Negative pressure optical fiber preparation device

Abstract

The negative pressure optical fiber preparation device comprises an optical fiber preform rod connecting sub-device and a negative pressure sub-device, and the negative pressure sub-device provides a negative pressure environment for the interior of the optical fiber preform rod connecting sub-device; the sample is an optical fiber preform, and the connection of the sample is that the optical fiber preform and the connecting pipe are welded to form a blank rod; the air extractor comprises the blank rod, an air pipe and a vacuum pump with a pressure controller; and the negative pressure is controlled by a pressure controller. The device has the technical effects of low cost, simple structure, high control precision, automation and convenience in operation.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical fibers and relates to a negative pressure device used for preparing optical fibers. Technical Background

[0002] Visible light fiber lasers have important application needs in laser medical treatment, laser radar, remote sensing detection, and other fields. Quartz optical fiber has become the most mature gain fiber matrix due to its excellent physical, chemical and mechanical properties. Chemical vapor deposition is a commonly used method for preparing quartz optical fiber preforms. However, there are certain limitations on the types and concentrations of doping components in the core of quartz optical fibers prepared by this method; researchers usually use multi-material core rods and quartz tube claddings to prepare optical fibers through the tube-and-rod method to meet the special composition requirements of the core. In the process of preparing optical fibers with larger diameters by the tube-and-rod method, there is often a problem that the gap between the core and the cladding remains in the optical fiber to form bubbles, which affects the optical fiber loss and laser efficiency. Utility Model Content

[0003] In order to overcome the shortcomings and difficulties of the prior art as much as possible, the utility model provides a low-cost negative pressure device that can be used for preparing different types of tube-and-rod optical fibers.

[0004] The utility model adopts the following technical solutions to achieve the above objectives:

[0005] A negative pressure optical fiber preparation device, comprising an optical fiber preform connecting sub-device and a negative pressure sub-device, wherein the negative pressure sub-device provides a negative pressure environment in the optical fiber preform connecting sub-device; characterized in that the optical fiber preform connecting sub-device is sequentially connected by a connecting air nozzle, a connecting tube, and a cladding tube of the optical fiber preform; the negative pressure sub-device is sequentially connected by an air pipe, a pressure controller, and a vacuum pump;

[0006] The connecting air nozzle is respectively sealed and connected to the air pipe and the connecting pipe of the negative pressure distribution device;

[0007] An optical fiber core rod is fitted in the cladding tube of the optical fiber preform, and the bottom of the cladding tube is in an open state;

[0008] The connecting tube and the optical fiber cladding tube are sealed and connected by fusion;

[0009] Optionally, the negative pressure distribution device can provide a negative pressure environment of 10 -3 Pa~0.1Pa;

[0010] Optionally, the size difference between the inner diameter of the cladding tube and the outer diameter of the optical fiber preform is: 0.01mm-0.5mm;

[0011] Preferably, the size difference between the inner diameter of the cladding tube and the outer diameter of the optical fiber preform is: 0.1mm to 0.5m;

[0012] Optionally, the air pipe is made of plastic, and the connecting pipe is made of quartz glass;

[0013] Optionally, the connecting tube and the optical fiber cladding tube are connected by oxyhydrogen flame welding and sealing.

[0014] Optionally, negative pressure is provided by a vacuum pump (8) and a pressure controller is used to control the gas flow rate in the cladding tube to be 0.5 to 20 L / min, thereby removing defects such as bubbles and air lines that may be generated between the optical fiber core rod and the optical fiber cladding tube during the process of preparing optical fiber by the tube-to-rod method.

[0015] Technical effects of the utility model:

[0016] 1. The utility model effectively improves the air tightness and controllability of negative pressure in optical fiber drawing through a quartz tube, a vacuum pump and a precision negative pressure meter, can effectively reduce defects such as bubbles generated in the tube-rod method optical fiber preparation process, and improves optical fiber performance.

[0017] 2. The preparation method of the utility model is simple, which reduces the difficulty and cost of making optical fiber.

[0018] 3. The utility model is aimed at the tube-rod method optical fiber preparation process, which has important promoting significance for the field of special optical fiber preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of the utility model.

[0020] Figure 2 It is the principle diagram of the negative pressure device of the utility model.

[0021] Figure 3 This is a side view of the optical fiber prepared by the tube-rod method without using a negative pressure device.

[0022] Figure 4 This is a side view of the optical fiber prepared by the negative pressure device tube-rod method in Example 1.

[0023] In the figure: 1 optical fiber cladding tube, 2 optical fiber core rod, 3 fusion point between the cladding tube of the optical fiber preform and the connecting tube, 4 connecting tube, 5 connecting air nozzle, 6 air pipe, 7 pressure controller, 8 vacuum pump. DETAILED DESCRIPTION

[0024] Example

[0025] In the process of using the tube-rod method to prepare optical fibers with a diameter greater than 300 μm, due to the gap between the core rod and the fiber cladding tube, the drawing speed is too fast and the fiber diameter is large, which will lead to the problem of air line between the core rod and the fiber cladding tube in the optical fiber, such as Figure 3As shown, the figure shows a side view of an optical fiber prepared by the tube-rod method without a negative pressure device. The optical fiber has a diameter of 350 μm, and there is a gas line with a length of about 430 μm at the interface between the optical fiber core and the cladding.

[0026] Refer to the instruction manual Figure 1 , which shows a negative pressure optical fiber preparation device, including an optical fiber preform connecting sub-device and a negative pressure sub-device for evacuating the optical fiber preform. The optical fiber preform connecting sub-device includes a connecting pipe 4 and a connecting air nozzle 5; the negative pressure sub-device system includes an air pipe 6, a pressure controller 7, and a vacuum pump 8.

[0027] The connection tube 4 and the optical fiber preform cladding tube 1 are fused by oxyhydrogen flame fusion, which is used to increase the air tightness between the optical fiber preform and the connection tube 4 and form a fusion point 3 between the optical fiber cladding tube and the connection tube.

[0028] The connecting tube 4 is made of quartz glass, which matches the softening temperature of the optical fiber preform cladding tube.

[0029] The air pipe 6 is made of plastic.

[0030] The gas flow rate is controlled by the pressure controller 7 and the vacuum pump 8. The gas flow direction is as follows: Figure 2 As shown, the effect of removing bubbles is achieved.

[0031] The negative pressure drawing method of optical fiber comprises the following steps:

[0032] a) placing the optical fiber core rod 2 into the optical fiber cladding tube 1, and welding the optical fiber preform cladding tube 1 and the connecting tube 4 using a hydrogen-oxygen flame, using two hydrogen-oxygen flame burners at 80 mm below the welding point to provide 100 L / min of hydrogen and 50 L / min of oxygen for welding and sealing;

[0033] b) According to the same steps as above, the connecting nozzle 5 is sealed and connected to the air pipe 6;

[0034] c) In the process of drawing optical fiber, before heating, the argon atmosphere in the drawing tower heating furnace is turned on, the argon flow rate is 1 L / min, the vacuum pump 8 is turned on, and the gas flow rate in the optical fiber cladding tube is controlled to be 0.5 L / min by the pressure controller; when the heating is turned on, the lower end of the optical fiber preform begins to soften and descend when the temperature rises to 1950°C, and the optical fiber is collected. At this time, the negative pressure flow rate is set to 5-20 L / min, the optical fiber side structure is observed in real time, and the negative pressure gas flow rate is adjusted according to the observation results.

[0035] Figure 4 This is the side of the optical fiber prepared by the tube-rod method using a negative pressure device. No air lines were observed.

Claims

1. A negative pressure optical fiber preparation device, characterized in that: It comprises an optical fiber preform connecting sub-device and a negative pressure sub-device. The negative pressure sub-device provides a negative pressure environment in the optical fiber preform connecting sub-device. The optical fiber preform connecting sub-device is sequentially connected by a connecting air nozzle (5), a connecting tube (4), and a cladding tube (1) of the optical fiber preform; the negative pressure sub-device is sequentially connected by an air pipe (6), a pressure controller (7), and a vacuum pump (8); The connecting air nozzle (5) is respectively sealedly connected to the air pipe (6) and the connecting pipe (4) of the negative pressure distribution device; An optical fiber core rod (2) is adapted inside the optical fiber cladding tube (1), and the bottom of the cladding tube (1) is in an open state; The connecting tube (4) and the optical fiber cladding tube (1) are fused and sealed.

2. A negative pressure optical fiber preparation device according to claim 1, characterized in that: The negative pressure environment that the negative pressure distribution device can provide is: 10 -3 Pa~0.1Pa.

3. A negative pressure optical fiber preparation device according to claim 1, characterized in that: The matching size difference between the inner diameter of the optical fiber cladding tube (1) and the outer diameter of the fiber core rod is 0.01 mm to 0.5 mm.

4. A negative pressure optical fiber preparation device according to claim 3, characterized in that: The matching size difference between the inner diameter of the optical fiber cladding tube (1) and the outer diameter of the fiber core rod is 0.1 mm to 0.5 mm.

5. The negative pressure optical fiber preparation device according to claim 1, characterized in that: The air pipe (6) is made of plastic, and the connecting pipe (4) is made of quartz glass.

6. A negative pressure optical fiber preparation device according to claim 1, characterized in that: The connecting tube (4) and the optical fiber cladding tube (1) are connected by oxyhydrogen flame welding and sealing.

7. A negative pressure optical fiber preparation device according to claim 1, characterized in that: A negative pressure is provided by a vacuum pump (8), and a pressure controller controls the gas flow rate in the cladding tube to be 0.5 to 20 L / min.

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