Metal coating optical fiber and preparation method thereof

Abstract

The invention provides a metal coating optical fiber and a preparation method, and relates to the field of optical fiber coatings, and the preparation method comprises the following steps: step 1, drawing a bare optical fiber with a target size from an optical fiber preform through an optical fiber drawing tower, and step 2, preparing metal slurry; 3, coating the metal slurry on the surface of the optical fiber; step 4, drying the metal slurry, namely enabling the optical fiber to which the metal slurry is attached to pass through a high-temperature drying furnace to dry the organic solvent and the auxiliary agent; and step 5, laser sintering: sintering the dried metal film layer into a metal layer through laser. By the adoption of the metal coating optical fiber and the preparation method, stable combination of the metal coating and the optical fiber can be achieved.

Description

Technical Field

[0001] This invention relates to the field of optical fiber coating, and in particular to a metal-coated optical fiber and its preparation method. Background Technology

[0002] Metal-coated optical fibers, possessing both the signal transmission characteristics of optical fibers and the physical properties of metals (such as conductivity and abrasion resistance), are widely used in industrial sensing, submarine communication, and other fields. Existing metal coating preparation technologies mainly fall into three categories: Patent CN102385621A discloses an electroplating method that deposits a metal layer on the surface of an optical fiber through electrolysis. This method requires the use of an electrolyte containing metal ions, leading to waste liquid pollution and poor coating thickness uniformity (often exceeding 10%), making it difficult to adapt to thin-diameter optical fibers (diameter <125μm); Patent US9874321B2 discloses a physical vapor deposition method (PVD, such as sputtering or evaporation), which requires operation in a high-vacuum environment, resulting in high equipment costs (over 5 million RMB per unit) and slow deposition rates (<0.5μm / min), leading to low production efficiency; Chemical vapor deposition (CVD) relies on organometallic precursors, requiring harsh reaction conditions (300-500℃), which can easily cause changes in the refractive index of the fiber core, affecting signal transmission performance.

[0003] The above-mentioned technologies all have drawbacks such as complex processes, high costs, weak coating adhesion, and poor environmental performance. Therefore, there is an urgent need for a metal coating preparation method that simplifies the process, reduces costs, and improves coating quality. Summary of the Invention

[0004] The purpose of this invention is to provide a metal-coated optical fiber and its preparation method, which simplifies the process steps, eliminates the need for a high vacuum or high temperature reaction environment, improves the adhesion and thickness uniformity between the metal coating and the optical fiber surface, reduces pollutant emissions, and lowers production energy consumption and costs.

[0005] To achieve the above objectives, the present invention provides a method for preparing a metal-coated optical fiber, comprising the following steps: Step 1: Draw the optical fiber preform into bare optical fiber of the target size using an optical fiber drawing tower; Step 2: Prepare a metal slurry with a metal powder content of 50-80% by weight, an organic solvent content of 20%-50% by weight, and an additive content of 0.5%-5% by weight. Step 3: Coat the prepared metal paste onto the surface of the bare optical fiber; Step 4: Dry the metal paste coated on the surface of the bare optical fiber; Step 5: Using laser sintering, the metal paste solidified on the surface of the bare optical fiber is sintered and then naturally cooled to room temperature to obtain a metal-coated optical fiber.

[0006] Preferably, the metal powder includes gold powder, silver powder, aluminum powder, or other alloy powder.

[0007] Preferably, the particle size of the metal powder is in the range of 0.1-10 μm, and the viscosity of the metal slurry is controlled at 500-2000 mPa·s.

[0008] Preferably, the organic solvent is a volatile solvent that does not corrode the optical fiber quartz material, specifically including one of ethanol, acetone, and ethyl acetate; Additives include polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), or dimethylacetamide (DMA).

[0009] Preferably, the method of coating the prepared metal paste onto the surface of the bare optical fiber includes one of dip coating, spray coating or roll coating, and the thickness of the wet metal paste film after coating is 10-60 μm.

[0010] Preferably, the drying temperature is 80-200℃.

[0011] Preferably, the laser sintering uses a fiber laser with a wavelength of 1064nm or a CO2 laser with a wavelength of 10.6μm.

[0012] Preferably, the atmosphere during laser sintering is argon or nitrogen.

[0013] A method for preparing metal-coated optical fibers.

[0014] Therefore, the present invention employs the above-described metal-coated optical fiber and its preparation method, and the technical effects are as follows: 1. Process advantages: No high vacuum or high temperature reaction environment is required, which can reduce equipment investment and improve production efficiency; 2. Coating performance: The coating has small thickness uniformity error, strong adhesion, and high density, which can meet the mechanical and physical performance requirements of metal coatings in communication and sensing scenarios. 3. Environmental and economic benefits: No waste liquid discharge, reducing raw material costs; 4. Wide applicability: It can be adapted to various metal powders such as gold, silver, and aluminum, and the coating thickness can be adjusted according to requirements (5-50μm), and it is compatible with bare optical fibers of different diameters. Attached Figure Description

[0015] Figure 1 This is a scanning electron microscope image of a metal-coated optical fiber according to Embodiment 1 of the present invention; Figure 2 This is a process flow diagram of the preparation method of the present invention; Figure 3 This is a schematic diagram of the preparation method of the present invention; Figure 4 This is a scanning electron microscope image of a metal-coated optical fiber according to Embodiment 1 of the present invention; Figure 5 This is an energy dispersive spectroscopy spectrum of a gold-coated optical fiber according to Embodiment 1 of the present invention. Detailed Implementation

[0016] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0018] Under high temperatures, interdiffusion of atoms occurs at the interface between the metal and quartz, potentially leading to an interfacial reaction and the formation of strong chemical bonds. Figure 3 Scanning electron microscope (SEM) images and energy dispersive spectroscopy (EDS) spectra of a gold-coated optical fiber show that silicon elements diffused out from the metal layer.

[0019] Example 1 A method for preparing a metal-coated optical fiber includes the following steps: Metal paste preparation: Take 70wt% gold powder (particle size 0.5μm), 28wt% ethanol, and 2wt% PVP, stir for 40min and then ultrasonically disperse for 20min to obtain a copper paste with a viscosity of 1200mPa·s; Coating: such as Figure 2 As shown, open coating is used. The open coating device is located below the drawing furnace. The 125μm bare optical fiber prepared by drawing the single-mode optical fiber preform through the optical fiber drawing tower is passed through the metal paste coating device at a speed of 3m / min. The wet film thickness is about 15μm. Drying: The metal paste coated on the surface of the bare optical fiber is dried at 120℃ to obtain a gold powder pre-coating with a dry film thickness of 15μm. Laser sintering: The laser sintering apparatus is located between the drying furnace and the take-up device. It uses a fiber laser (300W power), a scanning speed of 100mm / s, and an argon flow rate of 8L / min to sinter the metal paste solidified on the surface of the bare optical fiber. After sintering and cooling to room temperature, a metal-coated optical fiber is obtained. Figure 1 As shown.

[0020] Performance Testing: The main performance parameters of this gold-coated single-mode metallic optical fiber are shown in Table 1. Figure 4 and Figure 5 As shown.

[0021] Table 1 shows the main performance parameters of the gold-coated single-mode metallic optical fiber in Example 1.

[0022] Example 2 A method for preparing a metal-coated optical fiber includes the following steps: Metal paste preparation: Take 80wt% aluminum powder (particle size 0.3μm), 18wt% acetone and 2wt% PEG, stir for 30min and then ultrasonically disperse for 15min to obtain aluminum paste with a viscosity of 800mPa·s; Coating: Open coating is adopted. The open coating device is located below the drawing furnace. The 125μm bare optical fiber prepared by drawing the optical fiber preform through the optical fiber drawing tower is passed through the metal paste coating device at a speed of 5m / min. The wet film thickness is about 20μm. Drying: Dry at 100℃ to obtain an aluminum powder pre-coating with a dry film thickness of 10μm; Laser sintering: The laser sintering device is located between the drying furnace and the take-up device. It uses a CO2 laser (power 200W), a scanning speed of 150mm / s, and an argon flow rate of 6L / min. After sintering, the laser is cooled to room temperature.

[0023] Performance testing: The main performance parameters of this silver-coated single-mode metallic optical fiber are shown in Table 2.

[0024] Table 2 shows the main performance parameters of the aluminum-coated single-mode metallic optical fiber in Example 2.

[0025] Comparative Example 1 A 100μm diameter optical fiber is used, and the cladding is etched with 0.5% hydrofluoric acid to roughen the outer surface of the cladding, forming a rough surface. Tin is melted at 270℃ and coated onto the surface of the optical fiber for 0.01s. After cooling to solidify, a first metal layer with a thickness of 2μm is formed. Aluminum is melted at 700℃ and coated onto the surface of the first metal layer for 0.01s. After cooling to solidify, a second metal layer with a thickness of 5μm is formed. Annealing is then performed at 400℃ to obtain a composite metal-coated optical fiber. This method requires pretreatment of the optical fiber with hydrofluoric acid, cannot be used for online production using an optical fiber drawing tower, and has low efficiency.

[0026] Comparative Example 2 The preform is drawn into bare fiber using an optical fiber drawing tower. A temporary protective wax layer is coated on the surface of the bare fiber to obtain a wax roll. The wax roll is then placed in a vacuum coating apparatus for magnetron sputtering coating. Before magnetron sputtering coating, the wax roll is unwound and the wax fiber is heated to remove the temporary protective wax layer. The vacuum system is evacuated to 3×10⁻⁶. -3 After Pa, argon gas is introduced to a concentration of 1×10⁻⁶. - 2At a target voltage of 250V and a power of 500W, without heating, the fiber is wound up after magnetron sputtering deposition; after winding, it is removed to obtain an optical fiber coated with a metal layer. This method requires the use of magnetron sputtering equipment, which is expensive, and also has high requirements for vacuum levels and a slow deposition rate.

[0027] Therefore, the present invention adopts the above-mentioned metal-coated optical fiber and preparation method, which simplifies the process steps and eliminates the need for a high vacuum or high temperature reaction environment; improves the bonding force and thickness uniformity between the metal coating and the optical fiber surface; reduces pollutant emissions and lowers production energy consumption and costs.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a metal-coated optical fiber, characterized in that, Includes the following steps: Step 1: Draw the optical fiber preform into bare optical fiber of the target size using an optical fiber drawing tower; Step 2: Prepare a metal slurry with a metal powder content of 50-80% by weight, an organic solvent content of 20%-50% by weight, and an additive content of 0.5%-5% by weight. Step 3: Coat the prepared metal paste onto the surface of the bare optical fiber; Step 4: Dry the metal paste coated on the surface of the bare optical fiber; Step 5: Using laser sintering, the metal paste solidified on the surface of the bare optical fiber is sintered and then naturally cooled to room temperature to obtain a metal-coated optical fiber.

2. The method for preparing a metal-coated optical fiber according to claim 1, characterized in that, Metal powders include gold powder, silver powder, aluminum powder, or other alloy powders.

3. The method for preparing a metal-coated optical fiber according to claim 1, characterized in that, The particle size of the metal powder ranges from 0.1 to 10 μm, and the viscosity of the metal slurry is controlled between 500 and 2000 mPa·s.

4. The method for preparing a metal-coated optical fiber according to claim 1, characterized in that, The organic solvent is a volatile solvent that does not corrode the optical fiber quartz material, specifically including one of ethanol, acetone, and ethyl acetate; Additives include polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), or dimethylacetamide (DMA).

5. The method for preparing a metal-coated optical fiber according to claim 1, characterized in that, The prepared metal paste is coated onto the surface of the bare optical fiber by one of the following methods: dip coating, spray coating, or roll coating. After coating, the thickness of the wet metal paste film is 10-60 μm.

6. The method for preparing a metal-coated optical fiber according to claim 1, characterized in that, The drying temperature is 80-200℃.

7. The method for preparing a metal-coated optical fiber according to claim 1, characterized in that, Laser sintering uses a fiber laser with a wavelength of 1064nm or a CO2 laser with a wavelength of 10.6μm.

8. The method for preparing a metal-coated optical fiber according to claim 1, characterized in that, The atmosphere during laser sintering is argon or nitrogen.

9. A metal-coated optical fiber prepared by a method for preparing a metal-coated optical fiber according to any one of claims 1-8.

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