Manufacturing method of tapered waveguide, tapered waveguide and multi-core optical fiber fan-in and fan-out assembly

Abstract

The invention relates to the technical field of optical fiber communication, and provides a tapered waveguide manufacturing method, a tapered waveguide and a multi-core optical fiber fan-in and fan-out assembly. The manufacturing method of the conical waveguide comprises the steps that a conical rod is provided and comprises a conical section, the radial size of the middle position of the conical section is smaller than that of the two ends of the conical section, and the conical rod is made of transparent materials; a laser inscribing technology is adopted, inscribing is carried out in the conical rod from the circumferential surface of the conical rod in the axial direction of the conical rod, and an optical waveguide is formed; repeating the previous step once when the conical rod rotates for a preset angle value around the central axis of the conical rod until the number of the optical waveguides on the conical rod reaches a preset value; and the conical rod is disconnected from the middle position of the conical section to form two conical waveguides. According to the multi-core optical fiber fan-in and fan-out assembly, the optical waveguide is inscribed on the conical rod body made of the transparent material, the conical waveguide is formed to be connected with the multi-core optical fiber and the single-core optical fibers, the problem of light leakage is avoided through the formed multi-core optical fiber fan-in and fan-out assembly, and the optical fiber communication quality is guaranteed.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a method for manufacturing a tapered waveguide, the tapered waveguide, and a multi-core fiber fan-in / fan-out assembly. Background Technology

[0002] In optical communication systems, with the development of space division multiplexing technology, multi-core optical fibers, as a key component that can significantly improve transmission capacity, are increasingly widely used. Multi-core optical fibers need to be connected to arrays of multiple single-core optical fibers to achieve optical signal transmission.

[0003] Currently, the main method to achieve fan-in and fan-out functionality between multi-core optical fibers and multiple single-core optical fibers is to tightly bundle multiple single-core optical fibers according to the geometric arrangement of the multi-core fiber cores, fuse the cladding of the single-core optical fibers into one through a tapering process, realize mode field coupling and spatial optical path convergence in the tapered region, and then fuse the output end of the fused taper device with the multi-core optical fiber.

[0004] However, in current methods for implementing fan-in / fan-out functionality, the tapering process of multiple single-core fibers proportionally reduces the size of the fiber core and cladding. When the core diameter is stretched too thin, its ability to confine light decreases drastically, causing optical signals to leak into the cladding, forming a so-called "evanescent core" and resulting in severe optical power loss. Furthermore, the tapering alters the mode field size and distribution of the core, making it difficult to precisely match the mode field of the standard fiber array to be coupled at the other end, leading to low coupling efficiency and affecting communication quality. Summary of the Invention

[0005] This application provides a method for manufacturing a tapered waveguide, a tapered waveguide, and a multi-core fiber fan-in / fan-out assembly to solve the technical problems that existing methods for implementing fan-in / fan-out functionality are prone to causing severe optical power loss and low coupling efficiency, thus affecting the quality of optical fiber communication.

[0006] To address the aforementioned problems, this application provides a method for manufacturing a tapered waveguide, wherein the tapered waveguide is used to connect a multi-core optical fiber and multiple single-core optical fibers, and the manufacturing method includes:

[0007] A conical rod is provided, the conical rod including a conical section, the radial dimension of the middle position of the conical section being smaller than the radial dimensions of the two ends, and the conical rod being made of a transparent material;

[0008] Using laser engraving technology, an optical waveguide is formed by engraving from the circumferential surface of the conical rod along its axial direction inside the conical rod.

[0009] The previous step is repeated once for each preset angle value that the conical rod is rotated around its central axis, until the number of optical waveguides on the conical rod reaches the preset value;

[0010] The conical rod is broken off at the middle position of the conical section to form two conical waveguides.

[0011] In some embodiments, the material of the tapered rod includes quartz;

[0012] The tapered rod is formed by drawing a capillary rod with a circular cross-section using a tapering technique.

[0013] In some embodiments, the use of laser engraving technology to engrave an optical waveguide from the circumferential surface of the tapered rod along its axial direction inside the tapered rod includes:

[0014] Position the laser spot at a preset starting point so that the optical waveguide to be formed can correspond to the position of the corresponding single fiber in the array of multiple single-core fibers.

[0015] When the laser spot is moved to the middle position of the conical section, it is positioned at a preset midpoint so that the optical waveguide to be formed can correspond to the position of the corresponding fiber core in the multi-core fiber array.

[0016] In some embodiments, the preset starting point is the center point of the single-core fiber in the array of multiple single-core fibers that corresponds to the optical waveguide to be formed.

[0017] In some embodiments, the preset midpoint is the center point of the fiber core in the multi-core fiber array corresponding to the optical waveguide to be formed.

[0018] In some embodiments, the use of laser engraving technology to engrave an optical waveguide from the circumferential surface of the tapered rod along its axial direction inside the tapered rod includes:

[0019] The radial position of the laser spot within the conical rod is controlled so that the trajectory of the formed optical waveguide conforms to the contour of the conical rod.

[0020] In some embodiments, the radius of curvature at the point where the refractive index of the optical waveguide changes is greater than a preset radius of curvature value.

[0021] In some embodiments, the method of using laser engraving technology to engrave an optical waveguide from the circumferential surface of the conical rod along its axial direction inside the conical rod further includes:

[0022] A reflector is inscribed at the point where the refractive index of the optical waveguide changes.

[0023] This application also provides a tapered waveguide, which is manufactured using any of the tapered waveguide manufacturing methods described above, and the tapered waveguide has a first connection end and a second connection end, wherein the radial dimension of the first connection end is smaller than the radial dimension of the second connection end, the first connection end is used to connect a multi-core optical fiber, and the second connection end is used to connect multiple single-core optical fibers.

[0024] This application also provides a multi-core fiber fan-in / fan-out assembly, including:

[0025] Multi-core optical fiber;

[0026] A single-core fiber bundle, wherein the single-core fiber bundle comprises multiple single-core fibers, and the array of the single-core fibers in the single-core fiber bundle is the same as the array of the cores in the multi-core fiber bundle;

[0027] As described above, the tapered waveguide has a first connection end connected to the multi-core optical fiber and a second connection end connected to the single-core optical fiber bundle.

[0028] The beneficial effects of the embodiments of this application are as follows: The manufacturing method of the tapered waveguide provided in this application completes the manufacturing of two tapered waveguides by writing optical waveguides on a tapered rod and then breaking the tapered rod from the middle position. Since the tapering process of forming the tapered rod occurs before writing the optical waveguides, each optical waveguide in the tapered waveguide is not affected by the tapering process. Furthermore, it eliminates the need for tapering the optical fibers connected to the tapered waveguides. Therefore, the multi-core fiber fan-in / fan-out assembly composed of tapered waveguides manufactured in this way will not experience optical power loss. Moreover, the tapered rod after writing the optical waveguides is only truncated, which does not affect the relative arrangement of the optical waveguide endpoints on the two mating surfaces of the tapered waveguide, ensuring the accuracy of the mating between the tapered waveguide and multi-core optical fibers and multiple single-core optical fibers. This ensures the fiber coupling efficiency in the multi-core fiber fan-in / fan-out assembly and improves communication quality. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments 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 these drawings without creative effort. Wherein:

[0030] Figure 1 This is a flowchart of a method for manufacturing a tapered waveguide according to an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of a method for manufacturing a tapered waveguide according to an embodiment of this application, in which a capillary rod is drawn into a tapered rod.

[0032] Figure 3 This is a schematic diagram of the process of etching the first optical waveguide on a tapered rod in a method for manufacturing a tapered waveguide according to an embodiment of this application;

[0033] Figure 4 This is a schematic diagram of the femtosecond laser direct writing system used in the manufacturing method of the tapered waveguide provided in an embodiment of this application;

[0034] Figure 5 This is a schematic diagram of the optical waveguide trajectory etched in the manufacturing method of the tapered waveguide provided in an embodiment of this application;

[0035] Figure 6 This is a schematic diagram of the manufacturing method of the tapered waveguide provided in one embodiment of the present application, in which one optical waveguide is inscribed with each rotation of the tapered rod;

[0036] Figure 7 This is a schematic diagram of the tapered waveguide and its two end faces formed by breaking a tapered rod after writing an optical waveguide in a method for manufacturing a tapered waveguide according to an embodiment of this application.

[0037] Figure 8 This is a schematic diagram of the trajectory of a smooth transition of an optical waveguide at a turning point in a manufacturing method of a tapered waveguide provided in an embodiment of this application.

[0038] Figure 9 This is a schematic diagram of the trajectory of the reflector etched at the inflection point of the optical waveguide in the manufacturing method of the tapered waveguide provided in an embodiment of this application;

[0039] Figure 10 This is a schematic diagram of the structure of a multi-core fiber fan-in / fan-out assembly provided in an embodiment of this application.

[0040] In the figure: 10, tapered waveguide; 11, first connection end; 12, second connection end; 13, optical waveguide; 20, multi-core optical fiber; 21, fiber core; 30, single-core fiber bundle; 31, single-core optical fiber; 100, femtosecond laser direct writing system; 101, femtosecond laser source; 102, beam transmission system; 103, three-dimensional scanning head; 104, worktable. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0042] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0043] Please refer to Figures 1, 7 and 10. This application provides a method for manufacturing a tapered waveguide 10, wherein the tapered waveguide 10 is used to connect a multi-core fiber 20 and multiple single-core fibers 31 in a multi-core fiber fan-in fan-out assembly.

[0044] The manufacturing method of the tapered waveguide 10 provided in this application includes the following steps:

[0045] Step S10: Provide a conical rod, the conical rod including a conical section, the radial dimension of the middle position of the conical section being smaller than the radial dimensions of the two ends, and the conical rod being made of transparent material.

[0046] This step aims to prepare a substrate for writing the optical waveguide 13 in subsequent steps, and the specific preparation method of the tapered rod is not limited. For example, as Figure 2 As shown, in some embodiments, the tapered rod can be formed by drawing a capillary rod with a circular cross-section using a tapering technique. The following embodiments of this application use the drawing of a tapered rod using a tapering technique as an example. As shown in Figure 2, the tapered section of the tapered rod formed by the tapering technique is generally located in the middle of the rod. It can be understood that the tapered rod also has a cylindrical section at each end of the tapered section.

[0047] In this design, the radial dimension at the middle position of the conical segment is smaller than the radial dimensions at both ends. This means the radial dimension of the conical segment gradually increases from the middle position towards both ends. Of course, in some embodiments, a flat segment with a uniform outer diameter can be retained in the middle of the conical segment, as shown in Figure 2. The length of the flat segment accounts for approximately one-third of the length of the conical segment, but this is not a limitation. It can be understood that the radial dimension of the flat segment is equal to the radial dimension at the middle position of the conical segment.

[0048] The conical rod is made of a transparent material, and there is no limitation on the specific material of the conical rod. For example, in some embodiments, the material of the conical rod may include quartz.

[0049] Taking a quartz capillary rod with a circular cross-section and uniform outer diameter as an example, the process of drawing a capillary rod into a tapered rod using tapering technology is explained as follows: First, the quartz capillary rod can be made of high-purity quartz material. The quartz capillary rod can be drawn using conventional fiber optic drawing tower equipment. Then, a predetermined length is cut from the drawn long rod as the raw material for drawing the tapered rod. The predetermined length can be selected from 50-150 mm, but is not limited to this. The outer diameter of the quartz capillary rod can be controlled at 500±5 micrometers to accommodate a single-core fiber bundle 30 composed of four single-core optical fibers 31 with an outer diameter of 500±5 micrometers. However, the outer diameter of the quartz capillary rod is not limited to this. Then, the central region of the predetermined length of quartz capillary rod is locally heated to a softened state and then stretched in the reverse direction. For example, this operation can be accomplished using the LZM100 glass processing system manufactured by Fujikura Corporation, but it is not limited to this. This glass processing system uses a carbon dioxide laser as a non-contact heat source to locally heat the central region of the quartz capillary rod to a softened state. Simultaneously, the clamp in this glass processing system can perform reverse stretching according to a preset programmed speed curve. Through precise control of heating power, heating area width, stretching speed, and displacement, the uniform quartz capillary rod is ultimately processed into a capillary rod structure with a conical region in the middle, i.e., a conical rod, thus obtaining a conical rod. During the reverse stretching of the quartz capillary rod, the length of the flat section can be controlled within the range of 5-15 mm, but it is not limited to this.

[0050] It should be noted that, in the embodiments of this application, it can be understood that the diameter of the widest part at both ends of the prepared tapered rod remains approximately 500 micrometers. It can be understood that the diameter of the widest part at both ends of the tapered rod and the diameter of the flat section correspond to the outer diameter of the multiple single-core optical fibers 31 and the outer diameter of the multi-core optical fibers 20, respectively, and the specific diameter can be adjusted according to the outer diameter of the multiple single-core optical fibers 31 and the multi-core optical fibers 20.

[0051] Step S20: Using laser engraving technology, an optical waveguide 13 is formed by engraving along the axial direction from the circumferential surface of the conical rod inside the rod. Laser engraving technology is a commonly used fabrication method in the field of optical fiber communication. For example, a femtosecond laser direct writing system 100 can be used to complete the laser engraving. The femtosecond laser direct writing system 100 may include a femtosecond laser source 101, a beam transmission system 102 for adjusting and guiding the laser beam, a three-dimensional scanning head 103 capable of achieving precise three-dimensional positioning and scanning of the laser focus, and a worktable 104 for firmly holding and precisely rotating the conical rod. The femtosecond laser source 101 may be a femtosecond laser with an emission wavelength of 515~1030 nm, a repetition rate of 1 MHz, and an output optical power of 0.1~20 watts. In this embodiment, a femtosecond laser with a wavelength of 1030 nm and a repetition rate of 1 MHz may be selected as the laser source.

[0052] When writing the optical waveguide 13 from the circumference of the conical rod along its axial direction inside the rod, the laser can be focused inside the rod, at a distance of 50-230 micrometers from the rod's surface, to process the circular cross-section of the optical waveguide 13. The processing power of the circular cross-section optical waveguide 13 can be selected within the range of 0.3-0.46 watts, and the direct writing speed can be selected within the range of 1-40 mm / s. Here, the direct writing speed refers to the speed at which the laser spot moves along the axial direction of the conical rod. The processing power refers to the writing power output by the femtosecond laser after transmission through the optical path.

[0053] It should be noted that during the manufacturing of the tapered waveguide 10, the multi-core optical fiber 20 and the multiple single-core optical fibers 31 connected to the tapered waveguide 10 to be manufactured are already determined. Therefore, this is equivalent to determining the positions of the optical waveguides 13 on both end faces of the tapered waveguide 10 when writing the optical waveguide 13. The positions of the optical waveguides 13 on both end faces of the tapered waveguide 10 are the starting / ending points and the midpoints of the optical waveguides 13 on the tapered rod.

[0054] Please refer to the following: Figures 3 to 5 In some embodiments, step S20 may specifically include:

[0055] Step S21: Position the laser spot to a preset starting point so that the optical waveguide 13 to be formed can correspond to the position of the corresponding single-core optical fiber 31 in the array composed of multiple single-core optical fibers 31.

[0056] During the etching of the optical waveguide 13, the preset starting point where the laser spot is positioned on the tapered rod is the starting point of the optical waveguide 13 to be etched. This ensures that the optical waveguide 13 to be formed corresponds to the position of the corresponding single-core fiber 31 in the array composed of multiple single-core fibers 31, that is, it enables the optical waveguide 13 to be formed to be connected with the corresponding single-core fiber 31, so that the optical signal can be transmitted between the corresponding single-core fiber 31 and the optical waveguide 13.

[0057] Since the multiple single-core optical fibers 31 to be connected in the tapered waveguide 10 have been determined before manufacturing the tapered waveguide 10, the starting point of each optical waveguide 13 to be inscribed can be determined based on the position of each single-core optical fiber 31 in the array composed of multiple single-core optical fibers 31. For example, in some embodiments, the preset starting point can be the center point of the single-core optical fiber 31 corresponding to the optical waveguide 13 to be formed in the array composed of multiple single-core optical fibers 31.

[0058] Step S22: When the laser spot is moved to the middle position of the conical section, it is positioned at a preset middle point so that the optical waveguide 13 to be formed can correspond to the position of the corresponding fiber core 21 in the array composed of fiber cores 21 in the multi-core optical fiber 20.

[0059] During the etching of the optical waveguide 13, the preset midpoint where the laser spot is positioned on the tapered rod is the midpoint of the optical waveguide 13 to be etched. This ensures that the optical waveguide 13 to be formed corresponds to the position of the corresponding fiber core 21 in the array of fiber cores 21 in the multi-core optical fiber 20, that is, it enables the optical waveguide 13 to be formed to mate with the corresponding fiber core 21, so that the optical signal can be transmitted between the corresponding fiber core 21 and the optical waveguide 13.

[0060] Since the multi-core optical fibers 20 to be connected to the tapered waveguide 10 have been determined before the tapered waveguide 10 is manufactured, the midpoint of each optical waveguide 13 to be inscribed can be determined based on the position of each fiber core 21 in the array of fiber cores 21 in the multi-core optical fiber 20. For example, in some embodiments, the preset midpoint can be the center point of the fiber core 21 in the array of fiber cores 21 in the multi-core optical fiber 20 that corresponds to the optical waveguide 13 to be formed.

[0061] Of course, when the conical section also has a flat area, since the middle position of the conical section is also the middle position of the flat area, when the laser spot moves along the axial direction of the conical rod to the flat area, it is also necessary to control the position of the laser spot in the radial direction of the conical rod to be positioned at the preset midpoint in the radial direction of the conical rod.

[0062] It should be noted that since the tapered rod, after being inscribed with optical waveguide 13, breaks in the middle to form two tapered waveguides 10, it can be understood that both end faces of the tapered rod are used to connect with multiple single-core optical fibers 31. Therefore, the endpoint of each optical waveguide 13 to be inscribed can also be determined based on the position of each single-core optical fiber 31 in the array composed of multiple single-core optical fibers 31. For example, in some embodiments, the preset endpoint can be the center point of the single-core optical fiber 31 corresponding to the optical waveguide 13 to be formed in the array composed of multiple single-core optical fibers 31. When inscribing the optical waveguide 13, when the laser spot moves from the preset starting point at one end of the tapered rod to the other end, it is necessary to control the laser spot to be positioned at the preset endpoint. That is, step S20 also includes the following steps:

[0063] Step S23: Control the laser spot to be positioned to a preset endpoint so that the optical waveguide 13 to be formed can correspond to the position of the corresponding single-core optical fiber 31 in the array composed of multiple single-core optical fibers 31.

[0064] During the etching process of the optical waveguide 13, the laser spot moves from a preset starting point to a preset intermediate point and then to a preset ending point, thus completing the etching of one optical waveguide 13 on the tapered rod. Since the preset starting point, preset ending point, and preset intermediate point are all determined based on the single-core fiber bundle 30 composed of the multi-core fiber 20 and multiple single-core fiber 31 to be connected to the tapered waveguide 10, the manufacturing precision of the optical waveguide 13 in the tapered waveguide 10 is effectively guaranteed, and the accuracy of the connection is improved.

[0065] It is understandable that the radial position of the laser spot within the conical rod needs to be dynamically controlled during the process of the laser spot moving from the preset starting point to the preset midpoint, and from the preset midpoint to the preset ending point.

[0066] In some embodiments, step S20 may further include the following steps:

[0067] Step S24: Control the radial position of the laser spot within the conical rod so that the trajectory of the formed optical waveguide 13 conforms to the contour of the conical rod.

[0068] It is understood that step S24 can occur between steps S21 and S22, and between steps S22 and S23.

[0069] Figure 5 illustrates the trajectory of the laser spot. In this figure, the Y-axis represents the distance traveled along the axial direction of the conical rod, and the Z-axis represents the depth of the laser focus within the rod. Z=0 is defined as the upper surface of the conical rod, and Y=0 is defined as the midpoint of the axial direction of the conical rod. As shown in Figure 5, the trajectory is trapezoidal in shape. Specifically, when the laser spot is located in the wide sections at both ends of the conical rod (e.g., at a diameter of 500 micrometers), the 3D scanning head 103 controls the objective lens to set the laser spot depth Z to -112 micrometers; when the laser focus moves to the flat area of ​​the waist of the conical rod (at a diameter of 125 micrometers), the spot depth Z is dynamically adjusted to -222 micrometers; and in the transitional conical region between the two, the focus depth Z value changes linearly with the Y-axis coordinate. In this way, the inscribed internal optical waveguide 13 can maintain a roughly constant distance from the outer surface of the tapered rod along its entire length, thereby ensuring the integrity of the optical waveguide 13 structure and the uniformity of its optical performance.

[0070] Please refer to the following: Figure 6 In step S30, the conical rod is rotated around its central axis by a preset angle value, and the previous step is repeated once until the number of optical waveguides 13 on the conical rod reaches a preset value.

[0071] The optical waveguide 13 formed in step S20 is the first optical waveguide 13 etched on the conical rod. After the first optical waveguide 13 is etched, the stage 104 in the femtosecond laser direct writing system 100 can be controlled to rotate the conical rod around its central axis by a preset angle value. Then, step S20 is repeated to complete the etching of the second optical waveguide 13. After the second optical waveguide 13 is etched, the stage 104 is controlled to rotate the conical rod by a preset angle value, and step S20 is repeated again to complete the etching of another optical waveguide 13. This process continues until the number of optical waveguides 13 etched on the conical rod reaches a preset value, thus completing the etching process.

[0072] like Figure 10As shown, the example illustrates the connection between a tapered waveguide 10 and a single-core fiber bundle 30 consisting of four-core optical fibers and four single-core optical fibers 31. Typically, the cores 21 of the four-core optical fibers are arranged in a square array (as shown in Figure 10), therefore the preset angle value is set to 90 degrees. After rotation, all operations in step S20 are repeated, using the exact same laser parameters and the ZY scanning trajectory shown in Figure 5, to etch the second optical waveguide 13 at the new angular position. Subsequently, the tapered rod is rotated 90 degrees again to etch the third waveguide, and then rotated another 90 degrees to etch the fourth optical waveguide 13, thus completing the etching action of the optical waveguide 13 on the tapered rod.

[0073] Please refer to the following: Figure 7 In step S40, the conical rod is broken from the middle position of the conical section to form two conical waveguides 10.

[0074] When breaking the tapered rod at the middle of the tapered section, it can be cut to avoid deformation at the break point, which would affect the manufacturing accuracy of the tapered waveguide 10. For example, a fiber optic cleaver can be used for cutting, but it is not limited to this. Since the initial tapered rod is centrally symmetrical and the marking process is also symmetrical, this cut can obtain two identical tapered waveguide 10 components, each containing four optical waveguides 13, in one operation.

[0075] Figure 7 The structure of the finally fabricated tapered waveguide 10 is shown. It clearly demonstrates the convergence of the four internal optical waveguides 13 from the narrow end (i.e., the first connection end 11, the end with the smaller radial dimension) to the wide end (i.e., the second connection end 12, the end with the larger radial dimension). The positions and spacing of these optical waveguides at both ends are precisely designed to match the structure of the target fiber array; for example, they can be matched with… Figure 10 The array aperture spacing in the target fiber array parameters shown is precisely matched.

[0076] After the tapered waveguide 10 is manufactured, the narrow end (first connection end 11) of the tapered waveguide 10 is aligned and fused with the end face of the multi-core optical fiber 20, and the wide end (second connection end 12) of the tapered waveguide 10 is aligned and fused with the end face of the single-core optical fiber bundle 30 composed of multiple single-core optical fibers 31, thereby applying the tapered waveguide 10 to the fan-in and fan-out assembly of the multi-core optical fiber 20.

[0077] It should be noted that in certain applications, such as high-density optical interconnect modules, the size requirements for fan-in and fan-out components are extremely stringent, necessitating the minimization of the overall length of the tapered waveguide 10. This means that the internal optical waveguide 13 must achieve a large angular deflection within an extremely short axial distance. According to waveguide theory, sharp bending (i.e., an extremely small bending radius) leads to significant bending losses, and may even prevent light from being properly confined.

[0078] Please refer to the following: Figure 8 In some embodiments, when writing the optical waveguide 13 in step S20, it is also necessary to control the radius of curvature at the point where the refractive index of the waveguide changes to be greater than a preset radius of curvature value.

[0079] Right now Figure 5 In this process, the depth variation along the Z-axis is no longer a linear function of the Y-axis, but rather a nonlinear, continuous variation control based on a preset smooth curve function. This ensures the constraint of the transmitted light by the inscribed optical waveguide 13 while shortening the overall length of the tapered waveguide 10. The smooth curve can take various mathematical forms, including but not limited to spline curves, Bézier curves, or sine function curves, to ensure the continuity of the first and second derivatives of the path, meaning that the path itself and its curvature are continuously changing.

[0080] In this embodiment, the specific value of the preset radius of curvature is not limited; for example, it can be set to 1m to 3m based on experience. It should be noted that in actual processing, the deflection angle of the laser can be controlled between 0.20° and 0.50°.

[0081] Please refer to the following: Figure 9 In some embodiments, the following steps may also be included when writing the optical waveguide in step S20:

[0082] Step S25: Inscribe the reflector at the location where the refractive index of the optical waveguide changes.

[0083] This step can occur after step S23, thus dividing the laser-etched waveguide 13 process into two stages. In the first stage, the trapezoidal trajectory described in Figure 5 is still used as the basic path to etch the main body of the waveguide 13 inside the conical rod. This trapezoidal path defines the straight sections of the waveguide 13 in the wide, conical, and narrow segments. Then, in the second stage, after completing the etch of the main waveguide path, or when etching the main path to the "inflection point," an additional, refined laser processing step is performed. In this step, the laser processing parameters are temporarily changed; for example, the laser power can be significantly increased, or different scanning modes such as multiple repeated scans or dot matrix scans can be used. The target position for processing is precisely aligned with the two "inflection points" of the trapezoidal trajectory. Through this special laser processing, a small, abruptly changed surface with a specific tilt angle and a more significant difference in refractive index compared to the surrounding medium can be etched at the corner of the waveguide path. When writing on the reflector, the processing power can be controlled within the range of 0.3-1.0 watts, and the direct writing speed can be controlled within the range of 1-40 mm / s.

[0084] As shown in Figure 7, in some embodiments, this application also provides a tapered waveguide 10, which is manufactured using the manufacturing method of the tapered waveguide 10 described in the above embodiments. The tapered waveguide 10 has a first connecting end 11 and a second connecting end 12. The radial dimension of the first connecting end 11 is smaller than the radial dimension of the second connecting end 12. The first connecting end 11 is used to connect a multi-core optical fiber 20, and the second connecting end 12 is used to connect multiple single-core optical fibers 31. It can be understood that the first connecting end 11 of the tapered waveguide 10 is the narrow end of the tapered waveguide 10, and the second connecting end 12 of the tapered waveguide 10 is the wide end of the tapered waveguide 10.

[0085] like Figure 10As shown, in some embodiments, this application also provides a multi-core fiber 20 fan-in / fan-out assembly. The multi-core fiber 20 fan-in / fan-out assembly includes a multi-core fiber 20, a single-core fiber bundle 30, and the tapered waveguide 10 described in the above embodiments. The single-core fiber bundle 30 includes multiple single-core fibers 31, and the array of single-core fibers 31 in the single-core fiber bundle 30 is the same as the array of fiber cores 21 in the multi-core fiber 20. The first connection end 11 of the tapered waveguide 10 is connected to the multi-core fiber 20, and the second connection end 12 of the tapered waveguide 10 is connected to the single-core fiber bundle 30. The connection between the tapered waveguide 10 and the multi-core fiber 20, and between the tapered waveguide 10 and the single-core fiber bundle 30, can be achieved using fusion splicing technology, but is not limited to this method. The tapered waveguide 10 and the multi-core optical fiber 20 fan-in / fan-out assembly including the tapered waveguide 10 provided in this application both adopt the tapered waveguide 10 manufactured in the above-described embodiment of the tapered waveguide 10 manufacturing method. Therefore, they at least have all the beneficial effects brought about by the technical solutions of the above-described embodiment of the tapered waveguide 10 manufacturing method, which will not be repeated here.

[0086] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for manufacturing a tapered waveguide, characterized in that, The tapered waveguide is used to connect multi-core optical fibers and multiple single-core optical fibers, and the manufacturing method includes: A conical rod is provided, the conical rod including a conical section, the radial dimension of the middle position of the conical section being smaller than the radial dimensions of the two ends, and the conical rod being made of a transparent material; Using laser engraving technology, an optical waveguide is formed by engraving from the circumferential surface of the conical rod along its axial direction inside the conical rod. The previous step is repeated once for each preset angle value that the conical rod is rotated around its central axis, until the number of optical waveguides on the conical rod reaches the preset value; The conical rod is broken off at the middle position of the conical section to form two conical waveguides.

2. The method for manufacturing a tapered waveguide according to claim 1, characterized in that, The material of the conical rod includes quartz; The tapered rod is formed by drawing a capillary rod with a circular cross-section using a tapering technique.

3. The method for manufacturing a tapered waveguide according to claim 1, characterized in that, The method employs laser engraving technology to engrave an optical waveguide from the circumferential surface of the conical rod along its axial direction inside the rod, forming an optical waveguide, comprising: Position the laser spot at a preset starting point so that the optical waveguide to be formed can correspond to the position of the corresponding single fiber in the array of multiple single-core fibers. When the laser spot is moved to the middle position of the conical section, it is positioned at a preset midpoint so that the optical waveguide to be formed can correspond to the position of the corresponding fiber core in the multi-core fiber array.

4. The method for manufacturing a tapered waveguide according to claim 3, characterized in that, The preset starting point is the center point of the single-core fiber in the array of multiple single-core fibers that corresponds to the optical waveguide to be formed.

5. The method for manufacturing a tapered waveguide according to claim 3, characterized in that, The preset midpoint is the center point of the fiber core in the multi-core fiber core array that corresponds to the optical waveguide to be formed.

6. The method for manufacturing a tapered waveguide according to any one of claims 1 to 5, characterized in that, The method employs laser engraving technology to engrave an optical waveguide from the circumferential surface of the conical rod along its axial direction inside the rod, forming an optical waveguide, comprising: The radial position of the laser spot within the conical rod is controlled so that the trajectory of the formed optical waveguide conforms to the contour of the conical rod.

7. The method for manufacturing a tapered waveguide according to claim 6, characterized in that, The radius of curvature at the point where the refractive index of the optical waveguide changes is greater than a preset radius of curvature value.

8. The method for manufacturing a tapered waveguide according to claim 6 or 7, characterized in that, The method employs laser engraving technology to engrave an optical waveguide from the circumferential surface of the conical rod along its axial direction inside the rod. It also includes: A reflector is inscribed at the point where the refractive index of the optical waveguide changes.

9. A tapered waveguide, characterized in that, The tapered waveguide is manufactured using the manufacturing method of the tapered waveguide according to any one of claims 1-8, and the tapered waveguide has a first connecting end and a second connecting end, the radial dimension of the first connecting end is smaller than the radial dimension of the second connecting end, the first connecting end is used to connect a multi-core optical fiber, and the second connecting end is used to connect multiple single-core optical fibers.

10. A multi-core fiber fan-in / fan-out assembly, characterized in that, include: Multi-core optical fiber; A single-core fiber bundle, wherein the single-core fiber bundle comprises multiple single-core fibers, and the array of the single-core fibers in the single-core fiber bundle is the same as the array of the fiber cores in the multi-core fiber bundle; The tapered waveguide of claim 9, wherein the first connection end of the tapered waveguide is connected to the multi-core optical fiber, and the second connection end of the tapered waveguide is connected to the single-core optical fiber bundle.

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