A method for manufacturing an in-fiber micro-flow sensing structure based on a pomelo type microstructure optical fiber integration

Abstract

This invention discloses a method for fabricating an in-fiber microfluidic sensing structure based on a grapefruit-shaped microstructured optical fiber, belonging to the field of optical fiber sensing technology. The sensing structure consists of a micro / nano fiber structure (1) obtained by tapering and cutting a single-mode fiber, a grapefruit-shaped microstructured optical fiber (2), and a micro / nano fiber structure (3). The single-mode fiber is tapered by arc discharge on an LDS2.5 fiber microfabrication platform. After tapering, it is cut at the middle of the tapered waist to obtain two micro / nano fiber structures. Finally, the two ends of the grapefruit-shaped microstructured optical fiber are fused to the micro / nano fiber structures. Liquid samples can flow into the grapefruit-shaped microstructured optical fiber through the air holes on the fused end face, thereby avoiding the use of complex femtosecond laser drilling methods to construct the inlet and outlet ports, significantly reducing the fabrication cost and difficulty of the in-fiber microfluidic sensing structure. At the same time, the unique geometric structure of the grapefruit-shaped microstructured optical fiber can not only transmit optical signals, but also provide a natural channel for loading microfluidic samples, further simplifying biochemical analysis operations and realizing a miniaturized optofluidic platform.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic sensing technology, specifically relating to a method for fabricating an in-fiber microcurrent sensing structure based on grapefruit-shaped microstructure fiber integration. Background Technology

[0002] Optofluidics, an emerging technology combining photonics and microfluidics, has become a powerful, intelligent, and versatile sensing platform in the field of biochemical sensing, holding significant research value and broad application potential in modern medicine, bioengineering, and many other fields. However, most traditional optofluidic sensing devices are constructed by integrating on-chip microchannel waveguides with additional fluid chambers and other off-chip optical components. Challenges remain in optimizing fabrication processes and reducing device size. Furthermore, low optical coupling efficiency between the chip and optical fiber, and limited contact area between the sample and the optical waveguide, severely restrict the further development of optofluidics.

[0003] Microfluidic technology based on microstructured optical fibers offers significant advantages such as low sample consumption, high sensitivity, compact structure, and ease of integration and operation. It enables the interaction of light and microfluidics within microchannels inside the optical fiber, addressing the issues of low optical coupling efficiency and low optical integration. However, for microfluidic devices fabricated from microstructured and ordinary optical fibers, drilling holes in the surface of the microstructured fiber using femtosecond laser technology is typically used to achieve the entry and exit of liquid samples. This process is not only costly and complex but also compromises the integrity and symmetry of the microstructured fiber. Therefore, it is necessary to develop a stable, easily integrated, and operable method for fabricating in-fiber microfluidic sensing structures based on microstructured optical fibers. Summary of the Invention

[0004] The purpose of this invention is to provide a method for fabricating an in-fiber microfluidic sensing structure based on a grapefruit-shaped microstructure fiber that is structurally stable, easy to integrate and operate. This method combines the advantages of microfluidic technology with the unique optical properties of grapefruit-shaped microstructure fibers, solving the problem that the construction of liquid inlet and outlet holes depends on femtosecond laser drilling, further simplifying biochemical analysis operations and realizing a miniaturized optofluidic platform.

[0005] To overcome the shortcomings of the prior art, this invention proposes a method for fabricating an in-fiber microcurrent sensing structure based on grapefruit-shaped microstructure fiber integration. The method for fabricating the in-fiber microcurrent sensing structure includes the following steps:

[0006] 1) Remove the coating layer from the middle of a single-mode fiber, wipe it clean with alcohol, and then perform arc discharge tapering on the LDS2.5 fiber micromachining platform. During the tapering process, the diameter of the single-mode fiber gradually decreases, and micro / nano fiber is obtained after tapering.

[0007] 2) The micro-nano fiber obtained after tapering in step 1) is precisely cut at the middle of its tapered waist using ultrasonic perturbation technology on the LDS2.5 fiber micromachining platform to obtain a micro-nano fiber structure with two flat end faces.

[0008] 3) Remove the coating from a section of grapefruit-shaped microstructure optical fiber, wipe it clean with alcohol, and then cut the two end faces flat with an optical fiber cleaver;

[0009] 4) The two micro / nano fiber structures from step 2) are respectively aligned and fused with the two ends of the grapefruit-shaped microstructure fiber from step 3) on a commercial fusion splicer.

[0010] Furthermore, the single-mode fiber has a cladding diameter of 125 μm and a core diameter of 8 μm; the grapefruit-shaped microstructure fiber has a cladding diameter of 130 μm, a core diameter of 7 μm, and a length of 3 cm.

[0011] Furthermore, the micro / nano fiber obtained after tapering consists of three parts: a tapered transition region, a tapered waist smooth region, and a tapered transition region. The diameter of the tapered region is 30 μm, the length of the smooth region is 600 μm, and the length of the transition region is 900 μm.

[0012] Furthermore, after fusing the two ends of the grapefruit-shaped microstructure fiber with the micro / nano fiber structure, liquid samples can flow into the grapefruit-shaped microstructure fiber through the air holes on the fusion end face.

[0013] The advantages and positive effects of this invention are:

[0014] This invention provides a method for fabricating fiber-in-fiber microfluidic sensing structures based on grapefruit-shaped microstructured optical fibers. This method is structurally stable, easy to integrate and operate, and enables the interaction between light and microfluidics within the optical fiber. The unique geometry of the grapefruit-shaped microstructured fiber not only transmits optical signals but also provides a natural channel for loading microfluidic samples, further simplifying biochemical analysis operations and realizing a miniaturized optofluidic platform. Furthermore, this invention significantly reduces the fabrication cost and difficulty of fiber-in-fiber microfluidic sensing structures, avoiding the use of complex femtosecond laser drilling methods to construct inlet and outlet ports. Because fiber optic optofluidics technology has advantages such as compact structure, resistance to electromagnetic interference, low sample consumption, high sensitivity, and real-time dynamic response, it is widely used in many fields. Therefore, the fiber-in-fiber microfluidic sensing structure fabrication method proposed in this invention has significant application value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating a method for fabricating an in-fiber microfluidic sensing structure based on grapefruit-shaped microstructure optical fiber integration, as provided by the present invention.

[0016] Figure 2 This is an end-face view of the grapefruit-shaped microstructure fiber optic microscope provided by the present invention.

[0017] Figure 3 This is an experimental schematic diagram of the fusion splice between the micro / nano fiber structure and the grapefruit-shaped microstructure fiber provided by the present invention.

[0018] Figure 4 The image shows the transmission spectrum response results of different liquid samples after the fiber-in-fiber microfluidic sensing structure designed in this invention is encapsulated.

[0019] In the figure: 1 is a micro-nano fiber structure, 2 is a grapefruit-shaped microstructure fiber, and 3 is a micro-nano fiber structure. Detailed Implementation

[0020] To make the technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] This example provides a method for fabricating an intrafiber microfluidic sensing structure based on a grapefruit-shaped microstructure fiber, which is structurally stable, easy to integrate and operate. The sensing structure consists of a micro / nano fiber structure (1) obtained by tapering and cutting a single-mode fiber, a grapefruit-shaped microstructure fiber (2), and a micro / nano fiber structure (3).

[0022] Combined with appendix Figure 1 A method for fabricating an in-fiber microcurrent sensing structure based on grapefruit-shaped microstructure optical fiber integration includes the following steps:

[0023] Step 1: Remove the coating layer from the middle of a single-mode fiber, wipe it clean with alcohol, and then perform arc discharge tapering on the LDS2.5 fiber micromachining platform. During the tapering process, the diameter of the single-mode fiber gradually decreases, and micro / nano fiber is obtained after tapering.

[0024] Step 2: The micro / nano fiber obtained after tapering is precisely cut at the middle of its tapered waist using ultrasonic perturbation technology on the LDS2.5 fiber micromachining platform to obtain a micro / nano fiber structure with two flat end faces.

[0025] Step 3: Remove the coating from a section of grapefruit-shaped microstructure optical fiber, wipe it clean with alcohol, and then cut the two end faces flat with an optical fiber cleaver.

[0026] Step 4: Perform core alignment and fusion splicing of the two micro / nano fiber structures from Step 2 with the two ends of the grapefruit-shaped microstructure fiber from Step 3 on a commercial fusion splicer.

[0027] Combined with appendix Figure 2 The grapefruit-shaped microstructure optical fiber has a cladding diameter of 130μm, a core diameter of 7μm, and a length of 3cm; the single-mode optical fiber has a cladding diameter of 125μm and a core diameter of 8μm.

[0028] Combined with appendix Figure 3The micro / nano fiber obtained after tapering consists of three parts: a tapered transition region, a tapered waist flattened region, and a tapered transition region. The diameter of the tapered region is 30 μm, the length of the flattened region is 600 μm, and the length of the transition region is 900 μm. The micro / nano fiber is cut at the middle of the tapered waist to obtain two micro / nano fiber structures. After the two ends of the grapefruit-shaped microstructure fiber are fused to the micro / nano fiber structure, the liquid sample can flow into the grapefruit-shaped microstructure fiber through the air hole gap on the fused end face, thus avoiding the use of complex femtosecond laser drilling methods to construct the liquid inlet and outlet ports.

[0029] Combined with appendix Figure 4 The microcurrent sensing structure based on a grapefruit-shaped microstructure fiber integrated using the above method was encapsulated and experimentally tested. Incident light from the supercontinuum spectrum was transmitted to the sensor via a single-mode fiber, and the transmission spectrum was analyzed using a spectrometer. Liquid sample solutions with RI ranges of 1.3338, 1.3348, and 1.3369 were introduced into the sensing structure. Figure 4 The figure shows the transmission spectral response of the optical fluidic sensor based on a grapefruit-shaped microstructured fiber when different liquid samples are introduced. As can be seen from the figure, the transmission spectrum of the sensor shifts towards longer wavelengths as the refractive index of the liquid within the grapefruit-shaped microstructured fiber increases from 1.3338 to 1.3369. The calculated RI sensitivity of the optical fluidic sensor based on the grapefruit-shaped microstructured fiber is approximately 4463.7 nm / RIU.

[0030] In summary, this invention provides a method for fabricating an in-fiber microfluidic sensing structure based on a grapefruit-shaped microstructure fiber integration that is structurally stable, easy to integrate and operate. This method significantly reduces the fabrication cost and difficulty of the in-fiber microfluidic sensing structure, avoids the use of complex femtosecond laser drilling methods to construct inlet and outlet ports, further simplifies biochemical analysis operations, and realizes a miniaturized optofluidic platform. It has broad application prospects in the field of biochemical sensing.

Claims

1. A method for fabricating an in-fiber microfluidic sensing structure based on a pomelos-type microstructure optical fiber integration, belonging to the technical field of optical fiber sensing, characterized in that, This method only requires the formation of two weld points. The specific steps are as follows: (1) Remove the coating layer in the middle of a single-mode fiber, wipe it clean with alcohol, and then perform arc discharge tapering on the LDS2.5 fiber micromachining platform. During the tapering process, the diameter of the single-mode fiber gradually decreases, and a micro / nano fiber is obtained after tapering. The micro / nano fiber includes three parts: a tapered transition region, a tapered waist smooth region, and a tapered transition region. The diameter of the tapered region is 30 μm, the length of the smooth region is 600 μm, and the length of the transition region is 900 μm. (2) The micro-nano fiber obtained after tapering in step (1) is precisely cut at the middle of its tapered waist using ultrasonic perturbation technology on the LDS2.5 fiber micromachining platform to obtain a micro-nano fiber structure with two flat end faces. This process does not involve a fusion splicing step. (3) Remove the coating layer from a section of grapefruit-shaped microstructure optical fiber, wipe it clean with alcohol, and then cut the two end faces flat with an optical fiber cleaver. (4) The two micro-nano fiber structures in step (2) are respectively aligned and fused with the two ends of the grapefruit-shaped microstructure fiber in step (3) on a commercial fusion splicer to form only two fusion points, and finally the micro-flow sensing structure inside the fiber is obtained.

2. The method according to claim 1, wherein, After the grapefruit-shaped microstructure fiber is fused to the micro-nano fiber structure at both ends, liquid samples can flow into the grapefruit-shaped microstructure fiber through the air holes on the fused end face without the need for additional drilling.

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