A method and device for preparing a high beam quality combiner

Abstract

The present invention is applicable to the field of fiber laser technology, and provides a method and device for preparing a high-quality beam combiner. The preparation method is as follows: first, a central optical fiber and a peripheral optical fiber are processed, wherein one end of the central optical fiber is corroded when processing the central optical fiber, and the peripheral optical fiber is corroded into a fan-shaped cross section when processing the peripheral optical fiber, and the proximal end of the fan-shaped fiber is facing inward and the distal end is facing outward, and the fan-shaped fiber is arranged in a circle for beam assembly, and then the central optical fiber is inserted into the center position, and then the optical fiber bundle is melt-tapered, the tapered straight area of ​​the optical fiber bundle is cut off, and it is fused with the output optical fiber, and finally packaged to obtain a beam combiner. The present invention can significantly reduce the spacing between the cores of the input optical fibers by corroding the peripheral optical fibers into a fan shape through the end face, thereby reducing the taper ratio of the energy beam combiner, and optimizing the beam quality and divergence angle of the output laser; at the same time, the thickness of the distal cladding is retained to ensure the overall strength and reliability of the beam combiner.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fiber lasers, and in particular relates to a method and a device for preparing a high-quality beam combiner. Background Art

[0002] In recent years, with the increasing maturity of the manufacturing industry of various optical fiber devices and pump sources, the power of fiber lasers has also been rising. At present, the power of a single module has exceeded the 10,000-watt level. However, due to the influence of factors such as thermal lens effect, nonlinear effect, and mode instability, further power increase is limited. It is necessary to use an energy combiner to combine several single modules to increase the power to tens of kilowatts or even hundreds of kilowatts.

[0003] The input fiber of the energy combiner is determined by the specifications of the single-module output pigtail. The output fiber is generally a multimode fiber, such as 50 / 70 / 360, 100 / 120 / 360, etc. The production process generally involves fiber corrosion, fiber bundle assembly, fiber taper, fiber bundle fusion, device packaging and other steps. After the fiber is tapered, the light in the core will leak to the cladding, forming high-order mode and supermode transmission in the input fiber bundle fusion taper part, and further degraded to multimode transmission after passing through the melting point and entering the multimode fiber. The larger the taper ratio, the more laser light leaks into the cladding, and the higher the degree of degradation of the input laser beam quality by the combiner. In particular, for the beam combining of high-power single modules, since its input is usually a large-core, large-numerical-aperture optical fiber, such as the 34μm, 0.11NA optical fiber used in the current mainstream 6kW single module in the industry, its input is a multi-mode laser, and the beam quality M2 factor is usually between 2.5-3.5, which is 2-3 times that of a conventional quasi-single-mode laser. The worse the input laser beam quality, the greater the degree of degradation will be after passing through the tapered zone of the beam combiner.

[0004] For high-power laser beam combining, the beam quality of the output laser is an important parameter. Poor beam quality will cause the subsequent optical path devices such as the aperture in the cutting head and the collimating and focusing lens to heat up or even burn out. In addition, for actual cutting applications, poor beam quality means low brightness, which will have a great adverse effect on cutting speed, cutting plate morphology, cutting quality, etc. An effective way to reduce the taper ratio is to corrode the cladding of the input optical fiber as much as possible. At the same time, in order to avoid destroying the total reflection conditions of laser transmission, part of the quartz cladding must be retained. However, in the actual production process, if the optical fiber is corroded too little (<60μm), it will lead to low strength and easy breakage, which greatly increases the difficulty of production and poor product reliability. Therefore, the current energy combiner has the problem of poor beam quality after combining large mode field high-power fiber lasers. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a method and a device for preparing a high beam quality combiner, aiming to solve the technical problem that the existing energy combiner has poor beam quality after combining large mode field high power fiber lasers.

[0006] The present invention adopts the following technical solution:

[0007] On the one hand, the method for preparing a high beam quality combiner is as follows: first, a central optical fiber and a peripheral optical fiber are processed, wherein one end of the central optical fiber is corroded when processing the central optical fiber, and the peripheral optical fiber is corroded into a fan-shaped cross section when processing the peripheral optical fiber, and the proximal end of the fan-shaped fiber is facing inward and the distal end is facing outward, and they are arranged in a circle for bundle assembly, and then the central optical fiber is inserted into the center position, and then the optical fiber bundle is melt-tapered, the tapered straight area of ​​the optical fiber bundle is cut off, and it is fused with the output optical fiber, and finally packaged to obtain a combiner.

[0008] Furthermore, the method for preparing the high beam quality combiner specifically comprises the following steps:

[0009] Step S1: Processing center optical fiber

[0010] One end of the central optical fiber is corroded, the front end is a straight section, and the rear of the straight section is a tapered structure, then the corroded central optical fiber is rinsed and cut off, and finally the bare fiber part of the central optical fiber after corrosion is cleaned;

[0011] Step S2: Processing peripheral optical fibers

[0012] S21, stripping off half of the optical fiber coating layer inward in a half-wrapped form from a starting point at a certain distance from the outer optical fiber end face, and wiping and cleaning the stripped bare fiber;

[0013] S22, after treating multiple peripheral optical fibers in the same manner, straighten the peripheral optical fibers, place them side by side and fix them on the optical fiber horizontal clamping tooling, and remove some bare fibers with them facing downward, inject hydrofluoric acid into the etching plate, control the peripheral optical fibers to move downward so that most of the peripheral optical fibers are immersed in the hydrofluoric acid, and then take out the peripheral optical fibers and rinse them;

[0014] S23, after the washing is completed, the coating layer of the other half of the optical fiber is stripped off, one peripheral optical fiber is retained, the other peripheral optical fibers are cut off along the starting point of the corrosion straight area, and finally the bare fiber parts of all peripheral optical fibers are cleaned;

[0015] Step S3: Bundle peripheral optical fibers and central optical fibers

[0016] S31, arrange the peripheral optical fibers in a straight line with the core facing upwards, fix the back side with tape, the first optical fiber is an uncut optical fiber, a certain gap is kept between adjacent bare fibers of the peripheral optical fibers, the first optical fiber is slowly rotated, the peripheral optical fibers are bundled, and one end of the bare fiber is pre-fixed with tape after bundling;

[0017] S32, completely inserting the corroded end of the central optical fiber into the center position of the peripheral optical fiber of the bundle, and finally obtaining an optical fiber bundle;

[0018] Step S4: Fiber fusion taper

[0019] The optical fiber bundle is fixed with low-fold glue, the bare fiber end of the optical fiber bundle is inserted into the quartz tube and fixed with low-fold glue, and the optical fiber bundle is melt-tapered. After melt-tapering, the optical fibers are tightly combined into one;

[0020] Step S5: Welding and packaging

[0021] The output optical fiber is corroded, the tapered straight area of ​​the optical fiber bundle is cut off, the cut end of the optical fiber bundle is fused with the output optical fiber, and after the fusion is completed, the beam combiner is sealed by glue dispensing.

[0022] Furthermore, the specific process of step S1 is as follows:

[0023] Strip off the coating at one end of the central optical fiber, fix the central optical fiber on the optical fiber vertical clamping tooling with corrosion-resistant tape and low-fold glue respectively. The central optical fiber is in a stretched state. After the corrosion cylinder loaded with hydrofluoric acid is slowly moved to the bottom of the central optical fiber, the central optical fiber is controlled to move up and down for corrosion according to a four-stage program: in the first stage, the central optical fiber is driven to descend rapidly; in the second stage, the central optical fiber remains paused; in the third stage, the central optical fiber continues to descend slowly; in the fourth stage, the central optical fiber rises rapidly; the front section of the finally corroded central optical fiber is a straight section, and the rear of the straight section is a tapered structure; after the corrosion is completed, the central optical fiber is immediately rinsed with pure water, the optical fiber is cut along the edge of the low-fold glue, the central optical fiber is lowered, and the bare fiber part of the central optical fiber is ultrasonically cleaned with anhydrous ethanol.

[0024] Furthermore, the specific process of step S21 is as follows:

[0025] From the starting point at a certain distance from the left end of the peripheral optical fiber, half of the optical fiber coating is stripped to the right in a half-wrapped form. After wiping the coating residue with alcohol and dust-free paper, the stripped bare fiber part is ultrasonically cleaned with anhydrous alcohol. Multiple peripheral optical fibers are treated in the same way.

[0026] The specific process of step S22 is as follows:

[0027] Place the peripheral optical fibers side by side on the positioning grooves of the optical fiber horizontal clamping tooling, with the stripped bare fibers facing downward and the coated fibers facing upward. During the process of mounting the optical fibers on the disk, a certain pulling force is applied to the peripheral optical fibers to keep them in a taut and straightened state. Use corrosion-resistant high-temperature tape to fix the peripheral optical fibers on the optical fiber horizontal clamping tooling. Inject hydrofluoric acid into the etching disk. The hydrofluoric acid liquid level is higher than the upper surface of the etching disk but does not overflow. After the etching disk is slowly moved to the bottom of the peripheral optical fibers, control the peripheral optical fibers to move downward in the vertical direction so that most of the peripheral optical fibers are immersed in the hydrofluoric acid. Immediately rinse the optical fibers with pure water after etching.

[0028] In step S23, after the etching is completed, the cross section of the peripheral optical fiber is fan-shaped as a whole.

[0029] Furthermore, in step S32, whether the central optical fiber end face protrudes from the peripheral optical fiber end faces is confirmed to be completely inserted.

[0030] On the other hand, a preparation device for a high beam quality combiner preparation method is provided, the preparation device comprising a Z-axis drive mechanism and a Y-axis drive mechanism, the drive end of the Z-axis drive mechanism being fixed with a fixing fixture, the fixing fixture being L-shaped, the preparation device further comprising a horizontal optical fiber clamping tool and a vertical optical fiber clamping tool for being installed on the fixing fixture, the horizontal optical fiber clamping tool being a frame-type tool, one surface of which is engraved with semicircular grooves equidistantly on the left and right sides, the midlines of two opposite semicircular grooves on the left and right sides being on the same straight line, the preparation device further comprising a pad, an etching disk and an etching cylinder, wherein the pad is installed at the drive end of the Y-axis drive mechanism, the etching disk is placed on the pad, or the etching cylinder is installed at the drive end of the Y-axis drive mechanism.

[0031] Furthermore, a plurality of cylindrical magnets are fixed on both sides of the bottom of the horizontal part of the fixing fixture, and matching grooves are opened on both sides of the top surface of the frame-shaped tooling, and iron or magnetic materials are arranged in the grooves.

[0032] The beneficial effects of the present invention are as follows: in view of the problem of poor beam quality after existing energy combiners combine large-mode-field high-power fiber lasers, in order to reduce the taper ratio of the fiber bundle as much as possible and ensure high beam quality output, the present invention proposes a method for preparing a high beam quality combiner and an indicator device, wherein one end of the central optical fiber is corroded into a cone, and the peripheral optical fiber is corroded in a fan-shaped manner, all the peripheral optical fibers are symmetrically and evenly bundled, and the central optical fiber is inserted in the middle, so that the distance between the optical fiber cores is greatly reduced, which can effectively reduce the taper ratio, optimize the output beam quality, and at the same time ensure the optical fiber strength and product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a specific flow chart of a method for preparing a high beam quality combiner provided by an embodiment of the present invention;

[0034] Figure 2 This is a structural diagram of a use state of a preparation device provided by an embodiment of the present invention;

[0035] Figure 3 It is a side structural diagram of the fixing fixture;

[0036] Figure 4 This is a structural diagram of one side of the optical fiber horizontal clamping tooling;

[0037] Figure 5 This is the structural diagram of the other side of the optical fiber horizontal clamping tooling;

[0038] Figure 6 is another use state structure diagram of the preparation device provided by an embodiment of the present invention;

[0039] Figure 7 It is a schematic diagram of the corrosion process of the peripheral optical fiber;

[0040] in Figure 7 (a) is the cross-section of the peripheral optical fiber before corrosion. Figure 7 (b) is a diagram showing the state of the peripheral optical fiber partially immersed in the corrosion disk. Figure 7 (c) is a cross-sectional view of the coating layer after the peripheral optical fiber corrosion is completed;

[0041] Figure 8 This is a microscope photo of the coating stripped after the peripheral optical fiber corrosion is completed;

[0042] Fig. 9 This is a schematic diagram of the arrangement of peripheral optical fibers before bundling;

[0043] Fig.10 is a schematic diagram of the fiber bundle before tapering;

[0044] Fig.11 This is the cross-sectional view of the optical fiber bundle after the straight area is truncated after tapering. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution 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.

[0046] In order to illustrate the technical solution of the present invention, a specific embodiment is provided below for illustration.

[0047] The embodiment of the present invention provides a method for preparing a high beam quality combiner, the process of which is as follows: Figure 1As shown, the main process is: first, the central optical fiber is processed, one end of which is corroded into a cone, and a plurality of peripheral optical fibers are corroded in a fan-shaped manner. The peripheral optical fibers are corroded into a fan-shaped cross section, and the peripheral optical fibers and the central optical fibers are bundled. Specifically, the proximal end of the fan-shaped peripheral optical fibers is facing inward and the distal end is facing outward, and they are arranged in a circle for bundle assembly, and then the central optical fiber is inserted into the center position, and then the optical fiber bundle is melt-tapered, the tapered straight area of ​​the optical fiber bundle is cut off, and it is fused with the output optical fiber, and finally packaged to obtain a combiner. The fan-shaped corrosion method is one of the core innovations of this embodiment. By corroding the end face into a fan shape, the spacing between the cores of the input optical fibers can be significantly reduced, thereby reducing the taper ratio of the energy combiner and optimizing the beam quality and divergence angle of the output laser; at the same time, the thickness of the distal cladding is retained to ensure the overall strength and reliability of the combiner.

[0048] For the above method, an embodiment of the present invention also provides a device for preparing a high beam quality combiner, such as Figure 2-6 As shown, the preparation device includes a Z-axis drive mechanism and a Y-axis drive mechanism. The two drive structures in the figure are basically the same. The Z-axis drive mechanism includes a Z-axis high-precision linear motor module 01, with an effective stroke of 200mm and an accuracy of 3μm. Photoelectric switches are installed at both ends of the stroke for calibrating the initial position and anti-collision. It also includes a Z-axis slider 02 installed on the module, which is driven by a screw rod and moves on the Z axis. Similarly, the Y-axis drive mechanism includes a Y-axis high-precision linear motor module 07 and a Y-axis slider 08, and the parameters are the same as those of the Z-axis drive mechanism.

[0049] A fixing fixture 03 is fixed on the driving end of the Z-axis driving mechanism (i.e., the Z-axis slider 02). The fixing fixture 03 is L-shaped and is made of two polytetrafluoroethylene plates spliced ​​at 90 degrees. The thin plate perpendicular to the horizontal plane is screwed on the Z-axis slider 02 and can move with the Z-axis slider. The horizontal thin plate is a frame structure.

[0050] The preparation device also includes a horizontal optical fiber clamping tool 04 and a vertical optical fiber clamping tool 12 for installation on the fixing fixture 03. The structures of the two tools are roughly the same, wherein the horizontal optical fiber clamping tool 04 is fixedly installed horizontally, and the vertical optical fiber clamping tool 12 is fixedly installed vertically. The two tools are installed one by one according to the corrosion direction of the optical fiber. The horizontal optical fiber clamping tool 04 is used for the corrosion of the peripheral optical fiber, and the vertical optical fiber clamping tool 12 is used for the corrosion of the central optical fiber. With regard to the specific structure, such as the horizontal optical fiber clamping tool, its structure is a frame-type tool, which is made of a piece of polytetrafluoroethylene plate with the middle hollowed out. In order to ensure sufficient strength and no deformation, the tool thickness is 10mm, and the length and width of the middle hollow part are 155mm and 150mm respectively. Figure 4 , 5As shown, one side has semicircular grooves equidistantly carved on the left and right sides, and the midlines of the two opposite semicircular grooves on the left and right sides are on the same straight line, for example, the groove radius is 270μm. When the optical fiber is coiled, the optical fiber is placed horizontally on the frame-type tooling, and a certain pulling force is applied to the two ends of the optical fiber in opposite directions to make the optical fiber taut and straightened, and then the optical fiber is fixed on the clamping tooling with corrosion-resistant high-temperature tape.

[0051] As a specific installation method of the optical fiber horizontal clamping tool 04 and the fixing fixture 03, such as Figure 3 As shown, a number of cylindrical magnets 031 are embedded and fixed on both sides of the bottom of the horizontal part of the fixing fixture 03. The cylindrical magnets protrude 10mm from the surface of the polytetrafluoroethylene plate. In the figure, the centers of the three magnets on each side are on the same straight line, and the intervals between the magnets are equal, which are used to adsorb and fix the optical fiber horizontal clamping tooling 04. Figure 4 As shown, the two sides of the top surface of the optical fiber horizontal clamping tool 04 are provided with matching grooves, and iron or magnetic materials are arranged in the grooves. The optical fiber horizontal clamping tool 04 is adsorbed and fixed to the bottom of the horizontal part of the fixing fixture 03 by magnetic attraction. The optical fiber vertical clamping tool 12 is also a frame structure made of a hollowed-out polytetrafluoroethylene plate in the middle, with grooves on the surface. The optical fiber vertical clamping tool is placed vertically and fixed. The grooves are in two rows, upper and lower. The center optical fiber is placed on the groove and fixed with corrosion-resistant tape. The difference is that it is not fixed by magnetic attraction, and the side is locked to the fixing fixture.

[0052] When corroding the peripheral optical fiber, the preparation device adopts the form of a pad 09 and a corrosion disk 05. The pad 09 is installed on the Y-axis slider 08 of the Y-axis drive mechanism, and the corrosion disk 05 is placed on the pad 09. The corrosion disk made of polytetrafluoroethylene has a depth of 5mm and is used to contain hydrofluoric acid. After being filled with hydrofluoric acid, due to the surface tension of the liquid, the hydrofluoric acid liquid surface forms an arc surface. The hydrofluoric acid liquid surface in the center of the corrosion disk will be higher than the upper surface of the corrosion disk, so that the optical fiber can be immersed in hydrofluoric acid. 06 is the peripheral optical fiber to be corroded. After stripping the coating layer in the middle section of the optical fiber, the quartz cladding is corroded. The distance between the two stripping openings should be greater than the length of the corrosion disk 05. The pad 09 is made of polytetrafluoroethylene material and has a height of 150mm. It is used to place the corrosion disk 05. The pad 09 is provided with a pin for positioning the corrosion disk 05. When corroding the central optical fiber, the corrosion cylinder 11 is installed on the Y-axis slider 08 of the Y-axis drive mechanism. The etching cylinder 11 is made of tetrafluoroethylene, has a depth of 200 mm, and is used to contain hydrofluoric acid.

[0053] Finally, the preparation device also includes a computer control system 10 for human-computer interaction and controlling the movement of the two modules.

[0054] Based on the above-mentioned preparation device, the preparation method of the high beam quality combiner provided in this embodiment is specifically as follows:

[0055] Step S1, processing the central optical fiber: corrode one end of the central optical fiber, the front end is a straight section, the rear of the straight section is a tapered structure, then the corroded central optical fiber is rinsed and cut off, and finally the bare fiber part of the central optical fiber after corrosion is cleaned.

[0056] During the specific operation, the coating layer at one end of the central optical fiber is first stripped off, and the central optical fiber is fixed on the optical fiber vertical clamping tooling with corrosion-resistant tape and low-fold glue respectively. The central optical fiber is in a stretched state. After the etching cylinder loaded with hydrofluoric acid is slowly moved to the bottom of the central optical fiber, the central optical fiber is controlled to move up and down for etching according to a four-stage program: in the first stage, the central optical fiber is driven to descend rapidly; in the second stage, the central optical fiber remains paused; in the third stage, the central optical fiber continues to descend slowly; in the fourth stage, the central optical fiber rises rapidly; the front section of the finally corroded central optical fiber is a straight section, and the rear of the straight section is a tapered structure; after the etching is completed, the central optical fiber is immediately rinsed with pure water, the optical fiber is cut along the edge of the low-fold glue, the central optical fiber is lowered, and then the bare fiber part of the central optical fiber is ultrasonically cleaned with anhydrous ethanol.

[0057] Taking the preparation of a 7×1 high-power energy combiner as an example, the input fiber specification is 34 / 250, the numerical aperture is 0.11, and the output fiber specification is 100 / 120 / 360, the numerical aperture is 0.22. The central fiber and the peripheral fiber are used as input fibers and need to be processed separately. This step processes the central fiber.

[0058] according to Figure 6The structure shown vertically corrodes the center optical fiber. First, strip the coating layer at one end of the center optical fiber, the stripping length is 150mm, and then fix the center optical fiber on the vertical optical fiber clamping tool 12. The end immersed in hydrofluoric acid needs to be fixed with low-fold glue to avoid hydrofluoric acid corrosion. The other end that is not directly in contact with hydrofluoric acid can be fixed with corrosion-resistant tape. During the winding process, a certain pulling force needs to be applied to the center optical fiber to keep the optical fiber in a taut and straight state. Reset the state of the Z-axis drive mechanism through the computer, so that the Z-axis slider rises to the initial 0 scale position, and install the vertical clamping tool holding the optical fiber on the fixed fixture. Pour an appropriate amount of hydrofluoric acid into the corrosion cylinder 11, and the liquid level is about 30mm away from the upper surface of the container. The position of the Y-axis drive mechanism is controlled by a computer, so that the slide drives the etching cylinder to move slowly to the bottom of the central optical fiber, and then the adjusted automatic etching program is started: in the first stage, the Z-axis high-precision linear motor module 01 drives the optical fiber to descend, the descending speed is 10mm / s, and the time is 3s; in the second stage, the Z-axis high-precision linear motor module 01 pauses for 2min; in the third stage, the Z-axis high-precision linear motor module 01 continues to descend, the speed is 1.4mm / min, the time is 50min; in the fourth stage, the Z-axis high-precision linear motor module 01 rises, the speed is 4mm / s, and the time is 30s. The hydrofluoric acid etching speed is 2μm / min, so that the central optical fiber after etching is conical, and the front end of the cone is a straight section. The diameter of the most corroded and thinnest part is about 40um, and the length of the straight section is about 30mm. Immediately after the corrosion is completed, rinse the central optical fiber with 45°C pure water, cut the optical fiber along the edge of the low-fold glue, remove the central optical fiber, and then use anhydrous ethanol to ultrasonically clean the bare fiber parts of the 6 optical fibers for 1 minute.

[0059] Step S2, processing the peripheral optical fiber: S21, from the starting position at a certain distance from the end face of the peripheral optical fiber, half of the optical fiber coating is stripped inward in the form of a half-wrap, and the stripped part of the bare fiber is wiped and cleaned; S22, after treating multiple peripheral optical fibers in the same way, the peripheral optical fibers are straightened and placed side by side and fixed on the horizontal optical fiber clamping tooling, with the stripped part of the bare fiber facing downward, hydrofluoric acid is injected into the corrosion plate, and the peripheral optical fiber is controlled to move downward so that most of the peripheral optical fiber is immersed in the hydrofluoric acid, and then the peripheral optical fiber is taken out and rinsed; S23, after the rinsing is completed, the other half of the optical fiber coating is stripped, one peripheral optical fiber is retained, and the other peripheral optical fibers are cut off along the starting point of the corrosion straight area, and finally the bare fiber parts of all the peripheral optical fibers are cleaned.

[0060] This embodiment processes 6 peripheral optical fibers. The coating stripping process is performed. At 100 mm from the left end of the peripheral optical fiber, a stripping machine is used to strip half of the optical fiber coating to the right. The cross section of the optical fiber is as follows: Figure 7As shown in (a), the coating stripping length is 150mm. After wiping the coating residue with alcohol and dust-free paper, the stripped bare fiber part is ultrasonically cleaned with anhydrous alcohol for 1 minute. According to the positioning groove on the optical fiber horizontal clamping tooling, the optical fiber is arranged. It is necessary to ensure that the bare fiber part with the coating stripped is facing downward and the coated part is facing upward. The cleaned peripheral optical fiber is adhered and fixed to both sides of the frame tooling with corrosion-resistant high-temperature tape. During the winding process, a certain pulling force needs to be applied to the optical fiber to keep the peripheral optical fiber in a taut and straightened state. The hollow part of the frame tooling that clamps the peripheral optical fiber is 155mm long, which is slightly larger than the stripping length of the optical fiber coating. The stripping mouth of the peripheral optical fiber is 2.5mm away from the edge of the tooling to avoid contaminating the cleaned bare fiber part. The state of the Z-axis high-precision linear motor module 01 is reset by computer, so that the slider rises to the initial 0 scale position, and the frame tooling holding the optical fiber is installed on the fixed fixture. Pour a certain amount of hydrofluoric acid into the etching tray, and make sure that the hydrofluoric acid liquid level is higher than the upper surface of the etching tray, but not overflowing. The width of the etching tray is 90mm and the depth is 4mm. The position of the Y-axis high-precision linear motor module 08 is controlled by a computer, so that the slider drives the etching tray to move slowly below the peripheral optical fiber, and then adjust the position of the peripheral optical fiber on the Z axis, so that 4 / 5 of the peripheral optical fiber is finally immersed in hydrofluoric acid for etching. Figure 7 As shown in (b) in the figure. The hydrofluoric acid etching rate is 2μm / min, and the etching time is 52.5min. Immediately after etching, the optical fiber is rinsed with 45℃ pure water. After rinsing, the other half of the coating is stripped off. After etching, the optical fiber with the coating stripped off is as shown in the figure. Figure 7 As shown in (c) in the figure, the whole is fan-shaped, with an angle of about 60° between the two sides. The cladding at one end is etched to a minimum thickness of 3μm, and the cladding at the far end of the other end is 125μm from the core. Take 6 optical fibers and cut 5 of them along the starting point of the etched straight area with a diamond knife. The cross-sectional microscope photo is shown in Figure 8 As shown, the bare fiber parts of the six optical fibers are ultrasonically cleaned with anhydrous ethanol for 1 minute.

[0061] Step S3, bundle the peripheral optical fibers and the central optical fibers: S31, arrange the peripheral optical fibers in a straight line with the core facing upward, fix the back side with tape, the first optical fiber is an uncut optical fiber, keep a certain gap between adjacent bare fibers of the peripheral optical fibers, slowly rotate the first optical fiber, bundle the peripheral optical fibers, and pre-fix one end of the bare fiber with tape after bundling; S32, completely insert the corroded end of the central optical fiber into the center position of the bundled peripheral optical fibers, and finally obtain a fiber bundle.

[0062] After cleaning, press the 6 peripheral optical fibers as shown Fig. 9Arrange them straightly with the core facing upwards, and fix the back with tape. The first peripheral optical fiber is the uncut optical fiber, and the other five are cut optical fibers. A certain gap can be left between the bare fibers of adjacent peripheral optical fibers. With the first peripheral optical fiber as the axis, slowly rotate counterclockwise to bundle the six optical fibers. After bundling, one end of the bare fiber is pre-fixed with tape. Divide the six peripheral optical fibers into two groups, each with three optical fibers. Slightly push them apart and insert the corroded central optical fiber. Since the corrosion at the end of the central optical fiber is very thin, the end face of the central optical fiber can be protruded from the end face of the peripheral optical fiber to confirm whether it is fully inserted.

[0063] Step S4, optical fiber fusion taper: fix the optical fiber bundle with low-fold glue, insert the bare fiber end of the optical fiber bundle into the quartz tube and fix it with low-fold glue, fuse taper the optical fiber bundle, and the optical fibers after fusion taper will be tightly combined into one.

[0064] like Fig.10 As shown, one end of the fiber bundle with coating is fixed with low-fold glue (left end in the figure). During the glue dispensing process, the fiber bundle is kept straight and stress-free. The glue dispensing length is about 5mm, and the low-fold glue covers the coating stripping edge by about 2mm. Insert the bare fiber end of the bundled fiber bundle into a quartz tube with an inner and outer diameter ratio of 1000 / 1250, keep the fiber bundle in the center of the quartz tube, and the edge of the tape can be 5mm away from the quartz tube mouth. Apply low-fold glue to fix the quartz tube and the fiber bundle.

[0065] The fiber bundle is tapered with a taper machine. The left and right clamps of the taper machine clamp the coated fiber bundle and the quartz tube respectively. The sizes of the left and right clamps are designed to ensure that the central axis of the fiber bundle and the quartz tube are on the same horizontal line. The fiber bundle is tapered. The taper ratio before and after taper is 1.2 times. After fusion taper, the quartz optical fiber will be tightly combined into one. The cross section is as follows: Fig.11 As shown, the diameter of the optical fiber bundle is 330 μm, the diameter of the circumscribed circle of the outer optical fiber core is about 95 μm, and the core is 28 μm.

[0066] Step S5, fusion packaging: corrode the output optical fiber, cut off the tapered straight area of ​​the optical fiber bundle, fuse the cut end of the optical fiber bundle with the output optical fiber, and after the fusion is completed, glue the combiner for packaging.

[0067] The output optical fiber has a specification of 100 / 120 / 360, which is etched to 100 / 120 / 330 using a conventional etching process, and then cut in the fiber bundle taper area and fused with the output optical fiber. After the fusion is completed, the beam combiner is glued and packaged to obtain the final beam combiner.

[0068] Of course, it should be noted that the above-mentioned preparation device is only an example of a specific device structure for realizing this index method. In actual operation, other equipment structures can also be used to realize this preparation method, and it is not limited to this device.

[0069] In summary, the present invention reduces the spacing between the cores of the input optical fibers by adopting fan-shaped corrosion, thereby reducing the taper ratio of the energy combiner, optimizing the beam quality and divergence angle of the output laser, and retaining half of the cladding to ensure the overall strength and reliability of the combiner.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a high beam quality combiner, characterized in that: The preparation method is as follows: firstly, the central optical fiber and the peripheral optical fiber are processed, wherein one end of the central optical fiber is corroded when the central optical fiber is processed, and the peripheral optical fiber is corroded into a fan-shaped cross section when the peripheral optical fiber is processed, and the proximal end of the fan-shaped fiber is facing inward and the distal end is facing outward, and they are arranged in a circle for bundle assembly, and then the central optical fiber is inserted into the center position, and then the optical fiber bundle is melt-tapered, the tapered straight area of ​​the optical fiber bundle is cut off, and it is fused with the output optical fiber, and finally encapsulated to obtain a beam combiner; The preparation method specifically comprises the following steps: Step S1: Processing center optical fiber One end of the central optical fiber is corroded, the front end is a straight section, and the rear of the straight section is a tapered structure, then the corroded central optical fiber is rinsed and cut off, and finally the bare fiber part of the central optical fiber after corrosion is cleaned; Step S2: Processing peripheral optical fibers S21, stripping off half of the optical fiber coating layer inward in a half-wrapped form from a starting point at a certain distance from the outer optical fiber end face, and wiping and cleaning the stripped bare fiber; S22, after treating multiple peripheral optical fibers in the same manner, straighten the peripheral optical fibers, place them side by side and fix them on the optical fiber horizontal clamping tooling, and place the partially stripped bare fibers downward, inject hydrofluoric acid into the etching plate, control the peripheral optical fibers so that most of the peripheral optical fibers are immersed in the hydrofluoric acid, and then take out the peripheral optical fibers and rinse them; S23, after the washing is completed, the coating layer of the other half of the optical fiber is stripped off, one peripheral optical fiber is retained, the other peripheral optical fibers are cut off along the starting point of the corrosion straight area, and finally the bare fiber parts of all peripheral optical fibers are cleaned; Step S3: Bundle peripheral optical fibers and central optical fibers S31, arrange the peripheral optical fibers in a straight line with the core facing upwards, fix the back side with tape, the first optical fiber is an uncut optical fiber, a certain gap is kept between adjacent bare fibers of the peripheral optical fibers, the first optical fiber is slowly rotated, the peripheral optical fibers are bundled, and one end of the bare fiber is pre-fixed with tape after bundling; S32, completely inserting the corroded end of the central optical fiber into the center position of the peripheral optical fiber of the bundle, and finally obtaining an optical fiber bundle; Step S4: Fiber fusion taper The optical fiber bundle is fixed with low-fold glue, the bare fiber end of the optical fiber bundle is inserted into the quartz tube and fixed with low-fold glue, and the optical fiber bundle is melt-tapered. After melt-tapering, the optical fibers are tightly combined into one; Step S5: Welding and packaging The output optical fiber is corroded, the tapered straight area of ​​the optical fiber bundle is cut off, the cut end of the optical fiber bundle is fused with the output optical fiber, and after the fusion is completed, the beam combiner is sealed by glue dispensing.

2. The method for preparing a high beam quality combiner according to claim 1, characterized in that: The specific process of step S1 is as follows: Strip off the coating at one end of the central optical fiber, fix the central optical fiber on the optical fiber vertical clamping tooling with corrosion-resistant tape and low-fold glue respectively. The central optical fiber is in a stretched state. After the corrosion cylinder loaded with hydrofluoric acid is slowly moved to the bottom of the central optical fiber, the central optical fiber is controlled to move up and down for corrosion according to a four-stage program: in the first stage, the central optical fiber is driven to descend rapidly; in the second stage, the central optical fiber remains paused; in the third stage, the central optical fiber continues to descend slowly; in the fourth stage, the central optical fiber rises rapidly; the front section of the finally corroded central optical fiber is a straight section, and the rear of the straight section is a tapered structure; after the corrosion is completed, the central optical fiber is immediately rinsed with pure water, the optical fiber is cut along the edge of the low-fold glue, the central optical fiber is lowered, and the bare fiber part of the central optical fiber is ultrasonically cleaned with anhydrous ethanol.

3. The method for preparing a high beam quality combiner according to claim 2, characterized in that: The specific process of step S21 is as follows: From the starting point at a certain distance from the left end of the peripheral optical fiber, half of the optical fiber coating is stripped to the right in a half-wrapped form. After wiping the coating residue with alcohol and dust-free paper, the stripped bare fiber part is ultrasonically cleaned with anhydrous alcohol. Multiple peripheral optical fibers are treated in the same way. The specific process of step S22 is as follows: Place the peripheral optical fibers side by side on the positioning grooves of the optical fiber horizontal clamping tooling, with the stripped bare fibers facing downward and the coated fibers facing upward. During the process of mounting the optical fibers on the disk, a certain pulling force is applied to the peripheral optical fibers to keep them in a taut and straightened state. Use corrosion-resistant high-temperature tape to fix the peripheral optical fibers on the optical fiber horizontal clamping tooling; inject hydrofluoric acid into the etching disk, the hydrofluoric acid liquid level is higher than the upper surface of the etching disk but does not overflow. After the etching disk is slowly moved to the bottom of the peripheral optical fibers, the peripheral optical fibers are controlled to move downward in the vertical direction so that most of the peripheral optical fibers are immersed in the hydrofluoric acid. After etching, the optical fibers are immediately rinsed with pure water; In step S23, after the etching is completed, the cross section of the peripheral optical fiber is fan-shaped as a whole.

4. The method for preparing a high beam quality combiner according to claim 3, characterized in that: In step S32, whether the central optical fiber end face protrudes from the peripheral optical fiber end faces is confirmed.

5. A preparation device for the method for preparing a high beam quality combiner according to any one of claims 1 to 4, characterized in that: The preparation device includes a Z-axis drive mechanism and a Y-axis drive mechanism, and a fixing fixture is fixed on the driving end of the Z-axis drive mechanism, and the fixing fixture is L-shaped. The preparation device also includes a horizontal optical fiber clamping tool and a vertical optical fiber clamping tool for being installed on the fixing fixture. The horizontal optical fiber clamping tool is a frame-type tool, one of which has semicircular grooves equidistantly engraved on the left and right sides of one surface, and the midlines of the two opposite semicircular grooves on the left and right sides are on the same straight line. The preparation device also includes a pad, an etching disk and an etching cylinder, wherein the pad is installed at the driving end of the Y-axis drive mechanism, and the etching disk is placed on the pad, or the etching cylinder is installed at the driving end of the Y-axis drive mechanism.

6. The preparation device according to claim 5, characterized in that: A plurality of cylindrical magnets are fixed on both sides of the bottom of the horizontal part of the fixing fixture, and matching grooves are opened on both sides of the top surface of the frame-shaped tooling, and iron or magnetic materials are arranged in the grooves.

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