Optical fiber splicing method and system

Abstract

The invention relates to the technical field of optical fibers, in particular to an optical fiber splicing method and system, and the method comprises the following steps: enabling the end surfaces of a first optical fiber to be aligned and a second optical fiber to be aligned to be in contact, and rotating the first optical fiber to be aligned for a plurality of times, obtaining a plurality of side view images corresponding to the to-be-aligned first optical fiber and the to-be-aligned second optical fiber before rotation and after each rotation; extracting image features of the plurality of side view images; selecting an optimal rotation angle based on the similarity between the image feature corresponding to each side view image and the image feature of a preset reference image; after the position of the optical fiber is adjusted according to the optimal rotation angle, a first optical fiber to be aligned and a second optical fiber to be aligned are connected; according to the method and the system, on-site rapid and low-loss alignment continuous deployment can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fibers, and more specifically, to an optical fiber splicing method and system. Background Art

[0002] Optical fiber communication systems carry more than 90% of the global information data transmission and are an essential infrastructure in modern society. With the continuous emergence of new technologies such as data centers, the Internet of Things, big data, virtual reality, artificial intelligence, and cloud computing, there are application requirements for large-capacity, low-power consumption, and low-latency information transmission and exchange. However, limited by factors such as Rayleigh scattering loss, nonlinearity, and refractive index of existing silica optical fiber materials, standard single-mode optical fiber communication systems using silica optical fibers have performance bottlenecks such as loss, delay, and nonlinearity. Anti-resonant hollow-core fibers use a nested structure of multiple silica tubes and utilize the anti-resonant effect to confine light in the air medium for transmission, which can break through the inherent limitations of existing traditional solid-core single-mode optical fibers in terms of loss, delay, and nonlinear Shannon, etc., and bring about a comprehensive and transformative innovation to optical fiber communication systems.

[0003] Therefore, the on-site deployment of hollow-core fibers has been rapidly carried out at home and abroad, and its advantages in low-latency demand scenarios have been initially verified. However, due to the angular asymmetry and internal negative pressure characteristics of anti-resonant hollow-core fibers, the hollow-core fibers face three major problems in actual deployment. First, the thickness of the nested tube structure inside the hollow-core fiber is at the nanometer level, and the splicing process is more complex than that of traditional optical fibers, resulting in large splicing losses. Second, manual alignment is mostly used during deployment, and the single-point splicing time is long. The splicing loss is affected by manual operation errors, leading to low deployment efficiency. Third, due to the internal negative pressure characteristics of the hollow-core fiber, during the long-term splicing deployment process, the optical fiber is more vulnerable to the influence of external pollutants such as dust and water vapor, thereby affecting the communication performance.

[0004] In various application requirements of hollow-core fibers, the splicing or coupling of hollow-core fibers is involved, and splicing or coupling requires the realization of angle alignment, that is, the matching of the internal mode field. Most of the current splicing methods are based on manual visual alignment and manual core alignment, which often lead to low alignment efficiency, poor alignment accuracy, and a decrease in the reliability of long-term deployment, making it difficult to meet the continuously developing technical requirements of hollow-core fibers. Summary of the Invention

[0005] The present invention aims to overcome the defects of low core alignment efficiency and high optical fiber loss after splicing in the above-mentioned prior art, and provides an optical fiber splicing method and system that can achieve rapid splicing and low optical fiber loss after splicing.

[0006] To solve the above technical problems, the technical solution of the present invention is as follows:

[0007] An optical fiber splicing method, comprising the following steps:

[0008] Bring the end faces of the first optical fiber to be aligned and the second optical fiber to be aligned into contact, and rotate the first optical fiber to be aligned several times to obtain several side view images corresponding to the first optical fiber to be aligned and the second optical fiber to be aligned before rotation and after each rotation;

[0009] Extract the image features of several side view images;

[0010] Based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image, select the optimal rotation angle;

[0011] After adjusting the positions of the optical fibers according to the optimal rotation angle, perform a splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned.

[0012] The present invention also provides a system for an optical fiber splicing method, including:

[0013] A side view image acquisition unit, configured to bring the end faces of the first optical fiber to be aligned and the second optical fiber to be aligned into contact, and rotate the first optical fiber to be aligned several times to obtain several side view images corresponding to the first optical fiber to be aligned and the second optical fiber to be aligned before rotation and after each rotation;

[0014] An image feature extraction unit, configured to extract the image features of several side view images;

[0015] An optimal rotation angle selection unit, configured to select the optimal rotation angle based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image;

[0016] An optical fiber splicing unit, configured to perform a splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned after adjusting the positions of the optical fibers according to the optimal rotation angle.

[0017] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0018] By acquiring the side view images of the first optical fiber to be aligned and the second optical fiber to be aligned, selecting the optimal rotation angle based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image, and performing a splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned after adjusting the positions of the optical fibers according to the optimal rotation angle, the present invention can achieve fast and low-loss alignment and splicing deployment on site. Description of the Drawings

[0019] Figure 1 It is the first flow schematic diagram of the optical fiber splicing method described in Embodiment 1;

[0020] Figure 2The five - ring double - embedded sleeve anti - resonant hollow end - face image described in Embodiment 3;

[0021] Figure 3 The side - view image of randomly - oriented misaligned hollow optical fibers described in Embodiment 3;

[0022] Figure 4 The contrast difference image of the gray - value of the fiber column vectors to be aligned described in Embodiment 3;

[0023] Figure 5 The side - view image of the hollow optical fiber after pre - processing by the algorithm described in Embodiment 3;

[0024] Figure 6 The corresponding image of the one - dimensional gray - scale reference vector described in Embodiment 3;

[0025] Figure 7 The corresponding image of the one - dimensional gray - scale rotated vector after rotation described in Embodiment 3;

[0026] Figure 8 The side - view image of the hollow optical fiber after automatic alignment described in Embodiment 3;

[0027] Figure 9 The contrast difference image of the gray - value of the aligned column vectors described in Embodiment 3;

[0028] Figure 10 The second flow - schematic diagram of the optical - fiber splicing method described in Embodiment 3. Detailed implementation manners

[0029] The drawings are only for illustrative purposes and should not be construed as limitations on this patent;

[0030] To better illustrate this embodiment, some components in the drawings are omitted, enlarged or reduced, and do not represent the dimensions of the actual product;

[0031] For those skilled in the art, it is understandable that some well - known structures and their descriptions in the drawings may be omitted.

[0032] The technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0033] Embodiment 1

[0034] This embodiment proposes an optical - fiber splicing method, Figure 1 which is the first flow - schematic diagram of the optical - fiber splicing method proposed in this embodiment.

[0035] As Figure 1 shown, the optical - fiber splicing method of this embodiment includes the following steps:

[0036] Bring the end faces of the first optical fiber to be aligned and the second optical fiber to be aligned into contact, and rotate the first optical fiber to be aligned several times to obtain several side view images corresponding to the first optical fiber to be aligned and the second optical fiber to be aligned before rotation and after each rotation;

[0037] Extract the image features of several side view images;

[0038] Based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image, select the best rotation angle;

[0039] After adjusting the positions of the optical fibers according to the best rotation angle, perform a splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned.

[0040] In the specific implementation process, the present invention can realize fast and low-loss alignment and splicing deployment on site by obtaining the side view images of the first optical fiber to be aligned and the second optical fiber to be aligned, selecting the best rotation angle based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image, and performing a splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned after adjusting the positions of the optical fibers according to the best rotation angle.

[0041] In an optional embodiment, when performing a splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned, a fiber splicer is used for the splicing operation.

[0042] In an optional embodiment, the fiber splicer is equipped with functions of capturing side view images and rotating optical fibers, and both the side view images and the reference images are obtained by using the fiber splicer;

[0043] The steps of obtaining the side view images include:

[0044] Perform preprocessing on the first optical fiber to be aligned and the second optical fiber to be aligned. Use the fiber splicer to detect the cutting angles of the first optical fiber to be aligned and the second optical fiber to be aligned. If the cutting angles of the first optical fiber to be aligned and the second optical fiber to be aligned meet the preset standards, place the first optical fiber to be aligned and the second optical fiber to be aligned on the fiber splicer platform, adjust the positions between the first optical fiber to be aligned and the second optical fiber to be aligned so that their end faces are placed in the image acquisition device of the fiber splicer, and use the image acquisition device to collect the side view images of the first optical fiber to be aligned and the second optical fiber to be aligned; otherwise, cut the cutting angles of the first optical fiber to be aligned and the second optical fiber to be aligned to meet the preset standards, and then use the fiber splicer to collect the side view images.

[0045] In an alternative embodiment, before extracting the image features of a plurality of side view images, preprocessing for removing color interference is performed on each side view image, and the side view image after removing color interference through the preprocessing is converted into a grayscale image. When extracting the image features of a plurality of side view images, the grayscale image corresponding to each side view image is converted into a one-dimensional grayscale value vector to obtain the image features corresponding to each side view image.

[0046] In an alternative embodiment, before extracting the image features of the grayscale image, the grayscale image is sharpened.

[0047] In an alternative embodiment, the method adopted for sharpening the grayscale image includes an adaptive contrast enhancement algorithm.

[0048] In an alternative embodiment, the rotation angle range of the first optical fiber to be aligned includes [-180°, 180°], and the rotation angle difference between two adjacent rotations is a preset step value.

[0049] In an alternative embodiment, the steps of selecting the optimal rotation angle based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image include:

[0050] Calculating the cosine similarity between the image features corresponding to each grayscale image and the preset reference image features, and regarding the rotation angle corresponding to the image features with the largest cosine similarity value as the optimal rotation angle;

[0051] The calculation expression of the cosine similarity includes:

[0052]

[0053]

[0054] In the formula, D represents the cosine similarity value, A represents the image feature vector corresponding to the rotated side view image, B represents the image feature vector of the reference image, C is the dot product value of A and B, ||A|| and ||B|| respectively represent the norms of vector A and vector B, represents the square of the value of the i-th component of vector A, represents the square of the value of the i-th component of vector B, and n represents the total number of components of the image feature vector.

[0055] Embodiment 2:

[0056] This embodiment proposes a system based on the optical fiber splicing method described in Embodiment 1; Figure 3 is a schematic flow diagram of the system for the optical fiber splicing method proposed in this embodiment;

[0057] As Figure 3As shown, the system of the optical fiber splicing method includes:

[0058] A side view image acquisition unit, configured to bring the end faces of the first optical fiber to be aligned and the second optical fiber to be aligned into contact, and rotate the first optical fiber to be aligned several times, and acquire several side view images corresponding to the first optical fiber to be aligned and the second optical fiber to be aligned before rotation and after each rotation;

[0059] An image feature extraction unit, configured to extract the image features of several side view images;

[0060] An optimal rotation angle selection unit, configured to select an optimal rotation angle based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image;

[0061] An optical fiber splicing unit, configured to perform a splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned after adjusting the positions of the optical fibers according to the optimal rotation angle.

[0062] This embodiment also provides a computer device, including a memory and a processor. Computer-readable instructions are stored in the memory. When the computer-readable instructions are executed by the processor, the processor is caused to execute the steps of the optical fiber splicing method as described in Embodiment 1.

[0063] Embodiment 3:

[0064] Based on the optical fiber splicing method proposed in Embodiment 1 and the system of the optical fiber splicing method proposed in Embodiment 2, this embodiment provides a specific implementation example:

[0065] Figure 2 Is the five-ring double-sleeved anti-resonant hollow core end face image described in Embodiment 3; Figure 3 Is the side view image of randomly oriented misaligned hollow core optical fibers described in Embodiment 3; Figure 4 Is the comparison difference image of the column vector gray values of the optical fibers to be aligned described in Embodiment 3; Figure 5 Is the side view image of the hollow core optical fiber after algorithm preprocessing described in Embodiment 3; Figure 6 Is the corresponding image of the one-dimensional gray reference vector described in Embodiment 3; Figure 7 Is the corresponding image of the one-dimensional gray rotation vector after rotation described in Embodiment 3; Figure 8 Is the side view image of the hollow core optical fiber after automatic alignment described in Embodiment 3; Figure 9 Is the comparison difference image of the column vector gray values after alignment described in Embodiment 3; Figure 10 Is the second flow schematic diagram of the optical fiber splicing method described in Embodiment 3

[0066] In a specific implementation example, both the first optical fiber to be docked and the second optical fiber to be docked are hollow core optical fibers, such asFigure 2 As shown, taking the connection of a double-layer nested tube anti-resonant hollow fiber as an example, the method is not limited to this type of hollow fiber. This patent provides a specific implementation example of automatic alignment and self-connection of low-loss and high-efficiency hollow fibers based on machine vision. For the specific process, please refer to Figure 10 . Before measurement, use a cutter to cut the double-layer nested tube anti-resonant hollow fiber to ensure that the side view is flat to meet the pre-fusion requirements. Embodiment 1 provides a method for rapid and low-loss connection deployment of hollow fibers on-site. The following will describe Example 1 with reference to the accompanying drawings, which mainly includes the following steps:

[0067] Step 1: Obtain the side view image of the hollow fiber to be butt-jointed;

[0068] Step 2: Preprocess the side view image of the hollow fiber;

[0069] The preprocessing includes removing noise interference and converting the image into a grayscale image, etc.;

[0070] Step 3: Extract the image feature information and convert the image into a one-dimensional grayscale value vector;

[0071] Step 4: Rotate the image within a preset range of rotation angles to generate multiple rotated versions of the image feature vectors;

[0072] Step 5: Calculate the cosine similarity between the rotated image feature vector and the reference image feature vector, and select the best rotation angle;

[0073] Step 6: Combine with an optical fiber fusion splicer to adjust the position of the optical fiber according to the best rotation angle to complete precise alignment;

[0074] Step 7: Combine with an optical fiber fusion splicer to complete automatic low-loss optical fiber alignment and connection.

[0075] The acquisition of the side view image in Step 1 and the connection in Step 7 are completed by externally controlling an optical fiber fusion splicer, and the fusion splicer needs to have the functions of capturing side view images and rotating optical fibers.

[0076] As an exemplary illustration, for the hollow fiber to be fused, detect the cutting angle through an optical fiber fusion splicer. Place the hollow fiber on the platform of the optical fiber fusion splicer, adjust the position between the hollow fibers, so that the side view image of the hollow fiber is placed in the image acquisition device of the optical fiber fusion splicer, and capture the side view image of the optical fiber. The side view image is as Figure 3 shown.

[0077] Whether the alignment effect is achieved in the side view image can be judged by obtaining the grayscale values corresponding to the column vectors of the left and right hollow fibers to be fused in the side view. The difference in grayscale values of the hollow fibers to be aligned in the current state is as Figure 4 shown, which reflects the internal structure of the optical fiber.

[0078] In addition, before the feature information extraction of the side view image in step 2, the following steps are further included: performing sharpening processing on the side view image.

[0079] As an exemplary illustration, in step 2, the ACE adaptive contrast enhancement algorithm is used to preprocess the image.

[0080] When preprocessing the image, technical means such as gray conversion and denoising are used to improve the image quality. The image after image processing is as Figure 5 shown.

[0081] In step 3, the one-dimensional reference vector is obtained as Figure 6 shown.

[0082] In step 4, the rotation angle range is ±180°, and the step size of the rotation angle is a preset value. For the hollow core optical fiber as Figure 2 shown, the rotation angle can be set to 72° as the preset value to obtain the image information within one cycle. After rotation adjustment, the captured images with a fixed step size are converted into corresponding rotation vectors, and the one-dimensional rotation vector is obtained as Figure 7 shown.

[0083] In step 5, the calculation formula of the cosine similarity is:

[0084]

[0085] where A and B are the rotated image feature vectors, C is the dot product value of A and B, ||A|| and ||B|| are the vector norms, and D is the cosine similarity value, which is used to calculate the cosine similarity corresponding to the rotation angle to determine the optimal rotation angle.

[0086] In step 6, the rotation angle of the optical fiber is adjusted according to the calculated optimal rotation angle, and the alignment effect is verified after adjustment. The rotation alignment completion effect can be seen in Figure 8 , and the difference in gray values reflected by its corresponding column vectors is as Figure 9 shown, which reflects the alignment situation of the optical fiber.

[0087] The optical fiber fusion splicer completes the splicing of the optical fiber through discharge operation, and realizes precise control during the splicing process by controlling the current and time parameters.

[0088] To verify the splicing performance, the following takes Figure 2 the hollow core optical fiber with five nested sleeves and double-layer nesting as an example, and gives multiple examples (20 examples are given). Among them, Table 1 shows the optical power change and splicing loss after automatic splicing of the hollow core optical fiber in multiple examples. Table 1 is as follows:

[0089] Table 1 Optical power change and fusion loss after automatic fusion splicing of hollow-core optical fibers in multiple instances

[0090] Welding Loss (dBm) Alignment Time (S) Welding Loss (dBm) Alignment Time (S) 1 0.02 96.47 11 0.03 97 2 0.02 9652 12 003 96 3 0.02 96.49 13 0.01 96.45 4 0.01 96.26 14 0.03 96.77 5 0.01 95.93 15 0.02 96 6 0.01 96 16 0.02 95.91 7 0.01 96.97 17 0.02 96 8 0.01 97 18 0.01 96.71 9 0.02 95.82 19 0.02 96.31 10 0.02 96.97 20 0.01 96

[0091] As can be seen from Table 1, the average fusion loss of the method for automatic alignment and self-splicing of hollow-core optical fibers provided by the present invention is less than 0.03 dBm. When misaligned, the maximum fusion loss can reach 0.17 dBm, indicating that this method can effectively reduce the fusion loss. The entire process from side-view image capture to completion of fusion splicing is within 97 seconds, while the manual core alignment time is about 300 seconds, greatly reducing the time cost compared to manual alignment. The above data show that the present invention can effectively reduce the fusion loss in the deployment of hollow-core optical fibers and reduce the uncertainty and cost of manual alignment with the naked eye.

[0092] As an exemplary illustration, in the specific implementation process, the system based on the optical fiber splicing method may include: an image acquisition unit for acquiring a side-view image of the optical fiber to be aligned; an image processing unit for preprocessing and feature extraction of the side-view image to generate an image feature vector; a rotation transformation unit for rotating the image within a preset angle range to generate multiple rotated versions of the image feature vector; a similarity calculation unit for calculating the cosine similarity between the rotated image feature vector and the reference image feature vector and selecting the optimal rotation angle; and a rotation control unit for adjusting the position of the optical fiber according to the optimal rotation angle to achieve precise alignment.

[0093] The same or similar reference numerals correspond to the same or similar components;

[0094] The terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation of this patent;

[0095] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention and are not limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An optical fiber splicing method, characterized in that, Including the following steps: Making the end faces of the first optical fiber to be aligned and the second optical fiber to be aligned in contact, and rotating the first optical fiber to be aligned several times, and obtaining several side view images corresponding to the first optical fiber to be aligned and the second optical fiber to be aligned before rotation and after each rotation; Extracting the image features of several side view images; Based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image, selecting the best rotation angle; After adjusting the positions of the optical fibers according to the best rotation angle, performing a splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned.

2. The optical fiber splicing method according to claim 1, characterized in that, When performing the splicing operation on the first optical fiber to be aligned and the second optical fiber to be aligned, using an optical fiber fusion splicer to perform the splicing operation.

3. The optical fiber splicing method according to claim 2, wherein, The optical fiber fusion splicer is equipped with functions of capturing side view images and rotating optical fibers, and both the side view images and the reference image are obtained by using the optical fiber fusion splicer; The steps of obtaining the side view images include: Performing preprocessing on the first optical fiber to be aligned and the second optical fiber to be aligned, detecting the cutting angles of the first optical fiber to be aligned and the second optical fiber to be aligned through the optical fiber fusion splicer. If the cutting angles of the first optical fiber to be aligned and the second optical fiber to be aligned meet the preset standards, placing the first optical fiber to be aligned and the second optical fiber to be aligned on the platform of the optical fiber fusion splicer, adjusting the positions between the first optical fiber to be aligned and the second optical fiber to be aligned so that their end faces are placed in the image acquisition device of the optical fiber fusion splicer, and using the image acquisition device to acquire the side view images of the first optical fiber to be aligned and the second optical fiber to be aligned; Otherwise, after cutting the cutting angles of the first optical fiber to be aligned and the second optical fiber to be aligned to meet the preset standards, then using the optical fiber fusion splicer to acquire the side view images.

4. The optical fiber splicing method according to claim 1, characterized in that, Before extracting the image features of several side view images, performing preprocessing on each side view image to remove color interference, and converting the side view image after removing color interference through preprocessing into a grayscale image. When extracting the image features of several side view images, converting the grayscale image corresponding to each side view image into a one-dimensional grayscale value vector to obtain the image features corresponding to each side view image.

5. The optical fiber splicing method according to claim 4, characterized in that, Before extracting the image features of the grayscale image, performing a sharpening process on the grayscale image.

6. The optical fiber splicing method according to claim 5, characterized in that, The method adopted when performing the sharpening process on the grayscale image includes an adaptive contrast enhancement algorithm.

7. The optical fiber splicing method according to any one of claims 1 to 6, characterized in that, The rotation angle range of the first optical fiber to be aligned includes [-180°, 180°], and the rotation angle difference between two adjacent rotations is a preset step value.

8. The optical fiber splicing method according to any one of claims 1 to 6, characterized in that, The steps of selecting the best rotation angle based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image include: Calculating the cosine similarity between the image features corresponding to each grayscale image and the preset reference image features, and regarding the rotation angle corresponding to the image features with the largest cosine similarity value as the best rotation angle; The calculation expression of the cosine similarity includes: Wherein, D represents the cosine similarity value, A represents the image feature vector corresponding to the rotated side view image, B represents the image feature vector of the reference image, C is the dot product value of A and B, ||A|| and ||B|| respectively represent the norms of vector A and vector B, represents the square of the value of the i-th component of vector A, represents the square of the value of the i-th component of vector B, and n represents the total number of components of the image feature vector.

9. A system based on an optical fiber splicing method, characterized in that, Including: A side view image acquisition unit, configured to make the end faces of the first optical fiber to be aligned and the second optical fiber to be aligned in contact, and rotate the first optical fiber to be aligned several times, and obtain several side view images corresponding to the first optical fiber to be aligned and the second optical fiber to be aligned before rotation and after each rotation; An image feature extraction unit for extracting image features of a plurality of side view images; An optimal rotation angle selection unit for selecting an optimal rotation angle based on the similarity between the image features corresponding to each side view image and the image features of a preset reference image; An optical fiber splicing unit for splicing a first optical fiber to be aligned and a second optical fiber to be aligned after adjusting the position of the optical fiber according to the optimal rotation angle.

10. A computer device, comprising a memory and a processor, wherein computer-readable instructions are stored in the memory, characterized in that, When the computer-readable instructions are executed by the processor, the processor is caused to execute the steps of the optical fiber splicing method according to any one of claims 1 to 8.

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