Method for manufacturing an optical fiber preform

Abstract

The application relates to the technical field of optical fiber preparation, and provides a preparation method of an optical fiber preform, which comprises the following steps: fixing a head pipe and a tail pipe at two ends of a deposition lathe through a clamp respectively; placing a deposition pipe between the head pipe and the tail pipe; heating at least one of opposite ends of the head pipe and the deposition pipe and / or at least one of opposite ends of the deposition pipe and the tail pipe; adopting a flaring component to perform a flaring operation on the heated end of the head pipe, the deposition pipe and the tail pipe to be flared, the flaring part of the flaring component is in a conical shape; fusing the opposite ends of the head pipe and the deposition pipe and the opposite ends of the deposition pipe and the tail pipe; then forming a core layer on the head pipe, the deposition pipe and the tail pipe, and forming a core rod after rod shrinking; performing a sleeve operation on the core rod to form an optical fiber preform. The application can make the flared end formed symmetrical, so that the concentricity of the fusion of the head pipe, the deposition pipe and the tail pipe is improved, the core layer is deposited uniformly, and the quality of the optical fiber preform is improved.

Description

Technical Field

[0001] This invention relates to the field of optical fiber fabrication technology, and in particular to a method for fabricating an optical fiber preform. Background Technology

[0002] Optical fiber, also known as optical waveguide fiber, is a type of fiber made of glass or plastic. It mainly consists of a core, cladding, and coating. The specific manufacturing process involves first depositing the core layer in a deposition tube using MCVD or PCVD methods. Then, the deposited tube is fused together to form a core rod. Based on the required core-to-cladding ratio, a sleeve of a certain thickness is then fitted over the core rod, allowing the core rod and sleeve to be further fused together to form a preform. The qualified preform is then placed on a drawing tower for drawing. During the drawing process, an inner coating and a coating layer are uniformly coated around the fiber to form the optical fiber. In double-clad optical fibers, the cladding consists of an inner cladding and an outer cladding. The deposition tube and sleeve together form the inner cladding, while the inner coating forms the outer cladding. In single-clad optical fibers, the deposition tube and sleeve together form the cladding.

[0003] In existing technologies, during the core deposition process, a head tube and a tail tube need to be fused at both ends of the deposition tube. This serves two purposes: firstly, it facilitates the connection between the deposition tube and the fixtures at both ends of the deposition lathe; secondly, it effectively utilizes the preform and avoids waste. Since the diameters of the deposition tube, head tube, and tail tube are usually different, one or both ends of the deposition tube and / or head tube and / or tail tube need to be flared before the fusion operation. This ensures that the ends of the deposition tube, head tube, and tail tube to be fused have the same diameter, facilitating concentric fusion of the three tubes. However, the flaring operation is prone to errors leading to asymmetry, which prevents concentric fusion of the head tube, deposition tube, and tail tube, causing the deposition tube to be tilted and resulting in uneven core deposition. Furthermore, the temperature of the outer wall of the deposition tube needs to be monitored during deposition. If the deposition tube is tilted, the accuracy of the temperature detection head will be reduced, making it impossible to accurately adjust the deposition temperature as needed during deposition, affecting the quality of the preform, and ultimately preventing the optical fiber from meeting customer requirements, resulting in economic losses.

[0004] Therefore, it is necessary to provide a new technical solution to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a method for preparing optical fiber preforms, which aims to keep the deposition tube, head tube, and tail tube concentric after fusion splicing, thereby ensuring uniform core deposition, improving the accuracy of temperature detection on the outer wall of the deposition tube, and thus improving the quality of the preform.

[0006] This invention provides a method for fabricating an optical fiber preform, wherein the optical fiber includes a deposition tube, a head tube, and a tail tube, and the fabrication method includes the following steps:

[0007] Step 1: Fix the head tube and the tail tube to both ends of the deposition lathe using clamps;

[0008] Step 2: Place the deposition tube between the head tube and the tail tube, heat at least one end of the head tube and the deposition tube and / or at least one end of the deposition tube and the tail tube, and use a flaring component to flare the heated ends of the head tube, the deposition tube and the tail tube so that the ends of the head tube and the tail tube near the deposition tube have the same diameter as the two ends of the deposition tube, wherein the flared part of the flaring component is conical.

[0009] Step 3: Weld the opposite ends of the head tube and the deposition tube together, and weld the opposite ends of the tail tube and the deposition tube together.

[0010] Step 4: After the head tube, the deposition tube, and the tail tube are fused together, a core layer is formed on the head tube, the deposition tube, and the tail tube, and then the core is shrunk to form a core rod.

[0011] Step 5: Perform a sleeve operation on the core rod to form an optical fiber preform.

[0012] According to the method for preparing optical fiber preforms provided by the present invention, the flared component includes a first conical column and a second conical column, and the first conical column and the second conical column have different diameters, and the bottoms of the first conical column and the second conical column are fixedly connected at a preset included angle.

[0013] In step 2, the step of using a flaring component to flare the heating ends of the head tube, the deposition tube, and the tail tube includes: inserting the top end of the first conical column or the second conical column of the flaring component into the heating end of the head tube, the deposition tube, and the tail tube to form a corresponding flared end.

[0014] According to the fiber preform fabrication method provided by the present invention, in step 2, before heating at least one end of the head tube and the deposition tube and / or at least one end of the deposition tube and the tail tube, the method further includes the following steps:

[0015] A concentric component is placed at the position corresponding to the deposition tube, so that the head tube, the deposition tube and the tail tube are arranged along the same axis through the concentric component.

[0016] According to the fiber preform preparation method provided by the present invention, in step 2, after placing the concentric component at the position corresponding to the deposition tube and before the flaring operation, the following steps are further included:

[0017] The flaring component is fixed on the concentric component. By adjusting the position of the concentric component, the first conical column or the second conical column is coaxially arranged with one of the three components to be flared: the head tube, the deposition tube, and the tail tube. At the same time, the head tube, the deposition tube, and the tail tube are coaxially arranged.

[0018] According to the method for preparing optical fiber preforms provided by the present invention, the flaring component further includes a handle. The bottom center positions of the first conical column and the second conical column are respectively provided with a first handle slot and a second handle slot. The bottom of the connection between the first conical column and the second conical column is provided with a third handle slot. The handle is connected to the first conical column and / or the second conical column through one of the first handle slot, the second handle slot and the third handle slot.

[0019] In step 2, when the top end of the first conical column is inserted into the heating end to be expanded in the head tube, the deposition tube, and the tail tube, the handle is fixed to the first conical column through the first handle slot, and the handle is coaxial with the first conical column at this time; when the top end of the second conical column is inserted into the heating end to be expanded in the head tube, the deposition tube, and the tail tube, the handle is fixed to the second conical column through the second handle slot, and the handle is coaxial with the second conical column at this time.

[0020] In non-flaring operation, if the head tube, tail tube, or deposition tube requires support, the handle is fixed to the connection between the first conical column and the second conical column through the third handle slot, and the head tube, tail tube, or deposition tube is supported by the included angle between the first conical column and the second conical column.

[0021] According to the fiber preform preparation method provided by the present invention, the concentric component includes a base, two supports and two semi-fastening retaining rings. The base is mounted on the deposition lathe. The two supports are vertically arranged on the base and are located on opposite sides of the base. The two semi-fastening retaining rings are respectively disposed on the top of the two supports. The deposition tube is clamped on the concentric component by the two semi-fastening retaining rings.

[0022] The two semi-fastened retaining rings are rotatably connected to the two supports respectively, the clamp is rotatably connected to the deposition lathe, the semi-fastened retaining rings are used to drive the deposition tube to rotate, the two clamps are used to drive the head tube and the tail tube to rotate respectively, and the semi-fastened retaining rings and the clamps rotate in the same direction and at the same speed.

[0023] In step 2, when the flaring operation is performed, at least one of the head tube, the deposition tube, and the tail tube that needs to be flared rotates at a constant speed on the deposition lathe.

[0024] In step 3, during the welding operation, the head tube, the deposition tube, and the tail tube all rotate at a constant speed on the deposition lathe.

[0025] According to the fiber preform preparation method provided by the present invention, the base is provided with multiple graduated grooves, the multiple grooves extend along the length direction and the width direction of the base respectively, the grooves extending along the length direction and the width direction of the base are arranged to intersect each other, the two supports are slidably installed in the grooves, and the height of the two supports in the vertical direction is adjustable.

[0026] The step of arranging the head tube, the deposition tube, and the tail tube along the same axis using the concentric components includes: adjusting the position of the two supports in the chute to adjust the horizontal position of the deposition tube relative to the head tube and the tail tube; and / or adjusting the height of the two supports to adjust the vertical position of the deposition tube relative to the head tube and the tail tube, thereby arranging the head tube, the deposition tube, and the tail tube along the same axis.

[0027] According to the fiber preform preparation method provided by the present invention, the diameter of the two semi-fastening retainers can be adjusted. Each semi-fastening retainer consists of two identical semi-rings, one end of the two semi-rings is movably connected, and the other end of the two semi-rings can be locked or opened by a snap fastener.

[0028] According to the fiber preform preparation method provided by the present invention, in step 1, the two clamps respectively clamp and fix the opposite ends of the head tube and the tail tube at both ends of the deposition lathe, and the head tube and the tail tube are arranged along the same axis.

[0029] According to the fiber preform fabrication method provided by the present invention, in step 3, the steps of fusing the opposite ends of the head tube and the deposition tube, and fusing the opposite ends of the tail tube and the deposition tube include:

[0030] At least one end of the head tube and the deposition tube is heated to a molten state, and then the opposite ends of the head tube and the deposition tube are brought into contact and fused together.

[0031] At least one end of the tail tube and the deposition tube is heated to a molten state, and then the opposite ends of the tail tube and the deposition tube are brought into contact and fused together.

[0032] The above-described technical solution of the present invention has the following beneficial effects:

[0033] The fiber optic preform fabrication method provided by this invention designs the flaring portion of the flaring component into a conical shape. This flaring component is used to flare the heating ends in the head tube, deposition tube, and tail tube, resulting in good symmetry of the flared ends. This improves the concentricity of the fusion of the head tube, deposition tube, and tail tube. This high degree of concentricity ensures that the core layer material is uniformly distributed on the walls of the deposition tube, head tube, and tail tube during deposition, avoiding quality fluctuations caused by uneven deposition and significantly improving the uniformity and consistency of the core layer. Because the uniformity of core layer deposition is significantly improved, the fabricated fiber optic preform is structurally more uniform, reducing internal defects and stress concentration points, thereby improving the overall quality of the fiber optic preform. Furthermore, since the concentricity of the fusion of the head tube, deposition tube, and tail tube is guaranteed, the accuracy of temperature detection by the probe can be further improved during deposition, further enhancing the quality of the preform. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a flowchart of a method for preparing an optical fiber preform according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the operating platform for the optical fiber preform provided in an embodiment of the present invention;

[0037] Figure 3 This is a cross-sectional schematic diagram of the flared component provided in an embodiment of the present invention;

[0038] Figure 4 A front view of the first or second conical cylinder of the flared component provided in an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of the base structure of the concentric component provided in an embodiment of the present invention.

[0040] Figure label:

[0041] 1. Head tube; 2. Flared end of head tube; 3. Tail tube; 4. Flared end of tail tube; 5. Deposition tube; 6. First clamp; 7. Second clamp; 8. Base; 9. First support; 10. Second support; 11. First semi-fastening retaining ring; 12. Second semi-fastening retaining ring; 13. First buckle; 14. Second buckle; 15. First conical column; 16. Second conical column; 17. Handle; 18. First handle slot; 19. Second handle slot; 20. Third handle slot; 100. Flared part; 801. Slide groove. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0043] The following is combined Figures 1-5 The method for preparing the optical fiber core layer of the present invention will be described in detail.

[0044] like Figure 1 and Figure 2 As shown, the optical fiber includes a deposition tube 5, a head tube 1, and a tail tube 3. The method for preparing the optical fiber core layer of the present invention includes the following steps:

[0045] Step 1: Fix the head tube 1 and tail tube 3 to both ends of the deposition lathe using clamps;

[0046] Step 2: Place the deposition tube 5 between the head tube 1 and the tail tube 3, heat at least one end of the head tube 1 and the deposition tube 5 and / or at least one end of the deposition tube 5 and the tail tube 3, and use the flaring component 100 to flare the heated ends of the head tube 1, the deposition tube 5 and the tail tube 3 so that the ends of the head tube 1 and the tail tube 3 near the deposition tube 5 have the same diameter as the two ends of the deposition tube 5, wherein the flared part of the flaring component 100 is conical.

[0047] Step 3: Weld the opposite ends of the head tube 1 and the deposition tube 5 together, and weld the opposite ends of the tail tube 3 and the deposition tube 5 together.

[0048] Step 4: After the head tube 1, deposition tube 5 and tail tube 3 are fused together, a core layer is formed on the head tube 1, deposition tube 5 and tail tube 3, and the core is then shrunken to form a core rod.

[0049] Step 5: Perform a sleeve operation on the core rod to form an optical fiber preform.

[0050] It should be noted that the opposite ends of the head tube 1 and the sedimentation tube 5 refer to the end of the head tube 1 that is close to (or faces) the sedimentation tube 5 and the end of the sedimentation tube 5 that is close to (or faces) the head tube 1; similarly, the opposite ends of the tail tube 3 and the sedimentation tube 5 refer to the end of the tail tube 3 that is close to (or faces) the sedimentation tube 5 and the end of the sedimentation tube 5 that is close to (or faces) the tail tube 3.

[0051] Specifically, such as Figure 2 As shown, in this embodiment, the fixture includes a first fixture 6 and a second fixture 7, which are respectively disposed at both ends of the deposition lathe. In step 1, the first fixture 6 and the second fixture 7 respectively clamp and fix the opposite ends of the head tube 1 and the tail tube 3 (i.e., the ends of the head tube 1 and the tail tube 3 that are far apart from each other), and make the head tube 1 and the tail tube 3 arranged along the same axis.

[0052] Understandably, the diameters of the head tube, deposition tube, and tail tube used are not necessarily the same. The purpose of the flaring operation is to ensure that the diameters of the two tubes being fused together are consistent at the fusion point, thereby improving the uniformity of core deposition. The flaring operation can be performed on the smaller of two adjacent tubes, or on both adjacent tubes; there is no restriction on this.

[0053] Combination Figure 3 and Figure 4 As shown, the flared component 100 includes a first conical column 15, a second conical column 16, and a handle 17. The first conical column 15 and the second conical column 16 have different diameters, and their bottoms are fixedly connected at a preset angle. A first handle slot 18 and a second handle slot 19 are respectively located at the center of the bottom of the first conical column 15 and the second conical column 16. A third handle slot 20 is located at the bottom of the connection point between the first conical column 15 and the second conical column 16. The handle 17 is connected to the first conical column 15 and / or the second conical column 16 through one of the first handle slot 18, the second handle slot 19, or the third handle slot 20. Of course, in other embodiments, the handle 17 can also be connected to the first conical column 15 and / or the second conical column 16 in other ways.

[0054] Combination Figures 2-4 As shown, in step 2 above, the step of using the flaring component 100 to flare the heating ends to be flared in the head tube 1, deposition tube 5 and tail tube 3 includes: inserting the top end of the first conical column 15 or the second conical column 16 of the flaring component 100 into the heating ends to be flared in the head tube 1, deposition tube 5 and tail tube 3, so that the heating ends to be flared form corresponding flared ends.

[0055] Specifically, when the top end of the first conical column 15 is inserted into the heating end to be expanded in the head tube 1, deposition tube 5, and tail tube 3, the handle 17 is fixed to the first conical column 15 through the first handle slot 18, and the handle 17 is coaxially arranged with the first conical column 15. When the top end of the second conical column 16 is inserted into the heating end to be expanded in the head tube 1, deposition tube 5, and tail tube 3, the handle 17 is fixed to the second conical column 16 through the second handle slot 19, and the handle 17 is coaxially arranged with the second conical column 16.

[0056] When flaring at least one of the opposite ends of the head tube 1 and the deposition tube 5, the head tube 1 and the deposition tube 5 that need to be flared rotate at a constant speed on the deposition lathe, and the flared end of the head tube 1 and the deposition tube 5 is heated by the lathe heating flame torch. When the flared end of the head tube 1 and the deposition tube 5 is in a molten state, the flaring component is used to perform the flaring operation to form a uniform and symmetrical flared end.

[0057] From the perspective of saving processes and simplifying procedures, when the diameters of the head tube 1 and the deposition tube 5 are different, the one with the smaller diameter can be flared. For example, when the diameter of the head tube 1 is smaller than the diameter of the deposition tube 5, before the head tube 1 and the deposition tube 5 are fused, the end of the head tube 1 closest to the deposition tube 5 is flared as needed to form the flared end 2 of the head tube. This ensures that the diameter of the flared end 2 of the head tube is consistent with the diameter of the opposite side of the deposition tube 5, so that the head tube 1 and the deposition tube 5 can be fused better.

[0058] When flaring at least one of the opposite ends of the tailpipe 3 and the deposition tube 5, the tailpipe 3 and the deposition tube 5 that need to be flared rotate at a constant speed on the deposition lathe, and the end of the tailpipe 3 and the deposition tube 5 that needs to be flared is heated by the lathe heating flame torch. When the end of the tailpipe 3 and the deposition tube 5 that needs to be flared is in a molten state, the flaring operation is performed in order to form a uniform and symmetrical flared end.

[0059] From the perspective of saving processes and simplifying procedures, when the diameters of the tail tube 3 and the deposition tube 5 are different, the one with the smaller diameter can be flared. For example, when the diameter of the tail tube 3 is smaller than the diameter of the deposition tube 5, before the tail tube 3 and the deposition tube 5 are fused, the end of the tail tube 3 closest to the deposition tube 5 is flared as needed to form the flared end 4 of the tail tube, so that the tail tube 3 and the deposition tube 5 can be fused better.

[0060] During non-flaring operation, if the head tube 1, tail tube 3, or deposition tube 5 requires support, the handle 17 is fixed at the connection between the first conical column 15 and the second conical column 16 through the third handle slot 20, and the head tube 1, tail tube 3, or deposition tube 5 is supported by the included angle between the first conical column 15 and the second conical column 16.

[0061] In this embodiment, the top (tip) of the first or second conical column in the flaring component is inserted into the heating end to be flared in the head tube, deposition tube, and tail tube. Since both the first and second conical columns are conical, the flared end has good symmetry, thereby improving the concentricity of the three tubes of the head tube, deposition tube, and tail tube, making the core layer deposition uniform, and thus improving the quality of the optical fiber preform.

[0062] In one embodiment, before heating at least one end of the head tube 1 and the deposition tube 5 and / or at least one end of the deposition tube 5 and the tail tube 3 in step 2 above, the following step is further included:

[0063] A concentric component is placed at the position corresponding to the deposition tube 5, so that the head tube 1, deposition tube 5 and tail tube 3 are arranged along the same axis.

[0064] like Figure 2 As shown, the concentric component can be positioned below the deposition tube 5. The concentric component includes a base 8, two supports (i.e., the first support 9 and the second support 10), and two semi-fastening retaining rings (i.e., the first semi-fastening retaining ring 11 and the second semi-fastening retaining ring 12). The base 8 is mounted on a deposition lathe. The first support 9 and the second support 10 are both vertically mounted on the base 8 and located on opposite sides of the base 8. The first semi-fastening retaining ring 11 and the second semi-fastening retaining ring 12 are respectively positioned on top of the first support 9 and the second support 10. The deposition tube 5 is clamped to the concentric component by the first semi-fastening retaining rings 11 and the second semi-fastening retaining rings 12.

[0065] The first semi-fastening retaining ring 11 and the second semi-fastening retaining ring 12 are rotatably connected to the first support 9 and the second support 10, respectively. The first clamp 6 and the second clamp 7 are rotatably connected to the deposition lathe, respectively. The first semi-fastening retaining ring 11 and the second semi-fastening retaining ring 12 are both used to clamp the deposition tube 5 and jointly drive the deposition tube 5 to rotate. The first clamp 6 and the second clamp 7 are respectively used to drive the head tube 1 and the tail tube 3 to rotate.

[0066] In step 2 above, when the flaring operation is performed, at least one of the head tube 1, deposition tube 5 and tail tube 3 that needs to be flared rotates at a constant speed on the deposition lathe, and the flaring component can be used to form a flared end with good symmetry.

[0067] Furthermore, in combination Figure 2 and Figure 5As shown, the base 8 has multiple graduated grooves 801, which extend along the length and width directions of the base 8 respectively. These grooves 801 intersect each other. The first support 9 and the second support 10 are slidably mounted in the grooves 801, allowing them to move forward, backward, left, and right on the base 8. Furthermore, the vertical height of the first support 9 and the second support 10 is adjustable. The method of height adjustment for the first support 9 and the second support 10 is not limited here.

[0068] The step of setting the head tube 1, deposition tube 5 and tail tube 3 along the same axis using concentric components includes: adjusting the position of the first support 9 and the second support 10 in the slide 801 to adjust the position of the deposition tube 5 in the horizontal direction relative to the head tube 1 and tail tube 3; and / or adjusting the height of the first support 9 and the second support 10 to adjust the position of the deposition tube 5 in the vertical direction relative to the head tube 1 and tail tube 3, so that the head tube 1, deposition tube 5 and tail tube 3 can be set along the same axis, thereby avoiding the problem of misalignment of the three tubes (deposition tube, head tube and tail tube) due to errors such as manual visual operation.

[0069] This embodiment, based on the above embodiment, incorporates a concentric component, which can avoid the problem of misalignment of the deposition tube, head tube, and tail tube during fusion due to manual operation. It can ensure that the deposition tube, head tube, and tail tube remain concentric after fusion, thereby making the core layer deposition more uniform, improving the quality of the preform, reducing the fiber defect rate, and saving costs.

[0070] Furthermore, in step 2 above, after placing the concentric component at the position corresponding to the deposition tube and before the flaring operation, the following steps are also included:

[0071] The flaring component is fixed on the concentric component. By adjusting the position of the concentric component, the first or second conical column is made to be coaxial with one of the three components to be flared: the head tube, the deposition tube, and the tail tube. At the same time, the head tube, the deposition tube, and the tail tube are made to be coaxial.

[0072] By fixing the flaring component to the concentric component, when adjusting the concentricity of the head tube, deposition tube, and tail tube using the concentric component, the first or second conical column can be adjusted to be coaxial with the one of the three tubes to be flared. In this way, the symmetry of the flared ends formed by the head tube, tail tube, and deposition tube can be further improved in the subsequent flaring operation, the concentricity of the three tubes after fusion splicing is optimized, the core layer deposition is uniform, and the quality of the optical fiber preform is further improved.

[0073] Furthermore, multiple concentric components can be provided. When the deposition tube is flared, one concentric component is used to fix the deposition tube, and another concentric component is used to fix the flaring component.

[0074] like Figure 2 As shown, in one embodiment, the diameters of both the first semi-fastening retaining ring 11 and the second semi-fastening retaining ring 12 are adjustable. Specifically, each semi-fastening retaining ring consists of two identical semi-rings that are fastened together. One end of each semi-ring is movably connected, and the other end can be locked or unlocked by a latch (first latch 13 or second latch 14).

[0075] In step 2 above, after placing the concentric components below the deposition tube 5, first adjust the inner diameter of the first half-locking retainer 11 and the second half-locking retainer 12 to make them the same as the diameter of the deposition tube 5; then open the first half-locking retainer 11 and the second half-locking retainer 12, place the deposition tube 5 inside the first half-locking retainer 11 and the second half-locking retainer 12, close the first half-locking retainer 11 and the second half-locking retainer 12, and secure the first half-locking retainer 11 through the first latch 13 and the second latch 14. The first half-locking ring 11 and the second half-locking ring 12 are locked together. Then, by adjusting the height and position of the first support 9 and the second support 10, the head tube 1, the deposition tube 5 and the tail tube 3 are placed concentrically. Finally, the rotation direction and speed of the first half-locking ring 11 and the second half-locking ring 12 are set by the control system so that the rotation direction and speed of the first half-locking ring 11 and the second half-locking ring 12 driving the deposition tube 5 during the welding operation are consistent with the rotation direction and speed of the first clamp 6 and the second clamp 7.

[0076] Furthermore, the control system is connected to the drive components of the first semi-fastening retainer 11 and the second semi-fastening retainer 12, as well as the drive components of the first clamp 6 and the second clamp 7, thereby controlling the first semi-fastening retainer 11 and the second semi-fastening retainer 12 to rotate in the same direction and at the same speed with the first clamp 6 and the second clamp 7 at both ends of the deposition lathe, thereby ensuring that the deposition tube 5, the head tube 1, and the tail tube 3 rotate in the same direction and at the same speed, further improving the concentricity of the three tubes welding.

[0077] In one embodiment, the inner surfaces of the first semi-fastening retainer 11 and the second semi-fastening retainer 12 that contact the deposition tube 5 are both soft contact surfaces, so as to avoid damaging the deposition tube 5 when the first semi-fastening retainer 11 and the second semi-fastening retainer 12 come into contact with the deposition tube 5.

[0078] Combination Figure 2 As shown, in step 3 above, the steps of welding the opposite ends of the head tube 1 and the deposition tube 5, and welding the opposite ends of the tail tube 3 and the deposition tube 5 include:

[0079] At least one end of the head tube 1 and the deposition tube 5 is heated to a molten state, and then the opposite ends of the head tube 1 and the deposition tube 5 are brought into contact and fused together; and at least one end of the tail tube 3 and the deposition tube 5 is heated to a molten state, and then the opposite ends of the tail tube 3 and the deposition tube 5 are brought into contact and fused together.

[0080] For example, when welding the head tube 1 and the deposition tube 5, the flared end 2 of the head tube is heated using a lathe-heated flame torch. Once the flared end 2 is molten, it is brought into contact with the deposition tube 5 for welding. Since the head tube 1 has undergone high-temperature heating once when forming the flared end 2, continuing to heat the flared end 2 during welding can shorten the welding operation time. Similarly, when welding the tail tube 3 and the deposition tube 5, the flared end 4 of the tail tube is heated using a lathe-heated flame torch. Once the flared end 4 is molten, it is brought into contact with the deposition tube 5 for welding.

[0081] During the welding operation, the head tube 1, deposition tube 5, and tail tube 3 all rotate at a constant speed on the deposition lathe.

[0082] The fiber optic preform fabrication method provided by this invention designs the flaring portion of the flaring component into a conical shape. Using this flaring component to flare the heating ends in the head tube, deposition tube, and tail tube results in good symmetry of the flared ends, thus improving the concentricity of the fusion splicing of the head tube, deposition tube, and tail tube, ensuring uniform core layer deposition, and thereby improving the quality of the fiber optic preform. Furthermore, since the concentricity of the fusion splicing of the head tube, deposition tube, and tail tube is guaranteed, the accuracy of the probe's temperature detection during the deposition process can be further improved, further enhancing the preform quality.

[0083] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an optical fiber preform, characterized in that, The optical fiber includes a deposition tube, a head tube, and a tail tube, and the fabrication method includes the following steps: Step 1: Fix the head tube and the tail tube to both ends of the deposition lathe using clamps; Step 2: Place the deposition tube between the head tube and the tail tube, heat at least one end of the head tube and the deposition tube and / or at least one end of the deposition tube and the tail tube, and use a flaring component to flare the heated ends of the head tube, the deposition tube and the tail tube so that the ends of the head tube and the tail tube near the deposition tube have the same diameter as the two ends of the deposition tube, wherein the flared part of the flaring component is conical. Step 3: Weld the opposite ends of the head tube and the deposition tube together, and weld the opposite ends of the tail tube and the deposition tube together. Step 4: After the head tube, the deposition tube, and the tail tube are fused together, a core layer is formed on the head tube, the deposition tube, and the tail tube, and then the core is shrunk to form a core rod. Step 5: Perform a sleeve operation on the core rod to form an optical fiber preform; The flared component includes a first conical column and a second conical column, and the first conical column and the second conical column have different diameters. The bottoms of the first conical column and the second conical column are fixedly connected at a preset angle. In step 2, the step of using a flaring component to flare the heating ends of the head tube, the deposition tube, and the tail tube includes: inserting the top end of the first conical column or the second conical column of the flaring component into the heating end of the head tube, the deposition tube, and the tail tube to form a corresponding flared end. In step 2, before heating at least one end of the head tube and the deposition tube and / or at least one end of the deposition tube and the tail tube, the following steps are also included: A concentric component is placed at the position corresponding to the deposition tube, so that the head tube, the deposition tube and the tail tube are arranged along the same axis through the concentric component.

2. The method for preparing an optical fiber preform according to claim 1, characterized in that, In step 2, after placing the concentric component at the position corresponding to the deposition tube and before the flaring operation, the following steps are also included: The flaring component is fixed on the concentric component. By adjusting the position of the concentric component, the first conical column or the second conical column is coaxially arranged with one of the three components to be flared: the head tube, the deposition tube, and the tail tube. At the same time, the head tube, the deposition tube, and the tail tube are coaxially arranged.

3. The method for preparing an optical fiber preform according to claim 1, characterized in that, The flared component also includes a handle. The bottom center positions of the first conical column and the second conical column are respectively provided with a first handle slot and a second handle slot. The bottom of the connection between the first conical column and the second conical column is provided with a third handle slot. The handle is connected to the first conical column and / or the second conical column through one of the first handle slot, the second handle slot and the third handle slot. In step 2, when the top end of the first conical column is inserted into the heating end to be expanded in the head tube, the deposition tube, and the tail tube, the handle is fixed to the first conical column through the first handle slot, and the handle is coaxial with the first conical column at this time; when the top end of the second conical column is inserted into the heating end to be expanded in the head tube, the deposition tube, and the tail tube, the handle is fixed to the second conical column through the second handle slot, and the handle is coaxial with the second conical column at this time. In non-flaring operation, if the head tube, tail tube, or deposition tube requires support, the handle is fixed to the connection between the first conical column and the second conical column through the third handle slot, and the head tube, tail tube, or deposition tube is supported by the included angle between the first conical column and the second conical column.

4. The method for preparing an optical fiber preform according to claim 1, characterized in that, The concentric component includes a base, two supports, and two semi-fastening retaining rings. The base is mounted on the deposition lathe. The two supports are vertically arranged on the base and located on opposite sides of the base. The two semi-fastening retaining rings are respectively disposed on the top of the two supports. The deposition tube is clamped to the concentric component by the two semi-fastening retaining rings. The two semi-fastened retaining rings are rotatably connected to the two supports respectively, the clamp is rotatably connected to the deposition lathe, the semi-fastened retaining rings are used to drive the deposition tube to rotate, the two clamps are used to drive the head tube and the tail tube to rotate respectively, and the semi-fastened retaining rings and the clamps rotate in the same direction and at the same speed. In step 2, when the flaring operation is performed, at least one of the head tube, the deposition tube, and the tail tube that needs to be flared rotates at a constant speed on the deposition lathe. In step 3, during the welding operation, the head tube, the deposition tube, and the tail tube all rotate at a constant speed on the deposition lathe.

5. The method for preparing an optical fiber preform according to claim 4, characterized in that, The base is provided with multiple graduated sliding grooves, which extend along the length and width of the base respectively. The sliding grooves extending along the length and width of the base are intersected with each other. Both supports are slidably installed in the sliding grooves, and the height of the two supports in the vertical direction is adjustable. The step of arranging the head tube, the deposition tube, and the tail tube along the same axis using the concentric components includes: adjusting the position of the two supports in the chute to adjust the horizontal position of the deposition tube relative to the head tube and the tail tube; and / or adjusting the height of the two supports to adjust the vertical position of the deposition tube relative to the head tube and the tail tube, thereby arranging the head tube, the deposition tube, and the tail tube along the same axis.

6. The method for preparing an optical fiber preform according to claim 4, characterized in that, The diameter of both semi-fastening retaining rings is adjustable. Each semi-fastening retaining ring consists of two identical semi-rings. One end of the two semi-rings is movably connected, and the other end of the two semi-rings can be locked or opened by a buckle.

7. The method for preparing an optical fiber preform according to claim 1, characterized in that, In step 1, the two clamps respectively hold and fix the opposite ends of the head tube and the tail tube at both ends of the deposition lathe, and the head tube and the tail tube are arranged along the same axis.

8. The method for preparing an optical fiber preform according to claim 1, characterized in that, In step 3, the steps of welding the opposite ends of the head tube and the deposition tube, and welding the opposite ends of the tail tube and the deposition tube, include: At least one end of the head tube and the deposition tube is heated to a molten state, and then the opposite ends of the head tube and the deposition tube are brought into contact and fused together. At least one end of the tail tube and the deposition tube is heated to a molten state, and then the opposite ends of the tail tube and the deposition tube are brought into contact and fused together.

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