Semiconductor laser chip and laser

Abstract

The present invention discloses a semiconductor laser chip and a laser, and relates to the technical field of semiconductor lasers. The semiconductor laser chip comprises an N-type layer structure, an active layer and a P-type layer structure which are stacked in sequence, the P-type layer structure has a ridge, and the ridge is provided with a transverse mode reflection area near the cavity surface; the transverse mode reflection area has two reflection grooves respectively opened on opposite sides of the ridge in the slow axis direction, the reflection groove has a notch, a groove bottom arranged opposite to the notch, and a reflection groove wall extending from one end of the notch away from the cavity surface to the groove bottom; the reflection groove wall gradually approaches the cavity surface in the direction from the notch to the groove bottom. The semiconductor laser chip provided by the present invention can reduce the output of high-order transverse mode light beams without loss, so that the divergence angle is reduced, and high-brightness output is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor lasers, and in particular to a semiconductor laser chip and a laser. Background Art

[0002] Edge-emitting lasers are a widely used semiconductor laser structure. The chips configured with this type of laser usually use an etched ridge waveguide structure to reduce the mode volume.

[0003] Although this type of chip structure has reduced the mode volume to a certain extent, when applied to high-power semiconductor lasers, there are more high-order transverse mode beams, resulting in the chip still having a wide divergence angle problem and the output brightness is not ideal. Summary of the invention

[0004] The object of the present invention is to provide a semiconductor laser chip, which can reduce the divergence angle and improve the brightness of the light beam without loss.

[0005] Another object of the present invention is to provide a laser that can reduce the divergence angle and improve the brightness of the light beam without loss.

[0006] The embodiment of the present invention provides a technical solution:

[0007] A semiconductor laser chip, comprising an N-type layer structure, an active layer and a P-type layer structure stacked in sequence, wherein the P-type layer structure has a ridge strip, wherein the ridge strip is provided with a transverse mode reflection region at a position close to a cavity surface; the transverse mode reflection region has two reflection grooves respectively opened at opposite sides of the ridge strip in a slow axis direction; the reflection groove has a groove opening extending in a cavity length direction, a groove bottom arranged opposite to the groove opening in the slow axis direction, and a reflection groove wall extending from an end of the groove opening away from the cavity surface to the groove bottom;

[0008] The reflective groove wall gradually approaches the cavity surface in the direction from the groove opening to the groove bottom, and the cavity surface is arranged close to the reflective groove wall.

[0009] In an optional embodiment, the two reflection grooves in the transverse mode reflection area are symmetrically distributed along a straight line parallel to the cavity length direction.

[0010] In an optional embodiment, the width of the reflective groove in the cavity length direction gradually decreases from the groove opening to the groove bottom.

[0011] In an optional embodiment, the spacing between two of the reflection grooves in the transverse mode reflection region in the slow axis direction is less than or equal to one third of the size of the ridge strip in the slow axis direction.

[0012] In an optional embodiment, the groove depth of the reflective groove in the slow axis direction is greater than one tenth of the dimension of the ridge stripe in the slow axis direction and less than two fifths of the dimension of the ridge stripe in the slow axis direction.

[0013] In an optional embodiment, the width of the groove of the reflection groove in the cavity length direction is greater than half of the groove depth of the reflection groove in the slow axis direction, and less than twice the groove depth of the reflection groove in the slow axis direction.

[0014] In an optional embodiment, the distance between the end of the reflective groove wall away from the groove opening and the cavity surface in the cavity length direction is in the range of 20 μm to 80 μm.

[0015] In an optional embodiment, the reflective groove further has a protective groove wall extending from the groove opening to the groove bottom, the protective groove wall and the reflective groove wall form the reflective groove, and the protective groove wall is parallel to the cavity surface.

[0016] In an optional embodiment, in a plane perpendicular to the fast axis direction, the projection shape of the reflection groove wall is one of a straight line, a convex arc and a concave arc.

[0017] In an optional embodiment, the P-type layer structure includes a P-type waveguide layer, a P-type cladding layer and a P-type contact layer stacked in sequence, and the P-type cladding layer and the P-type contact layer form the ridge stripe.

[0018] In an optional embodiment, the reflection groove is opened on the surface of the P-type contact layer on one side in the fast axis direction, and extends on the other side in the fast axis direction to between the side surface of the P-type cladding layer facing away from the P-type waveguide layer and the side surface of the P-type waveguide layer facing away from the P-type cladding layer.

[0019] In an optional embodiment, the refractive index of the P-type waveguide layer is greater than the refractive index of the P-type cladding layer, and when the difference between the refractive index of the P-type waveguide layer and the refractive index of the P-type cladding layer is less than 0.15, the reflection groove extends into the P-type cladding layer;

[0020] When the difference between the refractive index of the P-type waveguide layer and the refractive index of the P-type cladding layer is greater than 0.15, the reflection groove extends into the P-type waveguide layer.

[0021] In an optional embodiment, the reflective groove is filled with a filler, the refractive index of the filler is smaller than the refractive index of the ridge, and / or the refractive index of the filler is greater than one quarter of the refractive index of the ridge.

[0022] In an optional embodiment, the difference between the refractive index of the ridge and the refractive index of the filler is greater than 1.

[0023] In an optional embodiment, the filler is at least one of air, silicon oxide and silicon nitride.

[0024] An embodiment of the present invention further provides a laser, comprising the semiconductor laser chip. The semiconductor laser chip comprises an N-type layer structure, an active layer and a P-type layer structure stacked in sequence, the P-type layer structure having a ridge strip, the ridge strip having a transverse mode reflection region at a position close to the cavity surface; the transverse mode reflection region having two reflection grooves respectively opened on opposite sides of the ridge strip in the slow axis direction;

[0025] The reflective groove comprises a groove opening extending in the cavity length direction, a groove bottom arranged opposite to the groove opening in the slow axis direction, and a reflective groove wall extending from one end of the groove opening away from the cavity surface to the groove bottom;

[0026] The reflective groove wall gradually approaches the cavity surface in the direction from the groove opening to the groove bottom, and the cavity surface is arranged close to the reflective groove wall.

[0027] Compared with the prior art, the semiconductor laser chip provided by the present invention has a transverse mode reflection area on its ridge strip, and the transverse mode reflection area has two reflection grooves on both sides of the cavity length. Due to the refractive index difference between the reflection groove and the ridge strip, the reflection groove walls of the two reflection grooves can reflect the light transmitted along the edges of the two sides of the cavity length back into the resonant cavity, so that the light beam is concentrated in the channel area between the two reflection grooves along the cavity length direction, and the output of the high-order transverse mode light beam is reduced without almost losing the output energy, thereby achieving the effect of reducing the divergence angle and high-brightness output. Therefore, the beneficial effects of the semiconductor laser chip provided by the present invention include: being able to reduce the output of the high-order transverse mode light beam without loss, so that the divergence angle is reduced, and high-brightness output is achieved.

[0028] In addition, the semiconductor laser chip provided by the present invention also has at least the following beneficial effects:

[0029] 1. The reflective groove also has a protective groove wall parallel to the cavity surface, which can prevent the cavity surface from overheating and achieve high temperature protection of the cavity surface;

[0030] 2. The reflective groove is spaced apart from the cavity surface to ensure the structural integrity of the cavity surface, thereby ensuring the coating effect of the cavity surface and avoiding the occurrence of film stripping caused by uneven coating of special shapes;

[0031] 3. The gap formed between the two reflection grooves in the transverse mode reflection area is located in the middle area of ​​the ridge in the slow axis direction, ensuring the concentration of the remaining mode, thereby obtaining a better emission effect;

[0032] 4. The filler of the reflection groove can be flexibly selected to meet different high-order transverse mode beam output requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative work.

[0034] Figure 1 A schematic structural diagram of a semiconductor laser chip provided by an embodiment of the present invention at a first viewing angle;

[0035] Figure 2 is a cross-sectional view of the semiconductor laser chip;

[0036] Figure 3 is a schematic structural diagram of the semiconductor laser chip at a second viewing angle;

[0037] Figure 4 The simulated light field reflection effect of the semiconductor laser chip when the refractive index of the ridge stripe body is 3.5 and the refractive index of the filler in the reflection groove is 1;

[0038] Figure 5 The simulated light field reflection effect of the semiconductor laser chip when the refractive index of the ridge stripe body is 3.5 and the refractive index of the filler in the reflection groove is 1.5;

[0039] Figure 6 The simulated light field reflection effect of the semiconductor laser chip when the refractive index of the ridge stripe body is 3.5 and the refractive index of the filler in the reflection groove is 2;

[0040] Figure 7 The simulated light field reflection effect of the semiconductor laser chip when the refractive index of the ridge stripe body is 3.5 and the refractive index of the filler in the reflection groove is 2.5;

[0041] Figure 8 The simulated light field reflection effect of the semiconductor laser chip when the refractive index of the ridge stripe body is 3.5 and the refractive index of the filler in the reflection groove is 3;

[0042] Fig. 9 The simulated light field reflection effect of the semiconductor laser chip when L1 is 20μm and L4 is 40μm;

[0043] Fig.10 The simulated light field reflection effect of the semiconductor laser chip when L1 is 30μm and L4 is 35μm;

[0044] Fig.11 This is the simulated light field reflection effect of the semiconductor laser chip when L1 is 40μm and L4 is 30μm;

[0045] Fig.12 This is the simulated light field reflection effect of the semiconductor laser chip when L1 is 50μm and L4 is 25μm;

[0046] Fig.13 The simulated light field reflection effect of the semiconductor laser chip when L1 is 60μm and L4 is 20μm;

[0047] Fig.14 This is the simulated light field reflection effect of the semiconductor laser chip when L1 is 70μm and L4 is 15μm;

[0048] Fig.15 The simulated light field reflection effect of the semiconductor laser chip when L is 100 μm, L4 is 30 μm, and L3 is 5 μm;

[0049] Fig.16 The simulated light field reflection effect of the semiconductor laser chip when L is 100 μm, L4 is 30 μm, and L3 is 10 μm;

[0050] Fig.17 The simulated light field reflection effect of the semiconductor laser chip when L is 100 μm, L4 is 30 μm, and L3 is 20 μm;

[0051] Fig.18 The simulated light field reflection effect of the semiconductor laser chip when L is 100 μm, L4 is 30 μm, and L3 is 30 μm;

[0052] Fig.19 The simulated light field reflection effect of the semiconductor laser chip when L is 100 μm, L4 is 30 μm, and L3 is 40 μm;

[0053] Fig. 20 The simulated light field reflection effect of the semiconductor laser chip when L is 100 μm, L4 is 30 μm, and L3 is 50 μm;

[0054] Fig.21 A schematic structural diagram of a semiconductor laser chip in which a transverse mode reflection region is provided only at a position of a ridge strip close to a rear cavity surface, provided for another embodiment;

[0055] Fig. 22 A schematic structural diagram of a semiconductor laser chip in which transverse mode reflection regions are arranged at positions of ridge strips close to the front cavity surface and the rear cavity surface for another embodiment;

[0056] Fig.23 A schematic structural diagram of a semiconductor laser chip with a convex arc surface structure in a reflection groove wall provided in another embodiment;

[0057] Fig.24A schematic structural diagram of a semiconductor laser chip with a reflective groove wall having a concave arc surface structure provided in another embodiment.

[0058] Icon: 10-semiconductor laser chip; 100-N-type layer structure; 110-N-type substrate; 120-N-type buffer layer; 130-N-type cladding layer; 140-N-type waveguide layer; 200-active layer; 300-P-type layer structure; 310-ridge stripe; 311-front cavity surface; 312-back cavity surface; 320-transverse mode reflection area; 321-reflection groove; 3211-reflection groove wall; 3212-protective groove wall; 330-P-type waveguide layer; 340-P-type cladding layer; 350-P-type contact layer. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions 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. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0060] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0061] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0062] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0063] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0064] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" 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 an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0066] Example

[0067] Please refer to Figure 1 and Figure 2 , Figure 1 FIG. 1 is a schematic structural diagram of a semiconductor laser chip 10 provided in this embodiment at a first viewing angle. Figure 2 A cross-sectional view of the semiconductor laser chip 10 is shown.

[0068] The semiconductor laser chip 10 provided in this embodiment includes an N-type layer structure 100, an active layer 200 and a P-type layer structure 300 which are stacked in sequence. In this embodiment, the N-type layer structure 100 includes an N-electrode layer (not shown in the figure), an N-type substrate 110, an N-type buffer layer 120, an N-type cladding layer 130 and an N-type waveguide layer 140 which are stacked in sequence; the P-type hierarchical structure includes a P-type waveguide layer 330, a P-type cladding layer 340, a P-type contact layer 350 and a P-electrode layer (not shown in the figure) which are stacked in sequence, and the P-type cladding layer 340 and the P-type contact layer 350 form a ridge 310.

[0069] The ridge strip 310 is provided with a transverse mode reflection area 320 at a position close to the cavity surface. The transverse mode reflection area 320 has two reflection grooves 321. The two reflection grooves 321 are respectively provided at opposite sides of the ridge strip 310 in the slow axis direction and are spaced apart in the slow axis direction. The reflection groove 321 has a notch extending in the cavity length direction, a groove bottom opposite to the notch in the slow axis direction, and a reflection groove wall 3211 extending from one end of the notch away from the cavity surface to the groove bottom. The reflection groove wall 3211 gradually approaches the cavity surface in the direction from the notch to the groove bottom, that is, from the notch to the groove bottom, the spacing between the reflection groove wall 3211 and the cavity surface gradually decreases. The cavity surface is arranged close to the reflection groove wall 3211.

[0070] It can be understood that the cavity surface includes a front cavity surface 311 and a rear cavity surface 312 respectively located at two ends in the cavity length direction. For any transverse mode reflection area 320, the cavity surface close to it can be either the front cavity surface 311 or the rear cavity surface 312. In addition, the number of transverse mode reflection areas 320 can be two, one of which is arranged close to the front cavity surface 311, and the remaining one is arranged close to the rear cavity surface 312.

[0071] In this embodiment, whether the reflective groove wall 3211 corresponds to the front cavity surface 311 or the rear cavity surface 312 depends on whether the cavity surface to which the reflective groove 321 is closer is the front cavity surface 311 or the rear cavity surface 312. If the reflective groove 321 is located at the end of the ridge 310 closer to the front cavity surface 311 in the cavity length direction, then the reflective groove wall 3211 corresponds to the front cavity surface 311, that is, the reflective groove wall 3211 gradually approaches the front cavity surface 311 in the direction from the groove opening to the groove bottom; if the reflective groove 321 is located at the end of the ridge 310 closer to the rear cavity surface 312 in the cavity length direction, then the reflective groove wall 3211 corresponds to the rear cavity surface 312, that is, the reflective groove wall 3211 gradually approaches the rear cavity surface 312 in the direction from the groove opening to the groove bottom.

[0072] Due to the refractive index difference between the interior of the reflection groove 321 and the ridge strip 310 body, in practical applications, the reflection groove walls 3211 of the two reflection grooves 321 of the transverse mode reflection area 320 can reflect the light transmitted along the edges of both sides along the cavity length direction back into the resonant cavity, so that the light beam is concentrated along the cavity length direction in the channel area between the two reflection grooves 321. The output of the high-order transverse mode light beam is reduced without almost losing the output energy, thereby achieving the effect of reducing the divergence angle and high brightness output.

[0073] It should be noted that the reflective groove 321 can be formed by wet etching. The reflective groove 321 is spaced apart from the corresponding front cavity surface 311 or rear cavity surface 312 to ensure the structural integrity of the front cavity surface 311 and the rear cavity surface 312, thereby ensuring the coating effect of the front cavity surface 311 and the rear cavity surface 312, thereby avoiding uneven coating of the special-shaped film and causing film peeling.

[0074] Figure 1 The direction indicated by the Z arrow is the fast axis direction, the direction indicated by the Y arrow is the slow axis direction, and the direction indicated by the X arrow is the cavity length direction. It can be understood that the fast axis direction is the stacking direction of each layer structure of the semiconductor laser chip 10, which is perpendicular to the surface of each layer structure of the semiconductor laser chip 10; the slow axis direction is parallel to the surface of each layer structure of the semiconductor laser chip 10, that is, the fast axis direction, the slow axis direction and the cavity length direction are perpendicular to each other.

[0075] Please refer to Figure 3 , Figure 3 FIG. 1 is a schematic structural diagram of the semiconductor laser chip 10 provided in this embodiment at a second viewing angle.

[0076] The position on the ridge strip 310 close to the front cavity surface 311 and the rear cavity surface 312 refers to the front and rear ends of the ridge strip 310 in the cavity length direction. In this embodiment, the transverse mode reflection area 320 is only provided at the position of the ridge strip 310 close to the front cavity surface 311. From the notch of the reflection groove 321 to the bottom of the groove, the distance between the reflection groove wall 3211 and the front cavity surface 311 gradually decreases. In practical applications, a part of the blank area between the transverse mode reflection area 320 and the rear cavity surface 312 on the surface of the ridge strip 310 can be selected as the injection area.

[0077] It can be understood that the two reflection grooves 321 of the transverse mode reflection area 320 are respectively opened on both sides of the ridge strip 310 in the slow axis direction, the groove depth direction of the reflection groove 321 is roughly parallel to the slow axis direction, and the length of the reflection groove 321 extends in the stacking direction, that is, in the fast axis direction. It can be seen that from the groove opening to the groove bottom, the reflection groove 321 extends from the side wall of the ridge strip 310 to the inside of the ridge strip 310, and the reflection groove wall 3211 blocks a part of the front cavity surface 311 in the cavity length direction.

[0078] In this embodiment, the two reflection grooves 321 in the transverse mode reflection area 320 are symmetrically distributed on both sides of the ridge strip 310 in the slow axis direction along a straight line parallel to the cavity length direction. In other words, the gap formed between the two reflection grooves 321 is in the middle area of ​​the ridge strip 310 in the slow axis direction, ensuring that the remaining mode is concentrated in the middle area in the slow axis direction, thereby obtaining a better emission effect.

[0079] It is understandable that the reflection groove 321 is filled with a filler, and the refractive index difference between the filler and the main body of the ridge 310 directly affects the reflection effect of the reflection groove wall 3211, that is, directly affects the output of the high-order transverse mode light beam.

[0080] Preferably, the refractive index of the ridge strip 310 in this embodiment is between 2.5 and 4.0. In this embodiment, the semiconductor laser chip 10 is simulated by fixing the refractive index of the ridge strip 310 at 3.5 and only changing the refractive index of the filler to obtain a variety of simulated light field reflection effect diagrams.

[0081] Please refer to Figures 4 to 8 , Figures 4 to 8 The simulated light field reflection effects are shown when the refractive index of the filler is 1, 1.5, 2, 2.5 and 3. Figure 4 , Figure 5 and Figure 6 The light field reflection effect shown is better, the multi-transverse mode light beams are effectively reduced to four, and there is no light beam leakage from the reflection groove 321 . Figure 7 and Figure 8 The light field reflection effect shown is poor, and there are light beams leaking from the reflection groove 321 .

[0082] Preferably, the difference between the refractive index of the ridge 310 and the refractive index of the filler is greater than 1, and the refractive index of the filler is less than the refractive index of the ridge 310 and greater than one quarter of the refractive index of the ridge 310 to improve the light field reflection effect.

[0083] In practical applications, the filler in the reflection groove 321 can be adjusted according to the actual application conditions to obtain a better light field reflection effect. For example, the filler can be air, silicon oxide, silicon nitride, etc.

[0084] The reflective groove 321 also has a protective groove wall 3212 extending from the groove opening to the groove bottom. The protective groove wall 3212 and the reflective groove wall 3211 form the reflective groove 321. The protective groove wall 3212 is opposite to the corresponding front cavity surface 311 or the rear cavity surface 312 in the cavity length direction. In order to prevent the corresponding front cavity surface 311 or the rear cavity surface 312 from overheating, the protective groove wall 3212 is parallel to the corresponding front cavity surface 311 or the rear cavity surface 312. That is, in this embodiment, the protective groove wall 3212 is opposite to and parallel to the front cavity surface 311 in the cavity length direction.

[0085] Please continue reading Figure 3 ,exist Figure 3 In the figure, the dimension of the ridge 310 in the slow axis direction is defined as L, the spacing between the two reflection grooves 321 in the transverse mode reflection zone 320 in the slow axis direction is L1, and the spacing between the reflection groove 321 and the corresponding front cavity surface 311 or rear cavity surface 312 in the cavity length direction is L2, that is, in this embodiment, the spacing between the reflection groove 321 and the front cavity surface 311 is L2, the groove width dimension of the reflection groove 321 in the cavity length direction is L3, and the groove depth dimension of the reflection groove 321 in the slow axis direction is L4.

[0086] It can be understood that L=L1+2L4. In this embodiment, preferably, the dimension L of the ridge 310 in the slow axis direction is in the range of 50μm~2000μm. In addition, the distance L2 between the end of the reflective groove wall 3211 away from the groove and the front cavity surface 311 in the cavity length direction is in the range of 20μm~80μm. Or the distance L2 between the protective groove wall 3212 and the front cavity surface 311 is in the range of 20μm~80μm.

[0087] In this embodiment, the semiconductor laser chip 10 is simulated by fixing the dimension L of the ridge strip 310 in the slow axis direction to 100 μm and only changing the spacing L1 of the two reflection grooves 321 in the slow axis direction and the groove depth L4 of the reflection groove 321 in the slow axis direction. Figures 9 to 14 Various simulated light field reflection effect diagrams are shown.

[0088] in, Fig. 9 The corresponding L1 is 20 μm and L4 is 40 μm; Fig.10The corresponding L1 is 30 μm and L4 is 35 μm; Fig.11 The corresponding L1 is 40 μm and L4 is 30 μm; Fig.12 The corresponding L1 is 50 μm and L4 is 25 μm; Fig.13 The corresponding L1 is 60 μm and L4 is 20 μm; Fig.14 The corresponding L1 is 70μm and L4 is 15μm.

[0089] Fig.11 The number of reduced transverse modes is reduced to 4, and the effect is ideal. As L1 increases, the number of residual modes of the light field at the center increases, which means that the number of output light field modes increases, the near-field spot size will increase significantly, and will indirectly affect the emission angle width, thereby affecting the beam quality. Since the module is mostly used for fiber transmission, it is limited by the maximum NA angle that the fiber can accept. The best ideal state is the number of modes allowed by the multimode fiber. As for why it is not limited to single mode, it is limited by how high the power density is after compression into single mode. The coating on the front and rear cavity surfaces is difficult to meet this requirement, which can easily cause device failure. Therefore, compression into single mode is not considered. In view of the above reasons, we currently recommend retaining 4 modes.

[0090] Preferably, in this embodiment, the distance between the two reflection grooves 321 in the transverse mode reflection region 320 in the slow axis direction is less than or equal to one third of the size of the ridge stripe 310 in the slow axis direction, that is, L1≤1 / 3L.

[0091] Preferably, the depth of the reflective groove 321 in the slow axis direction is greater than one tenth of the dimension of the ridge stripe 310 in the slow axis direction and less than two fifths of the dimension of the ridge stripe 310 in the slow axis direction. That is, 0.1L<L4<0.4L.

[0092] In this embodiment, the semiconductor laser chip 10 is simulated by fixing the dimension L of the ridge strip 310 in the slow axis direction to 100 μm, fixing the groove depth dimension L4 of the reflection groove 321 in the slow axis direction to 30 μm, and only changing the groove width dimension L3 of the two reflection grooves 321 in the cavity length direction. Figures 15 to 20 Various simulated light field reflection effect diagrams are shown.

[0093] Please combine the adoption month Figures 15 to 20 , Figures 15 to 20 The simulated light field reflection effects when the slot width L3 is 5 μm, 10 μm, 20 μm, 30 μm, 40 μm and 50 μm are shown in sequence.

[0094] The length of L1 directly affects the transmission distance of reflected light. In practical applications, it is necessary to design it in combination with the actual reliability of the device. While ensuring that all light is reflected back to the center, it is also necessary to ensure that the number of interference points in the diagram is as small as possible, and the injection energy is directly related to the injection area. Therefore, L3 is ensured to be as small as possible while meeting the light reflection requirements.

[0095] Fig.16 The effect shown is the best, and preferably, the width of the reflective groove 321 in the cavity length direction is greater than half of the groove depth of the reflective groove 321 and less than twice the groove depth of the reflective groove 321. That is, 0.5L4<L3<2L4.

[0096] In practical applications, L3 should be determined according to the number of modes. When the number of modes is large, L3 needs to be increased to prevent the reflector from receiving too much light intensity and being unable to return all of it to the original device. When the number of modes is small, L3 can be reduced, the injection area can be increased, and the output light intensity can be increased by increasing the injection power.

[0097] Regarding the length of the reflection groove 321, the reflection groove 321 is opened on the surface of the P-type contact layer 350 on one side of the fast axis direction, and extends to between the side surface of the P-type cladding layer 340 away from the P-type waveguide layer 330 and the side surface of the P-type waveguide layer 330 away from the P-type cladding layer 340 on the other side of the fast axis direction.

[0098] In fact, the refractive index of the P-type waveguide layer 330 is greater than the refractive index of the P-type cladding layer 340. In practical applications, if the difference between the refractive index of the P-type waveguide layer 330 and the refractive index of the P-type cladding layer 340 is less than 0.15, the light field will diffuse from the P-type waveguide layer 330 to the P-type cladding layer 340, and the side of the reflection groove 321 away from the P-type contact layer 350 only needs to extend into the P-type cladding layer 340.

[0099] If the difference between the refractive index of the P-type waveguide layer 330 and the refractive index of the P-type cladding layer 340 is greater than 0.15, the light field will be confined to the P-type waveguide layer 330 , and the side of the reflective groove 321 away from the P-type contact layer 350 needs to extend into the P-type waveguide layer 330 .

[0100] Since the difference between the refractive index of the P-type waveguide layer 330 and the refractive index of the P-type cladding layer 340 is affected by both the material wavelength, if the difference between the refractive index of the P-type waveguide layer 330 and the refractive index of the P-type cladding layer 340 is exactly equal to 0.15, the end of the reflection groove 321 away from the P-type contact layer 350 can be located in either the P-type waveguide layer 330 or the P-type cladding layer 340.

[0101] In this embodiment, the transverse mode reflection area 320 is only provided at the position of the ridge strip 310 close to the front cavity surface 311. In another embodiment, the transverse mode reflection area 320 may also be provided only at the position of the ridge strip 310 close to the rear cavity surface 312, such as Fig.21 As shown; the transverse mode reflection area 320 can also be set at the position of the ridge 310 close to the front cavity surface 311 and the rear cavity surface 312, such as Fig. 22 shown.

[0102] Moreover, in this embodiment, in a plane perpendicular to the fast axis direction, the projection shape of the reflection groove wall 3211 is a straight line, that is, the reflection groove wall 3211 is a planar structure. The protection groove wall 3212 is parallel to the front cavity surface 311 and is also a planar structure. Therefore, in this embodiment, the cross section of the reflection groove 321 defined by the reflection groove wall 3211 and the protection groove wall 3212 is a triangle, that is, from the groove opening to the groove bottom, the groove width of the reflection groove 321 gradually decreases.

[0103] In another embodiment, the reflection groove wall 3211 may also be a convex arc structure, that is, in a plane perpendicular to the fast axis direction, the projection shape of the reflection groove wall 3211 may also be a convex arc shape, such as Fig.23 The reflection groove wall 3211 may also be a concave arc structure, that is, in a plane perpendicular to the fast axis direction, the projection shape of the reflection groove wall 3211 may also be a concave arc shape, such as Fig.24 shown.

[0104] In addition, it should be noted that the semiconductor laser chip 10 provided in this embodiment is GaAs-based, suitable for high-power conditions above the watt level, and the applicable wavelength range is 600nm~1200nm. In other embodiments, it can also be adjusted according to actual application conditions to change the applicable wavelength range. For example, it can be adjusted to 800nm~1200nm, or 1200nm~1800nm, etc.

[0105] In summary, the semiconductor laser chip 10 provided in this embodiment can reduce the output of high-order transverse mode light beams without loss, thereby reducing the divergence angle and achieving high-brightness output.

[0106] In addition, this embodiment also provides a laser, which is equipped with the aforementioned semiconductor laser chip 10. Benefiting from the beneficial effects of the semiconductor laser chip 10, the laser provided by this embodiment has the characteristics of smaller divergence angle and higher output brightness.

[0107] The above description is only a preferred embodiment of the present invention and is 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 chip, characterized in that: The invention comprises an N-type layer structure (100), an active layer (200) and a P-type layer structure (300) which are stacked in sequence, wherein the P-type layer structure (300) has a ridge strip (310), and the ridge strip (310) has a transverse mode reflection region (320) at a position close to a cavity surface; the transverse mode reflection region (320) has two reflection grooves (321) respectively opened on opposite sides of the ridge strip (310) in a slow axis direction, and the reflection grooves (321) are filled with a filler, and the refractive index of the filler is less than the refractive index of the ridge strip (310); The reflection groove (321) comprises a groove opening extending in the cavity length direction, a groove bottom arranged opposite to the groove opening in the slow axis direction, and a reflection groove wall (3211) extending from an end of the groove opening away from the cavity surface to the groove bottom; The reflective groove wall (3211) gradually approaches the cavity surface in the direction from the groove opening to the groove bottom, and the cavity surface is arranged close to the reflective groove wall (3211).

2. The semiconductor laser chip according to claim 1, characterized in that: The two reflection grooves (321) in the transverse mode reflection area (320) are symmetrically distributed along a straight line parallel to the cavity length direction.

3. The semiconductor laser chip according to claim 1, characterized in that: From the slot opening to the slot bottom, the slot width of the reflection slot (321) in the cavity length direction gradually decreases.

4. The semiconductor laser chip according to claim 1, characterized in that: The spacing between the two reflection grooves (321) in the transverse mode reflection region (320) in the slow axis direction is less than or equal to one third of the size of the ridge strip (310) in the slow axis direction.

5. The semiconductor laser chip according to claim 1, characterized in that: The groove depth of the reflection groove (321) in the slow axis direction is greater than one tenth of the dimension of the ridge strip (310) in the slow axis direction, and less than two fifths of the dimension of the ridge strip (310) in the slow axis direction.

6. The semiconductor laser chip according to claim 1, characterized in that: The width dimension of the groove opening of the reflection groove (321) in the cavity length direction is greater than half of the groove depth dimension of the reflection groove (321) in the slow axis direction, and less than twice the groove depth dimension of the reflection groove (321) in the slow axis direction.

7. The semiconductor laser chip according to claim 1, characterized in that: The distance between one end of the reflective groove wall (3211) away from the groove opening and the cavity surface in the cavity length direction is in the range of 20 μm to 80 μm.

8. The semiconductor laser chip according to claim 1, characterized in that: The reflective groove (321) further comprises a protective groove wall (3212) extending from the groove opening to the groove bottom, the protective groove wall (3212) and the reflective groove wall (3211) forming the reflective groove (321), and the protective groove wall (3212) is parallel to the cavity surface.

9. The semiconductor laser chip according to claim 1, characterized in that: In a plane perpendicular to the fast axis direction, the projection shape of the reflection groove wall (3211) is one of a straight line, a convex arc, and a concave arc.

10. The semiconductor laser chip according to claim 1, characterized in that: The P-type layer structure (300) comprises a P-type waveguide layer (330), a P-type cladding layer (340) and a P-type contact layer (350) which are stacked in sequence, and the P-type cladding layer (340) and the P-type contact layer (350) form the ridge strip (310).

11. The semiconductor laser chip according to claim 10, characterized in that: The reflection groove (321) is opened on the surface of the P-type contact layer (350) on one side in the fast axis direction, and extends on the other side in the fast axis direction to between a surface of the P-type cladding layer (340) facing away from the P-type waveguide layer (330) and a surface of the P-type waveguide layer (330) facing away from the P-type cladding layer (340).

12. The semiconductor laser chip according to claim 11, characterized in that: The refractive index of the P-type waveguide layer (330) is greater than the refractive index of the P-type cladding layer (340), and when the difference between the refractive index of the P-type waveguide layer (330) and the refractive index of the P-type cladding layer (340) is less than 0.15, the reflection groove (321) extends into the P-type cladding layer (340); When the difference between the refractive index of the P-type waveguide layer (330) and the refractive index of the P-type cladding layer (340) is greater than 0.15, the reflection groove (321) extends into the P-type waveguide layer (330).

13. The semiconductor laser chip according to claim 1, characterized in that: The refractive index of the filler is greater than one quarter of the refractive index of the ridge (310).

14. The semiconductor laser chip according to claim 13, characterized in that: The difference between the refractive index of the ridge (310) and the refractive index of the filler is greater than 1.

15. The semiconductor laser chip according to claim 13, characterized in that: The filler is at least one of air, silicon oxide and silicon nitride.

16. A laser, characterized in that: Comprising the semiconductor laser chip (10) according to any one of claims 1 to 15.

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