A semiconductor laser module based on TO packaged multiple single tubes

Abstract

The present invention provides a semiconductor laser module based on TO packaged multiple single tubes, which relates to the field of semiconductor laser technology, including a base and multiple TO packaged single tubes on the same plane of the base, wherein the multiple TO packaged single tubes are arranged in odd paths; a fast axis collimator is arranged in the TO packaged single tube, and each TO packaged single tube is sequentially provided with a slow axis collimator and a reflector along the optical path; an optical steering element, an optical compression element and a focusing lens group are also sequentially arranged on the base; the fast axis collimator and the slow axis collimator collimate the light beam emitted by the corresponding TO packaged single tube in turn, and then the light beam is reflected by the reflector to the optical steering element for steering, and the optical compression element compresses and combines the light beam after steering, and finally couples it into the optical fiber through the focusing lens group. The present invention adopts TO packaging for a single tube in the green light band, abandons the traditional mechanical step structure, solves the problems of fast axis collimator application, dense arrangement and beam combination of light beams, and improves the output power of the semiconductor laser module.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor lasers, and in particular to a semiconductor laser module based on TO packaging multiple single tubes. Background Art

[0002] Since its invention, semiconductor lasers have been widely used in various fields due to their advantages such as high stability, high photoelectric conversion efficiency, and small size. In recent years, the demand for high-power green semiconductor lasers has been growing, but there are few reports on high-power green semiconductor lasers.

[0003] At present, the common single-tube packaging forms include: C-mount, COS, CT-mount, F-mount, TO, etc. The working life of the single-tube core in the infrared band will not be greatly affected in the air, so the first four packaging forms are often used to take into account the heat dissipation capacity. In the green light band, the working life of the single-tube core in the air will be greatly shortened, so TO packaging, a better sealing form, is selected.

[0004] Based on the above, there are some problems in the prior art: first, due to the limitation of the large external size of the TO package, the individual tubes cannot be densely arranged, and thus spatial beam combining is difficult; second, the distance from the light-emitting surface of the single-tube core in the TO package to the TO package window (several millimeters) is much larger than the working distance of most commonly used fast-axis collimators on the market (between tens of microns and hundreds of microns). In this case, the light beam divergence produces a larger spot size; third, it is not appropriate to use a more common mechanical step structure for TO packaging for spatial beam combining, which will reduce the heat dissipation capacity and impose strict requirements on the machining accuracy, thereby increasing the cost. Summary of the invention

[0005] In view of the above problems, the present invention provides a semiconductor laser module based on TO-packaged multiple single tubes, which adopts TO packaging for single tubes in the green light band, abandons the traditional mechanical step structure, ensures the life and heat dissipation capacity of the single tube, solves the problems of fast-axis collimator application, intensive arrangement of light beams and beam combining, and improves the output power of the semiconductor laser module.

[0006] To achieve the above object, the present invention provides a semiconductor laser module based on TO-packaged multiple single tubes, comprising: a base and a plurality of TO-packaged single tubes arranged on the base and located in the same plane, wherein the plurality of TO-packaged single tubes are evenly arranged in odd-numbered paths, and the number of the TO-packaged single tubes in each path is the same;

[0007] A fast-axis collimator is provided at the light-emitting position of the single-tube core in each TO-packaged single tube, and a slow-axis collimator and a reflector are sequentially provided above each TO-packaged single tube along the light path through a lens bracket; an optical steering element, an optical compression element and a focusing lens group are also sequentially provided on the base along the direction of the light path reflected by the reflector;

[0008] The fast-axis collimator and the slow-axis collimator collimate the light beams emitted from the corresponding single-tube cores in the TO-packaged single tube in turn, and then the light beams are reflected by the reflector to the optical steering element for steering. Except for the center path, the redirected light beams are compressed by the optical compression element, and then combined with the center path light beam, and finally coupled into the optical fiber through the focusing lens group.

[0009] As a further improvement of the present invention, the TO packaged single tubes are arranged in an odd-numbered manner in a slow axis direction, and the TO packaged single tubes in each manner are arranged in a fast axis direction;

[0010] The lens holders are provided on the base along the fast axis direction, between adjacent TO packaged single tubes and on the outside of the TO packaged single tubes at the boundaries. Multiple lens holders are vertically fixed on the base with the same height, and adjacent lens holders are separated by a specified distance.

[0011] As a further improvement of the present invention, the slow axis collimator is fixed directly above the TO packaged single tube, and the center of the slow axis collimator is located at the center of the output light of the TO packaged single tube.

[0012] As a further improvement of the present invention, the reflector is tiltedly arranged on the upper surface of the lens holder to densely arrange and reflect all the light beams collimated by the fast-axis collimator and the slow-axis collimator in space, and all of them are reflected to the optical steering element.

[0013] As a further improvement of the present invention, the angle between the reflector and the plane of the base is greater than 45° and less than 90°, and the angle between the light beam reflected by the reflector and the plane of the base is greater than 0° and less than 45°;

[0014] The angle between the reflector and the base plane is adjusted to adjust the distance of the reflected light beam in the fast axis direction.

[0015] As a further improvement of the present invention, the optical steering element is of transmission type, which steers the light beams reflected by each of the reflectors in the fast axis direction, so that the redirected light beams are parallel to the base plane, the paths are parallel to each other as a whole, and the light beams in each path are parallel to each other.

[0016] As a further improvement of the present invention, the optical compression element is reflective or refractive, and compresses the light beam of the TO-packaged single tube outside the center path. The compressed light beam and the light beam of the TO-packaged single tube in the center path should be at the same horizontal height after being combined.

[0017] As a further improvement of the present invention, the focusing lens group includes one or more optical elements, the light transmission size is greater than or equal to the size of the combined light beam, and the transmittance of the green light band anti-reflection film is greater than 99%.

[0018] As a further improvement of the present invention, the focusing lens group focuses the combined light beam at one point, and the size of the focused light beam in the fast axis direction and the slow axis direction are both smaller than the core diameter of the optical fiber, and the numerical aperture is also smaller than the numerical aperture of the optical fiber.

[0019] As a further improvement of the present invention, the laser wavelengths of all the TO-packaged single tubes are in the green light band, and the end faces of the optical fibers are coated with a green light band anti-reflection film.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention adopts TO packaging to avoid affecting the service life of the single tube core when working in the air. All TO packaged single tubes are based on the same horizontal plane, replacing the traditional mechanical steps, greatly reducing the requirements for mechanical processing accuracy and special processing of materials, saving time and manufacturing costs, and eliminating the influence of traditional mechanical steps on the heat dissipation capacity of the semiconductor laser; the present invention arranges the fast axis collimator in the single tube, the spot size of the single tube in the fast axis direction is effectively reduced, the beam quality is improved, the complexity of the overall optical path design is reduced, the space inside the module is effectively reduced, and the volume is small and easy to transport; the present invention compresses the light beam in the slow axis direction through the optical compression element, overcomes the disadvantage that the TO packaged single tubes cannot be densely arranged, improves the coupling efficiency, and increases the output power of the semiconductor laser module.

[0022] The present invention densely arranges each collimated light beam in space through a reflector. The cooperation between the reflector and the optical steering element can more easily complete the propagation of the light beam in a direction parallel to the plane of the base, and the flexibility of installation and adjustment is greatly improved, creating convenient conditions for subsequent coupling into the optical fiber.

[0023] The spacing between the light beams in the fast axis direction of the present invention can be adjusted by the tilt angle of the reflector, thereby improving the flexibility of installation and adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a three-dimensional structural diagram of a semiconductor laser module based on TO packaging multiple single tubes disclosed in Example 1 of the present invention;

[0025] Figure 2 It is a three-dimensional structural exploded view of a semiconductor laser module based on TO packaging multiple single tubes disclosed in Example 1 of the present invention;

[0026] Figure 3 It is a side view of a semiconductor laser module based on TO packaging multiple single tubes disclosed in Example 1 of the present invention;

[0027] Figure 4 A top view of a semiconductor laser module based on TO packaging multiple single tubes disclosed in Embodiment 1 of the present invention;

[0028] Figure 5 It is a three-dimensional structural diagram of a semiconductor laser module based on TO packaging multiple single tubes disclosed in Example 2 of the present invention;

[0029] Figure 6 It is a three-dimensional structural exploded view of a semiconductor laser module based on TO packaging multiple single tubes disclosed in Example 2 of the present invention;

[0030] Figure 7 A side view of a semiconductor laser module based on TO packaging multiple single tubes disclosed in Example 2 of the present invention;

[0031] Figure 8 This is a top view of a semiconductor laser module based on TO packaging multiple single tubes disclosed in Example 2 of the present invention.

[0032] Description of reference numerals:

[0033] 1. Base; 2. Lens holder; 3. TO package single tube; 3-1. TO package single tube cap; 3-2. TO package single tube core; 3-3. TO package single tube seat; 4. Slow axis collimator; 5. Reflector; 6. Optical steering element; 7. Optical compression element; 8. Focusing lens group; 8-1. Focusing lens in fast axis direction; 8-2. Focusing lens in slow axis direction; 9. Optical fiber; 10. Mounting slot; 11. Fast axis collimator. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0036] like Figure 1-8As shown, a semiconductor laser module based on TO-packaged multiple single tubes provided by the present invention comprises: a base 1, the base 1 is provided with two steps, a plurality of TO-packaged single tubes 3 are arranged on the first step on the same plane, the wavelengths of the plurality of TO-packaged single tubes 3 are all within the green light range, the width of the active region is 15 μm, they are evenly arranged in A paths, and the number B of TO-packaged single tubes 3 in each path is the same, wherein A and B are both positive integers greater than or equal to 1, and A is an odd number; adjacent TO-packaged single tubes 3 are spaced at a specified distance, the arrangement direction along the A path is the slow axis direction, and the direction along the B single tubes included in each path is the fast axis direction.

[0037] A fast-axis collimator 11 is provided at the light-emitting position of the core of each TO-packaged single tube 3, and the fast-axis collimator 11 is fixed by bonding in front of the light-emitting position of the core of the TO-packaged single tube 3. Lens holders 2 are provided on the base 1 along the fast-axis direction, between adjacent TO-packaged single tubes 3, and on the outer side of the TO-packaged single tube 3 at the boundary, with a total of B+1. Multiple lens holders 2 are vertically fixed on the base 1 with the same height, and adjacent lens holders 2 are separated by a specified distance; a slow-axis collimator 4 and a reflector 5 are sequentially provided along the optical path above each TO-packaged single tube 3 through the lens holder 2, the slow-axis collimator 4 is fixed directly above the TO-packaged single tube 3, and the center of the slow-axis collimator 4 is located at the center of the light emitted from the TO-packaged single tube 3, and the reflector 5 is obliquely arranged on the upper surface of the lens holder 2; an optical steering element 6, an optical compression element 7, and a focusing lens group 8 are also vertically provided in sequence on the second step of the base 1 along the direction of the light path reflected by the reflector 5;

[0038] The fast axis collimator 11 and the slow axis collimator 4 collimate the light beams emitted from the corresponding single tube cores in the TO packaged single tube 3 in turn. The collimated A×B beams are reflected by the reflector 5 in a densely arranged manner in space and reach the optical steering element 6 for steering. Except for the center path, the redirected light beams are compressed by the optical compression element 7, then combined with the center path light beam, and finally coupled into the optical fiber 9 through the focusing lens group 8.

[0039] Furthermore,

[0040] The angle between the reflector 5 and the plane of the base 1 of the present invention is greater than 45° and less than 90°, the angle between the light beam reflected by the reflector 5 and the plane of the base 1 is greater than 0° and less than 45°, and the reflector 5 does not block the light beam reflected from the rear; the angle between the reflector 5 and the plane of the base 1 is adjusted to adjust the distance of the reflected light beam in the fast axis direction.

[0041] The optical deflection element 6 of the present invention is of transmission type, which deflects the light beams reflected by each reflector 5 in the fast axis direction, so that the deflected light beams are parallel to the plane of the base 1, the paths are parallel to each other as a whole, and the light beams in each path are parallel to each other.

[0042] The optical compression element 7 of the present invention is reflective or refractive. The optical compression element 7 compresses the light beam of the TO-packaged single tube 3 outside the center path. The compressed light beam and the light beam of the TO-packaged single tube 3 in the center path should be at the same level after being combined.

[0043] The focusing lens group 8 of the present invention comprises one or more optical elements, and the light transmission size is greater than or equal to the size of the light beam after the combination, and the transmittance of the green light band anti-reflection film is greater than 99%. For example, a fast axis direction focusing lens 8-1 and a slow axis direction focusing lens 8-2 are sequentially arranged; the focusing lens group 8 focuses the combined light beam on one point, and the size of the focused light beam in the fast axis direction and the slow axis direction are both smaller than the core diameter of the optical fiber 9, and the numerical aperture is also smaller than the numerical aperture of the optical fiber 9.

[0044] In the present invention, the core diameter of the optical fiber 9 is 50 μm-400 μm, the numerical aperture is less than or equal to 0.22, and the end face of the optical fiber 9 is coated with a green light band anti-reflection film.

[0045] Embodiment 1:

[0046] like Figure 1-4 As shown, this embodiment discloses a semiconductor laser module based on TO-packaged multiple single tubes, including a base 1, a lens bracket 2, a TO-packaged single tube 3, a TO-packaged single tube cap 3-1, a TO-packaged single tube core 3-2, a TO-packaged single tube seat 3-3, a slow axis collimator 4, a reflector 5, an optical steering element 6, an optical compression element 7, a focusing lens group 8, a fast axis direction focusing lens 8-1, a slow axis direction focusing lens 8-2, an optical fiber 9, a mounting groove 10, and a fast axis collimator 11.

[0047] In this embodiment, the TO-packaged single tube 3 is arranged in the mounting groove 10 on the base 1, and the light beam emitted by each TO-packaged single tube core 3-2 passes through the corresponding fast-axis collimator 11 and slow-axis collimator 4 in sequence. The fast-axis collimator 11 collimates the fast-axis direction of the light beam emitted by the TO-packaged single tube core 3-2, and the slow-axis collimator 4 collimates the slow-axis direction of the light beam emitted by the TO-packaged single tube core 3-2. Each light beam collimated by the fast and slow axis collimators is reflected by the corresponding reflector 5, and the optical steering element 6 steers the reflected light beam. The direction of the light beam after steering is parallel to the plane of the base 1. The optical compression element 7 compresses the light beam of the TO-packaged single tube 3 outside the center path after steering, and the compressed light beam and the light beam of the TO-packaged single tube 3 in the center path are coupled into the optical fiber 9 via the focusing lens group 8.

[0048] in,

[0049] The wavelength of the TO-packaged single tube 3 arranged in the mounting groove 10 on the base 1 is within the green light range, the active area width of the TO-packaged single tube core 3-2 is 15μm, the TO-packaged single tube 3 is divided into 3 paths, each path of TO-packaged single tubes 3 contains 6, and adjacent single tubes are separated by a specified distance. The arrangement direction along the 3 paths is the slow axis direction of the TO-packaged single tube 3, and the direction along the 6 TO-packaged single tubes 3 contained in each path is the fast axis direction of the single tube.

[0050] The fast axis collimator 11 is arranged in each TO packaged single tube 3 and is fixed by bonding in front of the light emitting position of the TO packaged single tube core 3-2. The numerical aperture of the fast axis collimator 11 needs to be greater than or equal to the numerical aperture of the light beam in the fast axis direction of the TO packaged single tube 3. The TO packaged single tube cap 3-1 should not cause any interference to the fast axis collimator 11 after the TO packaged single tube seat 3-3 is sealed.

[0051] The base 1 is provided with 7 lens holders 7, and the slow axis collimator 4 and the reflector 5 are fixed on the lens holder 7. The adjacent lens holders 7 are spaced at a specified distance. The slow axis collimator 4 and the reflector 5 correspond to each TO packaged single tube 3 one by one, and the center of the slow axis collimator 4 is set at the center of the outgoing light of the TO packaged single tube 3. The reflectors 5 located on the same plane and parallel to each other are plane reflectors. The angle between the reflector 5 and the plane of the base 1 is greater than 45° and less than 90°. The reflector 5 reflects the 3x6 beams of light after collimation in the fast and slow axis directions in a dense arrangement in space. The reflector 5 should not block the beam reflected from the rear, and the spacing between each beam in the fast axis direction can be adjusted by the inclination angle of the reflector 5. The reflected light beam forms an angle greater than 0° and less than 45° with the plane of the base 1.

[0052] The optical steering element 6 is a light wedge, which steers the reflected light beam in the fast axis direction. After the steering, the direction of the light beam is parallel to the plane of the base 1. The paths in the light beam are parallel to each other as a whole, and the light beams in each path are parallel to each other. The size of the optical steering element 6 should be greater than or equal to the size of the reflected light beam. The incident light side of the light wedge has a certain tilt angle, which can determine the steering angle of the reflected light beam. According to the formula: n / n 1 = sinθ / sin(θ+α) can be determined, where n is the refractive index of air, n 1 is the refractive index of the optical deflection element 6 , θ is the inclination angle of the incident light surface of the wedge, and α is the inclination angle of the light beam relative to the plane of the base 1 .

[0053] The optical compression element 7 arranged on the base 1 is an rhombus prism, which adopts reflective light beam compression. The parallel surfaces of the two reflected light beams of the rhombus prism are coated with a green light band total reflection film. The optical compression element 7 compresses the 2-way TO packaged single tube 3 light beams outside the center path. After the compressed light beams are combined with the light beams of the single tube in the center path, they should be at the same horizontal height.

[0054] A focusing lens group 8 is also provided on the base 1. The focusing lens group 8 includes a focusing lens 8-1 in the fast axis direction and a focusing lens 8-2 in the slow axis direction. The focusing lens 8-1 and the focusing lens 8-2 in the slow axis direction are spherical cylindrical lenses or aspherical cylindrical lenses. Their light transmission size is larger than the size of the combined light beam. The transmittance of the green light band anti-reflection film plated is greater than 99%. The focusing lens group 8 focuses the combined light beam on one point. The size of the focused light beam in the fast axis direction and the slow axis direction of the focusing lens group 8 is smaller than the core diameter of the optical fiber 9. The numerical aperture of the focused light beam in the fast axis direction and the slow axis direction is smaller than the numerical aperture of the optical fiber 9. The core diameter of the optical fiber 9 is 50μm-400μm, the numerical aperture is less than or equal to 0.22, and the end face of the optical fiber is plated with a green light band anti-reflection film.

[0055] Embodiment 2:

[0056] like Figure 5-8 As shown, this embodiment discloses a semiconductor laser module based on TO packaging multiple single tubes.

[0057] The present embodiment is different from the embodiment 1 in that the optical compression element 7 disposed on the base 1 is still an oblique square prism, but a refraction-type light beam compression is adopted, and a green light band anti-reflection film is plated on the light beam incident surface and the light beam exit surface, and the distance moved by the incident light beam and the exit light beam is given by the formula: Determined, where X is the beam moving distance, β is the inclination angle of the mutually parallel incident surface and the exit surface relative to the bottom edge, L is the length, and n is the refractive index of the rhombus prism. By selecting β, L, and n, the moving distance X can be compressed, and the interval between the 2-way TO package single tube 3 beams outside the center path and the center path beam is reduced. After the compressed beam and the beam of the single tube in the center path are combined, they should be at the same horizontal height.

[0058] Advantages of the present invention:

[0059] The present invention adopts TO packaging to avoid affecting the service life of the single tube core when working in the air. All TO packaged single tubes are based on the same horizontal plane, replacing the traditional mechanical steps, greatly reducing the requirements for mechanical processing accuracy and special processing of materials, saving time and manufacturing costs, and eliminating the influence of traditional mechanical steps on the heat dissipation capacity of the semiconductor laser; the present invention arranges the fast axis collimator in the single tube, the spot size of the single tube in the fast axis direction is effectively reduced, the beam quality is improved, the complexity of the overall optical path design is reduced, the space inside the module is effectively reduced, and the volume is small and easy to transport; the present invention compresses the light beam in the slow axis direction through the optical compression element, overcomes the disadvantage that the TO packaged single tubes cannot be densely arranged, improves the coupling efficiency, and increases the output power of the semiconductor laser module.

[0060] The present invention densely arranges each collimated light beam in space through a reflector. The cooperation between the reflector and the optical steering element can more easily complete the propagation of the light beam in a direction parallel to the plane of the base, and the flexibility of installation and adjustment is greatly improved, creating convenient conditions for subsequent coupling into the optical fiber.

[0061] The spacing between the light beams in the fast axis direction of the present invention can be adjusted by the tilt angle of the reflector, thereby improving the flexibility of installation and adjustment.

[0062] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A semiconductor laser module based on TO packaged multiple single tubes, characterized in that: include: A base and a plurality of TO-packaged single tubes arranged on the base and located in the same plane, wherein the plurality of TO-packaged single tubes are evenly arranged in odd-numbered paths, and the number of TO-packaged single tubes in each path is the same, the TO-packaged single tubes are arranged in an odd-numbered path in a direction of a slow axis, and the TO-packaged single tubes in each path are arranged in a direction of a fast axis; A fast-axis collimator is provided at the light-emitting position of the core of each TO-packaged single tube, and the fast-axis collimator is arranged in each TO-packaged single tube and fixed in front of the light-emitting position of the core of the TO-packaged single tube. The numerical aperture of the fast-axis collimator is greater than or equal to the numerical aperture of the light beam in the fast-axis direction of the TO-packaged single tube. A slow-axis collimator and a reflector are arranged in sequence along the optical path above each TO-packaged single tube through a lens bracket. The slow-axis collimator is fixed directly above the TO-packaged single tube, and the center of the slow-axis collimator is located at the center of the light emitted by the TO-packaged single tube. The base is provided along the reflector. An optical steering element, an optical compression element and a focusing lens group are arranged in sequence in the direction of the mirror reflection light path. The optical steering element is of transmission type, and steers the light beam reflected by each of the reflectors in the fast axis direction, so that the steered light beams are parallel to the plane of the base, the paths are parallel to each other as a whole, and the light beams in each path are parallel to each other; the optical compression element is of reflection type or refraction type, and compresses the light beams of the TO packaged single tube outside the center path, and the compressed light beams and the light beams of the TO packaged single tube in the center path should be at the same horizontal height after being combined; The fast-axis collimator and the slow-axis collimator collimate the light beams emitted from the corresponding single-tube cores in the TO-packaged single tube in turn, and then the light beams are reflected by the reflector to the optical steering element for steering. Except for the center path, the steering light beams are compressed by the optical compression element, and then combined with the center path light beam, and finally coupled into the optical fiber through the focusing lens group, and the focusing lens group focuses the combined light beams at one point.

2. The semiconductor laser module according to claim 1, characterized in that: The lens holders are provided on the base along the fast axis direction, between adjacent TO packaged single tubes and on the outside of the TO packaged single tubes at the boundaries. Multiple lens holders are vertically fixed on the base with the same height, and adjacent lens holders are separated by a specified distance.

3. The semiconductor laser module according to claim 1, characterized in that: The reflector is tiltedly arranged on the upper surface of the lens bracket, and reflects all the light beams that have been collimated by the fast-axis collimator and the slow-axis collimator in a densely arranged manner in space, and all of them are reflected to the optical steering element.

4. The semiconductor laser module according to claim 2, characterized in that: The angle between the reflector and the plane of the base is greater than 45° and less than 90°, and the angle between the light beam reflected by the reflector and the plane of the base is greater than 0° and less than 45°; The angle between the reflector and the base plane is adjusted to adjust the distance of the reflected light beam in the fast axis direction.

5. The semiconductor laser module according to claim 1, characterized in that: The focusing lens group includes one or more optical elements, the light transmission size is greater than or equal to the size of the combined light beam, and the transmittance of the green light band anti-reflection film is greater than 99%.

6. The semiconductor laser module according to claim 2, characterized in that: The sizes of the focused light beam in the fast axis direction and the slow axis direction are both smaller than the core diameter of the optical fiber, and the numerical aperture is also smaller than the numerical aperture of the optical fiber.

7. The semiconductor laser module according to claim 1, characterized in that: The laser wavelengths of all the TO-packaged single tubes are in the green light band, and the end faces of the optical fibers are plated with a green light band anti-reflection film.

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