Stray light absorption mechanism and semiconductor laser

Abstract

The present invention relates to the field of laser technology, and in particular to a stray light absorption mechanism and a semiconductor laser. The stray light absorption mechanism provided by the present invention includes a shell and a focusing lens, wherein a first cavity and a second cavity are formed in the shell, and the first cavity and the second cavity are connected through a constriction; the stray light generated by the polarization beam combiner is gathered by the focusing lens and enters the second cavity through the constriction, and the energy of the stray light reflected in the second cavity is consumed, and at the same time, since the stray light enters the second cavity through the constriction, the size of the constriction is very small, so that an optical black body is formed in the second cavity, which can effectively prevent the stray light entering the second cavity from returning to the first cavity through the constriction, and effectively avoid the escape of the stray light; it avoids the generation of local high temperature during the reflection, transmission and absorption of the stray light on the inner wall of the laser housing, which can better protect the components inside the laser housing and improve the service life of the laser.

Description

Technical Field

[0001] The invention relates to the technical field of lasers, and in particular to a stray light absorption mechanism and a semiconductor laser. Background Art

[0002] Semiconductor lasers, also known as laser diodes, are lasers that use semiconductor materials as working materials. They are small in size, long in life, and can be pumped by simply injecting current. Therefore, semiconductor lasers are widely used in laser communications, optical storage, optical gyroscopes, laser printing, ranging, and radar.

[0003] The semiconductor laser includes a pump source, wherein the pump source emits P light and S light, and the incoming pump light is split into P light and S light with orthogonal polarization directions by a polarization beam splitter, and then the split P light and S light are combined into one beam of light by a polarization beam combiner. In existing semiconductor lasers, a portion of stray harmful light is generated when the light beams are combined, and the stray light can only be absorbed after multiple reflections on the inner wall of the laser housing, and when the energy density of the stray light is high, the stray light will generate local high temperature during the reflection, transmission, and absorption process of the inner wall of the laser housing, causing damage to the light-emitting unit inside the laser, the glue layer at the bottom of the lens, the output optical fiber, etc. Summary of the invention

[0004] (I) The technical problem to be solved by the present invention is that in the existing semiconductor laser, a part of stray harmful light will be generated during the light beam combining process. The stray light is reflected in the laser housing, causing local high temperature and even damaging the components inside the laser.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a stray light absorption mechanism for a semiconductor laser, wherein the semiconductor laser comprises a laser chip, a slow axis collimator and a polarization beam combiner, wherein the stray light absorption mechanism comprises a housing and a focusing lens, wherein a first cavity and a second cavity are formed in the housing, and the first cavity and the second cavity are connected through a constriction;

[0007] The housing is provided with a light inlet connected to the first cavity, the light inlet is arranged corresponding to the light exit position of the stray light of the polarization beam combiner, and the focusing lens is arranged in the first cavity;

[0008] A reflective surface is provided in the shell at a position corresponding to the light entrance, and the reflective surface is used to reflect stray light entering from the light entrance to the focusing mirror, and the focusing mirror is used to gather the stray light and make it enter the second cavity through the constricted opening.

[0009] According to an embodiment of the present invention, a light absorbing layer is provided on the inner surface of the second cavity, and the light absorbing layer is used to absorb stray light entering the second cavity through the constricted opening.

[0010] According to one embodiment of the present invention, the second cavity includes a first cavity close to the necking and a second cavity away from the necking;

[0011] The inner wall surfaces of the first cavity and the second cavity are both curved surfaces, and the curvature of the inner wall surface of the first cavity is greater than the curvature of the inner wall surface of the second cavity.

[0012] According to one embodiment of the present invention, the light absorbing layer includes a first absorbing layer and a second absorbing layer;

[0013] The first absorption layer is formed on the inner wall surface of the first cavity, and the second absorption layer is provided on the inner wall surface of the second cavity with a strip-shaped reflection layer and the second absorption layer, and the reflection layer and the second absorption layer are arranged in sequence at intervals.

[0014] According to an embodiment of the present invention, the second cavity is provided with a protrusion protruding toward one side of the necking, and the projection of the protrusion on the vertical plane where the necking is located is located on the upper side or the lower side of the necking.

[0015] According to one embodiment of the present invention, the protrusion comprises an arc surface of the inner wall of the second cavity protruding toward a side close to the necking;

[0016] The longitudinal cross-sectional area of ​​the first cavity gradually increases from a side close to the necking opening to a side away from the necking opening.

[0017] According to an embodiment of the present invention, the first absorption layer and the second absorption layer include black graphene layers, and the reflection layer includes a gold layer.

[0018] According to one embodiment of the present invention, the first cavity includes a third cavity close to the necking opening and a fourth cavity away from the necking opening;

[0019] The focusing mirror is arranged in the third cavity, the reflecting surface is arranged on the inner wall of the fourth cavity, and the light entrance is arranged at the upper end of the shell corresponding to the fourth cavity.

[0020] According to an embodiment of the present invention, the inclination angle between the reflection surface and the optical path of the stray light is 45°±1°.

[0021] According to one embodiment of the present invention, the third cavity includes a first section close to the necking and a second section close to the fourth cavity, the inner surface of the first section is conical, the inner diameter of the first section gradually increases from the side close to the necking toward the second section, and the inner wall surface of the first section is provided with a third absorption layer formed of a light-absorbing material; the inner surface of the second section is cylindrical.

[0022] According to one embodiment of the present invention, the diameter of the necking is Δx, Δx = ω / 95%;

[0023] Wherein, ω is the area of ​​the spot formed at the shrinkage after the stray light passes through the focusing lens, ω=X*R2 / R1, X is the strip width of the laser chip;

[0024] The R1 is the curvature of the slow axis collimating lens, and R2 is the curvature of the focusing lens.

[0025] According to one embodiment of the present invention, the length of the first segment is L1, L1≥ , where D2 is the strip width of the focusing mirror, D2=1.5*D1; f1 is the focal length of the focusing mirror 1113, f1=R2 / (n2-1), where n2 is the refractive index of the focusing mirror;

[0026] The transmission light radius of the focusing mirror is D1, D1=R1 / (n1-1)*tanα, where n1 is the refractive index of the slow axis collimator and α is the slow axis divergence angle of the laser chip.

[0027] According to one embodiment of the present invention, the distance between the focusing mirror and the neck is Z1, the length of the light spot is Z2, and the focal length of the focusing mirror is f1, then f1- <Z1+Z2≤f1.

[0028] On the other hand, an embodiment of the present invention further provides a semiconductor laser, including a laser chip, a slow-axis collimator and a polarization beam combiner, and also includes the stray light absorption mechanism described in any of the above embodiments, wherein the laser chip, the slow-axis collimator, the polarization beam combiner and the stray light absorption mechanism are arranged in sequence.

[0029] Beneficial effects of the present invention: The stray light absorption mechanism provided by the present invention comprises a shell and a focusing mirror, wherein a first cavity and a second cavity are formed in the shell, the first cavity and the second cavity are connected through a constriction, a light inlet connected to the first cavity is provided on the shell, the light exit position of the stray light of the polarization beam combiner is arranged on the upper side of the light inlet, and the focusing mirror is arranged in the first cavity;

[0030] The stray light generated by the polarization beam combiner enters the first cavity from the light entrance, and is reflected to the focusing mirror through the reflection surface. The stray light is gathered by the focusing mirror and enters the second cavity through the constriction. The reflected energy of the stray light in the second cavity is consumed. At the same time, since the stray light enters the second cavity through the constriction, the size of the constriction is very small, so that an optical black body is formed in the second cavity, which can effectively prevent the stray light entering the second cavity from returning to the first cavity through the constriction, and effectively prevent the stray light from escaping; it avoids the generation of local high temperature during the reflection, transmission and absorption of the stray light on the inner wall of the laser housing, which can better protect the components inside the laser housing and improve the service life of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0032] Figure 1 A schematic structural diagram of a stray light absorption mechanism provided in one embodiment of the present invention.

[0033] Icon: 1-shell; 11-first cavity; 111-third cavity; 1111-first section; 1112-second section; 1113-focusing mirror; 112-fourth cavity; 1121-reflecting surface; 1122-light entrance; 12-second cavity; 121-first cavity; 122-second cavity; 1221-protrusion; 13-reduction; 2-polarization combiner. DETAILED DESCRIPTION

[0034] In order to more clearly understand the above-mentioned purposes, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0035] like Figure 1As shown, an embodiment of the present invention provides a stray light absorption mechanism for a semiconductor laser, wherein the semiconductor laser comprises a laser chip, a slow axis collimator and a polarization beam combiner 2, wherein the laser chip, the slow axis collimator, the polarization beam combiner 2 and the stray light absorption mechanism are sequentially arranged along an optical path; the stray light absorption mechanism comprises a housing 1 and a focusing lens 1113, wherein a first cavity 11 and a second cavity 12 are formed in the housing 1, wherein the first cavity 11 and the second cavity 12 are connected via a constriction 13; and a A light inlet 1122 connected to the first cavity 11, the light inlet 1122 is arranged corresponding to the light exit position of the stray light of the polarization beam combiner 2, and the focusing mirror 1113 is arranged in the first cavity 11; a reflecting surface 1121 is provided in the shell 1 corresponding to the light inlet 1122, the reflecting surface 1121 is used to reflect the stray light entering from the polarization beam combiner 2 through the light inlet 1122 to the focusing mirror 1113, and the focusing mirror 1113 is used to gather the light beam and make it enter the second cavity 12 through the constriction 13.

[0036] Among them, the semiconductor laser includes a pump source, which emits P light (parallel light) and S light (vertical light). The polarization beam splitter splits the incoming pump light into P light and S light with orthogonal polarization directions, and then the split P light and S light are combined into one beam of light through the polarization beam combiner 2. The combined light is transmitted along the direction of the P light, and then after entering the polarization beam combiner 2, a part of the S light does not merge with the P light and is transmitted along the direction of the P light, but continues to be transmitted in the vertical direction. This part of the light cannot be transmitted to the optical fiber on the rear side, forming stray harmful light.

[0037] The stray light absorption mechanism provided in the present application is to absorb the stray light generated by the S light in the vertical direction. The stray light absorption mechanism in the present application includes a shell 1 and a focusing lens 1113; wherein a first cavity 11 and a second cavity 12 are formed in the shell 1, the first cavity 11 and the second cavity 12 are connected by a constriction 13, and a light inlet 1122 connected to the first cavity 11 is provided on the shell 1, and the light inlet 1122 corresponds to the light outlet position of the stray light of the polarization beam combiner 2; in this way, after the vertical light beam (S light) enters the polarization beam combiner 2, a small part of the S light (stray light) continues to transmit in the vertical direction, and then enters the first cavity 11 through the light inlet 1122, and the stray light entering the first cavity 11 is irradiated onto the reflecting surface 1121 , the stray light is reflected to the focusing mirror 1113 through the reflecting surface 1121, and the stray light is gathered by the focusing mirror 1113 and enters the second cavity 12 through the constriction 13. The reflected energy of the stray light is consumed in the second cavity 12. At the same time, since the size of the constriction 13 is very small, an environment similar to an optical black body is formed in the second cavity 12. The stray light entering the second cavity 12 will hardly return to the first cavity 11 from the constriction 13, which can effectively prevent the stray light from escaping from the second cavity 12. Therefore, the problem of local high temperature generated by the stray light during the reflection, transmission and absorption process of the inner wall of the laser housing 1 can be effectively solved, and the components inside the laser housing can be better protected, and the service life of the laser can be improved.

[0038] According to an embodiment of the present invention, a light absorbing layer is provided on the inner surface of the second cavity 12, and the light absorbing layer is used to absorb stray light entering the second cavity 12 through the constriction 13. In this embodiment, by providing the light absorbing layer in the second cavity 12, the stray light entering the second cavity 12 will not only consume energy due to reflection, but will also be absorbed by the light absorbing layer, which can further prevent the stray light entering the second cavity 12 from escaping through the constriction, thereby better protecting the components inside the laser housing and improving the service life of the laser.

[0039] According to one embodiment of the present invention, the second cavity 12 includes a first cavity 121 close to the constriction 13 and a second cavity 122 away from the constriction 13. According to one embodiment of the present invention, the inner wall surfaces of the first cavity 121 and the second cavity 122 are both curved surfaces, and the curvature of the inner wall surface of the first cavity 121 is greater than the curvature of the inner wall surface of the second cavity 122. In this embodiment, the first cavity 121 and the second cavity 122 are smooth curved surfaces, that is, the curvatures of various regions of the inner wall of the first cavity 121 are generally consistent, and the curvatures of various regions of the inner wall of the second cavity 122 are generally consistent. The curvature of the inner wall surface of the first cavity 121 is greater than the curvature of the inner wall surface of the second cavity 122, which has better reflection and absorption effects on stray light, and better light absorption per unit area.

[0040] According to one embodiment of the present invention, the light absorbing layer includes a first absorption layer and a second absorption layer; wherein the inner wall surface of the first cavity 121 forms the first absorption layer, and the inner wall surface of the second cavity 122 is provided with a strip-shaped reflection layer and the second absorption layer, and the reflection layer and the second absorption layer are arranged in sequence at intervals.

[0041] In this embodiment, the light absorbing layer includes a first absorption layer and a second absorption layer, wherein the first absorption layer is formed on the inner wall surface of the first cavity 121, and a strip-shaped reflection layer and a second absorption layer are provided on the inner wall surface of the second cavity 122, and the reflection layer and the second absorption layer are arranged in sequence; since the size of the constriction 13 is relatively small, the stray light entering from the constriction 13 can only be irradiated to the inner surface of the second cavity 122 first, and the inner surface of the second cavity 122 is provided with a reflection layer and a second absorption layer, wherein the stray light irradiated to the reflection layer is reflected, and according to the incident angle of the stray light, a part of the stray light irradiated to the reflection layer is reflected to the first absorption layer on the inner wall surface of the first cavity 121 and absorbed by the first absorption layer, a part of the stray light is reflected to the second absorption layer on the inner wall surface of the second cavity 122 and absorbed by the second absorption layer, and another part of the stray light is reflected to the other reflection layer through one reflection layer, and this part of the stray light will eventually be reflected by the reflection layer to the first absorption layer or the second absorption layer for absorption, thereby completing the complete absorption of the stray light entering the second cavity 122.

[0042] At the same time, since the reflective layer and the second absorption layer are alternately arranged, the stray light entering the second cavity 122 can be relatively evenly reflected to the inner surface of the entire second cavity 12 after being reflected by the reflective layer. The inner surface of the second cavity 12 evenly absorbs the heat, thereby increasing the heat dissipation speed, and will not cause local high temperature in the local area of ​​the cavity due to the inability to dissipate heat due to absorbing too much energy.

[0043] According to one embodiment of the present invention, Figure 1As shown, the inner wall of the second cavity 122 is provided with a protrusion 1221 protruding toward one side of the constriction 13, and the projection of the protrusion 1221 on the vertical plane where the constriction 13 is located is located on the upper side or the lower side of the constriction 13. The second cavity 12 is used to absorb stray light, thereby preventing the stray light entering the second cavity 12 from being directly reflected back to the first cavity 11 from the constriction 13 by the reflective layer. The stray light reflected by the reflective surface is basically parallel light, and then after being focused by the focusing mirror 1113, a part of the stray light entering the middle part of the focusing mirror 1113 is parallel light. If the convex point is facing the constriction 13, the stray light will be directly reflected back by the reflective layer set at the convex point, causing the stray light to escape. Therefore, in the present application, a protrusion 1221 structure is arranged at a position of the second cavity 122 directly opposite to the necking 13, and the position of the convex point of the protrusion 1221 is higher or lower than the position of the necking 13, that is, the stray light incident into the second cavity 12 through the focusing lens 1113 and the necking 13 in parallel will not directly irradiate the convex point position and be reflected back.

[0044] Of course, in the present application, if the convex point is arranged opposite to the constriction 13, a light absorbing layer may be arranged only at the convex point position to absorb stray light irradiated on the convex point and prevent the stray light from being reflected back to the first cavity 11; however, if the light absorbing layer is arranged only at the convex point position, excessive local heat absorption may occur, resulting in local overheating.

[0045] It should be noted that, in this embodiment, the convex point of the protrusion 1221 is protruding inwards, and in other embodiments, the convex point of the protrusion 1221 may also be protruding outwards, for example, the second cavity 12 is similar to a hemispherical structure, as long as it is ensured that the convex point position is not directly opposite the constriction 13, that is, the projection of the convex point in the horizontal direction is located on the upper and lower sides of the constriction, it can be ensured that the stray light incident into the second cavity 12 will not be reflected back to the second cavity 12 by the convex point along the original path. At the same time, the inner wall surface of the second cavity 12 corresponding to the constriction 13 is not a convex structure, for example, it is a plane, the normal of which does not coincide with the incident light, that is, the stray light will not return to the first cavity 11 through the constriction 13 after being reflected by the plane corresponding to the convex point position.

[0046] like Figure 1As shown, the inner wall surfaces of the first cavity 121 and the second cavity 122 are both curved structures; the protrusion 1221 includes an arc surface that protrudes from the inner wall of the second cavity 122 toward the side close to the necking 13; in this embodiment, an irregular spherical structure is formed inside the second cavity 12, and a protrusion 1221 structure that protrudes inward is formed inside the second cavity 122, and the convex point position of the protrusion 1221 is higher or lower than the position of the necking 13; the curved surface can make the stray light better reflected in the second cavity 12, thereby consuming the energy of the stray light entering the second cavity 12, and the curved surface can also make the stray light reflect more evenly on the inner wall surface of the second cavity 12 to prevent local overheating.

[0047] It should be noted that, in the present embodiment, the interior of the second cavity 12 is not limited to a curved surface structure, and it may be a special-shaped structure, such as a mixed structure of curved surfaces and flat surfaces. At the same time, the protrusion 1221 may not be an arc-shaped protrusion 1221, for example, the protrusion 1221 may be a triangular structure. As long as it is possible to prevent stray light entering the second cavity 12 from escaping from the second cavity 12, the design concept of the present invention can be realized and should fall within the protection scope of the present invention.

[0048] like Figure 1 As shown, the longitudinal cross-sectional area of ​​the inner wall of the first cavity 121 gradually increases from the side close to the constriction 13 to the side away from the constriction 13; that is, the height of the constriction 13 is the smallest, so the stray light entering the second cavity 12 through the constriction 13 is difficult to escape from the constriction 13, so as to better absorb the stray light.

[0049] According to one embodiment of the present invention, Figure 1 As shown, the first cavity 11 includes a third cavity 111 close to the constriction 13 and a fourth cavity 112 away from the constriction 13; the focusing mirror 1113 is provided in the third cavity 111, the reflecting surface 1121 is provided on the inner wall of the fourth cavity 112, the light inlet 1122 is provided at the upper end of the shell 1 corresponding to the fourth cavity 112, and the light exit position of the stray light of the polarization beam combiner 2 is set on the upper side of the light inlet 1122. In this embodiment, the light inlet 1122 is opened at the upper end of the shell 1 and away from one end of the second cavity 12, and the polarization beam combiner 2 is provided at a position directly opposite to the upper side of the light inlet 1122; as shown Figure 1As shown, two beams of light are incident on the polarization beam combiner 2, one beam of P light along the parallel direction and one beam of S light along the vertical direction. After passing through the polarization beam combiner 2, the P light continues to be transmitted in the parallel direction. After passing through the polarization beam combiner 2, most of the S light changes from the vertical direction to the parallel direction and is combined with the P light into one beam of light; however, about 5% of the S light still continues to be transmitted in the vertical direction, and this part of the stray light enters the first cavity 11 through the light inlet 1122. Specifically, the stray light enters the fourth cavity 112 through the light inlet 1122, and then an inclined reflecting surface 1121 is provided at the lower side of the fourth cavity 112 corresponding to the light inlet 1122, and the stray light is reflected by the reflecting surface 1121 to the focusing mirror 1113 located in the third cavity 111. Since the stray light is transmitted in the vertical direction after entering through the light inlet 1122, the reflecting surface 1121 is inclined, and the inclination angle between the reflecting surface 1121 and the optical path of the stray light is 45°±1°, so that the stray light entering the fourth cavity 112 is reflected by the reflecting surface 1121 and then incident on the focusing mirror 1113 in a generally horizontal direction, and then the stray light is focused by the focusing mirror 1113 and enters the second cavity 12 from the constriction 13.

[0050] like Figure 1 As shown, the third cavity 111 includes a first section 1111 close to the necking 13 and a second section 1112 close to the fourth cavity 112. The inner surface of the first section 1111 is conical, and the inner diameter of the first section 1111 gradually increases from the side close to the necking 13 to the direction of the second section 1112; the inner surface of the second section 1112 is cylindrical, and the maximum inner diameter of the first section 1111 is equal to the inner diameter of the second section 1112. Figure 1As shown, in this embodiment, the second section 1112 is set to be cylindrical, and the side wall of the second section 1112 is a linear structure and is parallel to the propagation direction of the stray light in the second section 1112. Therefore, the probability of the stray light in the second section 1112 being irradiated to the inner wall and reflected can be reduced, so that the stray light can smoothly pass through the focusing lens 1113 into the second cavity 12. The focusing mirror 1113 is close to the edge of one side of the third cavity 111, and is in the same vertical plane relative to the second section 1112 and the connection point of the second section 1112. The inner wall surface of the first section 1111 is provided with a third absorption layer formed by a light-absorbing material, wherein most of the stray light enters the second cavity 12 through the constriction after being focused by the focusing mirror 1113, but there may still be a very small part of the stray light that is not irradiated at the constriction 13, but directly irradiates the inner wall surface of the first section 1111. If this part of the stray light is not absorbed, it is possible that it will be in the first cavity 11 to the light entrance, and be reflected out of the first cavity 11 from the light entrance 1122, and then be reflected out of the first cavity 11 through the light entrance 1122. Therefore, in this embodiment, a third absorption layer formed by a light-absorbing material is provided on the inner wall surface of the first section 1111, and the stray light irradiated on the inner wall surface of the first section 1111 is absorbed by the third absorption layer, so that the stray light is prevented from escaping from the stray light absorption mechanism, thereby improving the absorption effect of the stray light.

[0051] In the above embodiment of the present invention, the first absorption layer, the second absorption layer and the third absorption layer are all black graphene layers, which can absorb a large amount of stray light and conduct heat quickly. The reflective layer is a gold layer, which reflects the stray light irradiated to the reflective layer to the first absorption layer on the inner wall of the first cavity 121 and to the second absorption layer on the inner wall of the second cavity 122, and the black graphene layer absorbs heat and dissipates heat. Optionally, in this embodiment, the second absorption layer and the reflective layer are both 3mm wide, and the second absorption layer and the reflective layer are arranged in sequence.

[0052] In this embodiment, the shapes of the first section 1111 and the second section 1112 are not limited to cylindrical and conical. For example, the second section 1112 is rectangular, the first section 1111 is square cone, or other irregular shapes. As long as the longitudinal cross-sectional area of ​​the first section 1111 can be gradually reduced from the focusing lens 1113 to the necking 13, the design concept of the present invention can be realized.

[0053] According to one embodiment of the present invention, the diameter of the necking 13 is Δx, Δx = ω / 95%;

[0054] Wherein, ω is the size of the spot area formed at the constriction after the stray light is focused by the focusing mirror 1113, ω=X*R2 / R1, and X is the strip width of the laser chip;

[0055] The R1 is the curvature of the slow axis collimating mirror, and R2 is the curvature of the focusing mirror 1113 .

[0056] The curvature of the slow axis collimator is R1, where the curvature of the slow axis collimator is determined by the power and model of the product design. The curvature of the focusing mirror 1113 is R2, where the curvature of the focusing mirror 1113 is selected based on the product design. The strip width X of the laser chip is determined by the model of the laser chip. R1, R2 and X are all known quantities. Therefore, the size of the light spot can be determined by the above formula, and then the diameter of the necking 13 can be determined.

[0057] According to one embodiment of the present invention, the length of the first segment 1111 is L1, L1≥ , where D2 is the strip width of the focusing mirror 1113, D2=1.5*D1; f1 is the focal length of the focusing mirror 1113, f1=R2 / (n2-1), where n2 is the refractive index of the focusing mirror 1113; the transmitted light radius of the focusing mirror 1113 is D1, D1=R1 / (n1-1)*tanα, where n1 is the refractive index of the slow axis collimator, and α is the slow axis divergence angle of the laser chip.

[0058] In this embodiment, the slow axis divergence angle of the laser chip is usually α, and usually the slow axis divergence angle of the laser chip is 10°. The divergence angle α of the laser chip is determined according to the type of the selected laser chip, so the divergence angle α of the laser chip is not limited to 10°.

[0059] The refractive index of the slow axis collimator is n1, which is determined by the material, and n1 is a known quantity; the refractive index of the focusing mirror 1113 is n2, which is determined by the material, so the above R2 and n2 are also known quantities. Therefore, the focal length f1 of the focusing mirror can be calculated and determined by the above formula, and D2 is the strip width of the focusing mirror 1113, D2=1.5*D1, and D1=R1 / (n1-1)*tanα, where α, R1 and n1 are all known quantities, so D1 can be calculated by the above formula, and D2=1.5*D1, thereby the strip width of the focusing mirror 1113 can be calculated. Then, by the formula L1≥ , the length of the first segment can be calculated. In this embodiment, L1≥ Therefore, it can be ensured that the stray light focused by the focusing mirror 1113 can smoothly pass through the narrowed opening to reach the second cavity 12.

[0060] According to an embodiment of the present invention, the distance between the focusing mirror 1113 and the constriction 13 is Z1, the length of the light spot is Z2, and the focal length of the focusing mirror 1113 is f1, then f1- <Z1+Z2≤f1, since Z1+Z2≤f1, it can be ensured that the light beam focused by the focusing mirror 1113 can enter the second cavity 12 through the constriction 13, and at the same time, in order to ensure that the stray light focused by the focusing mirror 1113 can all be smoothly irradiated into the constriction 13, no part of the stray light will be irradiated onto the surface of the first section 1111, so in this application, f1- <Z1+Z2, thus ensuring that the stray light can smoothly enter the second cavity 12, and at the same time, the stray light will not directly irradiate the surface of the first section 1111 located near the constriction 13 in the first cavity 11, ensuring that the stray light can smoothly pass through the constriction 13 into the second cavity 12, ensuring the absorption effect of the stray light absorption mechanism on the stray light.

[0061] Another embodiment of the present invention further provides a semiconductor laser, including a laser chip, a slow axis collimator and a polarization beam combiner 2, and also includes the stray light absorption mechanism described in any of the above embodiments, wherein the laser chip, the slow axis collimator, the polarization beam combiner 2 and the stray light absorption mechanism are arranged in sequence. The semiconductor laser provided in this embodiment is provided with a stray light receiving mechanism inside, and the stray light from the polarization beam combiner 2 can be absorbed by the light absorption mechanism, thereby solving the existing problem of local overheating caused by the transmission and reflection of stray light inside the surgical cavity, which damages the components inside the housing, and can better protect the components inside the housing.

[0062] In the description of the present invention, it should be noted that the terms "upper", "lower", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0063] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the inside of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0064] 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, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A stray light absorption mechanism for a semiconductor laser, the semiconductor laser comprising a laser chip, a slow axis collimator and a polarization beam combiner (2), characterized in that: The stray light absorption mechanism comprises a housing (1) and a focusing lens (1113); a first cavity (11) and a second cavity (12) are formed in the housing (1); the first cavity (11) and the second cavity (12) are connected via a constriction (13); The housing (1) is provided with a light inlet (1122) connected to the first cavity (11), the light inlet (1122) being arranged corresponding to the light exit position of the stray light of the polarization beam combiner (2), and the focusing mirror (1113) being arranged in the first cavity (11); A reflective surface (1121) is provided in the housing (1) at a position corresponding to the light entrance (1122), the reflective surface (1121) being used to reflect stray light entering from the light entrance (1122) to the focusing mirror (1113), and the focusing mirror (1113) being used to focus the stray light and allow it to enter the second cavity (12) through the constricted opening (13); The first cavity (11) comprises a third cavity (111) close to the necking (13) and a fourth cavity (112) away from the necking (13); The third cavity (111) comprises a first section (1111) close to the necking (13) and a second section (1112) close to the fourth cavity (112); the inner diameter of the first section (1111) gradually increases from a side close to the necking (13) towards the second section (1112); and the inner surface of the second section (1112) is cylindrical.

2. The stray light absorption mechanism according to claim 1, characterized in that: A light absorbing layer is provided on the inner surface of the second cavity (12), and the light absorbing layer is used to absorb stray light that enters the second cavity (12) through the constricted opening (13).

3. The stray light absorption mechanism according to claim 2, characterized in that: The second cavity (12) comprises a first cavity (121) close to the constricted opening (13) and a second cavity (122) away from the constricted opening (13); The inner wall surfaces of the first cavity (121) and the second cavity (122) are both curved surfaces, and the curvature of the inner wall surface of the first cavity (121) is greater than the curvature of the inner wall surface of the second cavity (122).

4. The stray light absorption mechanism according to claim 3, characterized in that: The light absorbing layer comprises a first absorbing layer and a second absorbing layer; The first absorption layer is formed on the inner wall surface of the first cavity (121), and the second absorption layer is provided on the inner wall surface of the second cavity (122), wherein the reflection layer and the second absorption layer are arranged in a strip shape, and the reflection layer and the second absorption layer are arranged in sequence and at intervals.

5. The stray light absorption mechanism according to claim 4, characterized in that: The second cavity (122) is provided with a protrusion (1221) protruding toward one side of the necking (13), and the projection of the protrusion (1221) on the vertical plane where the necking (13) is located is located on the upper side or the lower side of the necking (13).

6. The stray light absorption mechanism according to claim 5, characterized in that: The protrusion (1221) comprises an arc surface of the inner wall of the second cavity (122) protruding toward a side close to the necking (13); The longitudinal cross-sectional area of ​​the first cavity (121) gradually increases from a side close to the necking (13) to a side away from the necking (13).

7. The stray light absorption mechanism according to claim 4, characterized in that: The first absorption layer and the second absorption layer include black graphene layers, and the reflection layer includes a gold layer.

8. The stray light absorption mechanism according to any one of claims 1 to 7, characterized in that: The focusing mirror (1113) is provided in the third cavity (111), the reflecting surface (1121) is provided on the inner wall of the fourth cavity (112), and the light entrance (1122) is provided at the upper end of the shell (1) corresponding to the fourth cavity (112).

9. The stray light absorption mechanism according to claim 8, characterized in that: The inclination angle between the reflection surface (1121) and the optical path of the stray light is 45°±1°.

10. The stray light absorption mechanism according to claim 9, characterized in that: The inner surface of the first section (1111) is conical, and the inner wall surface of the first section (1111) is provided with a third absorption layer formed by a light-absorbing material.

11. The stray light absorption mechanism according to claim 10, characterized in that: The diameter of the necking (13) is Δx, Δx = ω / 95%; Wherein, ω is the area of ​​a light spot formed at the constriction (13) after the stray light passes through the focusing mirror (1113), ω=X*R2 / R1, X is the strip width of the laser chip, R1 is the curvature of the slow axis collimator, and R2 is the curvature of the focusing mirror (1113).

12. The stray light absorption mechanism according to claim 11, characterized in that: The length of the first segment (1111) is L1, L1≥ ; Wherein, D2 is the strip width of the focusing mirror (1113), D2=1.5*D1; f1 is the focal length of the focusing mirror (1113), f1=R2 / (n2-1), where n2 is the refractive index of the focusing mirror (1113); The transmission light radius of the focusing mirror (1113) is D1, where D1=R1 / (n1-1)*tanα; Among them, n1 is the refractive index of the slow axis collimator, and α is the slow axis divergence angle of the laser chip.

13. The stray light absorption mechanism according to claim 11 or 12, characterized in that: The distance between the focusing mirror (1113) and the constriction (13) is Z1, the length of the light spot is Z2, and the focal length of the focusing mirror (1113) is f1. Then, f1- <Z1+Z2≤f1.

14. A semiconductor laser comprising a laser chip, a slow axis collimator and a polarization beam combiner (2), characterized in that: It also comprises the stray light absorption mechanism as claimed in any one of claims 1 to 13, wherein the laser chip, the slow axis collimator, the polarization beam combiner (2) and the stray light absorption mechanism are arranged in sequence.

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