An apparatus and method for coating the inner wall of a hollow optical fiber cavity.

Abstract

This invention discloses an apparatus and method for coating the inner wall of a hollow fiber cavity. By filling a coating apparatus filled with solution with gas, the increased gas pressure inside the apparatus forces the solution into the hollow fiber to be coated. This coating method is simple and easy to operate, resulting in a uniform and controllable film. This invention can conveniently and quickly achieve coating on the inner wall of small-diameter hollow fibers or capillaries, producing a uniform film with easily adaptable dimensions. This invention overcomes the difficulties in coating the inner wall of ultra-fine hollow fibers or quartz capillaries, and is compatible with various inner diameters, meeting the application requirements of hollow fibers.

Description

Technical Field

[0001] This application relates to the technical field of coating, and in particular to an apparatus and method for coating the inner wall of a hollow optical fiber cavity. Background Technology

[0002] Hollow-core optical fibers, with their core layer guiding light, hollow structure, high integration, and wearability, can serve as core components for fabricating optical microcells. To increase light transmittance or extend lifespan, coatings are required on the inner walls of the hollow-core fiber cavity. A common coating method involves connecting the hollow-core fiber to be coated to an air pump, which draws the solution into the fiber. This method is prone to leakage, has high pumping resistance, and easily introduces air bubbles, resulting in uneven coating. Furthermore, the inner diameter of the hollow-core fiber is not well-suited to the air pump. Summary of the Invention

[0003] This application discloses an apparatus and method for coating the inner wall of a hollow optical fiber cavity. By filling a coating apparatus filled with solution with gas, the increased internal gas pressure forces the solution into the hollow optical fiber to be coated. This coating method is simple and easy to operate, and the resulting film is uniform and controllable. This invention overcomes the difficulties in coating the inner wall of ultrafine hollow optical fibers or quartz capillaries, and is compatible with various inner diameter sizes, meeting the application requirements of hollow optical fibers.

[0004] In a first aspect, an apparatus for coating the inner wall of a hollow optical fiber cavity is provided, comprising:

[0005] The coating chamber is a quartz or glass shell. The coating chamber is filled with a first solution, which is a solution used for coating. The upper surface of the coating chamber has two small holes.

[0006] The injection port is bonded and inserted into a small hole sealed in the coating cavity. Another small hole in the coating cavity is used to seal and set the hollow fiber. The bottom of the hollow fiber is immersed below the liquid surface.

[0007] A syringe is used to inject gas into the coating cavity through the injection port, so that the first solution is pushed into the hollow optical fiber to be coated under pressure.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, the device further includes two stationary cavities, which are quartz or glass shells. The two stationary cavities are filled with a first solution for coating. Each of the two stationary cavities has a small hole at the same height on its side for laterally placing the hollow optical fiber after the solution injection is completed.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the apparatus further includes a beaker containing a coating cavity, the coating cavity being immersed in a second solution, the surface of the second solution covering the upper surface of the coating cavity.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the second solution is the same as the first solution, and the second solution in the beaker is used to replenish the first solution in the coating cavity.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the second solution differs from the first solution in that the liquid surface of the second solution is located between the top of the coating cavity and the top of the injection nozzle.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the injection port is made of metal and the bottom of the injection port extends to the bottom of the coating cavity so that the vent is always below the liquid surface throughout the inflation process.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the hollow optical fiber is made of quartz or silicon, has an air hole in the middle, and is covered with a cladding, and the first solution is 10% alumina gel or other solution.

[0014] In a second aspect, a method for coating the inner wall of a hollow fiber cavity is provided, the method being applied to the apparatus described in any implementation of the first aspect above, the method comprising:

[0015] The coating cavity is filled with a coating solution, and the hollow fiber to be coated is inserted into a small hole in the coating cavity so that the bottom of the hollow fiber is submerged below the liquid surface.

[0016] Air is injected into the injection tube using a syringe, and the first solution in the coating chamber is pushed into the hollow optical fiber to be coated under pressure.

[0017] When the liquid level inside the hollow fiber to be coated reaches the top, seal the top, remove the hollow fiber from the coating chamber, place it horizontally, and let it stand for 2 hours.

[0018] Air is injected into the hollow fiber using a syringe to expel the first solution from the hollow fiber. The solution is then left to stand in the air for 2 to 4 hours, and finally subjected to high-temperature annealing to achieve coating on the inner wall of the hollow fiber cavity.

[0019] In conjunction with the second aspect, in some implementations of the second aspect, the hollow fiber is placed laterally, including:

[0020] The two ends of the hollow optical fiber are inserted into the small holes of two static cavities, which are filled with the first solution for coating. The small holes on the sides of the two static cavities are set at the same height.

[0021] In conjunction with the second aspect, in some implementations of the second aspect, the annealing process is a stepped heating process with a maximum temperature of 500℃.

[0022] Compared with the prior art, the solution provided in this application has at least the following beneficial technical effects:

[0023] 1. The process of injecting air into the coating device using a syringe is simpler and easier to operate, and effectively reduces the operating resistance of the coating process.

[0024] 2. The process of pressing the solution with air can reduce the time required for the coating process, avoid air bubbles introduced by air extraction, and make the film thickness of the inner wall uniform throughout the entire length of the hollow fiber.

[0025] 3. The method of injecting solution into the hollow optical fiber by blowing air avoids the air leakage problem of the bonding tube, making the whole process safer and more reliable.

[0026] 4. The aperture of the coating device is close to and slightly larger than the outer diameter of the hollow fiber to be coated, making the size matching process simpler and easier to operate.

[0027] 5. This invention simplifies the coating process on the inner wall of the hollow fiber cavity, improves the uniformity of the film layer, reduces the difficulty of operation, and facilitates various practical applications of hollow fiber. Attached Figure Description

[0028] Figure 1 This is a flowchart of the preparation method of the present invention.

[0029] Figure 2 This is a schematic diagram of the solution filling process apparatus of the present invention.

[0030] Figure 3 This is a schematic diagram of the static setting process of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Coating cavity; 2. Injection port; 3. Hollow-core optical fiber to be coated; 4. First solution; 5. Second solution; 6. Beaker; 7. Settling cavity; 8. Hollow-core optical fiber to be coated. Detailed Implementation

[0033] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0034] The present invention provides an apparatus and method for coating the inner wall of a hollow optical fiber cavity. By blowing air into the coating apparatus 1, the solution can be injected into the hollow optical fiber 3 to be coated more easily. Figure 1 This application illustrates a method for coating the inner wall of a hollow fiber cavity according to an embodiment of the present application. Figure 2 This application illustrates an apparatus for coating the inner wall of a hollow fiber cavity, according to an embodiment of the present application. The hollow fiber is made of quartz or silicon, with an air hole in the middle and a cladding layer on the outside. The specific steps of the method for coating the inner wall of the hollow fiber cavity are as follows.

[0035] Obtain the coating chamber 1. The coating chamber 1 is a cylindrical quartz or glass shell. Two small holes are provided on the upper surface of the coating chamber 1. One hole is connected to the injection port 2, and the other hole is used to place the hollow optical fiber 3. The small holes of the coating chamber 1, the injection port 2, and the hollow optical fiber 3 are sealed. The coating chamber 1 is filled with a first solution 4, which is the solution used for coating. The bottom of the hollow optical fiber 3 is immersed below the liquid surface.

[0036] Air is injected into the injection port 2 using a syringe, and the first coating solution 4 in the coating chamber 1 is pushed into the hollow fiber 3 to be coated under pressure. When the liquid level inside the hollow fiber 3 is close to the top, the top is sealed, and the hollow fiber 3 is removed from the device and placed horizontally, with both ends placed into two settling chambers 7 respectively, for 2 hours. The two settling chambers 7 are filled with the first coating solution 4. The settling chambers 7 are cylindrical quartz or glass shells. Each of the two settling chambers 7 has a small hole at the same height on its cylindrical surface for horizontally placing the hollow fiber 3 after the solution injection is completed.

[0037] Then, remove both ends of the hollow fiber 3 from the static cavity 7, inject air into the hollow fiber 3 using a syringe to expel the solution from the hollow fiber 3, let it stand in the air for 2 to 4 hours, and then anneal at high temperature to achieve the coating on the inner wall of the hollow fiber cavity.

[0038] In some embodiments, before injecting air into the injection port 2, the coating chamber 1 can be placed in a beaker 6, and a second solution 5 can be poured into the beaker 6. The second solution 5 may be the same as or different from the first solution 4.

[0039] In one embodiment, when the second solution 5 is the same as the first solution 4, the second solution 5 in the beaker 6 can be used to replenish the first solution 4 in the coating cavity 1, so as to reduce the number of times the material on the coating cavity 1 needs to be disassembled and reassembled. The second solution 5 can achieve the sealing of the gap between the hollow optical fiber 3 to be coated and the coating cavity 1 on a small scale through the surface tension effect.

[0040] In another embodiment, such as Figure 2 As shown, when the second solution 5 is different from the first solution 4, the liquid level of the second solution 5 can be between the top of the coating chamber 1 and the top of the injection port 2 to avoid contamination of the solution in the coating chamber 1. In addition, the second solution 5 can be a solution with a lower viscosity than the first solution 4, which makes it easier to observe bubbles and to check the airtightness of the coating chamber 1.

[0041] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. An apparatus for coating the inner wall of a hollow optical fiber cavity, characterized in that, include: The coating chamber is a quartz or glass shell. The coating chamber is filled with a first solution, which is a solution used for coating. The upper surface of the coating chamber has two small holes. The injection port is bonded and inserted into a small hole sealed in the coating cavity. Another small hole in the coating cavity is used to seal and set the hollow fiber. The bottom of the hollow fiber is immersed below the liquid surface. A syringe is used to inject gas into the coating cavity through the injection port so that the first solution is pushed into the hollow optical fiber to be coated under pressure. The device also includes two stationary cavities, which are quartz or glass shells. The two stationary cavities are filled with a first solution for coating. Each of the two stationary cavities has a small hole at the same height on its side for placing the hollow optical fiber laterally after the solution is injected.

2. The apparatus according to claim 1, characterized in that, The device also includes a beaker containing a coating chamber, which is immersed in a second solution, with the surface of the second solution covering the upper surface of the coating chamber.

3. The apparatus according to claim 2, characterized in that, The second solution is the same as the first solution, and the second solution in the beaker is used to replenish the first solution in the coating cavity.

4. The apparatus according to claim 2, characterized in that, The second solution differs from the first solution in that its liquid level is located between the top of the coating cavity and the top of the injection nozzle.

5. The apparatus according to claim 2, characterized in that, The injection nozzle is made of metal, and the bottom of the injection nozzle extends to the bottom of the coating cavity so that the vent is always below the liquid surface during the entire inflation process.

6. The apparatus according to claim 1, characterized in that, The hollow optical fiber is made of silicon, with an air hole in the middle and a cladding layer on the outside. The first solution is 10% alumina gel.

7. A method for coating the inner wall of a hollow optical fiber cavity, characterized in that, The method is applied to the apparatus as described in any one of claims 1 to 6, the method comprising: The coating cavity is filled with a coating solution, and the hollow fiber to be coated is inserted into a small hole in the coating cavity so that the bottom of the hollow fiber is submerged below the liquid surface. Air is injected into the injection tube using a syringe, and the first solution in the coating chamber is pushed into the hollow optical fiber to be coated under pressure. When the liquid level inside the hollow fiber to be coated reaches the top, seal the top, remove the hollow fiber from the coating chamber, place it horizontally, and let it stand for 2 hours. Air is injected into the hollow fiber using a syringe to expel the first solution from the hollow fiber. The solution is then left to stand in the air for 2 to 4 hours, and finally subjected to high-temperature annealing to achieve coating on the inner wall of the hollow fiber cavity.

8. The method according to claim 7, characterized in that, Laterally placed hollow optical fibers include: The two ends of the hollow optical fiber are inserted into the small holes of two static cavities, which are filled with the first solution for coating. The small holes on the sides of the two static cavities are set at the same height.

9. The method according to claim 7, characterized in that, The annealing process involves stepped heating, with a maximum temperature of 500℃.

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