A method for reverse beam combining and beam homogenization of a fiber bundle

Abstract

The application discloses a reverse beam combining weaving and beam homogenization method of an optical fiber bundle, adopts reverse beam combining for branch optical fiber bundles, uses different colors for each branch optical fiber coating, divides areas at branch ends, extracts a bundle of optical fibers from corresponding areas of each branch for grouping, each group is a small optical fiber filament bundle, and a light transmission micro area is formed. The micro areas are randomly and uniformly arranged on a light incidence end face (a beam combining end), and a required end face shape is formed. The application adopts reverse beam combining, guarantees uniformity of the number of branch optical fiber filaments of the branch optical fiber bundles, adopts optical fiber filament grouping, also called weaving, forms a light transmission micro area, and the light transmission micro area can refine and homogenize light emitted by a light source, is also called micro area homogenization, a small optical fiber filament bundle is then gathered into the whole optical fiber bundle, light emitted by the light source is homogenized again, and the gathering homogenization is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber bundles, and in particular to a method for reverse bundling and braiding of optical fiber bundles and light beam homogenization. Background Art

[0002] Fiber optic bundles, components composed of precisely bundled optical fibers, have demonstrated broad application potential and promising development prospects in a variety of high-tech fields, including energy and image transmission, laser medicine, energy detection, UV lithography, and quality inspection. However, significant shortcomings in the current manufacturing process for branched optical fiber bundles hinder performance optimization and cost reduction.

[0003] The traditional manufacturing process involves a splitting step, distinct from a combining step. This involves first fabricating the input end of the fiber bundle and then processing the branch ends. This sequential operation not only increases process complexity but also makes it difficult to precisely control the number of fiber filaments in each branch during the fabrication process, leading to uneven light output. Furthermore, given that fiber bundles are often used to transmit non-uniform light sources, improving the uniformity of the transmitted light field distribution presents a significant challenge.

[0004] To address the inherent lack of uniformity in the light source, existing technologies tend to employ a method of randomly breaking up the optical fibers during branching to achieve a homogenized beam. However, this approach often yields unsatisfactory results: either the fibers are insufficiently mixed, failing to meet light field uniformity requirements; or excessive breaking up causes damage to the fibers, significantly increasing breakage rates and reducing production efficiency. This trade-off not only increases uncertainty in the production process but also significantly reduces yield on the production line, directly driving up production costs.

[0005] In summary, current manufacturing processes for branched optical fiber bundles have significant shortcomings in maintaining consistent fiber count, improving optical field uniformity, and controlling production costs. Therefore, an innovative manufacturing process is urgently needed to overcome the limitations of existing technologies and achieve efficient homogenization of the optical beams between and within branches, while also reducing production costs and improving product yield. Summary of the Invention

[0006] To overcome the shortcomings of the aforementioned prior art, the present invention provides a method for reverse fiber bundle combining, braiding, and beam homogenization, designed to optimize the beam energy distribution and light field uniformity of single-branch or multi-branch fiber bundles. Through reverse beam combining technology, micro-zone construction, and uniform distribution of micro-zones at the incident end face, this method addresses the beam energy variation problem caused by poor fiber filament dispersion and uneven number of branch fiber filaments in traditional fiber bundle manufacturing, and significantly improves the uniformity of the light field distribution at the light output end face.

[0007] The technical solutions of the present invention are as follows:

[0008] A method for reversely combining and braiding optical fiber bundles and homogenizing optical beams, characterized in that the method comprises the following steps:

[0009] An optical fiber is provided, comprising a core and a cladding, wherein the refractive index of the cladding material is lower than the refractive index of the core material;

[0010] According to the total amount of optical fiber filaments required for the optical fiber bundle and the number of branches, the optical fibers are cut into equal parts for the number of branches, and then braided and combined in reverse. The coating of the optical fibers constituting each branch is distinguished by different colors.

[0011] Each branch end is divided into n equal-sized micro-regions, and a bundle of optical fibers is extracted from the corresponding region of each branch and grouped. Each group is composed of a small strand of optical fiber, forming a light-transmitting micro-region. The size of the micro-region is affected by the diameter of the optical fiber and the number of branches N. Within the micro-region, the number of optical fibers from the N branches is the same. For multi-branch optical fiber bundles with multiple types, if the number of input ends is M, then N divided by M is an integer to ensure that the micro-region bundle is evenly divided into M large bundles.

[0012] At the light incident end face, i.e., the beam combining end, the multiple light-transmitting micro-regions are randomly and evenly arranged and bundled into the entire end face to form the desired end face shape;

[0013] The reverse combining includes first completing the production of the branch ends of a single-branch optical fiber bundle and then combining the bundles, and first completing the production of the branch ends with more branches of a multi-branch optical fiber bundle and then combining the bundles.

[0014] Furthermore, in step 3), the size of the micro-region is also affected by the following factors:

[0015] a) The smaller the diameter of the optical fiber, the smaller the micro-region that can be achieved;

[0016] b) The larger the number of branches N, the larger the size of the micro-domain.

[0017] Furthermore, in step 4), the multiple light-transmitting micro-region head ends are aligned and placed in a mold that matches the light-transmitting area of ​​the optical fiber bundle, or are manually formed into the desired end face shape without a mold, and are randomly and evenly arranged and bundled into the entire end face to form the desired optical fiber bundle end face shape.

[0018] Furthermore, the mold is made of polymer material or metal material.

[0019] Furthermore, the end face of the optical fiber bundle is in a circular, wavy, rectangular or polygonal shape.

[0020] Furthermore, between step 3) and step 4), the method further includes performing light field homogenization processing on the light-transmitting micro-region to improve the light field uniformity in each micro-region.

[0021] Furthermore, the light field homogenization process includes adjusting the arrangement of optical fiber filaments, the diameter of optical fiber filaments or the spacing parameters between optical fiber filaments to achieve light field homogenization in the micro area.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The traditional multi-branch fiber bundle production process often starts from the light incident end, first finalizing the fiber arrangement at the incident end, then picking out the fibers from the middle section of the fibers and performing the beam splitting step. This makes it difficult to ensure a uniform number of optical fibers in each branch. The present invention, however, uses reverse beam combining technology, which first completes the production of each branch and then performs the beam combining operation. This reverse beam combining method not only improves the flexibility of fiber bundle production, but also facilitates precise regional division and fiber grouping at the branch ends, providing favorable conditions for subsequent light field homogenization processing.

[0024] 2) The present invention divides the branch end into several areas of equal area, and extracts a bundle of optical fibers from the corresponding area of ​​each branch for grouping to form a plurality of light-transmitting micro-regions. Each light-transmitting micro-region is formed by a small bundle of optical fiber filaments, which not only improves the light extraction efficiency of the optical fiber bundle, but also enables the light field to be initially uniformed within the micro-region. By adjusting parameters such as the arrangement mode, diameter or spacing of the optical fiber filaments, the light field distribution within the micro-region can be further optimized and the uniformity of the light field can be improved. At the same time, on the light incident end face, multiple light-transmitting micro-regions are randomly and evenly arranged to form the required end face shape of the optical fiber bundle. This random and uniform arrangement method not only breaks the regularity of the traditional optical fiber bundle arrangement, but also effectively avoids the problem of insufficient illumination uniformity caused by improper arrangement of optical fiber filaments. Through random and uniform arrangement, the light field can be more evenly distributed on the light-emitting end face of the optical fiber bundle, thereby improving the light field uniformity of the entire light-emitting end face. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is a schematic diagram of the end face of the constructed hexagonal light-transmitting micro-area.

[0027] Figure 2 Schematic diagram of the braiding operation framework of the one-to-three optical fiber bundle in the embodiment

[0028] Figure 3 Schematic diagram of the division of branch end micro-area production area

[0029] Figure 4 Schematic diagram of the reverse bundling and braiding process of a one-to-three optical fiber bundle in the embodiment

[0030] Figure 5 This is a schematic diagram of the bundled end face after weaving

[0031] Throughout the drawings, reference numerals are used to designate various elements and structures, wherein:

[0032] 1- Black, white and gray represent the optical fibers from the three branches.

[0033] 2-3 branches of a 1-to-3 fiber bundle

[0034] 3-Branch Fixing Clamp

[0035] 4-Inner diameter shrink ring

[0036] 5-One-to-three fiber bundle combined end

[0037] 6-Fiber optic

[0038] 7-Light-transmitting micro-region composed of optical fiber filaments from three branches

[0039] 8-The boxed area represents the end surface of the homogenized micro-region DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] A method for reversely combining and braiding optical fiber bundles and homogenizing optical beams, comprising the following steps:

[0042] 1) Provide an optical fiber, comprising a core and a cladding, wherein the core of the optical fiber is made of glass or other materials, and the cladding is made of glass or other materials with a lower refractive index than the core material

[0043] 2) According to the total amount of optical fiber and the number of branches required for the optical fiber bundle, the optical fiber is cut into equal parts as the number of branches for standby use, and then braided and reversely bundled. The optical fiber coatings that constitute each branch can be distinguished by different colors, which makes it easier to take optical fibers from each branch to construct micro-areas.

[0044] 3) The size of the micro-region is affected by factors such as the diameter of the optical fiber and the number of branches N.

[0045] The smaller the diameter of the optical fiber, the smaller the micro-region that can be achieved;

[0046] The larger the number of branches N is, the larger the size of the micro-region is;

[0047] Within a micro-area, the number of optical fibers from the N branches must be roughly the same;

[0048] In the multi-divide-multi mode, if the number of input ports is M, then N divided by M must be an integer to ensure that the micro-area beam is evenly divided into M large beams.

[0049] The light-transmitting micro-area is constructed starting from about 400 mm away from the beam-combining end face, and can be started closer or farther depending on actual needs.

[0050] 4) Micro-zone construction method: Each branch end is divided into n micro-zone production areas of equal area, and each area is numbered 1, 2, 3, ... n. Multiple micro-zones can be produced in each micro-zone production area. The above-mentioned light-transmitting micro-zone can be fixed by bundling multiple optical fibers, and the optical fibers in a single micro-zone must come from the micro-zone production area with the same number. The optical fiber end face of the micro-zone can be constructed into circular, wavy, rectangular, polygonal and other shapes as needed. Generally speaking, for a circular beam combining end, the micro-zone end face can be constructed into a hexagonal shape; for a rectangular beam combining end, the micro-zone end face can be constructed into a rectangular shape. If the goal of high transmittance of the optical fiber bundle is to achieve, the end face optical fibers need to be tightly packed hexagonally, and in this case, the micro-zone should be a hexagonal sub-bundle.

[0051] 5) Align the light-transmitting micro-region heads with the above-mentioned size and shape and place them in a mold that matches the light-transmitting area of ​​the optical fiber bundle, distribute them randomly and evenly, and bundle them into the entire end face.

[0052] The reverse beam combining is to complete the production of the branch end first and then combine the beam for the single-to-multiple branch optical fiber bundle.

[0053] The reverse beam combining is characterized in that for a multi-branch optical fiber bundle, the branch ends with more branches are first made, and then the beam combining operation is performed.

[0054] The weaving operation includes the construction of the light-transmitting micro-regions and the uniform arrangement of the micro-regions on the end surface after the micro-regions are constructed.

[0055] The mold material can be polymer material or metal material; or the mold can be not used and the end face shape can be formed manually.

[0056] The size and shape of each light-transmitting micro-area constituting the branch optical fiber bundle end face need not be specially specified.

[0057] There is no clear order of sequence for the braiding and reverse bundling operations involved

[0058] Example: A method for reversely combining and braiding a one-to-three optical fiber bundle and homogenizing the optical beam, wherein both the optical input and optical output ends of the optical fiber bundle are circular. The method comprises the following steps:

[0059] Take a total of 10km long optical fiber, the core material is pure quartz, the cladding material is fluorine-doped quartz, and the bare fiber outer diameter is 190μm

[0060] Cut the optical fibers into 1500±100mm lengths, which means a total of 6666 fibers can be cut and divided into three parts by counting. One end of the three optical fibers will form the three branches of the one-to-three optical fiber bundle, and the other end will be tied and fixed after braiding.

[0061] Place the three branch fiber bundles vertically as shown in the figure. Figure 2 The braiding operation frame shown is fixed at one end with a branch fixing clamp

[0062] After one end is fixed, pass the other end of the 3 branch fiber bundles through the Figure 2 The inner diameter shrinking ring shown in the figure can freely adjust the diameter of the inner ring and can move in the vertical direction.

[0063] Will Figure 2 The inner diameter of the middle shrink ring is adjusted to about 30mm, so that the optical fiber passing through it gradually shrinks into a circle, and the height of the shrink ring is adjusted to about 400mm from the bottom of the optical fiber.

[0064] At the branch end, 20 micro-area production areas of equal area are divided, and each area is numbered 1, 2, 3, ... 20. Multiple micro-areas can be produced in each micro-area production area, as shown in the schematic diagram. Figure 3 shown.

[0065] like Figure 4 As shown in the figure, an equal amount of optical fibers are taken from the three branches to construct a hexagonal light-transmitting micro-region. Figure 1 As shown. The number of optical fibers in this light-passing micro-area accounts for about 0.3% of the total number of optical fibers.

[0066] The location of the micro-zone is 400mm away from the beam combining end to avoid problems such as fiber breakage caused by too small a micro-zone area and increased fiber loss caused by too small a fiber bending radius.

[0067] The light-transmitting micro-region heads are aligned and placed in the mold, and randomly distributed on the entire end surface, and bundled into a light-transmitting end surface, such as Figure 5 shown.

[0068] Experiments have shown that this method, employing a reverse beam combining scheme, avoids the impact of varying fiber counts in each branch on inter-branch uniformity. By constructing micro-zone production areas within each branch of the fiber bundle and extracting fiber filaments from these areas to create fine, light-transmitting micro-zones, micro-zone homogenization is achieved. These micro-zones are then combined to achieve uniform beam convergence. This method is simple, convenient, and easy to implement, further optimizing the uniformity of light field distribution between and within branches of the fiber bundle compared to traditional schemes.

[0069] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A method for reverse bundling and beam homogenization of optical fiber bundles, characterized in that: The method comprises the following steps: 1) providing an optical fiber comprising a core and a cladding, wherein the refractive index of the cladding material is lower than the refractive index of the core material; 2) Based on the total amount of optical fiber filaments required for the optical fiber bundle and the number of branches, the optical fibers are cut into equal parts equal to the number of branches for standby use, and then braided and reversely bundled. The coatings of the optical fibers constituting each branch are different colors to distinguish them; 3) Each branch end is divided into n micro-regions of equal area, and a bundle of optical fibers is extracted from the corresponding area of ​​each branch and grouped. Each group is composed of a small strand of optical fiber, forming a light-transmitting micro-region. The size of the micro-region is affected by the diameter of the optical fiber and the number of branches N. Within the micro-region, the number of optical fibers from the N branches is consistent. For a multi-branch multi-type branch optical fiber bundle, if the number of input ends is M, then N divided by M is an integer to ensure that the micro-region bundle is evenly divided into M large bundles. 4) At the light incident end face, i.e., the beam combining end, the multiple light-transmitting micro-regions are randomly and evenly arranged and bundled into the entire end face to form the desired end face shape; The reverse combining includes first completing the production of the branch ends of a single-branch optical fiber bundle and then combining the bundles, and first completing the production of the branch ends with more branches of a multi-branch optical fiber bundle and then combining the bundles.

2. The method for reverse combining and braiding optical fiber bundles and light beam homogenization according to claim 1, characterized in that: In step 3), the size of the micro-zone is also affected by the following factors: a) the smaller the diameter of the optical fiber, the smaller the micro-zone that can be achieved; b) the larger the number of branches N, the larger the size of the micro-zone.

3. The method for reverse combining and braiding optical fiber bundles and light beam homogenization according to claim 1, characterized in that: In step 4), the multiple light-transmitting micro-region head ends are aligned and placed in a mold that matches the light-transmitting area of ​​the optical fiber bundle, or are manually formed into the desired end face shape without a mold, and are randomly and evenly arranged and bundled into the entire end face to form the desired optical fiber bundle end face shape.

4. The method for reverse combining and braiding optical fiber bundles and light beam homogenization according to claim 3, characterized in that: The mold is made of polymer material or metal material.

5. The method for reverse combining and braiding optical fiber bundles and light beam homogenization according to claim 3, characterized in that: The end face shape of the optical fiber bundle is circular, wavy, rectangular or polygonal.

6. The method for reverse combining and braiding optical fiber bundles and light beam homogenization according to claim 1, characterized in that: Between step 3) and step 4), the method further includes performing light field uniformization processing on the light-transmitting micro-region to improve the light field uniformity in each micro-region.

7. The method for reverse combining and braiding optical fiber bundles and light beam homogenization according to claim 6, characterized in that: The light field homogenization process includes adjusting the arrangement of optical fiber filaments, the diameter of optical fiber filaments or the spacing parameters between optical fiber filaments to achieve light field homogenization in the micro area.

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