Ultralow-loss optical fiber annealing device and method

Abstract

The invention discloses an annealing device and method for an ultra-low-loss optical fiber, and the device comprises an optical rod heating system, an optical fiber annealing system, a screw-in air inlet system, a fish-mouth stacked ceramic tube system, a coating system, and a take-up system. The optical wand heating system, the optical fiber annealing system, the screw-in type air inlet system, the coating system and the take-up system are sequentially arranged in the optical fiber entering direction, and the fish mouth stacked ceramic tube system is arranged in the optical fiber annealing system. According to the invention, through the design of the fish mouth stacked ceramic tube, the airflow path of the annealing area is optimized, so that airflow can be uniformly distributed in multiple directions, more uniform temperature distribution is realized, and the mechanical and optical performance of the optical fiber is improved; by means of a screw-in gas inlet mode, entered gas flow forms rotary motion, the gas mixing effect and flow speed control are enhanced, the gas flow stability in the annealing process is ensured, unnecessary fluctuation is reduced, and the optical fiber quality is improved. And the flexibility and adaptability of annealing equipment are improved, and different production requirements are met.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber manufacturing, and in particular relates to an annealing device and method for ultra-low loss optical fiber. Background Art

[0002] Optical fiber communication technology is an important part of modern communication technology. It has been widely used in communication networks, data transmission, optical fiber sensing and many other fields due to its advantages of high transmission rate, large capacity and low loss. The manufacturing technology of optical fiber directly affects the performance and reliability of optical fiber communication systems. Annealing process is a key step in the optical fiber manufacturing process. Annealing can eliminate the stress inside the optical fiber and improve the mechanical and optical properties of the optical fiber. Especially for ultra-low loss optical fiber, the quality of the annealing process is directly related to the attenuation characteristics of the optical fiber and the protection of a large effective area.

[0003] In the process of optical fiber annealing, temperature field control and gas intake control are two key factors affecting the annealing effect. However, existing optical fiber annealing equipment has limitations in temperature field control and gas intake control, which are mainly reflected in the following aspects:

[0004] (1) Uneven temperature distribution: Existing annealing equipment is difficult to achieve uniform temperature distribution in a high temperature environment, which leads to uneven annealing of ultra-low loss optical fiber during the annealing process, thereby affecting the effectiveness of optical fiber annealing and affecting the mechanical and optical properties of the optical fiber;

[0005] (3) Unstable airflow control or no active airflow: The airflow control system of existing annealing equipment is not well designed, the airflow path is complex, and the airflow cannot be stably controlled, which will lead to poor gas mixing effect and uneven flow rate during the annealing process, as well as unnecessary fluctuations, thus affecting the stability and accuracy of the annealing process;

[0006] (3) Unable to effectively control the uniformity of optical fiber diameter: Existing annealing equipment is unable to meet the high requirements for temperature control accuracy and airflow purity when processing ultra-low loss optical fibers. At the same time, no airflow or discrete airflow cannot achieve high-precision diameter uniformity requirements, making it difficult to maintain the large effective area of ​​ultra-low loss optical fibers.

[0007] The invention patent with application number IN202417014031 provides a method for manufacturing optical fiber in an optical fiber production system. By controlling the outlet nozzles of different sizes, the airflow entering the annealing furnace can be controlled, thereby producing optical fiber with low optical fiber attenuation. However, the airflow stability of the optical fiber annealing microenvironment in this patent is difficult to maintain, which can easily cause optical fiber disturbance and affect the uniformity of optical fiber diameter.

[0008] The Chinese patent application number CN211999466U provides a fiber annealing furnace, which focuses on the precise control of the annealing process to improve the quality of the fiber. However, the patent can provide a stable energy source for the precise control of the instrument, but cannot effectively guarantee the uniformity of the temperature field of the fiber annealing microenvironment.

[0009] The invention patent with application number WO2019153473A1 provides an optical fiber stretching and annealing device, which integrates optical fiber stretching and annealing processes, improves the structural performance of the optical fiber, but does not take into account the higher activity of ash caused by gas expansion at high temperature, and the cleanliness of the annealing microenvironment is difficult to guarantee. Summary of the invention

[0010] In order to solve the technical problems existing in the prior art, the object of the present invention is to provide an annealing device and method for ultra-low loss optical fiber.

[0011] In order to achieve the above purpose and the above technical effect, the technical solution adopted by the present invention is:

[0012] An annealing device for ultra-low loss optical fiber, comprising:

[0013] An optical rod heating system is used to heat and melt the optical rod and draw it into an optical fiber;

[0014] Optical fiber annealing system, used to anneal the drawn optical fiber;

[0015] The swirl-type air inlet system is used to form a stable swirl airflow in the annealing area;

[0016] Fish-mouth stacked ceramic tube system for even distribution of airflow in the annealing area;

[0017] Coating system, used to add protective material to the surface of optical fiber;

[0018] The take-up system is used to ensure the stability of the tension of the optical fiber during the drawing and coating process and to achieve the take-up of the optical fiber;

[0019] The optical rod heating system, optical fiber annealing system, spiral air intake system, coating system and take-up system are arranged in sequence along the optical fiber entry direction, and the fish-mouth stacked ceramic tube system is arranged in the optical fiber annealing system.

[0020] Furthermore, the optical rod heating system comprises:

[0021] Optical rods, as precursor materials for optical fibers, need to be heated and melted at high temperatures;

[0022] Optical fiber drawing furnace, used to heat the optical rod to form a cone head and draw it into an optical fiber of fixed size;

[0023] The optical fiber is formed by melting the optical rod and is drawn into the required diameter by a fiber drawing furnace. The optical fiber maintains a uniform speed and direction during the drawing process to ensure the consistency of the optical fiber diameter.

[0024] Furthermore, the optical fiber annealing system comprises:

[0025] Annealing furnace;

[0026] The heating coil is installed in the annealing furnace.

[0027] A quartz barrel is arranged in the annealing furnace, and a heating coil is wound around the quartz barrel;

[0028] Metal clamp ring, set at the entrance end of the annealing furnace, used to fix the fish mouth stacked ceramic tube system;

[0029] The lower tray is arranged at the exit of the annealing furnace to facilitate the disassembly and installation of the internal components of the annealing furnace.

[0030] Furthermore, the total height of the heating coil is 1500-3000 mm, the inner diameter is 45-70 mm, the number of turns is 7-15, and cooling water is passed into the interior of the heating coil to prevent the coil from deforming and ensure uniform heating.

[0031] Furthermore, the outer diameter of the quartz barrel is 43-70 mm, and the inner diameter is 40-65 mm. In the assembly of the heating coil and the quartz barrel, the distance between the two ends of the quartz barrel and the heating coil is controlled to be 1-3 mm to ensure uniform heating.

[0032] Furthermore, the spiral-inlet air intake system is arranged at the outlet end of the optical fiber annealing system, has an outer diameter of 40 to 80 mm, and an inner diameter of 18 to 32 mm, and comprises:

[0033] The air inlet pipe is used to provide a channel for gas flow, with a diameter of 4 to 8 mm;

[0034] Gas one-way throttle valve;

[0035] Proportional control valve;

[0036] Gas source storage tank;

[0037] The angle formed by the air intake pipe and the normal line is 20 to 60°, the angle formed by the air intake pipe and the lower wall is 20 to 45°, and a gas one-way throttle valve and a proportional regulating valve are arranged on the pipeline between the air intake pipe and the gas source storage tank.

[0038] Furthermore, the plurality of fish-mouth stacked ceramic tube systems include a plurality of fish-mouth stacked ceramic tubes, which are connected together from bottom to top through fish-mouth stacked ceramic tube connecting rings, and the lower fish-mouth stacked ceramic tubes extend upward by 5 to 15 mm. After all the fish-mouth stacked ceramic tubes are successfully connected, the total length is 1600 to 3100 mm.

[0039] Furthermore, the maximum outer diameter of the fish-mouth stacked ceramic tube is 30 to 48 mm, and the size decreases by 0.6 to 0.8 times from bottom to top.

[0040] Furthermore, the maximum inner diameter of the fish-mouth stacked ceramic tube is 18.5-29.6 mm, and the size decreases by 0.6-0.8 times from bottom to top, and the minimum inner diameter is 0.618 times the maximum inner diameter.

[0041] The present invention also discloses an annealing method for ultra-low loss optical fiber, which uses the annealing device for ultra-low loss optical fiber as described above to perform annealing, and comprises the following steps:

[0042] 1) Complete the layout of the optical rod heating system, optical fiber annealing system, spiral air intake system, fish-mouth stacked ceramic tube system, coating system and take-up system;

[0043] 2) The optical rod enters the optical fiber drawing furnace and is heated and melted under high temperature conditions; the optical fiber drawing furnace is used to draw the molten optical rod along the optical fiber drawing direction to form an optical fiber of the required diameter;

[0044] 3) The optical fiber obtained in step 2) enters an annealing furnace for annealing treatment.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1) Through the fish-mouth stacked ceramic tube design, the airflow path in the annealing area is optimized so that the airflow can be evenly distributed in multiple directions, thereby achieving a more uniform temperature distribution and improving the mechanical and optical properties of the optical fiber;

[0047] 2) Increase airflow stability control: Through the spiral air intake method, the incoming airflow forms a rotating motion, which enhances the gas mixing effect and flow rate control, ensures the stability of the airflow during the annealing process, reduces unnecessary fluctuations, and improves the quality of the optical fiber;

[0048] 3) Enhanced adaptability: Provide annealing devices and methods suitable for optical fibers with high diameter uniformity requirements, improve the flexibility and adaptability of annealing equipment, and meet different production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0050] Figure 2It is a structural schematic diagram of the swirl-in type air intake system of the present invention;

[0051] Figure 3 A potential gas migration path diagram of the present invention;

[0052] Figure 4 It is a dimension change diagram of the fish-mouth stacked ceramic tube of the present invention;

[0053] Figure 5 It is a connection schematic diagram of the fish-mouth stacked ceramic tube of the present invention. DETAILED DESCRIPTION

[0054] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0055] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0056] like Figure 1-5 As shown, the present invention discloses an annealing device for ultra-low loss optical fiber, comprising an optical rod heating system 1, an optical fiber annealing system 2, a spiral air intake system 3, a fish-mouth stacked ceramic tube system 4, a coating system 5 and a take-up system 6. Through the mutual cooperation between the above systems, the quality and efficiency of optical fiber production can be effectively improved.

[0057] The main function of the optical rod heating system 1 is to heat and melt the optical rod and draw it into optical fiber. The specific structure and technical implementation scheme are as follows:

[0058] The optical rod 11, as a precursor material of the optical fiber, needs to be heated and melted at a high temperature;

[0059] The main function of the optical fiber drawing furnace 12 is to heat the optical rod 11 so that it forms a cone head and can be drawn into an optical fiber of a fixed size. The interior of the optical fiber drawing furnace 12 reaches a high temperature through the heating element, so that the optical rod 11 melts;

[0060] The optical fiber 13 is formed by melting the optical rod 11 and is drawn into a desired diameter by the optical fiber drawing furnace 12;

[0061] The optical fiber pulling direction 14, during the pulling process of the optical fiber 13, needs to maintain a uniform speed and direction to ensure the consistency of the optical fiber diameter.

[0062] The main function of the optical fiber annealing system 2 is to anneal the drawn optical fiber 13 to eliminate internal stress, reduce the fictive temperature, promote the relaxation of the optical fiber molecular structure, and improve the optical and mechanical properties of the optical fiber. The specific structure and technical implementation scheme are as follows:

[0063] Annealing furnace, the outer wall 21 of the annealing furnace is made of high temperature resistant material, which can withstand high temperature environment, and can be made of existing conventional products;

[0064] The heating coil 22 is arranged in the annealing furnace, with a total coil height of 1500-3000 mm, an inner diameter of 45-70 mm, and a number of turns of 7-15. Cooling water is passed into the heating coil 22 to prevent the coil from deforming and ensure uniform heating;

[0065] The quartz barrel 23 is arranged in the annealing furnace. The quartz barrel 23 is wound with a heating coil 22, with an outer diameter of 43 to 70 mm and an inner diameter of 40 to 65 mm, for transferring heat. In the assembly of the heating coil 22 and the quartz barrel 23, the distance between the two ends of the quartz barrel 23 and the heating coil 22 is controlled to be 1 to 3 mm to ensure uniform heating.

[0066] A metal clamp ring 24 is provided at the entrance of the annealing furnace and is used to fix the fish-mouth stacked ceramic tube 4. The inner diameter of the clamp ring is rotatable and retractable, and is used to accurately control the fish-mouth stacked ceramic tube 4 to be located at the center;

[0067] The lower tray 25 is arranged at the exit end of the annealing furnace to facilitate the disassembly and installation of the internal components of the annealing furnace, and to facilitate maintenance and replacement.

[0068] The design of the swirl-in air intake system 3 can make the airflow form a stable swirl motion in the annealing area, that is, it is used to form a stable swirl airflow in the annealing area. The outer diameter 31 of the swirl-in air intake system 3 is 40-80 mm, the wall thickness is 15-30 mm, the inner diameter 32 is 18-32 mm, and the wall thickness is 15-30 mm. The swirl-in air intake system 3 includes:

[0069] The air inlet pipe 33 is used to provide a channel for gas flow, and has a diameter of 4 to 8 mm;

[0070] An air inlet direction 34 is used to allow the gas to enter the device from the air inlet pipe 33;

[0071] The angle 35 formed between the air intake duct 33 and the normal line in the top view is 20 to 60°;

[0072] The angle 36 formed between the air intake duct 33 and the lower wall in the top view is 20 to 45°;

[0073] Gas one-way throttle valve 37;

[0074] Proportional control valve 38;

[0075] Gas source storage tank 39;

[0076] The potential movement path 310 of the gas into the channel, the gas flow forms a stable rotational motion after entering the device, which helps to maintain the consistency of the optical fiber diameter.

[0077] A gas one-way throttle valve 37 and a proportional regulating valve 38 are arranged on the pipeline between the air intake pipe 33 and the gas source storage tank 39. The gas one-way throttle valve 37 and the proportional regulating valve 38 are arranged in sequence in the order of proximity to the terminal gas outlet. The function of the gas one-way throttle valve 37 is to stabilize the rear end airflow, and the function of the proportional regulating valve 38 is to provide a stable airflow input.

[0078] The design of the fish-mouth stacked ceramic tube system 4 can make the airflow more evenly distributed in the annealing area, effectively preventing fiber quality problems caused by excessive temperature gradients. The specific structure and technical implementation scheme are as follows:

[0079] Fish mouth stacked ceramic tube, maximum outer diameter 41A-41D, wherein the inner diameter 41A is 30-48 mm, from 41A to 41D, the inner diameter is reduced by 0.6-0.8 times, and the minimum inner diameter 42A-42D, wherein the inner diameter 42A is 18.5-29.6 mm, from 42A-42D, the inner diameter is reduced by 0.6-0.8 times, and the minimum inner diameter is 0.618 times the maximum inner diameter;

[0080] The fish-mouth stacked ceramic tube connecting ring 43 is used to connect adjacent fish-mouth stacked ceramic tubes. After all the fish-mouth stacked ceramic tubes are successfully connected, the total length is 1600-3100 mm, and the lower fish-mouth stacked ceramic tube will extend upward by 5-15 mm.

[0081] The connection between the fish-mouth stacked ceramic tube 4 and the fish-mouth stacked ceramic tube connecting ring 43 relies on gravity to overlap and combine, leaving room for expansion in a high temperature environment.

[0082] There is a gap between the combination of the quartz barrel 23 and the fish-mouth stacked ceramic tube 4, which is filled with soft elastic graphite felt to increase the heat preservation effect.

[0083] The coating system 5 is used to add protective material to the surface of the optical fiber and improve the mechanical strength and wear resistance of the optical fiber through the curing process. The specific structure and technical implementation scheme are as follows:

[0084] Coater: When the optical fiber passes through the coater, a layer of protective material will be evenly coated on the surface. Existing conventional products can be used;

[0085] Curing device: Rapidly cure the protective material by UV curing or heat curing to form a solid protective layer. Existing conventional products can be used.

[0086] The take-up system 6 is used to ensure that the optical fiber maintains a stable tension during the drawing and coating process, and collect the optical fiber into a storage device. The specific structure and technical implementation scheme are as follows:

[0087] A tension controller is used to maintain a stable tension of the optical fiber 13 during the drawing process, and an existing conventional product can be used;

[0088] The collecting device is used to collect the drawn and coated optical fiber 13 onto a storage reel or a take-up drum for subsequent transportation and use, and existing conventional products can be used.

[0089] The present invention also discloses an annealing method for ultra-low loss optical fiber, which uses the annealing device for ultra-low loss optical fiber as described above to perform annealing, and comprises the following steps:

[0090] 1) Complete the layout of the optical rod heating system 1, the optical fiber annealing system 2, the spiral air intake system 3, the fish-mouth stacked ceramic tube system 4, the coating system 5 and the take-up system 6; wrap the heating coil 22 around the outer wall of the quartz barrel 23 and place the whole in the annealing furnace, connect several fish-mouth stacked ceramic tubes 4 from bottom to top through the fish-mouth stacked ceramic tube connecting ring 43 and place them in the quartz barrel 23, fix the fish-mouth stacked ceramic tubes 4 through the metal clamp 24, and the assembly of the optical fiber annealing system 2 and the fish-mouth stacked ceramic tubes 4 can be completed. The spiral air intake system 3, the coating system 5, and the take-up system 6 are sequentially arranged at the outlet of the annealing furnace, and the annealing process can be carried out;

[0091] 2) The optical rod 11 enters the optical fiber drawing furnace 12 and is heated and melted under high temperature conditions; the optical fiber drawing furnace 12 draws the melted optical rod 11 along the optical fiber drawing direction 14 to form an optical fiber 13 of a desired diameter;

[0092] 3) The optical fiber 13 obtained in step 2) enters an annealing furnace for annealing treatment.

[0093] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0094] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An annealing device for ultra-low loss optical fiber, characterized in that: include: An optical rod heating system is used to heat and melt the optical rod and draw it into an optical fiber; Optical fiber annealing system, used to anneal the drawn optical fiber; The swirl-type air inlet system is used to form a stable swirl airflow in the annealing area; Fish-mouth stacked ceramic tube system for even distribution of airflow in the annealing area; Coating system, used to add protective material to the surface of optical fiber; The take-up system is used to ensure the stability of the tension of the optical fiber during the drawing and coating process and to achieve the take-up of the optical fiber; The optical rod heating system, optical fiber annealing system, spiral air intake system, coating system and take-up system are arranged in sequence along the optical fiber entry direction, and the fish-mouth stacked ceramic tube system is arranged in the optical fiber annealing system.

2. The annealing device for ultra-low loss optical fiber according to claim 1, characterized in that: The light rod heating system comprises: Optical rods, as precursor materials for optical fibers, need to be heated and melted at high temperatures; Optical fiber drawing furnace, used to heat the optical rod to form a cone head and draw it into an optical fiber of fixed size; The optical fiber is formed by melting the optical rod and is drawn into the required diameter by a fiber drawing furnace. The optical fiber maintains a uniform speed and direction during the drawing process to ensure the consistency of the optical fiber diameter.

3. The annealing device for ultra-low loss optical fiber according to claim 1, characterized in that: The optical fiber annealing system comprises: Annealing furnace; The heating coil is installed in the annealing furnace. A quartz barrel is arranged in the annealing furnace, and a heating coil is wound around the quartz barrel; Metal clamp ring, set at the entrance end of the annealing furnace, used to fix the fish mouth stacked ceramic tube system; The lower tray is arranged at the exit of the annealing furnace to facilitate the disassembly and installation of the internal components of the annealing furnace.

4. The annealing device for ultra-low loss optical fiber according to claim 3, characterized in that: The total height of the heating coil is 1500-3000 mm, the inner diameter is 45-70 mm, the number of turns is 7-15, and cooling water is passed into the interior of the heating coil to prevent the coil from deforming and ensure uniform heating.

5. The annealing device for ultra-low loss optical fiber according to claim 3, characterized in that: The outer diameter of the quartz barrel is 43-70 mm, and the inner diameter is 40-65 mm. When assembling the heating coil and the quartz barrel, the distance between the two ends of the quartz barrel and the heating coil is controlled to be 1-3 mm to ensure uniform heating.

6. The annealing device for ultra-low loss optical fiber according to claim 1, characterized in that: The spiral-inlet air intake system is arranged at the outlet end of the optical fiber annealing system, has an outer diameter of 40 to 80 mm, and an inner diameter of 18 to 32 mm, and comprises: The air inlet pipe is used to provide a channel for gas flow, with a diameter of 4 to 8 mm; Gas one-way throttle valve; Proportional control valve; Gas source storage tank; The angle formed by the air intake pipe and the normal line is 20 to 60°, the angle formed by the air intake pipe and the lower wall is 20 to 45°, and a gas one-way throttle valve and a proportional regulating valve are arranged on the pipeline between the air intake pipe and the gas source storage tank.

7. The annealing device for ultra-low loss optical fiber according to claim 1, characterized in that: The plurality of fish-mouth stacked ceramic tube systems include a plurality of fish-mouth stacked ceramic tubes, which are connected together from bottom to top through fish-mouth stacked ceramic tube connecting rings, the lower fish-mouth stacked ceramic tubes extend upward by 5 to 15 mm, and the total length of all the fish-mouth stacked ceramic tubes after successful connection is 1600 to 3100 mm.

8. The annealing device for ultra-low loss optical fiber according to claim 1, characterized in that: The maximum outer diameter of the fish-mouth stacked ceramic tube is 30 to 48 mm, and the size is reduced by 0.6 to 0.8 times from bottom to top.

9. The annealing device for ultra-low loss optical fiber according to claim 1, characterized in that: The maximum inner diameter of the fish-mouth stacked ceramic tube is 18.5-29.6 mm, and the size decreases by 0.6-0.8 times from bottom to top, and the minimum inner diameter is 0.618 times the maximum inner diameter.

10. A method for annealing an ultra-low loss optical fiber, characterized in that: Annealing is performed using an ultra-low loss optical fiber annealing device as claimed in any one of claims 1 to 9, comprising the following steps: 1) Complete the layout of the optical rod heating system, optical fiber annealing system, spiral air intake system, fish-mouth stacked ceramic tube system, coating system and take-up system; 2) The optical rod enters the optical fiber drawing furnace and is heated and melted under high temperature conditions; the optical fiber drawing furnace is used to draw the molten optical rod along the optical fiber drawing direction to form an optical fiber of the required diameter; 3) The optical fiber obtained in step 2) enters an annealing furnace for annealing treatment.

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