (6) cut in S2 with the two ends of the double-hole microstructure optical fiber (4), respectively, and perform the fusion on an optical fiber fusion splicer in an arc discharge manner, and obtain a sensing structure of polished multimode optical fiber unit 1-dual-hole microstructure optical fiber-polished multimode optical fiber unit 2 after fusion, and construct a liquid inlet (3) and a liquid outlet (5). The two ends are then aligned and fused with the input single-mode optical fiber (1) and the output single-mode optical fiber (7) in an automatic fusion splicing manner on an optical fiber fusion splicer.
[0040] Specifically, when the dual-hole microstructure fiber is fused with the multimode fiber unit, the dual-hole microstructure fiber needs to be away from the discharge electrode to avoid air hole collapse during discharge. The discharge current is set to 37mA and the number of discharges is 15. The end face structure after fusion is shown in the figure below: Figure 2 As shown, the two air hole channels of the double-hole microstructure optical fiber are independent of each other. The lower air hole is a closed air hole channel, leaving only the upper air hole channel to communicate with the external environment. The two ends serve as the inlet and outlet of the microfluidic, which can be encapsulated with a three-way pipe and connected to a microfluidic pump. Different microfluids will have different interference when flowing through the upper air hole. The fluid sample is efficiently coupled with the optical waveguide to realize microflow sensing in the fiber.
[0041] Among them, the input and output single-mode optical fiber cladding diameter is 125μm, and the core diameter is 9μm; the multimode optical fiber cladding diameter is 125μm, and the core diameter is 62.5μm; the double-hole microstructure optical fiber cladding diameter is 125μm, and the core diameter is 6μm.
[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on the vernier effect, belonging to the field of optical fiber sensing technology, characterized in that: The method is divided into the following steps: 1) Strip off the coating of the middle section of about 3 cm of the multimode optical fiber, wipe it clean with alcohol, and then place it on a high-precision optical fiber grinder for grinding and polishing; 2) The ground and polished multimode optical fiber is placed on the LDS 2.5 optical fiber micromachining platform, and the ground and polished areas at both ends are accurately cut using ultrasonic assisted cutting technology to ensure that the end faces are cut smoothly and the length of the ground and polished areas at both ends is controlled within 30 μm. After cutting, two multimode optical fiber units are obtained, namely, multimode optical fiber unit 1 (2) and multimode optical fiber unit 2 (6); 3) Take a section of double-hole microstructured optical fiber (4), remove the coating layer about 2 cm from both ends, and cut the end surface flat with an optical fiber cutter; 4) Aligning and fusing the multimode optical fiber unit 1 (2) and the multimode optical fiber unit 2 (6) cut in step 2) with the two ends of the dual-hole microstructure optical fiber (4) respectively, and fusing them on an optical fiber fusion splicer in an arc discharge manner, to obtain a sensing structure of a ground and polished multimode optical fiber unit 1-dual-hole microstructure optical fiber-ground and polished multimode optical fiber unit 2, and constructing a liquid inlet (3) and a liquid outlet (5); 5) The two ends of the sensing structure of the ground and polished multimode optical fiber unit-dual-hole microstructure optical fiber-ground and polished multimode optical fiber unit obtained by the process in step 4) are aligned and fused with the input single-mode optical fiber (1) and the output single-mode optical fiber (7) respectively on an optical fiber fusion splicer in an automatic fusion splicing manner.
2. The method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on the vernier effect according to claim 1, characterized in that: The input and output single-mode optical fiber has a cladding diameter of 125 μm and a core diameter of 9 μm; the multimode optical fiber has a cladding diameter of 125 μm and a core diameter of 62.5 μm; the double-hole microstructure optical fiber has a cladding diameter of 125 μm and a core diameter of 6 μm.
3. The method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on vernier effect according to claim 1, characterized in that: The grinding and polishing process of the multimode optical fiber in step 1 needs to be carried out in a clean room or a clean workbench to prevent dust and pollutants from affecting the optical fiber end face, and the grinding and polishing time is set to 60s.
4. The method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on vernier effect according to claim 1, characterized in that: In the step 2, the ground and polished multimode optical fiber is cut to obtain two multimode optical fiber units, and the cut end faces thereof are characterized by being D-shaped.
5. The method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on vernier effect according to claim 1, characterized in that: When the dual-hole microstructure fiber is fused with the multimode fiber unit in step 4, the dual-hole microstructure fiber needs to be away from the discharge electrode to avoid air hole collapse during discharge. The discharge current is set to 37 mA and the number of discharges is 15 times.
6. The method for manufacturing a parallel MZI intra-fiber microfluidic sensor based on vernier effect according to claim 1, characterized in that: After the dual-hole microstructure optical fiber is fused with the multimode optical fiber unit in step 4, the two air hole channels of the dual-hole microstructure optical fiber are independent of each other, the lower air hole is a closed air hole channel, and only the upper air hole channel is left to communicate with the external environment, and the two ends serve as the inlet and outlet of the microfluid.