Semiconductor laser and method for preparing semiconductor laser

Abstract

The present invention relates to the field of laser technology, and specifically to a semiconductor laser and a method for preparing a semiconductor laser; the semiconductor laser provided by the present invention comprises a laser chip; at least one of a P-type ohmic contact layer and a P-type electrode layer is not provided in at least one region near the cavity surface of the front cavity surface and the back cavity surface of the laser chip, so that the absorption of the laser reflected back to the cavity surface of the laser chip during optical fiber coupling can be reduced, thereby reducing the thermal effect of the near-cavity surface of the laser chip and improving the reliability of the cavity surface. At the same time, when the wafer is cut and split, since the near-cavity surface is not provided with a P-type ohmic contact layer and / or a P-type electrode layer, the reflection and absorption of light caused by the metal wire drawing extending to the edge of the cavity surface, thereby causing the nonlinear effect of light and the thermal effect, leading to the problem of COMD failure.

Description

Technical Field

[0001] The present invention relates to the technical field of lasers, and in particular to a semiconductor laser and a method for preparing the 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] Optical catastrophic damage to the cavity surface is one of the main factors that limit the maximum output optical power of semiconductor lasers. The laser chip of a semiconductor laser is divided into multiple small chips by cutting and splitting from a large wafer. However, during the above-mentioned cutting process, metal wire drawing is prone to occur during the cutting process. The metal wire drawing extends to the edge of the light-emitting area. A part of the light beam emitted by the laser chip is reflected to the direction of the laser chip through the optical device. When the reflected light is irradiated to the metal wire drawing position, the metal wire drawing reflects and absorbs the reflected light again, causing nonlinear effects and thermal effects of light, and then optical catastrophe of the cavity surface occurs. At the same time, when the light beam reflected back to the laser chip is irradiated to the metal layer of the laser chip, the metal layer has a stronger absorption capacity for the light beam. After the metal layer absorbs the light beam, it will cause the device to heat up, resulting in catastrophic optical damage and thus affecting the reliability of the device and the light output quality of the semiconductor laser. Summary of the invention

[0004] (I) The technical problem to be solved by the present invention is that metal wire drawing and optical catastrophe are prone to occur on the cavity surface of existing semiconductor lasers, which affects the light output quality of the laser.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a semiconductor laser, wherein the semiconductor laser comprises a laser chip, wherein the laser chip comprises a substrate, an N-type cladding layer, an N-type waveguide layer, a quantum well active layer, a P-type waveguide layer, a P-type cladding layer and a P-type ohmic contact layer connected in sequence along a fast axis direction;

[0007] The P-type ohmic contact layer and the P-type cladding layer together form a ridge waveguide, and grooves are arranged on both sides of the ridge waveguide, and the ridge waveguide and the grooves together form a light absorption region;

[0008] Along the cavity length direction of the laser chip, the light absorption region includes two edge sections respectively arranged close to the front cavity surface of the laser chip and the back cavity surface of the laser chip, and a middle section arranged between the two edge sections;

[0009] The edge section does not have at least one of a P-type ohmic contact layer and a P-type electrode layer; the middle section has a P-type ohmic contact layer and a P-type electrode layer.

[0010] According to an embodiment of the present invention, the edge section has neither a P-type ohmic contact layer nor a P-type electrode layer.

[0011] According to an embodiment of the present invention, the width of the ridge waveguide along the slow axis direction is L1; the width of the edge segment along the slow axis direction is L2, and L2 ≥ L1+10 μm.

[0012] According to an embodiment of the present invention, the width L1 of the ridge waveguide along the slow axis direction is greater than 50 μm; and the length of the edge segment along the cavity length direction is 5-50 μm.

[0013] According to an embodiment of the present invention, the width L1 of the ridge waveguide along the slow axis direction is 3-15 μm, and the length of the edge section close to the front cavity surface of the laser chip along the cavity length is 5-100 μm.

[0014] According to one embodiment of the present invention, it also includes a lens arranged on one side of the front cavity surface of the laser chip, and the distance between the front cavity surface of the laser chip and the lens is 3-15μm; the curvature of the lens is 5-9μm; the fast axis divergence angle of the laser chip is 10-30°, and the slow axis divergence angle is 3-20°.

[0015] According to one embodiment of the present invention, a lens is further provided on one side of the front cavity surface of the laser chip, and the reflection spot reflected by the lens to the front cavity surface of the laser chip is elliptical or circular, and the reflection spot at least covers a part of the light absorption area.

[0016] According to an embodiment of the present invention, the height of the reflection light spot extending along the fast axis direction is 15-50 μm, and the width of the reflection light spot along the slow axis direction is 3-7 μm.

[0017] According to an embodiment of the present invention, the laser chip further comprises a dielectric layer, a portion of which is disposed on the P-type ohmic contact layer, and another portion of which is disposed on the P-type cladding layer.

[0018] According to an embodiment of the present invention, the edges on both sides of the edge segment extend to the edge of the groove in the slow axis direction.

[0019] Another aspect of the present invention is to provide a method for preparing a semiconductor laser, comprising:

[0020] Growing an epitaxial film layer on a substrate, wherein the epitaxial film layer includes an N-type cladding layer, an N-type waveguide layer, a quantum well active layer, a P-type waveguide layer, a P-type cladding layer and a P-type ohmic contact layer which are sequentially stacked along a fast axis direction;

[0021] Etching a P-type ohmic contact layer and a P-type cladding layer in sequence to form a groove and a ridge waveguide, wherein the ridge waveguide and the groove together form a light absorption region;

[0022] Wherein, along the cavity length direction of the laser chip, the light absorption region includes two edge sections respectively arranged close to the front cavity surface of the laser chip and the back cavity surface of the laser chip, and a middle section arranged between the two edge sections;

[0023] forming a dielectric layer on the epitaxial film layer;

[0024] A window is opened on the ridge waveguide to remove the dielectric layer on the ridge waveguide structure;

[0025] Evaporating a patterned P-type electrode layer;

[0026] The P-type electrode layer on the edge section is peeled off along the cavity length direction.

[0027] Another aspect of the present invention provides a method for preparing a semiconductor laser, comprising:

[0028] Growing an epitaxial film layer on a substrate, wherein the epitaxial film layer includes an N-type cladding layer, an N-type waveguide layer, a quantum well active layer, a P-type waveguide layer, a P-type cladding layer and a P-type ohmic contact layer which are sequentially stacked along a fast axis direction;

[0029] Etching a P-type ohmic contact layer and a P-type cladding layer in sequence to form a groove and a ridge waveguide, wherein the ridge waveguide and the groove together form a light absorption region;

[0030] Wherein, along the cavity length direction of the laser chip, the light absorption region includes two edge sections respectively arranged close to the front cavity surface of the laser chip and the back cavity surface of the laser chip, and a middle section arranged between the two edge sections;

[0031] Etching and removing the P-type ohmic contact layer in the edge section along the cavity length direction;

[0032] forming a dielectric layer on the epitaxial film layer;

[0033] A window is opened on the ridge waveguide to remove the dielectric layer on the ridge waveguide structure;

[0034] A patterned P-type electrode layer is evaporated.

[0035] Beneficial effects of the present invention: The semiconductor laser provided by the present invention comprises a laser chip, and the laser chip comprises a substrate, an N-type cladding, an N-type waveguide layer, a quantum well active layer, a P-type waveguide layer, a P-type cladding and a P-type ohmic contact layer which are sequentially connected along a fast axis direction; the P-type ohmic contact layer forms a ridge waveguide and grooves arranged on both sides of the ridge waveguide, and the ridge waveguide and the grooves jointly form a light absorption region; at least one of the P-type ohmic contact layer and the P-type electrode layer is not arranged on the two edge sections of the front cavity surface and the back cavity surface of the laser chip, and since the P-type ohmic contact layer and / or the P-type electrode layer formed by the metal are reduced on the near-cavity surface, the absorption of the laser reflected back to the laser chip by the optical fiber module can be reduced, and then the absorption of the laser reflected by the optical fiber module by the metal layer of the laser chip can be reduced, the thermal effect of the near-cavity surface of the laser chip is reduced, and the reliability of the cavity surface is improved. At the same time, when the wafer is cut and split, since no P-type ohmic contact layer and / or P-type electrode layer is set on the near-cavity surface, it is possible to avoid the reflection and absorption of light caused by the metal wire drawing extending to the edge of the cavity surface, thereby causing nonlinear effects of light and thermal effects, leading to COMD failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] 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.

[0037] Figure 1 A schematic diagram of a waveguide cross-section of a laser chip provided by one embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a waveguide cross-section of a laser chip provided in another embodiment of the present invention;

[0039] Figure 3 A schematic cross-sectional view of a waveguide of a laser chip provided in yet another embodiment of the present invention;

[0040] Figure 4 A schematic side view of a laser chip provided by one embodiment of the present invention;

[0041] Figure 5 A schematic top view of a laser chip provided by one embodiment of the present invention;

[0042] Figure 6 A schematic top view of a laser chip provided in accordance with another embodiment of the present invention.

[0043] Icon: 1-laser chip; 11-substrate; 12-N-type cladding; 13-N-type waveguide layer; 14-quantum well active layer; 15-P-type waveguide layer; 16-P-type cladding; 161-ridge waveguide; 162-groove; 163-shoulder; 164-P-type ohmic contact layer; 165-P-type electrode layer; 17-dielectric layer; 18-edge segment; 19-middle segment; 2-lens. DETAILED DESCRIPTION

[0044] 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.

[0045] like Figures 1 to 6 As shown, the present invention provides a semiconductor laser, which includes a laser chip 1, and the laser chip 1 includes a substrate 11, an N-type cladding 12, an N-type waveguide layer 13, a quantum well active layer 14, a P-type waveguide layer 15, a P-type cladding 16 and a P-type ohmic contact layer 164 connected in sequence along a fast axis direction.

[0046] The P-type ohmic contact layer 164 and the P-type cladding layer 16 together form a ridge waveguide 161 and grooves 162 disposed on both sides of the ridge waveguide 161 . The ridge waveguide 161 and the grooves 162 together form a light absorption region.

[0047] Along the cavity length direction of the laser chip 1 , the light absorption region includes two edge segments 18 respectively disposed close to the front cavity surface of the laser chip 1 and the back cavity surface of the laser chip 1 , and a middle segment 19 disposed between the two edge segments 18 .

[0048] The edge section 18 does not have at least one of the P-type ohmic contact layer 164 and the P-type electrode layer 165 . The middle section 19 has the P-type ohmic contact layer 164 and the P-type electrode layer 165 .

[0049] When the laser chip 1 is working, the N-type waveguide layer 13, the quantum well active layer 14 and the P-type waveguide layer 15 emit laser light outward from the cavity surface, of which 60-90% of the laser light is transmitted by the optical fiber; the remaining 10-40% of the light is returned to the laser chip 1 from all directions, and the P-type ohmic contact layer 164, the P-type electrode layer 165 and the quantum well active layer 14 of the laser chip 1 have strong absorption properties for the reflected laser light. The P-type ohmic contact layer 164 and the P-type electrode layer 165 absorb the reflected laser light and heat up, which will cause the temperature of the cavity surface of the laser chip 1 to rise. The increase in the cavity surface temperature will eventually lead to irreversible optical damage, causing nonlinear effects of light and thermal effects, leading to COMD (Catastrophic Optical Mirror Damage).

[0050] The semiconductor laser provided by the present invention comprises a laser chip 1, which comprises a substrate 11, an N-type cladding 12, an N-type waveguide layer 13, a quantum well active layer 14, a P-type waveguide layer 15, a P-type cladding 16 and a P-type ohmic contact layer 164 connected in sequence along a fast axis direction; the P-type ohmic contact layer 164 and the P-type cladding 16 jointly form a ridge waveguide 161, and grooves 162 arranged on both sides of the ridge waveguide 161, and the ridge waveguide 161 and the grooves 162 jointly form a light absorption region; At least one of the P-type ohmic contact layer 164 and the P-type electrode layer 165 is not set in the two edge sections 18 of the front cavity surface and the back cavity surface of the laser chip 1. Since the metal forming the P-type ohmic contact layer 164 and / or the P-type electrode layer 165 is reduced on the near cavity surface, the absorption of the laser reflected back to the laser chip 1 by the optical fiber module can be reduced, thereby reducing the absorption of the laser reflected by the optical fiber module by the metal layer of the laser chip 1, reducing the thermal effect of the near cavity surface of the laser chip 1, and improving the reliability of the cavity surface. At the same time, when the wafer is cut and split, since the P-type ohmic contact layer 164 and / or the P-type electrode layer 165 are not set on the near cavity surface, the reflection and absorption of light caused by the metal wire drawing extending to the edge of the cavity surface can be avoided, thereby causing the nonlinear effect of light and thermal effect, resulting in COMD failure.

[0051] According to one embodiment of the present invention, Figure 2As shown, the edge section 18 is not provided with a P-type ohmic contact layer 164. Since the P-type ohmic contact layer 164 is not provided in the cavity surface area, the absorption of the laser reflected back from the optical fiber component by the P-type ohmic contact layer 164 can be reduced, thereby reducing the heat generated by the P-type ohmic contact layer 164 absorbing the reflected laser, reducing the thermal effect of the laser chip 1 near the cavity surface, and improving the reliability of the cavity surface. In addition, since the P-type ohmic contact layer 164 is not provided in the cavity surface area, during wafer cleavage (when cutting from a large wafer to a small chip), the metal wire generated by the cutting will not extend to the cavity surface area, which can effectively avoid the absorption of the reflected laser by the metal wire extending to the cavity surface, thereby reducing the cavity surface thermal effect and effectively avoiding COMD.

[0052] According to another embodiment of the present invention, Figure 1 As shown, the edge section 18 is not provided with a P-type electrode layer 165. Since the P-type electrode layer 165 is not provided in the cavity surface area, the absorption of the laser reflected back from the optical fiber component by the P-type electrode layer 165 can be reduced, thereby reducing the heat generated by the P-type electrode layer 165 absorbing the reflected laser, reducing the thermal effect of the near-cavity surface of the laser chip 1, and improving the reliability of the cavity surface; at the same time, since the P-type electrode layer 165 is stripped off in the cavity surface area, the metal wires generated by cutting will not extend to the cavity surface area when the wafer is cleaved, which can further reduce the thermal effect of the cavity surface and effectively avoid COMD.

[0053] According to another embodiment of the present invention, Figure 3 As shown, the edge segment 18 is provided with neither a P-type electrode layer 165 nor a P-type ohmic contact layer 164. Since neither a P-type electrode layer 165 nor a P-type ohmic contact layer 164 is provided in the cavity surface area, that is, the metal layer with a relatively high absorption of reflected light is removed in the cavity surface area at the same time, thereby effectively reducing the thermal effect of the cavity surface. At the same time, since the P-type electrode layer 165 and the P-type ohmic contact layer 164 are stripped off in the cavity surface area, when the wafer is cleaved, the metal wires generated by cutting will not extend to the cavity surface area, which can further reduce the thermal effect of the cavity surface and effectively avoid COMD.

[0054] According to an embodiment of the present invention, the two opposite surfaces of the P-type cladding layer 16 along the slow axis direction are convex in a direction away from the P-type waveguide layer 15 to form symmetrical shoulders 163; the ridge waveguide 161 is arranged between the two shoulders 163, and the grooves 162 are respectively formed between the two shoulders 163 and the ridge waveguide 161. Figure 1 , Figure 2 , Figure 4 and Figure 6 As shown, the shoulder 163 may be located at the edge of the laser chip 1 in the slow axis direction; of course, in this embodiment, the shoulder 163 may also be located near the middle region in the slow axis direction.

[0055] In this embodiment, the width of the ridge waveguide 161 is L1; the width of the edge segment 18 along the slow axis direction is L2, L2 ≥ L1 + 10 μm. In this embodiment, because the reflected light spot is wider than the ridge waveguide 161, the P-type electrode layer 165 of the ridge waveguide 161 and the groove 162 near the cavity surface area is peeled off in the slow axis direction. Optionally, in this embodiment, the maximum width of the edge segment 18 can be that its two side edges extend to the edge of the groove 162 in the slow axis direction. According to one embodiment of the present invention, Figure 4 As shown, the width L1 of the ridge waveguide 161 is greater than 50 μm; the length of the edge segment 18 along the cavity length direction is 5-50 μm; the width of the ridge waveguide 161 is greater than 50 μm, which is a wide ridge waveguide 161, and the P-type electrode layer 165 is packaged downward. Affected by the solder, the metal stripping area cannot be too large, that is, the length of the edge segment 18 along the cavity length cannot be too long. Optionally, the length of the edge segment 18 along the cavity length direction is 5-50 μm; preferably, the length of the edge segment 18 along the cavity length direction is 30 μm.

[0056] According to one embodiment of the present invention, Figure 5 As shown, the width L1 of the ridge waveguide 161 is 3-15 μm, and the length of the edge segment 18 along the cavity length close to the front cavity surface of the laser chip 1 is 5-100 μm. The ridge waveguide 161 with a width between 3-15 μm is a narrow ridge waveguide. The narrow ridge waveguide is a package with the P-type electrode layer 165 facing upward. The metal stripping distance can be longer, that is, the stripping length of the edge segment 18 along the cavity length direction can be larger. The preferred stripping length of the edge segment 18 along the cavity length direction is 100 μm. Considering the effect of fiber coupling feedback, in this embodiment, only the metal layer (that is, the P-type electrode layer 165 and the P-type ohmic contact layer 164) of the edge segment 18 close to the front cavity surface area is stripped.

[0057] like Figure 4 As shown, according to one embodiment of the present invention, the semiconductor laser further comprises a lens 2 arranged on one side of the front cavity surface of the laser chip 1, and the reflection spot reflected by the lens 2 to the front cavity surface of the laser chip 1 is elliptical or circular, and the reflection spot at least covers a portion of the light absorption area. Since the edge segment 18 of the light absorption area removes the P-type ohmic contact layer 164 and the P-type electrode layer 165, the absorption of reflected light energy can be reduced, thereby reducing the thermal effect of the near-cavity surface of the laser chip and improving the reliability of the cavity surface.

[0058] Specifically, the distance between the front cavity surface of the laser chip 1 and the lens 2 is 3-15 μm; the curvature of the lens 2 is 5-9 μm, the fast axis divergence angle of the laser chip 1 is 10-30°, and the slow axis divergence angle is 3-20°. Figure 4, since the distribution of the reflected light formed by the reflected light spot is a Gaussian distribution with the quantum well active layer 14 as the symmetric center, the sum of the heights of the quantum well active layer 14, the P-type waveguide layer 15, the P-type cladding layer 16 and the P-type ohmic contact layer 164 is 1-2μm, and the P-type electrode layer 165 is 2-5μm, according to the simulation of the optical simulation software or according to the law of reflection, it can be calculated that the height of the reflected light spot extending along the fast axis direction is 15-50μm, and the width of the reflected light spot along the slow axis direction is 3-7μm. The edge section 18 removes the P-type ohmic contact layer 164 and the P-type electrode layer 165, which can reduce the absorption of the reflected light energy by 30%-60%.

[0059] According to one embodiment of the present invention, the light emitting spot is elliptical, the reflected spot reflected by the lens 2 to the front cavity surface of the laser chip 1 is elliptical, the height of the reflected spot extending along the fast axis direction is 15-50μm, and the width of the reflected spot along the slow axis direction is 3-7μm; preferably, in this embodiment, the height of the reflected spot extending along the fast axis direction is 36μm, and the width of the reflected spot along the slow axis direction is 3μm, wherein in this embodiment, the width of the absorption zone in the slow axis direction is L2=L1+10, L1=3-10μm, so L2=13-20μm, and the width of the reflected spot along the slow axis direction is 3-7μm, so the reflected spot can be completely reflected to the edge segment 18 in the slow axis direction, and since the edge segment 18 is not provided with a metal layer (P-type ohmic contact layer 164 and P-type electrode layer 165), the absorption of the reflected spot energy can be reduced.

[0060] In this embodiment, Figure 4 As shown, the fast axis divergence angle of the laser chip 1 is 16-18°, and the slow axis divergence angle is 3-5°; and the fiber end faces of the laser chip 1 and the lens 2 are coupled at 12°; the reflectivity of the lens 2 decreases as the reflection angle increases. A coupling angle of 0 degrees represents the maximum reflectivity, which is about 4% (1W light, 0.04W (40mw) light is reflected back), and the fiber end faces of the laser chip 1 and the lens 2 in this application are coupled at 12°, so the light reflected back to the waveguide from the fiber surface will be less than 0.1%.

[0061] In this embodiment, the height of the light emitting spot extending along the fast axis direction is 1-4 μm, and the width of the light emitting spot along the slow axis direction is L1+1 μm. Wherein L1 is 2-3 μm, that is, the width of the light emitting spot along the slow axis direction is 3-4 μm. Preferably, the height of the light emitting spot is 1 μm and the width is 3.65 μm. According to another embodiment of the present invention, the height of the light emitting spot is 1 μm and the width is 4 μm.

[0062] According to another embodiment of the present invention, the light output spot emitted by the laser chip 1 is a circular light spot, the reflected light spot reflected by the lens 2 to the front cavity surface of the laser chip 1 is circular, the fast axis divergence angle and the slow axis divergence angle of the circular light output spot are both 20°, and the curvature of the lens 2 is 6-8μm. Preferably, the curvature of the lens 2 is 7μm; the distance between the laser chip 1 and the lens 2 is 10-15μm, and the height of the reflected light spot extending along the fast axis direction is 16-20μm.

[0063] According to one embodiment of the present invention, the laser chip 1 further comprises a dielectric layer 17, a portion of the dielectric layer 17 is disposed on the P-type ohmic contact layer 164, and another portion of the dielectric layer 17 is disposed on the P-type cladding layer 16; Figure 1 As shown, the P-type ohmic contact layer 164 and the P-type cladding layer 16 are sequentially etched to form a groove 162 and a ridge waveguide 161, wherein the P-type ohmic contact layer 164 in the groove 162 region is etched, so that the dielectric layer 17 in the groove 162 region is formed on the surface of the P-type cladding layer 16, and the P-type ohmic contact layer 164 on the shoulder 163 and the ridge waveguide 161 is not etched away, so the dielectric layer 17 corresponding to the shoulder 163 and the ridge waveguide 161 is arranged on the P-type ohmic contact layer 164, wherein the dielectric layer 17 is an insulating layer. Figure 2 and Figure 3 As shown, when the P-type ohmic contact layer 164 of the edge section 18 is removed, there is no P-type ohmic contact layer 164 on the upper side of the ridge waveguide 161 of the edge section 18 , and at this time the dielectric layer 17 is directly disposed on the ridge waveguide 161 .

[0064] Preferably, the sum of the heights of the P-type ohmic contact layer 164 , the dielectric layer 17 and the P-type electrode layer 165 is h, and the length of the edge section 18 along the cavity length direction is greater than h / tanθ, where θ is the fast axis divergence angle of the reflected light spot.

[0065] In one aspect, an embodiment of the present invention provides a method for preparing a semiconductor laser, comprising the following steps: growing an epitaxial film layer on a substrate 11, wherein the epitaxial film layer comprises an N-type cladding layer 12, an N-type waveguide layer 13, a quantum well active layer 14, a P-type waveguide layer 15, a P-type cladding layer 16, and a P-type ohmic contact layer 164 which are sequentially stacked along a fast axis direction; sequentially etching the P-type ohmic contact layer 164 and the P-type cladding layer 16 to form a groove 162 and a ridge waveguide 161, wherein the ridge waveguide 161 and the groove 162 jointly form a light absorption region; wherein, along the cavity length direction of the laser chip 1, the light absorption region comprises the light absorption regions close to the light absorption regions, respectively. Two edge sections 18 are provided on the front cavity surface of the laser chip 1 and the back cavity surface of the laser chip 1, and a middle section 19 is provided between the two edge sections 18; a dielectric layer 17 is formed on the epitaxial film layer, specifically, the dielectric layer 17 corresponding to the shoulder 163 and the ridge waveguide 161 is provided on the P-type ohmic contact layer 164, and the dielectric layer 17 in the groove 162 area is formed on the surface of the P-type cladding 16; a window is opened on the ridge waveguide 161 to remove the dielectric layer 17 on the ridge waveguide 161 structure; a patterned P-type electrode layer 165 is evaporated; and the P-type electrode layer 165 on the edge section 18 is peeled off along the cavity length direction.

[0066] The semiconductor laser manufacturing method provided in this embodiment is used to prepare Figure 1 The semiconductor laser shown in the figure is prepared by the semiconductor laser preparation method provided by the present invention, and the P-type electrode layer 165 is stripped off at the edge section 18 of the cavity surface, so that the absorption of the laser reflected back to the laser chip 1 by the optical fiber module can be reduced, and then the absorption of the laser reflected by the optical fiber module by the metal layer of the laser chip 1 can be reduced, and the thermal effect of the near-cavity surface of the laser chip 1 can be reduced, thereby improving the reliability of the cavity surface. At the same time, when the wafer is cut and split, since the P-type electrode layer 165 is not set on the near-cavity surface, it is possible to avoid the reflection and absorption of light caused by the metal wire drawing extending to the edge of the cavity surface, thereby causing the nonlinear effect of light and thermal effect, leading to the problem of COMD failure.

[0067] In another aspect, an embodiment of the present invention provides a method for preparing a semiconductor laser, comprising the following steps: growing an epitaxial film layer on a substrate 11, the epitaxial film layer comprising an N-type cladding layer 12, an N-type waveguide layer 13, a quantum well active layer 14, a P-type waveguide layer 15, a P-type cladding layer 16 and a P-type ohmic contact layer 164 stacked in sequence along a fast axis direction; etching the P-type ohmic contact layer 164 and the P-type cladding layer 16 in sequence to form a groove 162 and a ridge waveguide 161, wherein the ridge waveguide 161 and the groove 162 together form a light absorption region; wherein, along the cavity length direction of the laser chip 1, the light absorption region comprises two edge sections 18 respectively arranged near the front cavity surface of the laser chip 1 and the back cavity surface of the laser chip 1, and an intermediate section 19 arranged between the two edge sections 18; etching and removing the P-type ohmic contact layer 164 of the edge section 18 in the cavity length direction; forming a dielectric layer 17 on the epitaxial film layer, specifically, as Figure 2 As shown, in this embodiment, the dielectric layer 17 in the groove 162 area is formed on the surface of the P-type cladding 16, the dielectric layer 17 on the corresponding shoulder 163 is arranged on the P-type ohmic contact layer 164, and the P-type ohmic contact layer 164 on the ridge waveguide 161 of the middle section 19 is not removed, so the dielectric layer 17 on the ridge waveguide 161 of the middle section 19 is arranged on the P-type ohmic contact layer 164; and the P-type ohmic contact layer 164 on the upper side of the ridge waveguide 161 on the edge section 18 is removed, so the dielectric layer 17 corresponding to the ridge waveguide 161 of the edge section 18 is directly arranged on the ridge waveguide 161; a window is opened on the ridge waveguide 161 to remove the dielectric layer 17 on the ridge waveguide 161 structure; and a patterned P-type electrode layer 165 is evaporated.

[0068] The semiconductor laser manufacturing method provided in this embodiment is used to prepare Figure 2 The semiconductor laser shown in the figure is prepared by the semiconductor laser preparation method provided by the present invention, and the P-type ohmic contact layer 164 is removed from the edge section 18 of the cavity surface, so that the absorption of the laser reflected from the optical fiber module back to the laser chip 1 by the P-type ohmic contact layer 164 can be reduced, thereby reducing the absorption of the laser reflected from the optical fiber module by the metal layer of the laser chip 1, reducing the thermal effect of the near-cavity surface of the laser chip 1, and improving the reliability of the cavity surface. At the same time, when the wafer is cut and split, since the P-type ohmic contact layer is not set on the near-cavity surface, it is possible to avoid the reflection and absorption of light caused by the metal wire drawing extending to the edge of the cavity surface, and avoid the problem of COMD failure.

[0069] In another aspect, an embodiment of the present invention provides a method for preparing a semiconductor laser, comprising the following steps: growing an epitaxial film layer on a substrate 11, the epitaxial film layer comprising an N-type cladding layer 12, an N-type waveguide layer 13, a quantum well active layer 14, a P-type waveguide layer 15, a P-type cladding layer 16 and a P-type ohmic contact layer 164 stacked in sequence along a fast axis direction; etching the P-type ohmic contact layer 164 and the P-type cladding layer 16 in sequence to form a groove 162 and a ridge waveguide 161, wherein the ridge waveguide 161 and the groove 162 together form a light absorption region; wherein, along the cavity length direction of the laser chip 1, the light absorption region comprises two edge sections 18 respectively arranged near the front cavity surface of the laser chip 1 and the back cavity surface of the laser chip 1, and an intermediate section 19 arranged between the two edge sections 18; etching and removing the P-type ohmic contact layer 164 of the edge section in the cavity length direction; forming a dielectric layer 17 on the epitaxial film layer, specifically, in this embodiment, as Figure 3 As shown, the dielectric layer 17 in the groove 162 area is formed on the surface of the P-type cladding 16, the dielectric layer 17 on the corresponding shoulder 163 is arranged on the P-type ohmic contact layer 164, and the P-type ohmic contact layer 164 on the ridge waveguide 161 of the middle section 19 is not removed, so the dielectric layer 17 on the ridge waveguide 161 of the middle section 19 is arranged on the P-type ohmic contact layer 164; and the P-type ohmic contact layer 164 on the upper side of the ridge waveguide 161 on the edge section 18 is removed, so the dielectric layer 17 corresponding to the ridge waveguide 161 of the edge section 18 is directly arranged on the ridge waveguide 161; a window is opened on the ridge waveguide 161 to remove the dielectric layer 17 on the ridge waveguide 161 structure; a patterned P-type electrode layer 165 is evaporated, and the P-type electrode layer 165 on the edge section 18 is peeled off along the cavity length direction.

[0070] The semiconductor laser manufacturing method provided in this embodiment is used to prepare Figure 3 The semiconductor laser shown in the figure is prepared by the method for preparing a semiconductor laser provided by the present invention, and the P-type ohmic contact layer 164 is removed from the edge section 18 of the cavity surface, and the P-type electrode layer 165 of the edge section 18 is also peeled off at the same time, so that the absorption of the laser reflected from the optical fiber module back to the laser chip 1 by the P-type ohmic contact layer 164 and the P-type electrode layer 165 can be reduced, thereby reducing the absorption of the laser reflected from the optical fiber module by the metal layer of the laser chip 1, reducing the thermal effect of the near-cavity surface of the laser chip 1, and improving the reliability of the cavity surface. At the same time, when the wafer is cut and split, since the P-type ohmic contact layer 164 and the P-type electrode layer 165 are not provided on the near-cavity surface, the reflection and absorption of light caused by the metal wire drawing extending to the edge of the cavity surface can be avoided, and the problem of COMD failure can be avoided.

[0071] In this embodiment, the substrate 11 is made of GaAs or InP material, and the thickness of the substrate 11 is greater than 100 μm; an epitaxial film layer is grown on the substrate 11, and the epitaxial film layer includes an N-type cladding layer 12, an N-type waveguide layer 13, a quantum well active layer, a P-type waveguide layer 15, a P-type cladding layer 16, and a P-type ohmic contact layer 164; the P-type ohmic contact layer 164 and the P-type cladding layer 16 are sequentially etched to form two grooves 162, and the ridge waveguide 161 is formed between the two grooves 162, and the outer sides of the two grooves 162 are shoulders 163. A dielectric layer 17 is formed on the epitaxial film layer, and a window is opened on the ridge waveguide 161, and the dielectric layer 17 on the ridge waveguide 161 structure is removed; then a patterned P-type electrode layer 165 is evaporated. The thickness of the P-type electrode layer 165 is 2-5 μm.

[0072] 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.

[0073] 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.

[0074] 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 semiconductor laser, characterized in that: The semiconductor laser comprises a laser chip (1), wherein the laser chip (1) comprises a substrate (11), an N-type cladding layer (12), an N-type waveguide layer (13), a quantum well active layer (14), a P-type waveguide layer (15), a P-type cladding layer (16), and a P-type ohmic contact layer (164) which are sequentially connected along a fast axis direction; The P-type ohmic contact layer (164) and the P-type cladding layer (16) together form a ridge waveguide (161), and grooves (162) arranged on both sides of the ridge waveguide (161), and the ridge waveguide (161) and the grooves (162) together form a light absorption region; Along the cavity length direction of the laser chip (1), the light absorption region comprises two edge sections (18) respectively arranged close to the front cavity surface of the laser chip (1) and the back cavity surface of the laser chip (1), and a middle section (19) arranged between the two edge sections (18); The edge section (18) does not have at least one of a P-type ohmic contact layer (164) and a P-type electrode layer (165); and the middle section (19) has a P-type ohmic contact layer (164) and a P-type electrode layer (165).

2. The semiconductor laser according to claim 1, characterized in that The edge section (18) has neither a P-type ohmic contact layer (164) nor a P-type electrode layer (165).

3. The semiconductor laser according to claim 1, characterized in that The width of the ridge waveguide (161) along the slow axis direction is L1; the width of the edge section (18) along the slow axis direction is L2, and L2≥L1+10μm.

4. The semiconductor laser according to claim 1, characterized in that The width L1 of the ridge waveguide (161) along the slow axis direction is greater than 50 μm; and the length of the edge section (18) extending along the cavity length direction is 5-50 μm.

5. The semiconductor laser according to claim 1, characterized in that The width L1 of the ridge waveguide (161) along the slow axis direction is 3-15 μm, and the length of the edge section (18) close to the front cavity surface of the laser chip (1) extending along the cavity length direction is 5-100 μm.

6. The semiconductor laser according to claim 1, characterized in that It also comprises a lens (2) arranged on one side of the front cavity surface of the laser chip (1); the distance between the front cavity surface of the laser chip (1) and the lens (2) is 3-15 μm; the curvature of the lens (2) is 5-9 μm; the fast axis divergence angle of the laser chip (1) is 10-30°, and the slow axis divergence angle is 3-20°.

7. The semiconductor laser according to claim 1, characterized in that It also comprises a lens (2) arranged on one side of the front cavity surface of the laser chip (1), wherein the reflection spot reflected by the lens (2) to the front cavity surface of the laser chip (1) is elliptical or circular, and the reflection spot at least covers a part of the light absorption area.

8. The semiconductor laser according to claim 7, characterized in that The height of the reflected light spot extending along the fast axis direction is 15-50 μm, and the width of the reflected light spot along the slow axis direction is 3-7 μm.

9. The semiconductor laser according to any one of claims 1 to 7, characterized in that: The laser chip (1) further comprises a dielectric layer (17), a portion of the dielectric layer (17) being arranged on the P-type ohmic contact layer (164), and another portion of the dielectric layer (17) being arranged on the P-type cladding layer (16).

10. The semiconductor laser according to any one of claims 1 to 7, characterized in that: The edges on both sides of the edge section (18) extend in the slow axis direction to the edge of the groove (162).

11. A method for preparing a semiconductor laser, characterized in that: include: Growing an epitaxial film layer on a substrate (11), the epitaxial film layer comprising an N-type cladding layer (12), an N-type waveguide layer (13), a quantum well active layer (14), a P-type waveguide layer (15), a P-type cladding layer (16), and a P-type ohmic contact layer (164) sequentially stacked along a fast axis direction; Sequentially etching a P-type ohmic contact layer (164) and a P-type cladding layer (16) to form a groove (162) and a ridge waveguide (161), wherein the ridge waveguide (161) and the groove (162) together form a light absorption region; Wherein, along the cavity length direction of the laser chip (1), the light absorption region comprises two edge sections (18) respectively arranged close to the front cavity surface of the laser chip (1) and the back cavity surface of the laser chip (1), and a middle section (19) arranged between the two edge sections (18); forming a dielectric layer (17) on the epitaxial film layer; A window is opened on the ridge waveguide (161), and the dielectric layer (17) on the ridge waveguide (161) structure is removed; Evaporating a patterned P-type electrode layer (165); The P-type electrode layer (165) on the edge section (18) is peeled off along the cavity length direction.

12. A method for preparing a semiconductor laser, characterized in that: include: Growing an epitaxial film layer on a substrate (11), the epitaxial film layer comprising an N-type cladding layer (12), an N-type waveguide layer (13), a quantum well active layer (14), a P-type waveguide layer (15), a P-type cladding layer (16), and a P-type ohmic contact layer (164) sequentially stacked along a fast axis direction; Sequentially etching a P-type ohmic contact layer (164) and a P-type cladding layer (16) to form a groove (162) and a ridge waveguide (161), wherein the ridge waveguide (161) and the groove (162) together form a light absorption region; Wherein, along the cavity length direction of the laser chip (1), the light absorption region comprises two edge sections (18) respectively arranged close to the front cavity surface of the laser chip (1) and the back cavity surface of the laser chip (1), and a middle section (19) arranged between the two edge sections (18); Etching and removing the P-type ohmic contact layer (164) in the edge section along the cavity length direction; forming a dielectric layer (17) on the epitaxial film layer; A window is opened on the ridge waveguide (161), and the dielectric layer (17) on the ridge waveguide (161) structure is removed; A patterned P-type electrode layer (165) is evaporated.

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