Invisible optical fiber rapid welding method and device

Abstract

The invention discloses an invisible optical fiber rapid welding method and device, and relates to the technical field of optical fiber welding. The method comprises the following steps: stripping outer coatings and coating layers of two optical fibers to be welded, and then cutting and cleaning to obtain two pretreated optical fibers; the welding end faces of the two preprocessed optical fibers are aligned with each other, and the positions of the two preprocessed optical fibers are adjusted through an automatic alignment system, so that the alignment precision reaches 99.95% or above; the aligned welding end face is heated to a molten state through arc discharge, welding is carried out, and a welded optical fiber is obtained; placing the welding optical fiber in an injection mold, adding a sheath material for injection extrusion molding, maintaining pressure, cooling, demolding, and carrying out post-processing to obtain the invisible optical fiber with the outer sheath; and performing quality inspection on the invisible optical fiber to complete welding. According to the invention, high-precision alignment can be carried out on the optical fiber, and the protection layer is added at the outer side, so that the conditions of fiber core offset, unnatural bending of the optical fiber and the like are avoided, and the optical fiber welding quality is improved.

Description

Technical Field

[0001] The present application relates to the technical field of optical fiber fusion splicing, and in particular to a method and device for rapid fusion splicing of invisible optical fibers. Background Art

[0002] FTTR (Fiber to the Room) technology can provide up to 10 Gigabit uplink capability, directly lay optical fiber to each room, achieve true Gigabit network speed, meet users' demand for high bandwidth, and enjoy a non-stuttering and delay-free network experience. When upgrading the network, laying invisible optical fiber can achieve high-speed network coverage without destroying the original decoration style and the beauty of the indoor environment. Invisible optical fiber is prone to damage due to accidental scratches, excessive bending or squeezing by heavy objects during construction and laying. Hot melt welding is usually used for welding. However, the existing technology usually has problems such as excessive welding loss, bubbles and cracks, core deviation, unnatural fiber bending, protrusions at the joints, and insufficient mechanical strength due to the unskilled operation of the operator during the welding process, which makes it easy for the fiber to break. Based on this, the present application proposes a method and device for rapid welding of invisible optical fibers. Summary of the invention

[0003] The main purpose of the present application is to provide a method and device for rapid fusion splicing of invisible optical fibers, aiming to solve the technical problem of poor fusion splicing quality of invisible optical fibers in the prior art.

[0004] To achieve the above object, the present application proposes a method for rapid fusion splicing of invisible optical fibers, comprising the following steps:

[0005] The outer coating and the coating layer of the two optical fibers to be fused are stripped, and then the two pre-treated optical fibers are obtained after cutting and cleaning;

[0006] Aligning the fusion-spliced ​​end faces of the two pre-processed optical fibers with each other, and adjusting the positions of the two pre-processed optical fibers by an automatic alignment system so that the alignment accuracy reaches more than 99.95%;

[0007] The aligned fusion end faces are heated to a molten state by arc discharge, and fusion splicing is performed to obtain a fusion-spliced ​​optical fiber;

[0008] The fused optical fiber is placed in an injection mold, and a sheath material is added for injection extrusion molding, and then after pressure holding and cooling, demoulding and post-processing are performed to obtain a stealth optical fiber with an outer sheath;

[0009] The invisible optical fiber is subjected to quality inspection, and the fusion splicing is completed.

[0010] Optionally, the step of aligning the fusion-spliced ​​end faces of the two pre-processed optical fibers with each other and adjusting the positions of the two pre-processed optical fibers by an automatic alignment system so that the alignment accuracy reaches more than 99.95% comprises:

[0011] Placing the two pre-processed optical fibers into the fixtures respectively so that the fusion-spliced ​​end faces of the two pre-processed optical fibers are aligned with each other;

[0012] Acquire the fusion end face images of the two pre-processed optical fibers through an image acquisition module;

[0013] Based on the edge detection algorithm, the inspection module performs edge feature recognition on the fusion end face image, and then extracts the center position of the fiber core;

[0014] Based on the center position of the fiber core, the alignment accuracy is calculated and evaluated through the inspection module, and the clamp is controlled to drive the two pre-processed optical fibers to move in the three axial directions of X-axis, Y-axis and Z-axis. When the alignment accuracy detected in the inspection module reaches more than 99.95%, preparation for welding is carried out.

[0015] Optionally, the alignment accuracy calculation and evaluation includes position deviation calculation and angle deviation evaluation;

[0016] When the position deviation is detected to be less than 0.5 μm and the angle deviation is less than 0.3° in the inspection module, it is determined that the alignment accuracy reaches more than 99.95%.

[0017] Optionally, in the step of performing welding, the welding state is inspected by the inspection module and compared with the inspection index preset in the inspection module, and displayed in real time by a display;

[0018] The inspection indicators include bubbles, cracks, loss parameters, welding current and welding time;

[0019] The loss parameter is set to ≤0.01dB; the welding time is set to 10s-15s.

[0020] Optionally, the step of placing the fused optical fiber in an injection mold and adding a sheath material for injection extrusion molding comprises:

[0021] The clamp is moved by a slide rail to allow the fused optical fiber to enter the injection mold. After the sheath material is heated and melted at 230°C-250°C, the sheath material is injected at a pressure of 75MPa-85MPa at a speed of 0.4 cm. 3 / s-0.6cm 3 / s injection speed is injected into the injection mold to fill the injection mold cavity.

[0022] Optionally, the sheath material is polyamide.

[0023] Optionally, in the pressure-maintaining and cooling steps, a pressure of 30 MPa-60 MPa is maintained for 2.5 s-3.5 s, and air cooling is adopted for cooling for 10 s-20 s.

[0024] The present application also proposes an invisible optical fiber rapid welding device for implementing the above-mentioned invisible optical fiber rapid welding method, the welding device includes a workbench, a clamp, a welding cover, a display, a slide rail, an injection mold and a cooler, the clamps are symmetrically arranged with two and are respectively located on both sides of the workbench, the welding cover is located between the two clamps, the slide rails are symmetrically arranged with two, the injection mold is located on the workbench, the injection mold is connected to the cooler, the two clamps are respectively slidably connected to the two slide rails, and the two clamps can slide along the direction of the slide rails until they are aligned with the cavity of the injection mold, the display is installed on one side of the workbench, and an automatic alignment system is installed in the workbench, the automatic alignment system is connected to the two clamps and controls the two clamps to move in three axial directions of X-axis, Y-axis and Z-axis, and the automatic alignment system is connected to the display.

[0025] Optionally, the automatic alignment system includes an image acquisition module and a verification module;

[0026] The image acquisition module is used to acquire the fusion end face images of the two pre-processed optical fibers and perform denoising and contrast enhancement processing;

[0027] The inspection module is used to perform edge feature recognition and core center position extraction on the fusion end face image, perform fusion state inspection on the fusion end face, and perform quality inspection on the invisible optical fiber.

[0028] Optionally, the injection mold is connected to a sheath material placement area, and the sheath material placement area is connected to the injection mold through an injection pipe.

[0029] This application includes at least the following beneficial effects:

[0030] The present application first strips the outer coating and coating layer of the optical fiber to be fused, cuts and cleans it, then aligns the end faces of the two optical fibers with each other, and accurately adjusts the positions of the two optical fibers through an automatic alignment system, so that the alignment accuracy reaches more than 99.95%, and achieves alignment with micron-level or even higher precision, thereby ensuring that the fusion process is carried out in the best fusion state to ensure the quality of the fusion product, and then heats the aligned fusion end faces to a molten state through arc discharge to fuse them together, and then adds sheath material for injection molding and extrusion molding, thereby forming an outer sheath on the outside of the invisible optical fiber, which not only makes the appearance of the invisible optical fiber form a whole, without the invisible optical fiber bending, unnaturalness and protrusion at the joint, so as to improve the concealment and aesthetics of the invisible optical fiber, and the outer sheath is used as a protective layer on the outside of the invisible optical fiber, which can also improve the mechanical strength of the invisible optical fiber, and the present application does not need to use a heat shrink tube, which can reduce production costs, and at the same time, there will be no appearance problems such as deformation, burning, and uneven color, which will affect the overall aesthetics of the product. This application performs high-precision alignment of the optical fiber, adds a protective layer on the outside, and monitors the quality of the entire fusion splicing process so that timely adjustments and information feedback can be made. This can effectively avoid problems such as fiber core deviation, unnatural fiber bending, and protrusions at joints, thereby improving the quality and success rate of fiber fusion splicing and reducing the occurrence of fiber breakage during subsequent use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of the process of the invisible optical fiber rapid fusion splicing method described in an embodiment of the present application;

[0033] Figure 2 This is a schematic diagram of the structure of the invisible optical fiber rapid fusion splicing device described in an embodiment of the present application.

[0034] Reference numerals:

[0035] 1- fixture; 2- welding cover plate; 3- display; 4- slide rail; 5- injection mold; 6- jacket material placement area; 7- injection pipe; 8- cooler.

[0036] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] In view of the technical problems existing in the above-mentioned prior art, the embodiments of the present application provide a method for rapid fusion splicing of invisible optical fibers. Figure 1 As shown, the following steps are included:

[0039] S10, stripping the outer coating and the coating layer of the two optical fibers to be fusion-spliced, and then cutting and cleaning them to obtain two pre-treated optical fibers.

[0040] In the specific implementation process, when stripping the outer coating and coating layer of the optical fiber to be fused, use a stripping knife with an inclination of 45° to strip the outer coating of the optical fiber at an inclination of 45°, and then use a fiber stripping knife to strip the coating layer of the optical fiber to expose the clean bare fiber. During the stripping process, care should be taken to avoid damaging the bare fiber and prevent the bare fiber from being contaminated by impurities such as dust and oil. Then use a fiber optic cutter to cut off both ends of the broken fiber and ensure that the end face is flat, smooth and perpendicular to the optical fiber axis, because an uneven end face will cause bubbles and increased loss during fusion. During the cleaning process, alcohol cotton balls or dust-free paper can be used to gently wipe the surface of the bare fiber to remove residual dirt and impurities. The cleaned bare fiber should be fused as soon as possible to avoid long-term exposure to the air and re-contamination.

[0041] S20, placing the two pre-processed optical fibers into the fixtures of the fusion splicing device respectively, so that the fusion splicing end faces of the two pre-processed optical fibers are aligned with each other;

[0042] Acquire the fusion end face images of the two pre-processed optical fibers through an image acquisition module;

[0043] Based on the edge detection algorithm, the inspection module performs edge feature recognition on the fusion end face image, and then extracts the center position of the fiber core;

[0044] Based on the center position of the fiber core, the alignment accuracy is calculated and evaluated through the inspection module, and the clamp is controlled to drive the two pre-processed optical fibers to move in the three axial directions of X-axis, Y-axis and Z-axis. When the alignment accuracy detected in the inspection module reaches more than 99.95%, preparation for welding is carried out.

[0045] In the specific implementation process, the image acquisition module is based on the principle of optical imaging. The optical fiber end face is illuminated by a light source, and after being magnified by a microscope, the image is collected by a high-resolution CCD (charge coupled device) camera. The pixel accuracy of the camera is very high, which can reach the micron level, so that the details of the optical fiber end face can be accurately collected. After the image acquisition module collects the fusion end face image of the pre-processed optical fiber, it performs preliminary processing, namely, denoising and contrast enhancement processing. Denoising can use a variety of filtering methods, such as Gaussian filtering. Gaussian filtering is a linear smoothing filter that can effectively remove Gaussian noise in the image. It is achieved by weighted averaging the pixel values ​​around each pixel. For example, for a pixel point, the weight of the pixels around it is determined according to the Gaussian distribution. The closer the pixel is to the pixel, the greater the weight of the pixel is. In this way, the image can be made smoother without destroying the edge information of the image. The purpose of enhancing the contrast is to make the key areas such as the edge and core of the optical fiber more obvious. The histogram equalization method can be used to stretch the grayscale range of the image to make the details of the image clearer and more discernible.

[0046] Specifically, the edge detection algorithm adopts the Canny algorithm, which has the characteristics of high precision and low false detection rate. Based on the preliminary processed fusion end face image, the Canny algorithm first performs Gaussian blur on the image to reduce the impact of noise on edge detection, and then calculates the gradient amplitude and direction of the image, and refines the edge through non-maximum suppression. Finally, double threshold detection is used to determine the true edge, thereby accurately locating the outer edge of the optical fiber and providing a reference for subsequent fiber core positioning.

[0047] Furthermore, after identifying the edge features, the center position of the core is extracted through the inspection module. For single-mode optical fibers, the core is relatively thin, generally between a few microns and more than ten microns. The position of the core can be determined by analyzing the grayscale distribution within the edge of the optical fiber. For example, the grayscale value of the core area is usually different from that of the cladding, and has a certain symmetry. The center of the core can be calculated using the grayscale centroid method. The core area is regarded as an object with a mass (grayscale value) distribution, and the center of the core is determined by calculating its center of gravity.

[0048] In the specific implementation process, the alignment accuracy calculation and evaluation include position deviation calculation and angle deviation evaluation.

[0049] Position deviation calculation means that after the inspection module extracts the core center positions of the two optical fibers, it calculates the position deviation between them. Position deviation can include deviations in the X-axis and Y-axis directions, which can be obtained by calculating the coordinate difference. For example, the coordinates of the core center of one optical fiber are (x1, y1), and the coordinates of the core center of the other optical fiber are (x2, y2). Then the deviation in the X-axis direction is |x1-x2|, and the deviation in the Y-axis direction is |y1-y2|. The deviation value can intuitively reflect the alignment of the two optical fibers in the horizontal and vertical directions.

[0050] Angular deviation assessment is to calculate the angular deviation between two optical fibers by analyzing the shape and direction of the optical fiber edge. Angular deviation assessment is performed because angular deviation can affect the transmission of optical signals in optical fibers, resulting in signal loss. Specifically, angular deviation assessment can use Hough transform to detect the slope of the straight line at the edge of the optical fiber, and then calculate the angular deviation. Hough transform is a method of converting a straight line in image space to a point in parameter space. The parameters of the straight line, including slope and intercept, are determined by finding the peak in parameter space.

[0051] According to the calculation results of position deviation and angle deviation, the alignment accuracy is comprehensively evaluated and the threshold is set. That is, when the position deviation detected in the inspection module is less than 0.5μm and the angle deviation is less than 0.3°, the alignment accuracy is judged to be above 99.95%. If it exceeds the threshold, realignment or fine-tuning is performed. At the same time, the evaluation results of alignment accuracy can also be displayed on the display of the welding device in numerical or graphical form, so that the operator can intuitively understand the alignment situation.

[0052] S30, heating the aligned fusion end faces to a molten state by arc discharge, performing fusion splicing, and obtaining a fusion-spliced ​​optical fiber.

[0053] When welding is performed, the welding state is inspected by the inspection module and compared with the inspection index preset in the inspection module, and displayed in real time by the display;

[0054] The inspection indicators include bubbles, cracks, loss parameters, welding current and welding time;

[0055] Among them, a large number of pictures of bubbles and cracks are preset in the inspection module as the basis for inspection, comparison and judgment;

[0056] The loss parameter is set to ≤0.01dB;

[0057] The welding time is set to 10s-15s;

[0058] The fusion current is automatically optimized based on the photoelectric sensor and algorithm built into the inspection module according to the material, diameter and other characteristics of the optical fiber.

[0059] Specifically, the photoelectric sensor can detect the end face of the optical fiber, and it can sense the flatness, cleanliness and diameter of the optical fiber end face. For example, when there are tiny flaws or unevenness on the end face of the optical fiber, the photoelectric sensor can detect these situations through the change in the intensity and distribution of the reflected light; for the detection of the optical fiber diameter, it is based on the principle of refraction and reflection of light at the edge of the optical fiber, and the diameter of the optical fiber is determined by accurately measuring the change in the optical signal. Different optical fiber materials (such as quartz optical fiber, plastic optical fiber, etc.) have different optical properties such as absorption and reflection of light. The photoelectric sensor can use these characteristic differences to identify the optical fiber material. For example, when quartz optical fiber and plastic optical fiber are irradiated with light of a specific wavelength, the intensity and spectral distribution of the reflected light will be different. The photoelectric sensor can capture these signal changes and feed back the optical fiber material information to the inspection module. At the same time, the photoelectric sensor will continuously monitor the state of the optical fiber during the welding process, and it can sense the temperature change of the optical fiber during the welding process, the change in the transmission characteristics of light, etc. For example, when the welding current is applied, the temperature of the optical fiber will gradually increase, and the photoelectric sensor can monitor the temperature by detecting the thermal radiation light of the optical fiber or the attenuation change of light in the optical fiber. Based on the real-time monitoring data, the inspection module will make feedback adjustments to the welding current. If it is detected that the temperature rise rate of the optical fiber is too fast or too slow, it may mean that the welding current is too large or too small. The inspection module will adjust the welding current according to the pre-set adjustment strategy, such as increasing or decreasing the welding current in a certain proportion, to ensure that the welding process is carried out under the optimal temperature and current conditions, thereby effectively improving the quality and success rate of optical fiber welding.

[0060] The algorithms built into the inspection module include empirical formula algorithms and machine learning algorithms. The empirical formula algorithms are algorithms based on a large amount of experimental data. These algorithms will calculate the appropriate welding current based on the optical fiber diameter, material and other information obtained by the photoelectric sensor. For example, for quartz optical fiber, its welding current is roughly proportional to the square of the optical fiber diameter. When the photoelectric sensor detects the optical fiber diameter, the inspection module will calculate a preliminary welding current value based on this relationship. At the same time, considering the differences in purity, additives and other aspects of optical fiber materials produced by different manufacturers, the empirical formula algorithm will also correct the material factors. The machine learning algorithm can use a neural network to train the neural network through a large amount of welding experimental data. These data include the optimal welding current under different optical fiber materials and diameter combinations and the corresponding optical fiber welding quality evaluation results. The trained neural network can quickly and accurately predict the optimal welding current based on the optical fiber information fed back in real time by the photoelectric sensor. For example, the neural network can output a welding current value suitable for the optical fiber based on the input parameters such as the material type (represented by coding) and the diameter value of the optical fiber after calculation by multiple layers of neurons.

[0061] In specific applications, the range of the welding current is mainly determined by the fiber material, fiber diameter, fiber type (single mode or multimode) and the performance of the welding device. For example, for common quartz optical fibers, the welding current is generally between 8mA and 20mA.

[0062] S40, moving the clamp by a slide rail to allow the fused optical fiber to enter the injection mold, heating and melting the sheath material at 230°C-250°C, and then injecting it into the injection mold at an injection pressure of 75MPa-85MPa at an injection speed of 0.4cm3 / s-0.6cm3 / s to fill the injection mold cavity, and then performing injection extrusion molding, and then maintaining a pressure of 30MPa-60MPa for 2.5s-3.5s to further compact the melt to compensate for the shrinkage of the material and prevent the defects of shrinkage cavities and shrinkage. After cooling, demolding and post-processing are performed to obtain an invisible optical fiber with an outer sheath.

[0063] The sheath material is polyamide, which is a thermoplastic material. The melting point of polyamide during injection molding is about 220°C. During the injection molding process, the temperature of the polyamide melt is usually higher than the melting point. Therefore, the temperature of the polyamide melt is controlled between 230-250°C in this application to ensure that the polyamide has good fluidity. When the temperature is within this range, the polyamide melt presents a uniform viscous liquid state.

[0064] In the specific implementation process, air cooling is used for cooling, and the cooling time is 10s-20s. After a certain period of cooling and curing, a protective layer with sufficient strength and rigidity can be formed on the invisible optical fiber.

[0065] Specifically, after demoulding, burrs or excess sheath material may be generated at the edges, gates and other parts, which need to be post-processed and removed and trimmed with tools to ensure the appearance quality.

[0066] S50, performing quality inspection on the invisible optical fiber, and completing the fusion splicing.

[0067] During the specific implementation process, the present application presets the invisible optical fiber quality inspection standard in the inspection module. By comparing with the preset invisible optical fiber quality inspection standard and forming an inspection result report, the quality supervision and control of the entire process can be achieved, thereby improving the quality and efficiency of the fusion splicing.

[0068] An embodiment of the present application also provides an invisible optical fiber rapid welding device for implementing the above-mentioned invisible optical fiber rapid welding method, the welding device includes a workbench, a clamp 1, a welding cover plate 2, a display 3, a slide rail 4, an injection mold 5 and a cooler 8, the clamp 1 is symmetrically arranged with two and respectively located on both sides of the workbench, the welding cover plate 2 is located between the two clamps 1, the slide rail 4 is symmetrically arranged with two, the injection mold 5 is located on the workbench, the injection mold 5 is connected to the cooler 8, the two clamps 1 are respectively slidably connected to the two slide rails 4, and the two clamps 1 can slide along the direction of the slide rail 4 until they are aligned with the cavity of the injection mold 5, the display 3 is installed on one side of the workbench, and an automatic alignment system is installed in the workbench, the automatic alignment system is connected to the two clamps 1 and controls the two clamps 1 to move in three axial directions of X-axis, Y-axis and Z-axis, and the automatic alignment system is connected to the display 3.

[0069] As an implementable embodiment of the present application, the automatic alignment system includes an image acquisition module and a verification module;

[0070] The image acquisition module is used to acquire the fusion end face images of the two pre-processed optical fibers and perform denoising and contrast enhancement processing;

[0071] The inspection module is used to perform edge feature recognition and core center position extraction on the fusion end face image, perform fusion state inspection on the fusion end face, and perform quality inspection on the invisible optical fiber.

[0072] As an implementation method of the present application, the injection mold 5 is connected to a sheath material placement area 6 , and the sheath material placement area 6 is connected to the injection mold 5 via an injection pipe 7 .

[0073] In the specific implementation process, the pre-treated optical fibers are respectively placed in the clamps 1 of the fusion splicing device. The clamps 1 can firmly fix the optical fibers while avoiding damage to the optical fibers caused by excessive squeezing. The fusion splicing end face images of the two pre-treated optical fibers are then collected through the image acquisition module and denoised and contrast enhanced. The edge features of the fusion splicing end face images are identified and the core center position is extracted through the inspection module. The alignment accuracy is calculated and evaluated through the inspection module, and the clamps 1 are controlled to drive the two pre-treated optical fibers to move in the three axial directions of the X-axis, Y-axis and Z-axis. When the inspection module detects that the alignment accuracy reaches 99.95% or more, the fusion splicing cover plate 2 is covered to prepare for fusion splicing, and the aligned fusion splicing end faces are aligned by arc discharge. It is heated to a molten state, and at the same time, the inspection module inspects the welding state and compares it with the inspection indicators preset in the inspection module. At the same time, it is displayed in real time through the display 3, so that the operator can make timely adjustments. After the welding is completed, the two clamps 1 slide along the slide rail 4 to align with the cavity of the injection mold 5, and then move downward to allow the invisible optical fiber to enter the cavity of the injection mold 5. At the same time, the sheath material in the sheath material placement area 6 enters the cavity of the injection mold 5 through the injection molding pipe 7 for injection extrusion molding. After completion, the cooler 8 introduces cold air into the injection mold 5 for cooling to obtain an invisible optical fiber product with an outer sheath. Finally, the product is quality inspected by the inspection module to complete the entire welding process.

[0074] The above description is only an optional embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the inventive concept of the present application, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for rapid welding of invisible optical fibers, characterized in that: The following steps are involved: The outer coating and the coating layer of the two optical fibers to be fused are stripped, and then the two pre-treated optical fibers are obtained after cutting and cleaning; Aligning the fusion-spliced ​​end faces of the two pre-processed optical fibers with each other, and adjusting the positions of the two pre-processed optical fibers by an automatic alignment system so that the alignment accuracy reaches more than 99.95%; The aligned fusion end faces are heated to a molten state by arc discharge, and fusion splicing is performed to obtain a fusion-spliced ​​optical fiber; The fused optical fiber is placed in an injection mold, and a sheath material is added for injection extrusion molding, and then after pressure holding and cooling, demoulding and post-processing are performed to obtain a stealth optical fiber with an outer sheath; The invisible optical fiber is subjected to quality inspection, and the fusion splicing is completed.

2. The invisible optical fiber rapid welding method according to claim 1, characterized in that: The step of aligning the fusion-spliced ​​end faces of the two pre-processed optical fibers with each other and adjusting the positions of the two pre-processed optical fibers by an automatic alignment system so that the alignment accuracy reaches more than 99.95% comprises: Placing the two pre-processed optical fibers into the fixtures respectively so that the fusion-spliced ​​end faces of the two pre-processed optical fibers are aligned with each other; Acquire the fusion end face images of the two pre-processed optical fibers through an image acquisition module; Based on the edge detection algorithm, the inspection module performs edge feature recognition on the fusion end face image, and then extracts the center position of the fiber core; Based on the center position of the fiber core, the alignment accuracy is calculated and evaluated through the inspection module, and the clamp is controlled to drive the two pre-processed optical fibers to move in the three axial directions of X-axis, Y-axis and Z-axis. When the alignment accuracy detected in the inspection module reaches more than 99.95%, preparation for welding is carried out.

3. The invisible optical fiber rapid welding method according to claim 2, characterized in that: The alignment accuracy calculation and evaluation include position deviation calculation and angle deviation evaluation; When the position deviation is detected to be less than 0.5 μm and the angle deviation is less than 0.3° in the inspection module, it is determined that the alignment accuracy reaches more than 99.95%.

4. The invisible optical fiber rapid welding method according to claim 3, characterized in that: In the step of welding, the welding state is inspected by the inspection module and compared with the inspection index preset in the inspection module, and displayed in real time by the display; The inspection indicators include bubbles, cracks, loss parameters, welding current and welding time; The loss parameter is set to ≤0.01dB; the welding time is set to 10s-15s.

5. The invisible optical fiber rapid welding method according to claim 2, characterized in that: The step of placing the fused optical fiber in an injection mold and adding a sheath material for injection extrusion molding comprises: The clamp is moved by a slide rail to allow the fused optical fiber to enter the injection mold. After the sheath material is heated and melted at 230°C-250°C, the sheath material is injected at a pressure of 75MPa-85MPa at a speed of 0.4 cm. 3 / s-0.6cm 3 / s injection speed is injected into the injection mold to fill the injection mold cavity.

6. The invisible optical fiber rapid welding method according to claim 5, characterized in that: The sheath material is polyamide.

7. The invisible optical fiber rapid welding method according to claim 5, characterized in that: In the pressure-maintaining and cooling steps, the pressure of 30 MPa-60 MPa is maintained for 2.5 s-3.5 s, and air cooling is adopted for cooling for 10 s-20 s.

8. An invisible optical fiber rapid fusion splicing device, used for implementing the invisible optical fiber rapid fusion splicing method according to any one of claims 1 to 7, characterized in that: The welding device includes a workbench, a clamp, a welding cover, a display, a slide rail, an injection mold and a cooler. The clamps are symmetrically arranged with two and are respectively located on both sides of the workbench. The welding cover is located between the two clamps. The slide rails are symmetrically arranged with two. The injection mold is located on the workbench and is connected to the cooler. The two clamps are slidably connected to the two slide rails respectively, and the two clamps can slide along the direction of the slide rails until they are aligned with the cavity of the injection mold. The display is installed on one side of the workbench. An automatic alignment system is installed in the workbench. The automatic alignment system is connected to the two clamps and controls the two clamps to move in three axial directions of X-axis, Y-axis and Z-axis. The automatic alignment system is connected to the display.

9. The invisible optical fiber rapid fusion splicing device according to claim 8, characterized in that: The automatic alignment system includes an image acquisition module and a testing module; The image acquisition module is used to acquire the fusion end face images of the two pre-processed optical fibers and perform denoising and contrast enhancement processing; The inspection module is used to perform edge feature recognition and core center position extraction on the fusion end face image, perform fusion state inspection on the fusion end face, and perform quality inspection on the invisible optical fiber.

10. The invisible optical fiber rapid fusion splicing device according to claim 8, characterized in that: The injection mold is connected to a sheath material placement area, and the sheath material placement area is connected to the injection mold through an injection pipeline.

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