Annular light spot laser beam combiner

Abstract

The utility model provides an annular light spot laser beam combiner, which relates to the technical field of optical fibers, and comprises an output optical fiber structure which is coaxially arranged, and the output optical fiber structure sequentially comprises a first fiber core, a second fiber core, a third fiber core and a fourth fiber core from inside to outside, the first cladding wraps the first fiber core; the second fiber core is annularly arranged on the outer side of the first cladding and is used for forming an annular light spot; the second cladding wraps the second fiber core; the outer wrapping layer wraps the second wrapping layer; through the special design of the internal structure of the beam combiner and the arrangement of the optical fibers, higher laser power output can be realized, and through the design of the internal structure of the beam combiner, energy transmitted by three optical fibers can be simultaneously coupled into a fiber core at a central circular light spot, so that the maximum energy power of the central light spot can theoretically reach 18kw; the energy power of the outer ring can be coupled to the annular core layer through 1-2 optical fibers, so that the power can exceed 12kw, and the number of the optical fibers is increased.

Description

Technical Field

[0001] This utility model relates to the field of optical fiber technology, and in particular to a ring-shaped laser beam combiner. Background Technology

[0002] With the rapid development of the fiber laser industry, fiber lasers, with their advantages of high conversion efficiency, good beam quality, compact structure, easy heat dissipation, and good operational stability, have been widely used in industrial and defense fields. The transmission medium for laser energy is optical fiber, through which hundreds of kilowatts of energy can be transmitted. Currently, the power output of high-power fiber lasers has exceeded 10kW, and the combined power of high-power lasers has reached hundreds of kW.

[0003] Currently, the power of laser systems produced by ring-spot beam combining is generally low, with the highest reaching only around 12kW, and their stability needs improvement. High-power fiber laser systems mainly consist of numerous low-power lasers combined into a single beam, and there are two main methods to achieve high-energy, high-power output:

[0004] Spatial optical path combining method: Spatial optical path combining is performed by several low-power lasers, that is, by focusing and combining multiple sets of lenses. This method has harsh environmental requirements. The lenses need to be fixed stably, the entire combining environment needs to be dust-free and have high cleanliness requirements, and the system cannot have large vibrations. All of these factors will affect the output of high-power lasers.

[0005] Fiber optic energy combiner method: Fiber optics are mainly composed of a core, cladding, and coating. Laser energy is mainly transmitted in the core. It can be bundled by using fiber optics as a laser transmission carrier. The main fiber optic device is the fiber optic energy combiner. Compared with the spatial optical path combining method, it can output up to hundreds of kW of energy by combining multiple lasers. Its main advantages are that it is not affected by the environment, the system structure is simple and stable, the cost is low, and the vibration resistance is good.

[0006] In practical scientific research and industrial applications, technologies such as laser welding, laser cutting, laser 3D printing, and laser cladding have been widely used in various production fields. The processing requirements for different materials and fields vary, with varying demands on laser power, spot size, shape, and energy density. For example, in the welding field, welding the outer casing of new energy battery cells has specific requirements for the laser's spot size, energy density, and spot shape. Currently, the most widely used and effective laser is the ring-spot laser.

[0007] The working principle of the ring spot laser is that when welding metal materials, two laser spots act on the surface of the metal materials: a circular spot with concentrated energy located in the center, and an annular spot around it. The power, energy, time, etc. of the two laser spots can be adjusted independently.

[0008] The most effective and currently advanced method for achieving a ring-shaped laser spot is through a laser combiner. The principle of a laser combiner is that 2 to N input optical fibers are tapered together to form an optical fiber bundle, which is then fused with an output optical fiber to produce a high-energy laser. For example, a laser combiner composed of 4 optical fibers can connect to 4 lasers, and the output laser power is the sum of the power of these 4 lasers. If the power of a single laser is 3KW, then the combined laser energy is 12KW.

[0009] To transmit a ring-shaped dual-spot laser beam in an optical fiber, a specific design of the combiner is required to couple different laser energies into the core and ring layers of the ring fiber. Furthermore, ring-shaped dual-spot transmission necessitates the use of fiber with a ring core layer. Compared to ordinary fiber, ring fiber has several ring layers made of different core materials. The innermost core layer transmits laser energy to form the central circular spot. The outer ring layers are made of the same material as the core layer. The ring layers and the inner core layer are separated by a special quartz layer that cannot transmit energy. Therefore, the core layer and the ring layer can transmit two different shapes of laser spots without affecting each other's transmission. This type of fiber is relatively common in the market. However, the current technological bottleneck that needs to be overcome is the specific design of the combiner to couple different laser energies into the ring fiber, and it is also a significant factor limiting the power and beam quality of ring-shaped lasers in the industry.

[0010] In summary, the existing problems and defects in the industry's technology are as follows: the current ring spot laser beam combiner has low beam combining power (6KW for the inner ring and 6KW for the outer ring, totaling 12kW), which leads to incomplete welding of some thick metal materials, insufficient welding depth, and poor weld joint effect. Therefore, we propose a ring spot laser beam combiner. Utility Model Content

[0011] The purpose of this invention is to overcome the shortcomings of the existing technology and achieve higher laser power output through special design of the internal structure of the beam combiner and fiber arrangement.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] A ring-shaped laser beam combiner includes a coaxially arranged output fiber structure, wherein the output fiber structure comprises, from the inside out: a first fiber core for transmitting a circular light spot;

[0014] The first cladding layer encloses the first fiber core;

[0015] The second fiber core is arranged around the outside of the first cladding to form a ring-shaped light spot;

[0016] The second cladding layer wraps around the second fiber core;

[0017] Outer layer, which wraps around the second cladding layer;

[0018] The refractive indices of the first fiber core and the second fiber core are higher than the refractive indices of their corresponding first cladding and second cladding, respectively.

[0019] The diameter of the first fiber core is 50-100μm, and the diameter of the second fiber core is 150-300μm;

[0020] The first fiber core has 3 strands, and the second fiber core has 9 strands.

[0021] The bundle combiner further includes a fused tapered coupling structure, which includes: a central input fiber for coupling light to the first fiber core, and an outer low-bend glass tube for the central fiber;

[0022] The outer input fiber is used to couple light to the second fiber core, and a bundled fiber outer low-bend glass tube is sleeved on its outside.

[0023] Furthermore, the diameter of the first cladding layer is 70-150 μm, and the diameter of the second cladding layer is 200-400 μm. The first and second cladding layers are formed into low refractive index layers by fluorine doping.

[0024] Furthermore, the numerical aperture of the first fiber core and the first cladding is 0.22, and the numerical aperture of the second fiber core and the second cladding is 0.22.

[0025] Furthermore, the circular and annular light spots transmit laser light of the same or different wavelengths, respectively.

[0026] Furthermore, the tapered diameter of the fused tapered coupling structure matches the diameters of the first and second fiber cores.

[0027] Compared with the prior art, the beneficial effects of this utility model are:

[0028] 1. The first core of the dual-core fiber output by the combiner is a circular core, which can transmit a circular light spot. The two cores correspond to two transmitted light spots, a circular light spot and a ring light spot.

[0029] 2. Laser coupling is achieved by introducing a fused biconical taper (FBT) bundle. Twelve input fibers are tightly arranged into a bundle in two loops, with three central input fibers and nine peripheral input fibers. Before bundling, the central input fibers are encased in a low-refractive glass tube. The light from the central input fibers is coupled into the first core of the dual-core fiber after passing through the FBT bundle. The light from the second core is coupled into the second core through the nine peripheral FBT fibers. The entire fiber bundle is surrounded by a low-refractive glass tube as a sleeve. Then, the bundled FBT bundle and the dual-core fiber are fused together to achieve dual-core optical coupling.

[0030] This invention achieves higher laser power output through a special design of the internal structure of the beam combiner and the arrangement of optical fibers. By designing the internal structure of the beam combiner, the energy transmitted by the three optical fibers in the central circular spot can be coupled to the fiber core simultaneously. In this way, the energy power of the central spot can theoretically reach up to 18 kW. The energy power of the outer ring can be coupled to the annular core layer using the power of 1-2 optical fibers, so that the power can exceed 12 kW. By increasing the number of optical fibers, the laser spot after beam combining is flatter and the energy density is more uniform, which is beneficial to welding. Attached Figure Description

[0031] Figure 1 A schematic diagram of the overall structure of a high-power ring-shaped laser beam combiner provided by this utility model;

[0032] Figure 2 A schematic diagram of the cross-sectional structure of the fiber bundle in a high-power annular spot laser combiner provided by this utility model;

[0033] Figure 3 A schematic diagram of the longitudinal structure of a high-power annular spot laser beam combiner provided by this utility model;

[0034] Figure 4 A schematic diagram of the cross-section of the output ring optical fiber provided by this utility model.

[0035] Legend: 1. First fiber core; 2. First cladding; 3. Second fiber core; 4. Second cladding; 5. Outer cladding; 6. Low-bending glass tube outside the central fiber; 7. Low-bending glass tube outside the bundled fiber. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0037] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be provided below with reference to relevant embodiments, and several embodiments of this utility model will be given. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of this utility model more thorough and complete.

[0038] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0040] Example 1

[0041] like Figure 1-4 As shown, this utility model provides a technical solution: a ring-shaped laser beam combiner, comprising a coaxially arranged output fiber structure, the output fiber structure comprising, from the inside out: a first fiber core 1 for transmitting a circular light spot; a first cladding 2 for wrapping the first fiber core 1; a second fiber core 3, arranged around the outside of the first cladding 2 for forming a ring-shaped light spot; a second cladding 4 for wrapping the second fiber core 3; and an outer cladding 5 for wrapping the second cladding 4.

[0042] Among them, the refractive indices of the first fiber core 1 and the second fiber core 3 are higher than the refractive indices of their corresponding first cladding layer 2 and second cladding layer 4, respectively.

[0043] The diameter of the first fiber core 1 is 50-100μm, which can ensure both the amount of energy transmitted by the first fiber core 1 and the beam quality of the light from the first fiber core 1. The diameter of the second fiber core 3 is 150-300μm, which is mainly used to form a high-energy ring beam.

[0044] The first fiber core 1 has 3 strands, and the second fiber core 3 has 9 strands;

[0045] The combiner also includes a fused tapered coupling structure, which includes: a central input fiber for coupling light to the first fiber core 1, and an outer low-bend glass tube 6 for the central fiber;

[0046] The outer input optical fiber is used to couple light to the second fiber core 3, and a bundled optical fiber outer low-bend glass tube 7 is sleeved on its outer side.

[0047] Example 2

[0048] like Figure 1-4As shown, the diameter of the first cladding layer 2 is 70-150 μm, which is determined according to the size of the first core 1. The diameter of the second cladding layer 4 is 200-400 μm, which is determined according to the size of the second core 3. The first cladding layer 2 and the second cladding layer 4 form a low refractive index layer by doping with fluorine.

[0049] The numerical aperture of the first fiber core 1 and the first cladding 2 is 0.22, and different numerical apertures can also be set as needed. The numerical aperture of the second fiber core 3 and the second cladding 4 is 0.22, and different numerical apertures can also be set as needed.

[0050] Circular and annular light spots transmit laser light of the same or different wavelengths, and the energy of the two beams can be adjusted in any ratio as needed.

[0051] The tapered diameter of the fused tapered coupling structure matches the diameter of the first core 1 and the second core 3.

[0052] It should be noted that the present invention provides an optical fiber coupling method for transmitting a ring beam, which differs from the conventional bundle combiner manufacturing method in that: the bundle combiner has 12 optical fibers, and the arrangement order of the optical fibers is different. The three middle first optical fibers are covered with a first cladding 2 with an inner diameter between 100-180nm. A ring of optical fibers is arranged outside this capillary, with a number of 9 fibers.

[0053] Other steps use the conventional tapering method, employing a fused tapered bundle coupling method, wherein the fused tapered bundle includes an outer input fiber, a central input fiber, a low-bend glass tube 6 outside the central fiber, and a low-bend glass tube 7 outside the bundled fiber;

[0054] Light from the first fiber core 1 enters through optical coupling via the central input fiber of the fused tapered bundle.

[0055] Light from the second fiber core 3 enters through optical coupling via the peripheral input fiber of the fused tapered bundle.

[0056] The central input optical fiber requires a low-bend glass tube 6 as a sleeve for the central optical fiber.

[0057] The peripheral input optical fiber uses the bundled optical fiber outer low-bend glass tube 7 as a sleeve;

[0058] Then, the bundled optical fibers are fused and tapered, and the diameter after fused tapering is determined according to the diameter of the dual-core optical fiber.

[0059] Furthermore, based on Examples 1-2, the specific production implementation technology of this ring-shaped laser beam combiner uses conventional input fibers of 25 / 250µm and output fibers of 100 / 130 / 300 / 460µm, and is a 12-in-1 beam combiner (3 fibers in the inner ring and 9 fibers in the outer ring). The production steps are as follows:

[0060] Step 1: Prepare 12 25 / 250 optical fibers for the fiber optic bundle, about 3 meters in length. Arrange them neatly at one end, remove the coating layer to a remaining length of 6 cm (using an FCS fiber coating stripper). Then immerse this end of the fiber in an ultrasonic cleaner containing alcohol or acetone for one minute, and then remove the fiber for later use.

[0061] Step 2: Prepare a fluorine-doped capillary (second cladding 4), which is placed on the outermost layer of the fiber bundle. The capillary is generally 800um inner diameter and 1500um outer diameter. The fluorine-doped capillary has a very low refractive index, which can reduce laser transmission. Take a capillary length of 15cm, clean the dust in an ultrasonic cleaner containing acetone, and dry it at high temperature.

[0062] Step 3: Use a tapering machine to adjust specific parameters, tapere the capillary, and set the tapered-waist-tapered structure so that its internal size is just slightly larger than the outer circumference of the cladding of the 12 input fiber bundles. Insert the three inner ring fibers of the input fiber into a thin-walled glass tube with an inner diameter of 180μm, and then combine them with the nine outer ring fibers to form a fiber bundle. Then insert the input fiber bundle into the tapered capillary and place it in the tapering machine for a second tapering. The inner diameter of the capillary and the size of the tapering are determined by the core of the output fiber, approximately less than or equal to 300μm. Then cut the capillary on a specific cleaver with a flat, burr-free cutting angle of less than or equal to 0.5 degrees and set aside for later use.

[0063] Step 4: Prepare output optical fibers of type 100 / 130 / 300 / 460um, remove the coating, cut the optical fibers on a cutting machine with a flat cutting angle of less than or equal to 0.5 degrees, and set aside for later use;

[0064] Step 5: Take the fiber bundle prepared in step 3 and the output fiber prepared in step 4, place them in the fusion splicer that has been programmed, and perform discharge fusion. The fiber bundle and the output fiber are fused together by high-temperature discharge. Take out the fused fiber bundle and the output fiber (which can be called a bundle combiner at this time), and fix them in a specific fixture. The production of the bundle combiner is basically completed.

[0065] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A ring-shaped spot laser beam combiner, characterized by, The output fiber structure coaxially arranged includes, in sequence from inside to outside: a first core (1) for transmitting a circular light spot; a first cladding (2) wrapping the first core (1); a second core (3) annularly arranged outside the first cladding (2) for forming an annular light spot; a second cladding (4) wrapping the second core (3); an outer cladding (5) wrapping the second cladding (4); wherein the refractive index of the first core (1) and the second core (3) is higher than the refractive index of the corresponding first cladding (2) and the second cladding (4); the diameter of the first core (1) is 50-100 μm, and the diameter of the second core (3) is 150-300 μm; the number of the first core (1) is 3, and the number of the second core (3) is 9; the combiner further includes a fused taper coupling structure, which includes: a center input fiber for coupling light to the first core (1), and a center fiber outer low-refraction glass tube (6) arranged outside the center input fiber; a peripheral input fiber for coupling light to the second core (3), and a group fiber outer low-refraction glass tube (7) arranged outside the peripheral input fiber.

2. A ring mode laser beam combiner as claimed in claim 1, characterized in that: The diameter of the first cladding (2) is 70-150 μm, and the diameter of the second cladding (4) is 200-400 μm, and the first cladding (2) and the second cladding (4) form a low-refraction layer by doping fluorine.

3. The ring-sighting laser beam combiner of claim 1, wherein: The numerical aperture of the first core (1) and the first cladding (2) is 0.22, and the numerical aperture of the second core (3) and the second cladding (4) is 0.

22.

4. The ring-sighting laser beam combiner of claim 1, wherein: The circular light spot and the annular light spot respectively transmit laser beams of the same or different wavelengths.

5. The ring mode laser beam combiner of claim 1, wherein: The diameter of the fused taper coupling structure after tapering matches the diameter of the first core (1) and the second core (3).

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