A kind of anti-resonant hollow core optical fiber preform positioning mold and its assembling method

Abstract

The application provides an anti-resonance hollow-core optical fiber preform positioning mold and an assembling method thereof, which comprises: a first group of rod molds arranged in the center area of a sleeve and used for forming a core part of an optical fiber; and a second group of rod molds arranged in an anti-resonance area of a cladding and used for forming a specific structure in the cladding of the optical fiber; the first group of rod molds and the second group of rod molds are tapered along the longitudinal axis direction of the optical fiber, that is, along the longitudinal axis direction of the optical fiber, the outer boundary size of the first group of rod molds and the second group of rod molds gradually changes, so that they have different cross-sectional sizes at different positions of the optical fiber preform. The anti-resonance hollow-core optical fiber preform positioning mold provided by the application has the advantages of simple structure, convenient assembling operation, and solves the technical problems of low positioning precision, low manufacturing efficiency and poor repeatability of the anti-resonance hollow-core optical fiber preform.

Description

Technical Field

[0001] This invention relates to the field of optical fiber preform positioning mold technology, specifically to an anti-resonant hollow optical fiber preform positioning mold and its assembly method. Background Technology

[0002] Traditional silica optical fibers rely on the principle of total internal reflection to confine light transmission within a solid fiber core. However, inherent defects in the material, such as nonlinearity, dispersion, and light damage, limit their application in certain special scenarios. Hollow-core optical fibers utilize a special cladding structure to confine light transmission within a low-refractive-index air core, fundamentally avoiding the intrinsic confinement problems of light in silica glass or other media, and fully realizing the application potential of optical fibers in various fields.

[0003] Antiresonant hollow fiber guides light based on the antiresonant reflection waveguide theory. A high-refractive-index antiresonant thin layer acts as a Fabry-Perot resonant cavity. When the antiresonance condition is met, light is confined within the low-refractive-index fiber core for transmission. Antiresonant hollow fiber possesses characteristics such as low loss, low delay, low dispersion, low nonlinearity, large mode area, wide transmission band, and strong gas-light interaction, demonstrating significant advantages in fields such as fiber optic communication, laser transmission, fiber optic sensing, and laser medicine.

[0004] The unique advantages of antiresonant hollow-core optical fibers are attributed to the ingenious design of their internal microstructure. However, geometric deviations caused during the installation of the antiresonant hollow-core optical fiber preform directly affect the final internal geometry of the fiber, thus impacting its optical transmission characteristics. Currently, antiresonant hollow-core optical fibers are mostly drawn using a "stack-drawing" method. During preform assembly, glass tubes or rods with sufficient diameter are often used to support the internal structure of the preform, and these tubes or rods are only used in the central region [Reference: Revolver Hollow Core Optical Fibers, Fibers 2018, 6, 39; doi:10.3390 / fib6020039]. When the size of the filling glass tube or rod is large, the internal glass structure of the antiresonant hollow-core optical fiber preform is prone to breakage during the filling process; when the size of the filling glass tube is small, the internal structure of the preform cannot be tightly fixed, easily causing internal structural misalignment. Therefore, traditional anti-resonant hollow fiber preforms suffer from technical problems such as low positioning accuracy, low manufacturing efficiency, and poor repeatability.

[0005] The above background information is provided only to assist in understanding the inventive concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application, nor does it necessarily provide technical teaching. In the absence of clear evidence that the above information was disclosed before the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0006] To address the technical problems of low positioning accuracy, low manufacturing efficiency, and poor repeatability in traditional anti-resonant hollow fiber preforms, this invention proposes a positioning mold for anti-resonant hollow fiber preforms and its assembly method. The mold has a simple structure and is easy to operate, thus solving the technical problems of low positioning accuracy, low manufacturing efficiency, and poor repeatability in anti-resonant hollow fiber preforms.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] This invention provides a positioning mold for an anti-resonant hollow optical fiber preform, comprising:

[0009] The first set of rod molds is located in the central region of the sleeve and is used to form the core portion of the optical fiber.

[0010] And / or a second set of rod molds, the second set of rod molds being disposed in the anti-resonance region of the cladding, for forming a specific structure in the cladding of the optical fiber;

[0011] The first set of rod molds and / or the second set of rod molds both extend in a tapered shape along the longitudinal axis of the optical fiber. That is, along the longitudinal axis of the optical fiber, the outer boundary dimensions of the first set of rod molds and / or the second set of rod molds gradually change, so that they each have different cross-sectional dimensions at different positions on the optical fiber preform.

[0012] This invention proposes a positioning mold for anti-resonant hollow fiber preforms and its assembly method. The mold has a simple structure and is easy to operate, which solves the technical problems of low positioning accuracy, low manufacturing efficiency and poor repeatability of anti-resonant hollow fiber preforms.

[0013] As a preferred technical solution, the variation range of the outer boundary dimension of the first set of rod molds is designed to cover the outer boundary dimension of the cladding anti-resonance region;

[0014] The variation range of the outer boundary dimensions of the second set of rod molds is designed to cover the boundary dimensions of the region enclosed between adjacent anti-resonant tubes;

[0015] The first set of rod molds and / or the second set of rod molds can move along the longitudinal axis of the optical fiber to achieve a tight fit with the end face of the anti-resonant hollow optical fiber preform.

[0016] As a preferred technical solution, the outer boundary shape of the first set of rod molds is determined according to the outer boundary shape of the cladding anti-resonance region, and the outer boundary shape of the second set of rod molds is determined according to the boundary shape of the region enclosed between adjacent anti-resonance tubes.

[0017] As a preferred technical solution, the outer boundary of the first set of rod molds does not completely cover the area enclosed by the outer boundary of the cladding anti-resonance region inside the sleeve, thereby forming at least one gap between the first set of rod molds and the inner wall of the sleeve and / or the outer boundary of the cladding anti-resonance region.

[0018] The outer boundary of each of the second set of rod molds does not completely cover the area enclosed by the anti-resonant tubes between adjacent layers, thereby forming at least one gap between the anti-resonant tubes between adjacent layers.

[0019] Air pressure is used to fill the gaps during the preform wire drawing process.

[0020] As a preferred technical solution, when the number of cladding anti-resonant tube layers is n, the number of types of the second set of rod molds is n-1, where n≥1.

[0021] As a preferred technical solution, the angle of the cone angle of both the first set of rod molds and the second set of rod molds extending along the longitudinal axis of the optical fiber is 0.1° to 3°.

[0022] As a preferred technical solution, the thickness of both the first set of rod molds and the second set of rod molds extending along the longitudinal axis of the optical fiber is 5 to 20 mm.

[0023] As a preferred technical solution, the number of the second set of rod molds is ≥3.

[0024] The present invention also provides a method for assembling an anti-resonant hollow fiber preform positioning mold, comprising the following steps:

[0025] S1 At one end of the sleeve, at least one anti-resonance outer tube is placed inside the sleeve using the first set of rod molds;

[0026] S2 places the first set of rod molds at the other end of the sleeve;

[0027] S3 checks and confirms that the azimuth angles of the first set of rod molds used at both ends of the bushing are consistent to ensure that the positions of the anti-resonance outer tubes at both ends of the bushing are the same;

[0028] S4 In the anti-resonance outer tube that has been placed at one end of the sleeve, at least one anti-resonance inner tube is placed inside the anti-resonance outer tube using the second set of rod molds.

[0029] S5 places the second set of rod molds inside the anti-resonance outer tube that has been placed at the other end of the sleeve;

[0030] S6 checks and confirms that the azimuth angles of the second set of rod molds used at both ends of the sleeve are consistent, so that the anti-resonance inner tubes at both ends of the sleeve are in the same position in their respective anti-resonance outer tubes.

[0031] S7 is a fixed connection between the tubes in the anti-resonant hollow fiber preform, forming a complete preform structure.

[0032] As a preferred technical solution, the material of the first set of rod molds and / or the second set of rod molds is any one of glass, graphite, and metal;

[0033] When the material of the first set of rod molds and / or the second set of rod molds is glass, at least a portion of the preform is aligned with the first set of rod molds and / or the second set of rod molds along the longitudinal axis of the optical fiber. At the aligned position, the preform is connected to the first set of rod molds and / or the second set of rod molds by welding or bonding. The welding or bonding position covers at least a portion of the first set of rod molds and / or the second set of rod molds, so that the first set of rod molds and / or the second set of rod molds and the preform are integrated into a single structure.

[0034] When the material of the first set of rod molds and / or the second set of rod molds is graphite or metal, at least a portion of the preform is aligned with the first set of rod molds and / or the second set of rod molds along the longitudinal axis of the optical fiber. The preform is fixed by welding or bonding at a position that does not cover the first set of rod molds and / or the second set of rod molds. After the preform is fixed, the first set of rod molds and / or the second set of rod molds are removed from the preform.

[0035] The anti-resonant hollow fiber preform positioning mold and its assembly method provided by this invention have the following beneficial effects:

[0036] 1) The anti-resonant hollow fiber preform positioning mold has a simple structure and is easy to assemble and operate, which solves the technical problems of low positioning accuracy, low manufacturing efficiency and poor repeatability of anti-resonant hollow fiber preforms.

[0037] 2) By using the first and second sets of rod molds that extend in a tapered shape, the internal structure of the optical fiber preform can be positioned and fixed more effectively; the first and second sets of rod molds that extend in a tapered shape can also provide more uniform support and positioning, which helps to reduce the problem of breakage caused by improper glass tube size during the filling process and improves the positioning accuracy of the anti-resonant hollow optical fiber preform.

[0038] The design of the first and second sets of rod dies, which extend in a tapered shape, can simplify the manufacturing process because the gradually changing shape of the dies can better control the shape of the optical fiber preform, reduce manufacturing delays caused by size mismatch, and thus improve manufacturing efficiency.

[0039] Using standardized first and second set of rod dies with tapered extensions ensures that each manufactured fiber optic preform has the same shape, thereby improving manufacturing repeatability. The tapered die design also reduces manufacturing deviations caused by die wear or deformation, further enhancing manufacturing repeatability.

[0040] 3) The outer boundary dimensions of the first set of rod molds are designed to cover the outer boundary dimensions of the cladding anti-resonance region, which ensures that the fiber core can be formed accurately; the outer boundary dimensions of the second set of rod molds are designed to cover the boundary dimensions of the region enclosed between adjacent anti-resonance tubes, which helps to maintain the stability and consistency of the internal structure of the cladding.

[0041] Since the first set of rod molds and / or the second set of rod molds can move along the longitudinal axis of the optical fiber, they can achieve close contact with the end face of the anti-resonant hollow optical fiber preform. This close contact reduces positioning errors caused by the gap between the mold and the preform. The close contact also helps to reduce friction and wear caused by the relative movement between the mold and the preform during the fiber drawing process, thereby improving the quality of the optical fiber.

[0042] 4) By matching the outer boundary shape of the first set of rod molds with the outer boundary shape of the cladding anti-resonance region, the outer boundary shape of the fiber core can be ensured; this precise outer boundary shape helps to reduce positioning errors caused by shape mismatch, thereby improving the manufacturing accuracy of the fiber preform.

[0043] Similarly, the outer boundary shape of the second set of rod molds matches the boundary shape of the region enclosed between adjacent anti-resonant tubes, which can ensure the stability and consistency of the internal structure of the cladding; this matching helps to reduce structural deviations caused by shape differences, thereby improving the overall performance of the optical fiber preform.

[0044] Precise die shape ensures that the optical fiber preform maintains a stable shape and size during the fiber drawing process, thereby optimizing the optical transmission characteristics of the optical fiber. For example, by precisely controlling the die shape, the transmission loss of light in the optical fiber can be reduced, the axial consistency can be improved, and the transmission efficiency and bandwidth of the optical fiber can be increased.

[0045] 5) The outer boundary of the first set of rod dies does not completely cover the area enclosed by the outer boundary of the cladding anti-resonant region within the sleeve, thereby forming at least one gap between the first set of rod dies and the inner wall of the sleeve and / or the outer boundary of the cladding anti-resonant region; the outer boundary of each of the second sets of rod dies does not completely cover the area enclosed by the anti-resonant tubes of adjacent layers, thereby forming at least one gap between the anti-resonant tubes of adjacent layers. During the preform drawing process, air pressure is filled through the gaps, which can provide a uniform supporting force and help maintain the structural stability of the optical fiber during the drawing process. Especially in high-temperature drawing environments, the supporting effect of air pressure can prevent the optical fiber from collapsing due to surface tension. By optimizing the magnitude and distribution of air pressure, the optical performance of the optical fiber can be further improved, such as reducing optical loss and increasing transmission efficiency. In multilayer anti-resonant hollow optical fibers, the filling of air pressure helps maintain the relative position and structural stability between the layers. It can prevent deformation of the internal structures during the drawing process, thereby ensuring the axial structural consistency of the optical fiber. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the cross-sectional structure of one end of the anti-resonant hollow fiber preform of the present invention after it is installed by the anti-resonant hollow fiber preform positioning mold.

[0047] Figure 2 This is a schematic diagram of the side structure of the anti-resonant hollow fiber preform after it has been installed by the anti-resonant hollow fiber preform positioning mold.

[0048] Figure 3 A schematic diagram of the cross-sectional structure of the first set of rod molds provided by the present invention;

[0049] Figure 4 A side view of the first set of rod molds provided by the present invention;

[0050] Figure 5 A schematic diagram of the cross-sectional structure of the second set of rod molds provided by the present invention;

[0051] Figure 6 A side view of the second set of rod molds provided by the present invention;

[0052] Figure 7 The present invention provides a process flow diagram of an assembly method for a positioning mold for an anti-resonant hollow optical fiber preform.

[0053] Wherein: 1-Anti-resonant hollow fiber preform; 11-Sheath; 121-Anti-resonant inner tube; 122-Anti-resonant outer tube; 2-Anti-resonant hollow fiber preform positioning mold; 21-First set of molds; 22-Second set of molds. Detailed Implementation

[0054] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0055] like Figure 1-2 As shown, the present invention provides a positioning mold for an anti-resonant hollow optical fiber preform, comprising:

[0056] The first set of rod molds 21 is disposed in the central region of the sleeve 11 and is used to form the core portion of the optical fiber.

[0057] And / or a second set of rod molds 22, the second set of rod molds 22 being disposed in the anti-resonance region of the cladding, for forming a specific structure in the cladding of the optical fiber;

[0058] The first set of rod molds 21 and / or the second set of rod molds 22 both extend in a tapered shape along the longitudinal axis of the optical fiber. That is, along the longitudinal axis of the optical fiber, the outer boundary dimensions of the first set of rod molds 21 and / or the second set of rod molds 22 gradually change, so that they each have different cross-sectional dimensions at different positions on the optical fiber preform.

[0059] This invention proposes a positioning mold for anti-resonant hollow fiber preforms and its assembly method. The mold has a simple structure and is easy to operate, which solves the technical problems of low positioning accuracy, low manufacturing efficiency and poor repeatability of anti-resonant hollow fiber preforms.

[0060] By using the tapered first set of rod molds 21 and the second set of rod molds 22, the internal structure of the optical fiber preform can be positioned and fixed more effectively. The tapered first set of rod molds 21 and the second set of rod molds 22 can also provide more uniform support and positioning, which helps to reduce the problem of breakage caused by improper glass tube size during the filling process and improves the positioning accuracy of the anti-resonant hollow optical fiber preform.

[0061] The design of the first set of rod molds 21 and the second set of rod molds 22, which extend in a conical shape, can simplify the manufacturing process because the gradually changing shape of the molds can better control the shape of the optical fiber preform, reduce manufacturing delays caused by size mismatch, and thus improve manufacturing efficiency.

[0062] Using standardized, tapered first set of rod dies 21 and second set of rod dies 22 ensures that each manufactured fiber optic preform has the same shape, thereby improving manufacturing repeatability; the tapered die design also reduces manufacturing deviations caused by die wear or deformation, further enhancing manufacturing repeatability.

[0063] Preferably, such as Figure 1 As shown, the variation range of the outer boundary dimension of the first set of rod molds 21 is designed to cover the outer boundary dimension of the cladding anti-resonance region;

[0064] The variation range of the outer boundary dimension of the second set of rod molds 22 is designed to cover the boundary dimension of the region enclosed between adjacent anti-resonant tubes;

[0065] The first set of rod molds 21 and / or the second set of rod molds 22 can move along the longitudinal axis of the optical fiber to achieve a tight fit with the end face of the anti-resonant hollow optical fiber preform.

[0066] The outer boundary dimension of the first set of rod molds 21 is designed to cover the outer boundary dimension of the cladding anti-resonance region, which ensures that the fiber core can be formed accurately; the outer boundary dimension of the second set of rod molds 22 is designed to cover the boundary dimension of the region enclosed between adjacent anti-resonance tubes, which helps to maintain the stability and consistency of the internal structure of the cladding.

[0067] Since the first set of rod molds 21 and / or the second set of rod molds 22 can move along the longitudinal axis of the optical fiber, they can achieve close contact with the end face of the anti-resonant hollow optical fiber preform 1. This close contact reduces the positioning error caused by the gap between the mold and the preform. The close contact also helps to reduce the friction and wear caused by the relative movement between the mold and the preform during the fiber drawing process, thereby improving the quality of the optical fiber.

[0068] Preferably, such as Figure 3 As shown, the outer boundary shape of the first set of rod molds 21 is determined according to the outer boundary shape of the cladding anti-resonance region, and the shape of the first set of rod molds 21 is preferably star-shaped; as Figure 4 As shown, the side structure of the first set of rod molds 21 is tapered along the longitudinal axis of the optical fiber.

[0069] like Figure 5 As shown, the outer boundary shape of the second set of rod molds 22 is determined according to the boundary shape of the region enclosed between adjacent anti-resonant tubes, and the shape of the second set of rod molds 22 is preferably crescent-shaped; as Figure 6 As shown, the side structure of the second set of rod molds 22 is tapered along the longitudinal axis of the optical fiber;

[0070] By matching the outer boundary shape of the first set of rod molds 21 with the outer boundary shape of the cladding anti-resonance region, the outer boundary shape of the fiber core can be ensured; this precise outer boundary shape helps to reduce positioning errors caused by shape mismatch, thereby improving the manufacturing accuracy of the fiber preform.

[0071] Similarly, the outer boundary shape of the second set of rod molds 22 matches the boundary shape of the region enclosed between adjacent anti-resonant tubes, which can ensure the stability and consistency of the internal structure of the cladding; this matching helps to reduce structural deviations caused by shape differences, thereby improving the overall performance of the optical fiber preform.

[0072] Precise die shape ensures that the optical fiber preform maintains a stable shape and size during the fiber drawing process, thereby optimizing the optical transmission characteristics of the optical fiber. For example, by precisely controlling the die shape, the transmission loss of light in the optical fiber can be reduced, the axial consistency can be improved, and the transmission efficiency and bandwidth of the optical fiber can be increased.

[0073] Preferably, the outer boundary of the first set of rod molds 21 does not completely cover the area within the sleeve 11 enclosed by the outer boundary of the cladding anti-resonance region, thereby forming at least one gap between the first set of rod molds 21 and the inner wall of the sleeve 11 and / or the outer boundary of the cladding anti-resonance region;

[0074] The outer boundary of each of the second set of rod molds 22 does not completely cover the area enclosed by the anti-resonant tubes between adjacent layers, thereby forming at least one gap between the anti-resonant tubes between adjacent layers.

[0075] Air pressure is filled into the gaps during the preform wire drawing process;

[0076] The outer boundary of the first set of rod molds 21 does not completely cover the area enclosed by the outer boundary of the cladding anti-resonant region within the sleeve 11, thereby forming at least one gap between the first set of rod molds 21 and the inner wall of the sleeve 11 and / or the outer boundary of the cladding anti-resonant region; the outer boundary of each of the second set of rod molds 22 does not completely cover the area enclosed by the anti-resonant tubes of adjacent layers, thereby forming at least one gap between the anti-resonant tubes of adjacent layers. During the preform drawing process, air pressure is filled through the gaps, which can provide a uniform supporting force, helping to maintain the structural stability of the optical fiber during the drawing process; especially in high-temperature drawing environments, the supporting effect of air pressure can prevent the optical fiber from collapsing due to surface tension; by optimizing the magnitude and distribution of air pressure, the optical performance of the optical fiber can be further improved, such as reducing optical loss and increasing transmission efficiency; in multilayer anti-resonant hollow optical fibers, the filling of air pressure helps to maintain the relative position and structural stability between the layers; it can prevent deformation of the internal structures during the drawing process, thereby ensuring the axial structural consistency of the optical fiber.

[0077] Preferably, when the number of anti-resonant tube layers in the cladding is n, the number of types of the second set of rod molds 22 is n-1, where n≥1. By precisely designing and using n-1 types of second set of rod molds 22, the cladding structure of the optical fiber preform can be ensured to maintain symmetry in the longitudinal direction. This symmetry helps to improve the transmission performance and stability of the optical fiber. Each mold can precisely control the position and shape of its corresponding anti-resonant tube, thereby optimizing the anti-resonance effect of the entire cladding. This helps to improve the bandwidth of the optical fiber and reduce optical loss and other performance indicators.

[0078] It should be noted that the above embodiments of the present invention only demonstrate one anti-resonant hollow fiber preform positioning mold and its assembly method. For the anti-resonant hollow fiber preform with two-layer cladding anti-resonant tubes shown in the embodiments, a total of one type of first set of molds 21 and one type of second set of molds 22 are used. When the anti-resonant hollow fiber preform cladding anti-resonant tube is a single-layer tube, only the first set of molds 21 is needed. When the anti-resonant hollow fiber preform cladding anti-resonant tube is a three-layer tube or more, the types of second set of molds 22 need to be increased accordingly. That is, when the number of cladding anti-resonant tube layers is n, the number of types of second set of molds 22 is n-1 (n≥1).

[0079] Preferably, the angle of the cone angle of both the first set of rod molds 21 and the second set of rod molds 22 extending along the longitudinal axis of the optical fiber is 0.1° to 3°.

[0080] Preferably, the thickness of both the first set of rod molds 21 and the second set of rod molds 22 extending along the longitudinal axis of the optical fiber is 5 to 20 mm.

[0081] The thickness of the mold determines its support for the optical fiber preform; a thicker mold can provide stronger support, ensuring that the optical fiber preform remains stable during the preparation and drawing process and is not easily deformed or bent.

[0082] The thickness of the mold also directly affects its strength. Thicker molds have higher resistance to deformation and fracture, and can better withstand harsh conditions such as high temperature and high pressure during the preparation process, thereby ensuring the quality of optical fiber preforms.

[0083] Preferably, the number of the second set of rod molds 22 is ≥3; by using multiple second set of rod molds 22, the position and distribution of anti-resonant elements in the cladding can be precisely controlled, thereby optimizing the anti-resonance effect; this helps to improve the transmission performance of optical fiber, such as reducing optical loss and improving transmission efficiency.

[0084] like Figure 7 As shown, the present invention also provides a method for assembling an anti-resonant hollow fiber preform positioning mold, comprising the following steps:

[0085] S1 places the first set of rod molds 21 at one end of the sleeve 11;

[0086] S2 At the other end of the sleeve 11, another anti-resonance outer tube is placed inside the sleeve using the first set of rod molds 21. The anti-resonance outer tubes placed at both ends of the sleeve 11 are positioned in the sleeve 11 in a corresponding manner.

[0087] S3 checks and confirms that the azimuth angles of the first set of rod molds 21 used at both ends of the sleeve 11 are consistent, so as to ensure that the positions of the anti-resonance outer tubes at both ends of the sleeve 11 are the same;

[0088] S4 In the anti-resonance outer tube that has been placed at one end of the sleeve 11, at least one anti-resonance inner tube is placed inside the anti-resonance outer tube using the second set of rod molds 22.

[0089] S5 places the second set of rod molds 22 inside the anti-resonance outer tube that has been placed at the other end of the sleeve 11;

[0090] S6 checks and confirms that the azimuth angles of the second set of rod molds 22 used at both ends of the sleeve 11 are consistent, so that the anti-resonance inner tubes at both ends of the sleeve 11 are in the same position in their respective anti-resonance outer tubes.

[0091] S7 is fixedly connected to the connection points between the tubes in the anti-resonant hollow fiber preform 1, forming a complete preform structure.

[0092] In steps S1 and S2, the first set of rod molds 21 are used at both ends of the sleeve 11 to set the anti-resonant outer tubes inside the sleeve 11, and to ensure that their positions in the sleeve 11 correspond. This step provides the basis for subsequent assembly and ensures that the fiber core part of the optical fiber preform has a stable structure.

[0093] In step S3, by checking and confirming that the azimuth angles of the first set of rod molds 21 used at both ends of the sleeve 11 are consistent, it can be ensured that the positions of the anti-resonant outer tubes at both ends of the sleeve 11 are the same. This step ensures the longitudinal symmetry and consistency of the optical fiber preform, which helps to improve the performance of the optical fiber.

[0094] In steps S4 and S5, the second set of rod molds 22 is used to place the anti-resonant inner tube inside the already placed anti-resonant outer tube, and to ensure that they are positioned accordingly in their respective anti-resonant outer tubes. This step further increases the complexity of the optical fiber preform and optimizes the anti-resonance effect, thereby improving the transmission performance of the optical fiber.

[0095] In step S6, the azimuth angles of the second set of rod molds 22 used at both ends of the sleeve 11 are checked and confirmed to ensure that the anti-resonant inner tubes at both ends of the sleeve 11 are in the same position in their respective anti-resonant outer tubes. This step also ensures the symmetry and consistency of the optical fiber preform in the longitudinal and transverse directions, which helps to improve the stability and reliability of the optical fiber.

[0096] In step S7, by fixing the connection between the tubes in the anti-resonant hollow fiber preform 1, a complete and stable preform structure can be formed, which helps to keep the shape and size of the fiber preform unchanged during the subsequent stretching process.

[0097] A stable preform structure can ensure better transmission performance and lower loss in optical fiber during fabrication, while also helping to improve the mechanical strength and durability of the optical fiber.

[0098] Precise assembly and fixed connection can simplify the fiber optic preform fabrication process and reduce errors and losses caused by improper operation.

[0099] Preferably, the material of the first set of rod molds 21 and / or the second set of rod molds 22 is any one of glass, graphite, or metal;

[0100] When the material of the first rod mold 21 and / or the second rod mold 22 is glass, at least a portion of the preform is aligned with the first rod mold 21 and / or the second rod mold 22 along the longitudinal axis of the optical fiber. At the aligned position, the preform is connected to the first rod mold 21 and / or the second rod mold 22 by welding or bonding. The welding or bonding position covers at least a portion of the first rod mold 21 and / or the second rod mold 22, so that the first rod mold 21 and / or the second rod mold 22 and the preform become an integral structure.

[0101] When the material of the first set of rod molds 21 and / or the second set of rod molds 22 is graphite or metal, at least a portion of the preform is aligned with the first set of rod molds 21 and / or the second set of rod molds 22 along the longitudinal axis of the optical fiber. The preform is fixed by welding or bonding at a position that does not cover the first set of rod molds 21 and / or the second set of rod molds 22. After the preform is fixed, the first set of rod molds 21 and / or the second set of rod molds 22 are removed from the preform.

[0102] The selection of mold materials and their connection with the preform play a crucial role in the fabrication of anti-resonant hollow fiber preforms. These selections and designs not only ensure the shape and dimensional accuracy of the fiber preforms but also improve their overall quality and transmission performance.

[0103] It is understood that this invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this invention. Therefore, this invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by this invention.

Claims

1. A positioning mold for an anti-resonant hollow optical fiber preform, characterized in that, include: The first set of rod molds is located in the central region of the sleeve and is used to form the core portion of the optical fiber. The second set of rod molds is disposed in the anti-resonance region of the cladding and is used to form a specific structure in the cladding of the optical fiber. Both the first set of rod molds and the second set of rod molds extend in a tapered shape along the longitudinal axis of the optical fiber. That is, along the longitudinal axis of the optical fiber, the outer boundary dimensions of the first set of rod molds and the second set of rod molds gradually change, so that they have different cross-sectional dimensions at different positions on the optical fiber preform. The angle of the tapered angle of the first set of rod molds and the second set of rod molds extending along the longitudinal axis of the optical fiber is 0.1° to 3°. The outer boundary shape of the first set of rod molds is determined according to the outer boundary shape of the cladding anti-resonance region, and the outer boundary shape of the second set of rod molds is determined according to the boundary shape of the region enclosed between adjacent anti-resonance tubes. The variation range of the outer boundary dimensions of the first set of rod molds is designed to cover the outer boundary dimensions of the cladding anti-resonance region; The variation range of the outer boundary dimensions of the second set of rod molds is designed to cover the boundary dimensions of the region enclosed between adjacent anti-resonant tubes; The first set of rod molds and the second set of rod molds can move along the longitudinal axis of the optical fiber to achieve a tight fit with the end face of the anti-resonant hollow optical fiber preform.

2. The anti-resonant hollow fiber preform positioning mold according to claim 1, characterized in that, The outer boundary of the first set of rod molds does not completely cover the area inside the sleeve enclosed by the outer boundary of the cladding anti-resonance region, thereby forming at least one gap between the first set of rod molds and the inner wall of the sleeve and / or the outer boundary of the cladding anti-resonance region. The outer boundary of each of the second set of rod molds does not completely cover the area enclosed by the anti-resonant tubes between adjacent layers, thereby forming at least one gap between the anti-resonant tubes between adjacent layers. Air pressure is used to fill the gaps during the preform wire drawing process.

3. The anti-resonant hollow fiber preform positioning mold according to claim 1, characterized in that, When the number of cladding anti-resonant tube layers is n, the number of types of the second set of rod molds is n-1, where n≥1.

4. The anti-resonant hollow fiber preform positioning mold according to claim 1, characterized in that, The thickness of both the first and second sets of rod molds, which extend along the longitudinal axis of the optical fiber, is 5–20 mm.

5. The anti-resonant hollow fiber preform positioning mold according to claim 1, characterized in that, The number of the second set of rod molds is ≥3.

6. A method for assembling an anti-resonant hollow fiber preform positioning mold, comprising assembling the anti-resonant hollow fiber preform positioning mold as described in any one of claims 1-5, characterized in that, Includes the following steps: S1 At one end of the sleeve, at least one anti-resonance outer tube is placed inside the sleeve using the first set of rod molds; S2 places another first set of rod molds at the other end of the sleeve; S3 checks and confirms that the azimuth angles of the first set of rod molds used at both ends of the bushing are consistent to ensure that the positions of the anti-resonance outer tubes at both ends of the bushing are the same; S4 In the anti-resonance outer tube that has been placed at one end of the sleeve, at least one anti-resonance inner tube is placed inside the anti-resonance outer tube using the second set of rod molds. S5 places another second set of rod molds inside the anti-resonance outer tube already placed at the other end of the sleeve; S6 checks and confirms that the azimuth angles of the second set of rod molds used at both ends of the sleeve are consistent, so that the anti-resonance inner tubes at both ends of the sleeve are in the same position in their respective anti-resonance outer tubes. S7 is a fixed connection between the tubes in the anti-resonant hollow fiber preform, forming a complete preform structure.

7. The assembly method of the anti-resonant hollow fiber preform positioning mold according to claim 6, characterized in that, The first set of rod molds and the second set of rod molds are made of any one of glass, graphite, or metal; When the materials of the first set of rod molds and the second set of rod molds are glass, at least a portion of the preform is aligned with the first set of rod molds and the second set of rod molds along the longitudinal axis of the optical fiber. At the aligned position, the preform is connected to the first set of rod molds and the second set of rod molds by welding or bonding. The welding or bonding position covers at least a portion of the first set of rod molds and the second set of rod molds, so that the first set of rod molds and the second set of rod molds and the preform are integrated into a single structure. When the materials of the first set of rod molds and the second set of rod molds are graphite or metal, at least a portion of the preform is aligned with the first set of rod molds and the second set of rod molds along the longitudinal axis of the optical fiber. The preform is fixed by welding or bonding in a position that does not cover the first set of rod molds and the second set of rod molds. After the preform is fixed, the first set of rod molds and the second set of rod molds are removed from the preform.

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