Optical fiber bionic cilium flow velocity sensor and preparation method thereof

Abstract

The invention belongs to the technical field of optical sensing, and particularly relates to an optical fiber bionic cilium flow velocity sensor and a preparation method thereof, and the method comprises the following steps: 1, continuously splicing a fixed-length single-mode optical fiber and a special optical fiber through a high-precision optical fiber cutting platform, and preparing a combined LPFG; 2, modulating the combined LPFG obtained in the step 1 by using a laser until a groove-shaped structure is formed on the side surface of the combined LPFG; and 3, printing a periodic bionic cilia structure, namely the polymer cilia, in the groove of the combined LPFG obtained in the step 2 by utilizing 3D printing equipment. The periodic waveguide is established on the optical fiber by using a special optical fiber combination method, and the periodic cilia structure is attached to the periodic waveguide by using a two-photon polymerization technology, so that the applicability of the optical fiber type flow velocity sensor is improved, the sensing sensitivity is improved, and the novel high-sensitivity flow velocity sensor is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of optical sensing, and in particular relates to an optical fiber bionic ciliary flow velocity sensor and a preparation method thereof. Background Art

[0002] With the rapid development of underwater unmanned submersible technology, the demand for high-precision flow sensors is also increasing. The accurate measurement of underwater flow velocity is of great significance for the navigation, attitude control and environmental monitoring of submersibles. The change of flow velocity not only affects the stability and navigation efficiency of submersibles, but also may provide key information about the underwater environment, such as the characteristics of ocean currents and eddies. In addition, flow velocity data is also of great reference value for underwater resource exploration, ecological environmental protection, and underwater communications.

[0003] Traditional mechanical and electromagnetic sensors face many challenges in complex underwater environments. Mechanical sensors are easily affected by tiny particles and biological attachment in seawater, which leads to decreased sensor sensitivity and increased measurement errors. Electromagnetic sensors perform poorly in strong electromagnetic interference environments, and their measurement accuracy and stability are difficult to guarantee. In addition, these traditional sensors are usually large in size and have high power consumption, which is not conducive to miniaturization and integration application requirements. Fiber optic sensors have the advantages of small size, light weight, resistance to electromagnetic interference and corrosion resistance, and have gradually become a research hotspot in the field of flow velocity measurement.

[0004] Traditional fiber optic flow sensors usually use single-mode optical fiber, but their application in complex underwater environments is limited and they have the problem of low sensitivity. Summary of the invention

[0005] The purpose of the present invention is to provide a fiber optic bionic ciliary flow velocity sensor and a preparation method thereof, which can improve the applicability of the fiber optic flow velocity sensor and improve the sensing sensitivity, thereby realizing a high-sensitivity new flow velocity sensor.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for preparing an optical fiber bionic ciliary flow velocity sensor comprises the following steps:

[0008] Step 1: Continuously splice fixed-length single-mode optical fiber and special optical fiber to prepare a combined LPFG;

[0009] Step 2: Modulating the combined LPFG until a groove-shaped structure is formed on the side of the combined LPFG;

[0010] Step 3: Use 3D printing equipment to print a periodic bionic ciliary structure in the groove of the combined LPFG.

[0011] Furthermore, the step 1 comprises the following steps:

[0012] Step 101: cutting a section of single-mode optical fiber;

[0013] Step 102: Then splice the single-mode optical fiber and the coreless optical fiber;

[0014] Step 103: Find the fusion point between the single-mode optical fiber and the coreless optical fiber;

[0015] Step 104: using a high-precision translation stage to translate a cutting knife to cut the coreless optical fiber fused with the single-mode optical fiber to obtain a 500-micron coreless optical fiber;

[0016] Step 105: Repeat steps 101-104 until a combined LPFG is obtained.

[0017] Furthermore, the single-mode optical fiber in step 101 is cut using an optical fiber cutter of a high-precision optical fiber cutting platform.

[0018] Furthermore, in step 103, the fusion point between the single-mode optical fiber and the coreless optical fiber is found using a CCD camera.

[0019] Furthermore, in step 2, the combined LPFG is modulated by etching the side surface of the combined LPFG using a high-frequency carbon dioxide laser until a fiber groove is prepared on the coreless optical fiber.

[0020] Furthermore, the shape of the optical fiber groove is a D-shaped groove.

[0021] Furthermore, the step 3 comprises the following steps:

[0022] Using two-photon polymerization technology, by controlling the focusing position and scanning path of the laser, a periodic bionic ciliary structure is printed layer by layer in the groove of the processed combined LPFG according to the preset shape using a 3D printing device.

[0023] A fiber optic bionic cilia flow velocity sensor comprises a single-mode optical fiber, a plurality of coreless optical fibers are fused inside the single-mode optical fiber, optical fiber grooves are etched on the sides of the coreless optical fiber, and polymer cilia are arranged inside the optical fiber grooves.

[0024] The technical effects achieved by the present invention are:

[0025] The preparation method of the optical fiber bionic cilia flow velocity sensor of the present invention utilizes a special optical fiber combination method to establish a periodic waveguide on the optical fiber, and utilizes two-photon polymerization technology to attach a periodic cilia structure thereon. The structure is flexible, and the bionic cilia bend under the impact of water flow, and under the action of the elasto-photoelectric effect, its refractive index changes, and the transmission spectrum changes accordingly, thereby improving the applicability of the optical fiber flow velocity sensor and the sensing sensitivity, thereby realizing a high-sensitivity new flow velocity sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the combined LPFG of the present invention;

[0027] Figure 2 It is a schematic diagram of the cutaway structure of the combined LPFG of the present invention;

[0028] Figure 3 It is a schematic diagram of the combined LPFG structure with side-etched D-shaped grooves of the present invention;

[0029] Figure 4 It is a schematic diagram of the cross-sectional structure of the combined LPFG with surface-etched D-shaped grooves of the present invention;

[0030] Figure 5 Schematic diagram of the structure of the combined LPFG implanted with cilia of the present invention;

[0031] Figure 6 It is a schematic diagram of the cross-sectional structure of the combined LPFG implanted with cilia of the present invention.

[0032] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0033] 1. Single-mode optical fiber; 2. Coreless optical fiber; 3. Optical fiber groove; 4. Polymer cilia. DETAILED DESCRIPTION

[0034] 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.

[0035] Embodiment 1:

[0036] like Figure 1-6 As shown, a method for preparing an optical fiber bionic ciliary flow velocity sensor, the specific preparation method is to use a special optical fiber combination method to establish a periodic waveguide on the optical fiber, and use two-photon polymerization technology to attach a periodic ciliary structure on the optical fiber;

[0037] Specifically, a method for preparing an optical fiber bionic ciliary flow velocity sensor comprises the following steps:

[0038] Step 1: Use a high-precision fiber cutting platform to continuously splice a fixed-length single-mode fiber 1 and a special fiber to prepare a combined LPFG;

[0039] The special optical fiber is coreless optical fiber2.

[0040] Specifically, step 1 includes the following steps:

[0041] Step 101: using a high-precision optical fiber cutting platform optical fiber cutting knife to cut off a section of single-mode optical fiber 1;

[0042] Step 102: then splicing the single-mode optical fiber 1 and the coreless optical fiber 2;

[0043] Step 103: using a CCD camera to find the fusion point between the single-mode optical fiber 1 and the coreless optical fiber 2;

[0044] Step 104: using a high-precision translation stage to translate the cutting knife by 500 microns, cutting the coreless optical fiber 2 fused with the single-mode optical fiber 1, to obtain a coreless optical fiber 2 of 500 microns;

[0045] Step 105: Repeat steps 101-104 until the following is obtained: Figure 1-2 The periodic optical fiber structure shown is a combined LPFG.

[0046] Step 2: Use a laser to modulate the combined LPFG obtained in step 1 until a groove-shaped structure is formed on the side of the combined LPFG;

[0047] Here, the combined LPFG obtained in step 1 is modulated by laser, and the side of the combined LPFG is etched by high-frequency carbon dioxide laser until a fiber groove 3 is prepared on the coreless optical fiber 2. The structure after modulation is as follows: Figure 3-4 shown.

[0048] High-frequency carbon dioxide lasers can emit laser beams of specific frequency and energy. By modulating the combined LPFG structure with the laser, the optical properties of the combined LPFG can be changed, thereby establishing a periodic waveguide on the optical fiber.

[0049] Furthermore, the shape of the optical fiber groove 3 is preferably a D-shaped groove.

[0050] Introducing multimode optical fiber into long-period fiber grating (LPFG) sensors can significantly improve the sensitivity and measurement accuracy of the sensors. By polishing the sides of the combined LPFG, a strong evanescent field effect can be stimulated in the optical fiber, allowing the structure to achieve higher sensing performance. The evanescent field effect can enhance the sensitivity of the optical fiber to changes in the external environment, allowing the sensor to perform accurate measurements under a wider range of conditions.

[0051] Step 3: Use a 3D printing device to print out a periodic bionic ciliary structure, namely, polymer ciliary 4, in the groove of the combined LPFG obtained in step 2.

[0052] Specifically, step 3 includes the following steps:

[0053] Using two-photon polymerization technology, by controlling the focus position and scanning path of the laser, a periodic bionic cilia structure is printed layer by layer in the groove of the processed combined LPFG using a 3D printing device according to the preset shape. The schematic diagram of the structure is shown in the figure. Figure 5-6 shown.

[0054] The connection between bionic cilia and optical fiber is an important channel for sensing external water flow disturbance information. The rough micro-machined surface can provide more contact area and stronger friction, thereby increasing the adhesion between the bionic cilia structure and the optical fiber.

[0055] As an advanced micro-nano processing technology, two-photon polymerization technology has been widely used in the preparation of fiber optic sensors. This technology uses two beams of photons to initiate polymerization reactions in polymer materials, which can achieve high-precision processing of three-dimensional structures. Compared with traditional micro-processing technologies, two-photon polymerization technology has many unique advantages. First, it can accurately manufacture complex three-dimensional structures at the micro-nano scale to meet the design requirements of high precision and high complexity. Secondly, two-photon polymerization technology has the characteristics of non-contact processing, which can realize the manufacture of fine structures without damaging the substrate. Finally, this technology can directly build structures in three-dimensional space without the need to use traditional photolithography and etching processes, greatly expanding the possibilities of materials and designs, and making it show great application potential in fields such as precision optics, biomedicine and microfluidics.

[0056] When making bionic cilia structures on optical fibers, two-photon polymerization technology can accurately construct bionic cilia according to preset shapes, giving them excellent mechanical flexibility and response characteristics. This bionic cilia structure can be combined with a structure-modulated LPFG optical fiber sensor to simulate cilia in nature, and reflect the flow rate through the degree of bending and deformation of the bionic cilia.

[0057] Embodiment 2:

[0058] A fiber optic bionic cilia flow velocity sensor comprises a single-mode optical fiber 1, a plurality of coreless optical fibers 2 are fused inside the single-mode optical fiber 1, optical fiber grooves 3 are etched on the sides of the coreless optical fibers 2, and polymer cilia 4 are arranged inside the optical fiber grooves 3.

[0059] The present invention improves the applicability of the optical fiber flow velocity sensor and improves the sensing sensitivity. A periodic waveguide is established on the optical fiber by a special optical fiber combination method, and a periodic ciliary structure is attached thereon by two-photon polymerization technology. The structure is flexible, and the bionic cilia bend under the impact of water flow. Under the action of the elastic-photoelectric effect, the refractive index changes, and the transmission spectrum changes accordingly, thereby realizing a high-sensitivity new flow velocity sensor. The sensor can be used in the field of optical fiber sensing.

[0060] 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

1. A method for preparing an optical fiber bionic ciliary flow velocity sensor, characterized in that: The following steps are involved: Step 1: Continuously splice fixed-length single-mode optical fiber and special optical fiber to prepare a combined LPFG; Step 2: Modulating the combined LPFG until a groove-shaped structure is formed on the side of the combined LPFG; Step 3: Use 3D printing equipment to print a periodic bionic ciliary structure in the groove of the combined LPFG.

2. The method for preparing a fiber optic bionic ciliary flow velocity sensor according to claim 1, characterized in that: The step 1 comprises the following steps: Step 101: cutting off a section of single-mode optical fiber (1); Step 102: Then splice the single-mode optical fiber (1) and the coreless optical fiber (2); Step 103: Find the fusion point between the single-mode optical fiber (1) and the coreless optical fiber (2); Step 104: using a high-precision translation stage to translate a cutting knife to cut the coreless optical fiber (2) fused with the single-mode optical fiber (1) to obtain a coreless optical fiber (2) of 500 microns; Step 105: Repeat steps 101-104 until a combined LPFG is obtained.

3. The method for preparing a fiber optic bionic ciliary flow velocity sensor according to claim 2, characterized in that: The single-mode optical fiber (1) in step 101 is cut using a fiber cleaver on a high-precision fiber cleaving platform.

4. The method for preparing a fiber optic bionic ciliary flow velocity sensor according to claim 2, characterized in that: In step 103, the fusion point between the single-mode optical fiber (1) and the coreless optical fiber (2) is found using a CCD camera.

5. The method for preparing a fiber optic bionic ciliary flow velocity sensor according to claim 1, characterized in that: In the step 2, the combined LPFG is modulated by etching the side surface of the combined LPFG using a high-frequency carbon dioxide laser until a fiber groove (3) is prepared on the coreless optical fiber (2).

6. The method for preparing a fiber optic bionic ciliary flow velocity sensor according to claim 5, characterized in that: The shape of the optical fiber groove (3) is a D-shaped groove.

7. The method for preparing a fiber optic bionic ciliary flow velocity sensor according to claim 1, characterized in that: The step 3 comprises the following steps: Using two-photon polymerization technology, by controlling the focusing position and scanning path of the laser, a periodic bionic ciliary structure is printed layer by layer in the groove of the processed combined LPFG according to the preset shape using a 3D printing device.

8. An optical fiber bionic ciliary flow velocity sensor, prepared by the method for preparing an optical fiber bionic ciliary flow velocity sensor according to any one of claims 1 to 7, characterized in that: The optical fiber bionic cilia flow velocity sensor comprises a single-mode optical fiber (1), a plurality of coreless optical fibers (2) are fused inside the single-mode optical fiber (1), optical fiber grooves (3) are etched on the sides of the coreless optical fibers (2), and polymer cilia (4) are arranged inside the optical fiber grooves (3).

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