Optical fiber connecting device and manufacturing method and manufacturing equipment thereof
By employing computational methods and advanced manufacturing techniques for tapered fiber connectors, the problem of beam quality degradation during the output of large-core fiber lasers was solved, achieving both energy concentration and improved beam quality.
Patent Information
- Application Number
- CN202511701978.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-01-13
AI Technical Summary
When using large-core fiber lasers for output, high-order mode excitation leads to unconcentrated beam energy, degraded beam quality, and increased susceptibility to welding defects.
By obtaining the core diameters and propagation constants of the fundamental and higher-order modes of the connecting fiber, input fiber, and transmission fiber, the target mode field diameter and core radius are determined, the coupling beat length and taper length are calculated, and the connecting fiber is tapered to manufacture an optical fiber connector, so that its mode field diameter matches that of the input fiber and suppresses the excitation of higher-order modes.
It improves beam quality, makes the beam energy more concentrated, simplifies the manufacturing process, and avoids the core expansion step.
Smart Images
Figure CN121325327A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical transmission technology, and in particular to an optical fiber connection device and its manufacturing method and equipment. Background Technology
[0002] Laser processing technology boasts advantages such as high energy density, narrow heat-affected zone, and minimal deformation, making it widely applicable in fields like automotive, new energy, and aerospace. In laser processing, to ensure compatibility with welding various materials (such as steel, copper, and aluminum among non-ferrous metals), and in applications requiring a balance between process window, heat input control, and high power transmission, using a larger core diameter output fiber is often a superior or more feasible option.
[0003] However, when using large-core fiber lasers for output, there is often a problem that high-order mode excitation leads to non-concentrated beam energy, degraded beam quality, and easy welding defects. Summary of the Invention
[0004] This application provides an optical fiber connection device and its manufacturing method and equipment, which can improve beam quality.
[0005] In a first aspect, embodiments of this application provide a method for manufacturing an optical fiber connector, the method comprising the following steps: The core diameters of the connecting fiber, the input fiber, and the transmission fiber, as well as the propagation constants corresponding to the fundamental mode and higher-order modes of the connecting fiber, are obtained. The core diameter of the input fiber is smaller than that of the transmission fiber. The core diameter, cladding diameter, core material, and cladding material of the connecting fiber are the same as those of the transmission fiber. All three fibers—the connecting fiber, the input fiber, and the transmission fiber—are multimode fibers. The target mode field diameter is determined based on the core diameter of the input optical fiber; The target fiber core radius is determined based on the target mode field diameter; The coupling beat length is determined based on the propagation constants corresponding to the fundamental mode and the higher-order mode, respectively. The cone length is determined based on the target fiber core radius, the coupling beat length, and the fiber core diameter of the transmission fiber; The connecting optical fiber is tapered according to the target core radius and the tapered length to obtain the optical fiber connector; wherein the optical fiber connector is used to connect the input optical fiber and the transmission optical fiber.
[0006] In some possible implementations of the first aspect, the step of taperling the connecting fiber according to the target core radius and the taper length to obtain the fiber optic connector includes: The connecting optical fiber is tapered according to the target fiber core radius and the taper length; The tapered connecting optical fiber is cut to obtain the optical fiber connector.
[0007] In some possible implementations of the first aspect, the cutting angle of the cut end face of the connecting optical fiber is less than or equal to 0.5°.
[0008] In some possible implementations of the first aspect, the step of taperning the connecting optical fiber according to the target core radius and the taper length includes: Obtain compensation error; The waist radius is determined based on the target fiber core radius and the compensation error; The connecting optical fiber is tapered according to the waist radius and the taper length.
[0009] In some possible implementations of the first aspect, the step of determining the taper length based on the target core radius, the coupling beat length, and the core diameter of the transmission optical fiber includes: The critical taper angle is determined based on the core diameter of the transmission optical fiber and the coupling beat length; The taper length is determined based on the target fiber core radius, the fiber core diameter of the transmission fiber, and the tapering critical angle.
[0010] In some possible implementations of the first aspect, the step of determining the taper length based on the target fiber core radius, the fiber core diameter of the transmission fiber, and the tapering critical angle includes: The critical length is determined based on the target fiber core radius, the fiber core diameter of the transmission fiber, and the tapered critical angle; The cone length is determined based on the critical length; wherein the critical length and the cone length satisfy: L 临 ≤L 锥 ≤2L 临 L 临 L is the critical length. 锥 Let be the length of the cone.
[0011] In some possible implementations of the first aspect, the step of obtaining the propagation constants corresponding to the fundamental mode and higher-order modes of the connecting optical fiber includes: Obtain the effective refractive indices corresponding to the fundamental mode and the higher-order modes, respectively; The propagation constants corresponding to the fundamental mode and the higher-order modes are determined based on the effective refractive indices corresponding to the fundamental mode and the higher-order modes, respectively.
[0012] In some possible implementations of the first aspect, the connecting optical fiber is integrally connected with the transmission optical fiber.
[0013] Secondly, embodiments of this application provide an optical fiber connection device, which is prepared based on the manufacturing method of the optical fiber connection device described in any of the above technical solutions.
[0014] Thirdly, embodiments of this application provide a manufacturing apparatus for an optical fiber connector, the manufacturing apparatus being used to execute the manufacturing method for an optical fiber connector described in any of the above technical solutions.
[0015] The fiber optic connector and its manufacturing method and equipment provided in this application involve obtaining the core diameters of the connecting fiber, the input fiber, and the transmission fiber, as well as the propagation constants corresponding to the fundamental and higher-order modes of the connecting fiber. Then, the target mode field diameter is determined based on the core diameter of the input fiber; the target core radius is determined based on the target mode field diameter; the coupling beat length is determined based on the propagation constants corresponding to the fundamental and higher-order modes; the taper length is determined based on the target core radius, the coupling beat length, and the core diameter of the transmission fiber; finally, the connecting fiber is tapered based on the target core radius and the taper length to obtain the fiber optic connector. By connecting the input and transmission fibers using the fiber optic connector, the mode field diameter of the fiber optic connector can be matched with that of the input fiber to suppress the excitation of higher-order modes, resulting in a more concentrated beam energy and improved beam quality. Furthermore, the core expansion step is eliminated, simplifying the manufacturing method of the fiber optic connector. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this application 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 only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0017] Figure 1 This is a flowchart illustrating an embodiment of the method for manufacturing the optical fiber connector device according to this application; Figure 2 This is a schematic diagram of the structure of an embodiment of the optical fiber connector device of this application.
[0018] Explanation of icon numbers: 10. Fiber optic connector; 11. Waist section; 12. Taper section; 13. Unchanged connector section; 14. Fiber core; 15. Cladding.
[0019] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0022] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0023] It should be understood that the term "and / or" as used in this application specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.
[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0025] This application provides an optical fiber connection device and its manufacturing method and equipment to solve the technical problem of beam quality degradation when a mode field adapter connects two optical fibers with different core diameters.
[0026] In the embodiments of this application, such as Figure 1 As shown, the manufacturing method of this optical fiber connector includes the following steps: Step S10: Obtain the core diameters of the connecting fiber, the input fiber, and the transmission fiber, as well as the propagation constants corresponding to the fundamental mode and higher-order modes of the connecting fiber. Step S20: Determine the target mode field diameter based on the core diameter of the input optical fiber; Step S30: Determine the target fiber core radius based on the target mode field diameter; Step S40: Determine the coupling beat length based on the propagation constants corresponding to the fundamental mode and higher-order modes, respectively; Step S50: Determine the taper length based on the target fiber core radius, coupling beat length, and fiber core diameter of the transmission fiber; Step S60: Taper the optical fiber according to the target core radius and taper length to obtain the optical fiber connector.
[0027] The fiber optic connector manufactured by the method described in this application, also known as a mode field adapter, is used to connect an input fiber and a transmission fiber, both of which are multimode fibers. Therefore, the input and transmission fibers are used as the target fibers to be connected, and the parameters of the fiber optic connector are calculated based on the type of the target fibers to concentrate the beam energy and improve the beam quality.
[0028] The other end of the input optical fiber is connected to the output optical fiber of the optical module. The laser emitted from the output optical fiber of the optical module is transmitted sequentially along the direction of input optical fiber - optical fiber connector - transmission optical fiber. The optical module includes a pump source and a gain fiber. The core diameter, cladding diameter, core material, and cladding material of the output optical fiber and the input optical fiber of the optical module are all the same.
[0029] The core diameter of the input fiber is smaller than that of the transmission fiber so that the connecting fiber can be tapered to obtain the fiber optic connector. The small-diameter end of the fiber optic connector is connected to the input fiber, and the large-diameter end of the fiber optic connector is connected to the transmission fiber. This suppresses the excitation of higher-order modes, makes the beam energy more concentrated, and improves the beam quality.
[0030] The core diameters of the input and transmission optical fibers can be measured directly, as can the cladding diameters of the input and transmission fibers. The diameters of the input and transmission fibers can then be calculated using the ratio of the core diameter to the cladding diameter. The ratio of the core diameter to the cladding diameter can be obtained from a table.
[0031] The propagation constants of the connecting optical fiber can be found in the fiber's instruction manual. Alternatively, the effective refractive index of the fundamental mode and the effective refractive index of higher-order modes can be found in the fiber's instruction manual, publicly available literature, or research reports. The propagation constants of the fundamental mode and higher-order modes can then be calculated using these effective refractive indices.
[0032] The method for calculating the propagation constant using the effective refractive index is as follows: β=n eff •2π / λ, Where β is the propagation constant, n effThe effective refractive index is denoted by λ, and λ is the operating wavelength of the beam. The effective refractive index can also be obtained using optical software, such as COMSOL software, through characteristic mode analysis.
[0033] The connecting fiber is exactly the same as the transmission fiber, or the core diameter, cladding diameter, core material, and cladding material of the connecting fiber are all the same as those of the transmission fiber. This is so that the larger diameter end of the fiber optic connector manufactured after tapering the connecting fiber can be connected to the transmission fiber.
[0034] After obtaining the core diameter of the input fiber, the mode field diameter of the input fiber is calculated based on the core diameter. The calculation method for the mode field diameter of the input fiber is as follows: D 输入MFD =D 输入core (0.65 + 1.619V) 输入 -3 / 2 +2.879V 输入 -6 ), Among them, D 输入MFD D is the mode field diameter of the input fiber. 输入core V is the core diameter of the input optical fiber. 输入 V is the normalized parameter of the input fiber. 输入 It can be obtained by looking up a table. V 输入 It can also be calculated, as follows: , where r 输入 n is the core radius of the input optical fiber. co n is the refractive index of the fiber core of the input optical fiber. cl This refers to the refractive index of the cladding of the input optical fiber. The refractive indices of the core and cladding can be obtained from tables or from the specifications provided by the manufacturer.
[0035] To match the mode field diameter of the small-diameter end of the fiber optic connector with that of the input fiber, thus suppressing the excitation of higher-order modes, the mode field diameter of the input fiber can be used as the mode field diameter of the small-diameter end of the connector. Since the fiber optic connector is obtained by connecting tapered fibers, the mode field diameter of the input fiber can be used as the target mode field diameter of the connecting fiber tapered fiber.
[0036] After obtaining the target mode field diameter, the target core diameter is then deduced from the target mode field diameter, thus obtaining the target core radius. The calculation method is as follows: D 目标core =D 输入MFD / (0.65 + 1.619V) 连接 -3 / 2 +2.879V 连接 -6 ), Among them, D 目标core V is the target core diameter. 连接 V is the normalized parameter for connecting optical fibers. 连接 It can be obtained by looking up a table. V 连接 It can also be obtained through calculation, and the calculation method can refer to the calculation method of the normalized parameters of the input optical fiber.
[0037] After obtaining the propagation constants of the fundamental mode and higher-order modes of the connecting optical fiber, the coupling beat length when the fundamental and higher-order modes are coupled is calculated using these constants. The calculation method is as follows: Z b =2π / (β1-β2) Among them, Z b Let β1 be the propagation constant of the fundamental mode and β2 be the propagation constant of the higher-order modes.
[0038] After obtaining the target fiber core radius, coupling beat length, and transmission fiber core diameter, the taper length is calculated based on the target fiber core radius, coupling beat length, and transmission fiber core diameter.
[0039] Specifically, when calculating the taper length, the critical taper angle is determined based on the target fiber core radius and the coupling plate length. The calculation method for the critical taper angle is as follows: θ(x)=r 锥 (x)(β1-β2) / 2π, Where θ(x) is the critical angle of the tapered section, r 锥 (x) represents the core radius of the tapered region formed after the connecting optical fiber is tapered, and x represents the position of the tapered region in the connecting optical fiber. The target core radius is the radius of the small-diameter end of the tapered region of the optical fiber connector. Since the target core radius is known, r can be determined. 锥 (x). Then, the propagation constants corresponding to the fundamental mode and higher-order modes at this position can be determined by software simulation, thereby determining the critical angle of the tapered section.
[0040] After obtaining the critical taper angle, the taper length is determined based on the target fiber core radius, the fiber core radius of the transmission fiber, and the critical taper angle.
[0041] The critical length of the tapered fiber connection can be calculated first based on the target fiber core radius, the fiber core radius of the transmission fiber, and the tapering critical angle. The calculation method for the critical length is as follows: L 临 =(D 传输core / 2-D 目标rore / 2) / tanθ,where, L 临 D is the critical length. 传输core This refers to the core diameter of the optical fiber, which is the core diameter of the connecting optical fiber before it is tapered.
[0042] When taper-connecting optical fibers, the taper length needs to be greater than or equal to the critical length so that the mode field diameter of the small-diameter end of the fiber connector obtained after taper-connecting the fiber matches the mode field diameter of the input fiber, thereby suppressing the excitation of higher-order modes.
[0043] After determining the critical length based on the target fiber core radius, the transmission fiber core radius, and the tapering critical angle, the taper length is then determined based on the critical length. The taper length satisfies the following condition: L 临 ≤L 锥 ≤2L 临 , where L 锥 The length is the cone length.
[0044] By limiting the taper length, it is possible to easily fusion splice input and transmission fibers in fiber optic connectors, simplifying the splicing and tapering processes.
[0045] Once the target fiber core radius and taper length are determined, the tapering parameters for connecting the optical fibers are also determined, and thus the parameters of the resulting optical fiber connector are also determined. Therefore, by tapering and connecting optical fibers according to the target fiber core radius and taper length, an optical fiber connector can be obtained.
[0046] After tapering the connecting fiber according to the target core radius and taper length, the end of the connecting fiber connected to the input fiber does not participate in the thermal fusion deformation process due to the fixed clamping of the tapering equipment. This may result in the end parameters of the tapered connecting fiber not meeting the requirements for connection with the input fiber, necessitating the removal of the portion with non-compliant parameters. Therefore, the tapered connecting fiber is cut to remove the non-compliant portion, leaving the portion containing the taper region as the fiber optic connector.
[0047] like Figure 2 As shown, the fiber optic connector 10 is obtained by cutting the tapered connecting fiber. The fiber optic connector 10 includes a waist section 11, a taper section 12, and an unchanged connector section 13 connected in sequence, with a cladding 15 covering the fiber core 14. The end of the waist section 11 is used to connect the input fiber, and the end of the unchanged connector section 13 is used to connect the transmission fiber. Typically, the light beam propagates from the input fiber - fiber optic connector - transmission fiber.
[0048] After cutting the ends of the connecting optical fibers, the cutting angle of the cut end face of the connecting optical fiber is less than or equal to 0.5°, so as to reduce the impact of end face angle deviation on splice loss and strength.
[0049] When taper-connecting optical fibers based on the target core radius and taper length, a compensation error can be obtained first. Then, the sum of the target core radius and the compensation error is used as the waist radius. The optical fibers are then tapered and connected based on the waist radius and taper length. This method can compensate for inherent dimensional tolerances in the optical fiber and errors generated during subsequent fusion splicing with the input fiber. This ensures a better match between the mode field diameter of the small-diameter end of the fiber connector and the mode field diameter of the input fiber, suppressing the excitation of higher-order modes and reducing energy loss. The compensation error is set by the user, typically between 3μm and 5μm, and is usually a positive value.
[0050] In one embodiment, the connecting optical fiber and the transmission optical fiber are integrally connected, that is, the connecting optical fiber is the end portion of the transmission optical fiber.
[0051] When splicing the input optical fiber to the optical fiber connector, the cladding of the input optical fiber can be etched to reduce the cladding diameter of the input optical fiber to within ±10μm of the cladding diameter of the waist section of the optical fiber connector, so as to facilitate the splicing of the input optical fiber to the optical fiber connector.
[0052] The input fiber and the transmission fiber can also be connected hierarchically via multiple fiber optic connectors. When the fiber optic connectors between the input fiber and the transmission fiber are interconnected, the waist section of one fiber optic connector is connected to the unchanged section of another fiber optic connector.
[0053] In this embodiment, after obtaining the core diameters of the connecting fiber, the input fiber, and the transmission fiber, as well as the propagation constants corresponding to the fundamental and higher-order modes of the connecting fiber, the target mode field diameter is determined based on the core diameter of the input fiber. Then, the target core radius is determined based on the target mode field diameter. Next, the coupling beat length is determined based on the propagation constants corresponding to the fundamental and higher-order modes. Finally, the taper length is determined based on the target core radius, the coupling beat length, and the core diameter of the transmission fiber. Finally, the connecting fiber is tapered based on the target core radius and the taper length to obtain the fiber optic connector. By connecting the input and transmission fibers using the fiber optic connector, the mode field diameter of the fiber optic connector can be matched with that of the input fiber to suppress the excitation of higher-order modes, resulting in a more concentrated beam energy and improved beam quality. Furthermore, the core expansion step is eliminated, simplifying the manufacturing method of the fiber optic connector.
[0054] Furthermore, this application also provides an optical fiber connector, which is prepared based on the manufacturing method of the optical fiber connector described in any of the above embodiments.
[0055] Furthermore, this application also provides a manufacturing apparatus for an optical fiber connector, which is used to perform the manufacturing method of the optical fiber connector described in any of the above embodiments.
[0056] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.
Claims
1. A method of manufacturing an optical fiber connection device, characterized by, The manufacturing method of the optical fiber connecting device comprises the following steps: obtaining the core diameter of the connecting optical fiber, the core diameter of the input optical fiber, the core diameter of the transmission optical fiber, and the propagation constant corresponding to the fundamental mode and the high-order mode of the connecting optical fiber respectively; wherein the core diameter of the input optical fiber is smaller than the core diameter of the transmission optical fiber, the core diameter, the cladding diameter, the core material and the cladding material of the connecting optical fiber are the same as those of the transmission optical fiber, and the input optical fiber, the connecting optical fiber and the transmission optical fiber are all multimode optical fibers; determining a target mode field diameter according to the core diameter of the input optical fiber; determining a target core radius according to the target mode field diameter; determining a coupling beat length according to the propagation constant corresponding to the fundamental mode and the high-order mode respectively; determining a taper length according to the target core radius, the coupling beat length and the core diameter of the transmission optical fiber; tapering the connecting optical fiber according to the target core radius and the taper length to obtain the optical fiber connecting device; wherein the optical fiber connecting device is used to connect the input optical fiber and the transmission optical fiber.
2. The method of manufacturing an optical fiber connection device according to claim 1, wherein, The step of tapering the connecting optical fiber according to the target core radius and the taper length to obtain the optical fiber connecting device comprises: tapering the connecting optical fiber according to the target core radius and the taper length; cutting the tapered connecting optical fiber to obtain the optical fiber connecting device.
3. The method of manufacturing an optical fiber connection device according to claim 2, wherein, The cutting angle of the cutting end face of the connecting optical fiber is less than or equal to 0.5°.
4. The method of manufacturing a fiber optic connection device of claim 2, wherein, The step of tapering the connecting optical fiber according to the target core radius and the taper length comprises: obtaining a compensation error; determining a waist radius according to the target core radius and the compensation error; tapering the connecting optical fiber according to the waist radius and the taper length.
5. The method of manufacturing a fiber optic connection device of claim 1, wherein, The step of determining a taper length according to the target core radius, the coupling beat length and the core diameter of the transmission optical fiber comprises: determining a taper critical angle according to the target core radius and the coupling beat length; determining the taper length according to the target core radius, the core diameter of the transmission optical fiber and the taper critical angle.
6. The method of manufacturing a fiber optic connection device of claim 5, wherein, The step of determining a taper length according to the target core radius, the core diameter of the transmission optical fiber and the taper critical angle comprises: determining a critical length according to the target core radius, the core diameter of the transmission optical fiber and the taper critical angle; The taper length is determined according to the critical length; wherein the critical length and the taper length satisfy: L 临 ≤ L 锥 ≤ 2L 临 , L 临 is the critical length, L 锥 is the taper length.
7. The method of manufacturing a fiber optic connection device of claim 1, wherein, The step of obtaining the propagation constant corresponding to the fundamental mode and the high-order mode of the connecting optical fiber respectively comprises: obtaining the effective refractive index corresponding to the fundamental mode and the high-order mode respectively; determining the propagation constant corresponding to the fundamental mode and the high-order mode respectively according to the effective refractive index corresponding to the fundamental mode and the high-order mode respectively.
8. The method of manufacturing a fiber optic connection device of claim 1, wherein, The connecting optical fiber is integrally connected with the transmission optical fiber.
9. An optical fiber connection device, characterized by, The optical fiber connecting device is prepared based on the manufacturing method of the optical fiber connecting device according to any one of the above claims 1 to 8.
10. An apparatus for manufacturing an optical fiber connection device, characterized by comprising: The manufacturing equipment of the optical fiber connecting device is used to execute the manufacturing method of the optical fiber connecting device according to any one of the above claims 1 to 8.