Multi-beam dark space filling prism and optical fiber coupling system
By using a multi-beam dark-area filling prism and an optical fiber coupling system, the problems of insufficient power and beam quality differences in single-tube semiconductor laser chips were solved, achieving efficient beam focusing and uniformity optimization, and improving optical fiber coupling efficiency and system stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-29
- Publication Date
- 2026-03-31
AI Technical Summary
In existing technologies, the power of single-tube semiconductor laser chips is too low to meet the needs of industrial processing, and multi-beam shaping schemes have residual dark areas and beam quality differences, which affect the uniformity of energy distribution and the fiber coupling effect.
A multi-beam dark area filling prism is used to eliminate the dark area of the beam by using a multi-beam dark area filling prism composed of seven reflective surfaces. Combined with a parallel plate prism, a beam expanding cylindrical mirror and a focusing lens, the beam can be efficiently focused and its uniformity optimized.
It can effectively eliminate dark areas in the beam without the need for a refractive prism, reduce optical loss, improve the reliability and stability of the optical path, and enhance beam quality and coupling efficiency.
Smart Images
Figure CN121763475A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor laser beam shaping, and relates to a multi-beam dark area filling prism and fiber coupling system. Background Technology
[0002] Although semiconductor laser chips offer advantages such as small size, long lifespan, and high electro-optical conversion efficiency, the power of a single-tube chip is too low to meet the demands of high-power lasers in industrial processing fields such as metal cutting, welding, and surface treatment. These industrial scenarios typically require high-power laser beams for rapid and efficient material processing. Currently, the solution is to encapsulate lasers composed of multiple single-tube, single-bar, or multi-bar lasers to increase the output power at the light source. While this can output sufficiently high power, two key problems exist: first, dark areas exist within the beam, affecting the uniformity of energy distribution; second, there is a significant difference in beam quality between the fast and slow axes, causing the beam to fail to meet fiber coupling conditions. Therefore, it is necessary to utilize optical elements to reshape and optimize the beam, focusing a large spot into a small spot that meets coupling requirements.
[0003] Previous beam shaping methods primarily employed single-beam dark area filling, where a single beam filled the dark areas between beams. However, this method still leaves some dark areas, resulting in insufficient beam focus along the fast axis and thus minimal improvement in beam quality in that direction. Therefore, single-beam dark area filling methods typically incorporate a refractive prism to further compress the beam along the fast axis. However, this increases the complexity of the entire system and necessitates consideration of the impact of material refractive index changes (at different temperatures) on the optical path, reducing its stability. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to provide a multi-beam dark area filling prism and fiber optic coupling system.
[0005] Technical solution: The present invention provides a multi-beam dark area filling prism, which includes a filling compression section and a compression section. The filling compression section is used to compress the spacing of multiple filling beams in the outer left beam group and fill them into the dark area between two filled beams in the outer left beam group to form a first beam group, and to compress the spacing of multiple filling beams in the outer right beam group and fill them into the dark area between two filled beams in the outer right beam group to form a second beam group; the compression section is used to compress the spacing between the first beam group and the second beam group.
[0006] Furthermore, the bottom of the multi-beam dark area filling prism is a first incident surface, a second incident surface, and a third incident surface. The third incident surface is located between the first incident surface and the second incident surface. The adjacent beams of the outer left beam group and the outer right beam group are incident from the third incident surface. The filling compression part includes two sets of stepped reflective surfaces and directional reflective surfaces that are symmetrically distributed from left to right. The stepped reflective surfaces include at least two reflective surfaces arranged in a stepped manner. The directional reflective surfaces are respectively disposed between the first incident surface and the second incident surface, and between the second incident surface and the third incident surface.
[0007] Furthermore, the multi-beam dark-area filling prism includes seven reflecting surfaces at a 45° angle to the horizontal plane, namely a first reflecting surface, a second reflecting surface, a third reflecting surface, a fourth reflecting surface, a fifth reflecting surface, a sixth reflecting surface, and a seventh reflecting surface; the outer left beam group includes beams A1, A2, B1, and B2 arranged sequentially from left to right, and the outer right beam group includes beams A3, A4, B3, and B4 arranged sequentially from right to left; the first and second reflecting surfaces are arranged in a stepped pattern. The third reflecting surface is located between beams B1 and B2. The seventh and sixth reflecting surfaces are arranged in a stepped manner. The fifth reflecting surface is located between beams B3 and B4. The second and fourth reflecting surfaces are arranged in a stepped manner to compress the distance between beams B2 and B4. After beams A1 and A2 undergo total reflection by the three reflecting surfaces, they are filled into the dark areas of beams B1 and B2. After beams A3 and A4 undergo total reflection by the three reflecting surfaces, they are filled into the dark areas of beams B3 and B4.
[0008] Furthermore, all seven reflective surfaces are coated with a high-reflectivity film.
[0009] Furthermore, the lengths of the first and seventh reflective surfaces are 1.1mm-1.3mm, the lengths of the third and fifth reflective surfaces are 1.5mm-1.7mm, the length of the second reflective surface is 5.9mm-6.1mm, the length of the fourth reflective surface is 4.1mm-4.3mm, and the length of the sixth reflective surface is 1.7mm-1.9mm.
[0010] Furthermore, the thickness of the multi-beam dark area filling prism is 9mm-12mm.
[0011] Another aspect of the present invention is to provide an optical fiber coupling system employing the above-mentioned multi-beam dark area filling prism, including a semiconductor laser stack, a multi-beam dark area filling prism, a set of parallel flat plate prisms, a set of beam expanding cylindrical mirrors, a focusing lens, and a target optical fiber. The multi-beam dark area filling prism is disposed at the output end of the semiconductor laser stack. The multi-beam dark area filling prism is used to change the path of the output beam of the semiconductor laser stack and compress the dark area of the beam; the parallel plate prism is used to cut and rearrange the compressed beam. The beam-expanding cylindrical mirror is used to enlarge the spot size in the fast axis direction, making the spot square in shape; the focusing lens is used to focus and couple the shaped beam into the target optical fiber.
[0012] Furthermore, the focusing lens is an aspherical lens.
[0013] Furthermore, the beam incident surfaces of the multi-beam dark-area filling prism, parallel plate prism, beam expanding cylindrical mirror, and focusing lens are all coated with anti-reflection coatings.
[0014] Beneficial Effects: The core advantage of the fiber optic coupling system of this invention lies in its ability to efficiently eliminate dark areas in the beam without the need for a refraction prism. This multi-beam dark area filling prism, composed of seven total internal reflection surfaces, allows a laser stack consisting of multiple semiconductor laser bars to pass through it, enabling two beams to fill each other without the need for subsequent dark area compression processes. This results in a more focused beam, requiring only balancing of the fast and slow axis beam quality and focusing coupling to finally couple the beam into a smaller diameter optical fiber. The entire fiber optic coupling system using this prism requires only a single total internal reflection prism to eliminate dark areas, reducing the number of prisms used and effectively lowering optical loss. Furthermore, the elimination of a refraction prism improves the reliability and stability of the optical path. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the overall structure of an optical fiber coupling system based on a multi-beam dark area filling prism. Figure 2 Beam filling optical path diagram for a multi-beam dark area filling prism; Figure 3 A schematic diagram of a prism used to fill a multi-beam dark area; Figure 4 A schematic diagram of the dimensions of the prism used to fill the dark area of the multi-beam region. Detailed Implementation
[0016] The technical solution of the present invention will be further described below with reference to the accompanying drawings.
[0017] A multi-beam dark area filling prism includes a filling compression section and a compression section. The filling compression section is used to compress the spacing of multiple filling beams in the outer left beam group and fill them into the dark area between two filled beams in the outer left beam group to form a first beam group, and to compress the spacing of multiple filling beams in the outer right beam group and fill them into the dark area between two filled beams in the outer right beam group to form a second beam group; the compression section compresses the spacing between the first beam group and the second beam group.
[0018] Furthermore, the bottom of the multi-beam dark area filling prism is a first incident surface 18a, a second incident surface 18b, and a third incident surface 18c. The third incident surface 18c is located between the first incident surface 18a and the second incident surface 18b. Adjacent beams from the outer left beam group and the outer right beam group are incident from the third incident surface 18c. The filling compression section includes two sets of stepped reflective surfaces and directional reflective surfaces that are symmetrically distributed from left to right. The stepped reflective surfaces include at least two reflective surfaces arranged in a stepped manner. The directional reflective surfaces are respectively disposed between the first incident surface 18a and the second incident surface 18b, and between the second incident surface 18b and the third incident surface 18c.
[0019] like Figure 1 As shown, the multi-beam dark-area filling prism 1 of the present invention can be installed in an optical fiber coupling system. The high-brightness optical fiber coupling system based on the multi-beam dark-area filling prism includes a semiconductor laser stack composed of eight bars, the multi-beam dark-area filling prism 1, a set of parallel plate prisms 2, a set of beam-expanding cylindrical mirrors 3, a focusing lens 4, and a target optical fiber 5. There are luminous dark areas between the beams of the semiconductor laser stack. The multi-beam dark-area filling prism 1 is disposed at the output end of the semiconductor laser stack. The multi-beam dark-area filling prism 1 is used to change the path of the output beam of the semiconductor laser stack and compress the beam dark areas, eliminating the luminous dark areas and making the beam more focused, thereby improving the beam quality in the fast axis direction. Each reflective surface of the prism is coated with a high-reflectivity thin film. The parallel plate prisms 2 are used to cut and rearrange the compressed beam; the beam-expanding cylindrical mirrors 3 are used to enlarge the spot size in the fast axis direction, making the spot square in shape, and finally coupled into the target optical fiber 5 through the focusing lens 4.
[0020] like Figure 2-4As shown, taking dual-beam filling as an example, the multi-beam dark area filling prism 1 includes seven reflective surfaces, each at a 45° angle to the horizontal plane and coated with a high-reflectivity film. The eight bars of the semiconductor laser stack emit beams A1, A2, B1, and B2 arranged from left to right, and A3, A4, B3, and B4 arranged from right to left. Beams B1 and B2 exit at the exit end of the multi-beam dark area filling prism 1 after one total internal reflection. Beams A1 and A2 are filled into the dark areas of beams B1 and B2 after three total internal reflections. Beams B3 and B4 exit at the exit end 19 of the multi-beam dark area filling prism after one total internal reflection. Beams A3 and A4 are filled into the dark areas of beams B3 and B4 after three total internal reflections, thus eliminating the dark areas of the beams in one step to the maximum extent.
[0021] The seven reflecting surfaces of the multi-beam dark area filling prism 1 are a first reflecting surface 11, a second reflecting surface 12, a third reflecting surface 13, a fourth reflecting surface 14, a fifth reflecting surface 15, a sixth reflecting surface 16, and a seventh reflecting surface 17. Among them, the first reflecting surface 11, the second reflecting surface 12, the third reflecting surface 13, the fifth reflecting surface 15, the sixth reflecting surface 16, and the seventh reflecting surface 17 constitute the filling compression part of the multi-beam dark area filling prism 1, and the second reflecting surface 12 and the fourth reflecting surface 14 constitute the compression part of the multi-beam dark area filling prism 1. The first reflecting surface 11 and the second reflecting surface 12 are arranged in a stepped manner. The third reflecting surface 13 is located between beams B1 and B2. The seventh reflecting surface 17 and the sixth reflecting surface 16 are arranged in a stepped manner. The fifth reflecting surface 15 is located between beams B3 and B4. The second reflecting surface 12 and the fourth reflecting surface 14 are arranged in a stepped manner to compress the distance between beams B2 and B4. After beams A1 and A2 undergo total reflection through the three reflecting surfaces, they are filled into the dark areas of beams B1 and B2. After beams A3 and A4 undergo total reflection through the three reflecting surfaces, they are filled into the dark areas of beams B3 and B4.
[0022] The specific beam filling path is as follows: The first reflecting surface 11 is located on the far left, receiving and performing the first total internal reflection of the A1 beam, deflecting its optical path to the right. The second reflecting surface 12 receives the direct incident light from beams A2, B1, and B2, and performs the first total internal reflection on the three beams respectively, deflecting their optical paths to the right, so that beams B1 and B2 exit from the right side. The third reflecting surface 13 receives the two beams A1 and A2 after being reflected by the first reflecting surface 11 and the second reflecting surface 12, and performs a second total internal reflection. After being reflected by the third reflecting surface 13, the beams A1 and A2 are filled into the dark area of the beams B1 and B2 after being reflected by the second reflecting surface 12 for a third total internal reflection. The seventh reflecting surface 17 is located on the far right and is symmetrically distributed with the first reflecting surface 11. It receives and performs the first total internal reflection of A3, deflecting its light path to the left. The sixth reflecting surface 16 receives and performs the first total internal reflection of the A4 beam, deflecting its optical path to the left. The fifth reflecting surface 15 receives the A3 and A4 beams after being reflected by the seventh reflecting surface 17 and the sixth reflecting surface 16, and performs a second total internal reflection. The four-reflector surface 14 receives the direct incident light from beams B3 and B4. After the two beams undergo a first total internal reflection, they exit from the right side. The four-reflector surface 14 receives beams A3 and A4 after two total internal reflections. After a third total internal reflection, the beams are filled into the dark areas of beams B3 and B4.
[0023] In one specific embodiment, the thickness D1 of the multi-beam dark-area filling prism 1 is 10 mm. The length L1 of the first reflecting surface 11 and the length L7 of the seventh reflecting surface 17 are both 1.2 mm. The length L3 of the third reflecting surface 13 and the length L5 of the fifth reflecting surface 15 are both 1.6 mm. The length L2 of the second reflecting surface 12 is 6.0 mm. The length L4 of the fourth reflecting surface 14 is 4.2 mm. The length L6 of the sixth reflecting surface 16 is 1.8 mm. The exit end height H2 of the multi-beam dark-area filling prism 1 is 6 mm, the height H1 is 1.6 mm, the length S1 of the plane separating each reflecting surface is 1.2 mm, the length S2 of the third incident surface 18c is 2.5 mm, and the length S3 of the first incident surface 18a and the second incident surface 18b is 4.5 mm.
[0024] In one specific implementation, a pair of parallel plate prisms 2 cut and rearrange the compressed beam. These parallel plates 2 divide the compressed beam into three equal parts along the slow axis. The leftmost beam is cut downwards and then shifted to the right. Similarly, the rightmost beam is cut upwards and then shifted to the left, increasing the fast-axis beam mass to three times its original size and reducing the slow-axis beam mass to one-third of its original size, thus achieving a balance between the fast and slow axis beam masses. A set of beam-expanding cylindrical mirrors 3 is used to expand the spot size along the fast axis, making the spot square. Finally, the beam is coupled into the target fiber 5 via a focusing lens 4, which not only improves fiber coupling efficiency but also makes the system simpler and more reliable.
[0025] In one specific embodiment, the focusing lens 4 is an aspherical lens. In the fiber optic coupling system of the present invention, the beam incident surfaces of the lenses and prisms are coated with anti-reflection films, and the beam reflecting surfaces are coated with anti-reflection films to reduce energy loss and improve light-to-light conversion efficiency.
[0026] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A multi-beam dark space filling prism, characterized by, The multi-beam dark area filling prism comprises a filling compression part and a compression part, the filling compression part is used for compressing the interval of multiple filling beams in the outer left beam group and filling into the dark area between two filled beams in the outer left beam group to form a first beam group, and the filling compression part is used for compressing the interval of multiple filling beams in the outer right beam group and filling into the dark area between two filled beams in the outer right beam group to form a second beam group; the compression part is used for compressing the interval of the first beam group and the second beam group.
2. The multi-beam dark space filling prism of claim 1, wherein, The bottom of the multi-beam dark area filling prism is a first incident surface (18a), a second incident surface (18b) and a third incident surface (18c), the third incident surface (18c) is located between the first incident surface (18a) and the second incident surface (18b), adjacent beams of the outer left beam group and the outer right beam group are incident from the third incident surface (18c), the filling compression part comprises two groups of left-right symmetric distributed stepped reflection surfaces and turning reflection surfaces, the stepped reflection surfaces comprise at least two stepped arranged reflection surfaces, and the turning reflection surfaces are respectively arranged between the first incident surface (18a) and the second incident surface (18b) and between the second incident surface (18b) and the third incident surface (18c).
3. The multi-beam dark space filling prism of claim 2, wherein, The multi-beam dark area filling prism (1) comprises seven reflection surfaces which are at an angle of 45° with the horizontal plane, the seven reflection surfaces are a first reflection surface (11), a second reflection surface (12), a third reflection surface (13), a fourth reflection surface (14), a fifth reflection surface (15), a sixth reflection surface (16) and a seventh reflection surface (17); the outer left beam group comprises A1, A2, B1 and B2 beams which are arranged in sequence from left to right, and the outer right beam group comprises A3, A4, B3 and B4 beams which are arranged in sequence from right to left; the first reflection surface (11) and the second reflection surface (12) are arranged in steps, the third reflection surface (13) is located between the B1 and B2 beams, the seventh reflection surface (17) and the sixth reflection surface (16) are arranged in steps, the fifth reflection surface (15) is located between the B3 and B4 beams, the second reflection surface (12) and the fourth reflection surface (14) are arranged in steps and are used for compressing the interval between the B2 and B4 beams, A1 and A2 beams are filled into the dark area of the B1 and B2 beams after full reflection through three reflection surfaces, and A3 and A4 beams are filled into the dark area of the B3 and B4 beams after full reflection through three reflection surfaces.
4. The multi-beam dark space filling prism of claim 3, wherein, The seven reflection surfaces are all coated with high reflection film.
5. The multi-beam dark space filling prism of claim 3, wherein, The length of the first reflection surface (11) and the seventh reflection surface (17) is 1.1mm-1.3mm, the length of the third reflection surface (13) and the fifth reflection surface (15) is 1.5mm-1.7mm, the length of the second reflection surface (12) is 5.9mm-6.1mm, the length of the fourth reflection surface (14) is 4.1mm-4.3mm, and the length of the sixth reflection surface (16) is 1.7mm-1.9mm.
6. The multi-beam dark space filling prism of claim 3, wherein, The thickness of the multi-beam dark area filling prism (1) is 9-12 mm.
7. A fiber coupling system employing the multi-beam dark-space filling prism according to any one of claims 1 to 6, characterized in that, The system comprises a semiconductor laser stack, a multi-beam dark area filling prism (1), a set of parallel plate prisms (2), a set of beam expanding cylindrical lenses (3), a focusing lens (4) and a target optical fiber (5). The multi-beam dark area filling prism (1) is arranged at the exit end of the semiconductor laser stack, and is used for changing the path of the output light beam of the semiconductor laser stack and compressing the light beam dark area; the parallel plate prisms (2) are used for cutting and rearranging the compressed light beam. The beam expanding cylindrical lenses (3) are used for expanding the spot size in the fast axis direction, so that the spot presents a square shape; the focusing lens (4) is used for focusing and coupling the reshaped light beam into the target optical fiber (5).
8. The fiber coupling system of claim 7, wherein, The focusing lens (4) is an aspheric lens.
9. The fiber coupling system of claim 7, wherein, The light beam incident surfaces of the multi-beam dark area filling prism (1), the parallel plate prisms (2), the beam expanding cylindrical lenses (3) and the focusing lens (4) are coated with an anti-reflection film.