Semiconductor laser and optical apparatus

Abstract

The application discloses a semiconductor laser and an optical device. The semiconductor laser comprises a substrate, a first Bragg mirror located on one side of the substrate, a first barrier layer located on the side of the first Bragg mirror away from the substrate, an active layer located on the side of the first barrier layer away from the substrate, a second barrier layer located on the side of the active layer away from the substrate, and a second Bragg mirror located on the side of the second barrier layer away from the substrate, wherein the second Bragg mirror comprises at least one current diffusion layer; the first Bragg mirror and the second Bragg mirror are both N-type Bragg mirrors; one of the first barrier layer and the second barrier layer is a P-type barrier layer; and the semiconductor laser further comprises a first tunnel junction located between the N-type Bragg mirror and the P-type barrier layer. By arranging the at least one current diffusion layer in the second Bragg mirror of the semiconductor laser, the diffusion effect of the current is improved, and the uniformity of the current injection is ensured.

Description

Technical Field

[0001] This invention relates to the field of semiconductor laser technology, and more particularly to a semiconductor laser and optical device. Background Technology

[0002] A semiconductor laser (Vertical Cavity Surface Emitting Laser, or VCSEL) uses two highly reflective distributed Bragg reflectors (DBRs) formed on the top and bottom of the active region, with the laser beam emitted perpendicularly along the epitaxial growth direction of the material. However, in conventional semiconductor laser structures, to improve the uniformity of P-type carrier (hole) injection, a highly doped P-type GaAs or AlGaAs current diffusion layer is often introduced near the top surface to allow holes to diffuse rapidly laterally. When the emission aperture of the semiconductor laser is relatively large, the low mobility of the highly doped P-type carriers leads to insufficient current diffusion, resulting in uneven emission and severely affecting the light output performance. Summary of the Invention

[0003] This invention provides a semiconductor laser and optical device to improve the uniformity of current injection and the uniformity of light output in the semiconductor laser.

[0004] In a first aspect, the present invention provides a semiconductor laser, comprising:

[0005] Substrate;

[0006] A first Bragg reflector is located on one side of the substrate;

[0007] The first barrier layer is located on the side of the first Bragg mirror away from the substrate;

[0008] The active layer is located on the side of the first barrier layer away from the substrate;

[0009] The second barrier layer is located on the side of the active layer away from the substrate;

[0010] A second Bragg reflector is located on the side of the second barrier layer away from the substrate, and the second Bragg reflector includes at least one current diffusion layer.

[0011] Both the first and second Bragg reflectors are type N Bragg reflectors;

[0012] One of the first barrier layer and the second barrier layer is a P-type barrier layer;

[0013] It also includes a first tunnel junction, located between the N-type Bragg reflector and the P-type barrier layer.

[0014] Optionally, one of the first barrier layer and the second barrier layer is an N-type barrier layer;

[0015] The semiconductor laser also includes a first oxide layer located in the second barrier layer.

[0016] Optionally, the semiconductor laser further includes a third Bragg reflector located between the first barrier layer and the first tunnel junction or between the second barrier layer and the first tunnel junction, wherein the third Bragg reflector is a P-type Bragg reflector.

[0017] Optionally, the semiconductor laser may further include a second oxide layer located within the third Bragg mirror.

[0018] Optionally, a second tunnel junction is located on the side of the second Bragg mirror away from the substrate, and a fourth Bragg mirror is located on the side of the second tunnel junction away from the substrate; the fourth Bragg mirror is a P-type Bragg mirror.

[0019] Optionally, the first tunnel junction or the second tunnel junction includes a P-type heavily doped tunnel junction film layer and an N-type heavily doped tunnel junction film layer, wherein the doping concentration of the P-type heavily doped tunnel junction film layer is in the range of 5 × 10⁻⁶. 18 ~4×10 20 cm -3 The doping concentration of the N-type highly doped tunnel junction layer ranges from 5 × 10⁻⁶. 18 ~4×10 20 cm -3 .

[0020] Optionally, the material of the current diffusion layer includes at least one of GaAs, AlGaAs, GaInAs, AlGaInAs, GaAsP, AlGaAsP, GaInAsP, GaInP, or AlGaInP, and the doping element of the current diffusion layer includes at least one of tellurium, silicon, or germanium.

[0021] Optionally, the doping concentration M of the current diffusion layer is M≥5×10¹⁸cm⁻³.

[0022] Optionally, the number of current diffusion layers is n, and the thickness of each current diffusion layer is h, where 1≤n≤30 and 5≤h≤1000nm.

[0023] In a second aspect, the present invention provides an optical device comprising the semiconductor laser described in any one of the first aspects.

[0024] The technical solution of this invention includes a semiconductor laser comprising: a substrate; a first Bragg reflector located on one side of the substrate; a first barrier layer located on the side of the first Bragg reflector away from the substrate; an active layer located on the side of the first barrier layer away from the substrate; a second barrier layer located on the side of the active layer away from the substrate; a second Bragg reflector located on the side of the second barrier layer away from the substrate, the second Bragg reflector including at least one current diffusion layer; a first tunnel junction located between the current diffusion layer and the second barrier layer; both the first and second Bragg reflectors are N-type Bragg reflectors; one of the first and second barrier layers is a P-type barrier layer; and the invention further includes a first tunnel junction located between the N-type Bragg reflector and the P-type barrier layer. By providing at least one current diffusion layer in the second Bragg reflector of the semiconductor laser, the current diffusion effect is improved, and the uniformity of current injection is ensured.

[0025] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a semiconductor laser provided in an embodiment of the present invention;

[0028] Figure 2 An optical field distribution diagram of a semiconductor laser provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of another semiconductor laser provided in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of another semiconductor laser provided in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of another semiconductor laser provided in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of another semiconductor laser provided in an embodiment of the present invention;

[0033] Figure 7This is a schematic diagram of another semiconductor laser provided in an embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the structure of an optical device provided in an embodiment of the present invention. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0036] Figure 1 This is a schematic diagram of the structure of a semiconductor laser provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the semiconductor laser 100 includes: a substrate 101; a first Bragg mirror 102 located on one side of the substrate 101; a first barrier layer 103 located on the side of the first Bragg mirror 102 away from the substrate 101; an active layer 104 located on the side of the first barrier layer 103 away from the substrate 101; a second barrier layer 105 located on the side of the active layer 104 away from the substrate 101; a second Bragg mirror 106 located on the side of the second barrier layer 105 away from the substrate 101, the second Bragg mirror 106 including at least one current diffusion layer 107; both the first Bragg mirror 102 and the second Bragg mirror 106 are N-type Bragg mirrors; one of the first barrier layer 103 and the second barrier layer 105 is a P-type barrier layer; and a first tunnel junction 108 located between the N-type Bragg mirror and the P-type barrier layer.

[0037] The substrate 101 can be the material used to form the laser, typically an N-type material such as gallium arsenide. All the films of the semiconductor laser 100 are grown on the substrate 101. One side of the substrate 101 includes at least a stacked first Bragg mirror 102, a first barrier layer 103, an active layer 104, a second barrier layer 105, a second Bragg mirror 106, and at least one current diffusion layer 107 located within the second Bragg mirror 106. Both the first and second Bragg mirrors 102 and 106 are N-type Bragg mirrors, which can be doped with tellurium, tin, or selenium to form highly reflective films. In contrast, in the prior art, the top Bragg mirror is a P-type Bragg mirror with a highly doped P-type current diffusion layer. Highly doped P-type mirrors have low carrier mobility, typically less than 100 cm⁻¹. 2The thickness of the P-type highly doped current diffusion layer ( / Vs) results in slow current diffusion. If the P-type highly doped current diffusion layer is thin, the current diffusion effect is poor. Increasing the thickness of the P-type highly doped current diffusion layer, however, leads to a higher absorption intensity of the P-type material compared to the N-type material, increasing light absorption, energy loss, and reducing output power and efficiency. Especially when the aperture of the semiconductor laser 100 is relatively large, insufficient current diffusion can cause uneven light emission, resulting in a dark center and bright edges. In the second Bragg reflector 106, which is an N-type Bragg reflector, the corresponding current diffusion layer 107 is an N-type highly doped current diffusion layer. The base material for current diffusion is typically GaAs or AlGaAs. The carrier mobility of the N-type highly doped current diffusion layer is typically greater than 1000 cm⁻¹. 2 / Vs is more conducive to improving the current diffusion effect and ensuring the uniformity of current injection. The arrangement of the first barrier layer 103 and the second barrier layer 105 is beneficial to improving the quality of the active layer 104 and improving the recombination efficiency of electrons and holes; the active layer 104 is an electron accumulation site, which improves the recombination efficiency of electrons and holes. For example, Figure 1 Taking a semiconductor laser 100 as an example, an example is provided where a substrate 101, a first Bragg mirror 102, a first barrier layer 103, an active layer 104, a second barrier layer 105, a first tunnel junction 108, a second Bragg mirror 106, and three current diffusion layers 107 disposed in the second Bragg mirror 106 are all N-type highly doped current diffusion layers. Since both the first Bragg mirror 102 and the second Bragg mirror 106 are N-type Bragg mirrors, this is an exemplary embodiment. Figure 1 In this structure, the first barrier layer 103 is an N-type barrier layer, and the second barrier layer 105 is a P-type barrier layer. The corresponding first tunnel junction 108 is located in front of the P-type second barrier layer 105 and the N-type second Bragg reflector 106, and its structure includes at least two layers: a P-type highly doped tunnel junction film layer 10 near the substrate 101 and an N-type highly doped tunnel junction film layer 11 away from the substrate 101. The doping concentration of the P-type highly doped tunnel junction film layer 10 ranges from 5 × 10⁻⁶. 18 ~4×10 20 cm -3 The doping concentration of the N-type highly doped tunnel junction layer 11 ranges from 5 × 10⁻⁶. 18 ~4×10 20 cm -3The specific doping concentration can be selected according to actual design requirements, and this embodiment of the invention does not impose specific limitations. The electron current output from the outside and uniformly diffused by the current diffusion layer 107 is converted into hole current after passing through the first tunnel junction 108, and then injected into the active layer 104. At the same time, the electron current output by the second Bragg reflector 106 is also injected into the active layer 104. The hole current and electron current recombine in the active region to generate radiation in the infrared or visible spectrum range, thereby achieving light emission. Figure 2 An optical field distribution diagram of a semiconductor laser provided for an embodiment of the present invention, as shown below. Figure 2 As shown, the first tunnel junction 108 and the current diffusion layer 107 are typically located at the trough of the optical field to reduce the optical loss of the semiconductor device and thus ensure the light output performance of the semiconductor device. The current diffusion direction in the current diffusion layer 107 is parallel to the active layer 104, meaning that the current diffusion direction in the current diffusion layer 107 extends from the current injection site of the current diffusion layer 107 to the light emission overlap site of the light emission region of the current diffusion layer 107 located in the active layer 104. The vertical projections of the current injection site and the light emission overlap site in the active layer 104 do not overlap. Therefore, the electrical signal input to the outside can flow to the active layer 104 through the conductivity of the current diffusion layer 107, thereby generating laser light. While achieving the current injection function, when the light emission aperture of the semiconductor laser 100 is large, the current diffusion layer 107 effectively diffuses the light, ensuring the energy conversion efficiency and beam quality of the semiconductor laser 100 and avoiding the phenomenon of dark light emission in the center and bright light emission at the edges.

[0038] In this embodiment of the invention, a current diffusion layer is provided on at least one side of the second Bragg reflector to ensure uniform current diffusion. At the same time, a first tunnel junction is provided between the current diffusion layer and the second barrier layer. The specific structure of the first tunnel junction is selected according to the specific film properties of the first and second barrier layers, thereby ensuring the conversion between electron current and hole current. When both the first and second Bragg reflectors are N-type Bragg reflectors, the circuit injection uniformity in the semiconductor laser 100 is ensured, thereby ensuring the light output effect.

[0039] Optional, continue to refer to Figure 1A first oxide layer 109 is additionally formed in the second barrier layer 105. The first oxide layer 109 can grow a layer of AlGaAs with a high aluminum content in the original second barrier layer 105, and then oxidize most of the film layer, retaining the central region of the original composition, thereby forming an effective light-emitting region for the light beam emitted from the active layer 104. Since both the first Bragg reflector 102 and the second Bragg reflector 106 are N-type Bragg reflectors, a first tunnel junction 108 needs to be introduced between the second barrier layer 105 and the second Bragg reflector 106. The side away from the second barrier layer 105 and close to the second Bragg reflector 106 is an N-type highly doped tunnel junction film layer 11, and the side close to the second barrier layer 105 and away from the second Bragg reflector 106 is a P-type highly doped tunnel junction film layer 10. The externally output electron current is converted into hole current after passing through the N-type highly doped tunnel junction film layer 11 and the P-type highly doped tunnel junction film layer 10 in sequence. Then, it combines with the electron current injected on the side of the first Bragg reflector 102 and the first barrier layer 103 in the active layer 104 to realize light emission.

[0040] Optional, Figure 3 This is a schematic diagram of another semiconductor laser provided in an embodiment of the present invention. Figure 3 and Figure 1 The structures are similar, except that the first barrier layer 103 is a P-type barrier layer and the second barrier layer 105 is an N-type barrier layer; the semiconductor laser 100 also includes a first tunnel layer 108 located between the N-type first Bragg reflector 102 and the P-type first barrier layer 103.

[0041] Among them, such as Figure 3As shown, the semiconductor laser 100 comprises, in sequence, a substrate 101, a first Bragg mirror 102, a first tunnel layer 108, a first barrier layer 103, an active layer 104, a second barrier layer 105, a second Bragg mirror 106, a first oxide layer 109 located in the second barrier layer 105, and three current diffusion layers 107 disposed in the second Bragg mirror 106. The current diffusion layers 107 are all N-type highly doped current diffusion layers. The first barrier layer 103 is a P-type barrier layer, the second barrier layer 105 is an N-type barrier layer, and the first oxide layer 109 is used to form an effective light-emitting region for the beam emitted from the active layer 104. The first tunnel layer 108 is located between the first Bragg reflector 102 and the first barrier layer 103. Specifically, the surface of the first tunnel layer 108 away from the substrate 101 is in contact with the surface of the first barrier layer 103 near the substrate 101, and the surface of the first tunnel layer 108 near the substrate 101 is in contact with the surface of the first Bragg reflector 102 away from the substrate 101. The first Bragg reflector 102 is an N-type Bragg reflector. In this case, the first tunnel layer 108 comprises at least two layers: an N-type highly doped tunnel junction layer 11 near the substrate 101 and a P-type highly doped tunnel junction layer 10 away from the substrate 101. The doping concentration of the P-type highly doped tunnel junction layer 10 and the N-type highly doped tunnel junction layer 11 can be selected according to… Figure 1 The doping concentration of the films in the first tunnel junction 108 is the same to reduce the complexity of the process. The specific doping concentration can be selected according to the actual design requirements, and this embodiment of the invention does not impose a specific limitation. The electron current output from one side of the first Bragg reflector 102 is converted into hole current through the first tunnel layer 108 and then injected into the active layer 104. At the same time, the electron current input from one side of the second Bragg reflector 106 is uniformly diffused through the current diffusion layer 107 and then injected into the active layer 104. The hole current and electron current combine in the active layer 104 to achieve light emission. By reasonably setting the N-type highly doped current diffusion layer 107, uniform light output of the semiconductor laser 100 is ensured.

[0042] Continue to refer to Figure 1 and Figure 3 When the second barrier layer 105 is a P-type barrier layer, the first tunnel junction 108 is located between the N-type second Bragg reflector 106 and the second barrier layer 105; when the first barrier layer 103 is a P-type barrier layer, the first tunnel junction 108 is located between the first barrier layer 103 and the N-type first Bragg reflector 102; that is, the first tunnel junction 108 is located between the N-type Bragg reflector and the P-type barrier layer.

[0043] Optional, Figure 4 A schematic diagram of another semiconductor laser provided in an embodiment of the present invention is shown below. Figure 4As shown, the first barrier layer 103 is an N-type barrier layer, and the second barrier layer 105 is a P-type barrier layer; the semiconductor laser 100 also includes a third Bragg mirror 110 located on the side of the second barrier layer 105 away from the substrate 101 and on the side of the first tunnel junction 108 close to the substrate 101, and a second oxide layer 111 located in the third Bragg mirror 110. The third Bragg mirror 110 is a P-type Bragg mirror.

[0044] Among them, such as Figure 4 As shown, the semiconductor laser 100 comprises, in sequence, a substrate 101, a first Bragg mirror 102, a first barrier layer 103, an active layer 104, a second barrier layer 105, a third Bragg mirror 110, a first tunnel junction 108, a second Bragg mirror 106, a second oxide layer 111 located in the third Bragg mirror 110, and three current diffusion layers 107 disposed in the second Bragg mirror 106. All current diffusion layers 107 are N-type highly doped current diffusion layers. The first barrier layer 103 is an N-type barrier layer, the second barrier layer 105 is a P-type barrier layer, the fourth Bragg mirror 112 is a P-type Bragg mirror, and the first tunnel junction 108 is located between the third Bragg mirror 110 and the second Bragg mirror 106 (while the third Bragg mirror 104...). 10 is located between the first tunnel junction 108 and the second barrier layer 105, that is, the surface of the first tunnel junction 108 away from the substrate 101 is in contact with the surface of the second Bragg mirror 106 near the substrate 101, and the surface of the first tunnel junction 108 near the substrate 101 is in contact with the surface of the third Bragg mirror 110 away from the substrate 101. The second Bragg mirror 106 is an N-type Bragg mirror, and the third Bragg mirror 110 is a P-type Bragg mirror. At this time, the first tunnel junction 108 includes at least two layers, including a P-type highly doped tunnel junction film layer 10 near the substrate 101 and an N-type highly doped tunnel junction film layer 11 away from the substrate 101. The doping concentration of the P-type highly doped tunnel junction film layer 10 and the N-type highly doped tunnel junction film layer 11 can be selected according to the... Figure 1The doping concentration of the films in the first tunnel junction 108 is the same to reduce the complexity of the process. The specific doping concentration can be selected according to the actual design requirements, and this embodiment of the invention does not impose a specific limitation. The electron current injected through one side of the second Bragg reflector 106 is uniformly diffused through the current diffusion layer 107, and then converted into hole current through the first tunnel junction 108, and then injected into the active layer 104. At the same time, the electron current injected through one side of the first Bragg reflector 102 is injected into the active layer 104. The hole current and the electron current combine in the active layer 104 to achieve light emission. The semiconductor laser 100 is equipped with a third Bragg reflector 110, and the first tunnel junction 108 is positioned away from the second barrier layer 105. In this case, the first tunnel junction 108 is far away from the active layer 104, which can effectively reduce the absorption of light energy by the first tunnel junction 108. At the same time, since the film structure in the first tunnel junction 108 is highly doped, it can prevent the highly doped impurities in the first tunnel junction 108 from diffusing into the active layer 104, affecting the binding effect of electron current and hole current in the active layer 104, and thus affecting the light output effect of the semiconductor laser 100.

[0045] Optional, Figure 5 This is a schematic diagram of another semiconductor laser provided in an embodiment of the present invention. Figure 5 and Figure 4 The structures are similar, except that the first barrier layer 103 is a P-type barrier layer and the second barrier layer 105 is an N-type barrier layer; the semiconductor laser 100 also includes a first oxide layer 109 located in the second barrier layer 105, a third Bragg reflector 110 located between the first Bragg reflector 102 and the first barrier layer 103, and a first tunnel junction 108 located between the third Bragg reflector 110 and the first Bragg reflector 102, wherein the third Bragg reflector 110 is a P-type Bragg reflector.

[0046] Among them, such as Figure 5As shown, the semiconductor laser 100 comprises, in sequence, a substrate 101, a first Bragg mirror 102, a first tunnel junction 108, a third Bragg mirror 110, a first barrier layer 103, an active layer 104, a second barrier layer 105, a second Bragg mirror 106, a first oxide layer 109 located in the second barrier layer 105, and three current diffusion layers 107 disposed in the second Bragg mirror 106. The current diffusion layers 107 are all N-type highly doped current diffusion layers, the first barrier layer 103 is a P-type barrier layer, and the second barrier layer 105 is an N-type barrier layer. The third Bragg reflector 110 is a P-type Bragg reflector, the second Bragg reflector 106 is an N-type Bragg reflector, and the first tunnel junction 108 is located between the third Bragg reflector 110 and the second Bragg reflector 106 (while the third Bragg reflector 110 is located between the first barrier layer 103 and the first tunnel junction 108). Specifically, the surface of the first tunnel junction 108 away from the substrate 101 is in contact with the surface of the third Bragg reflector 110 near the substrate 101, and the surface of the first tunnel junction 108 near the substrate 101 is in contact with the surface of the first Bragg reflector 102 away from the substrate 101. The first Bragg reflector 102 is an N-type Bragg reflector. In this case, the first tunnel junction 108 includes at least two layers: an N-type highly doped tunnel junction film layer 11 near the substrate 101 and a P-type highly doped tunnel junction film layer 10 away from the substrate 101. The doping concentration of the P-type highly doped tunnel junction film layer 10 and the N-type highly doped tunnel junction film layer 11 can be selected according to… Figure 1 The doping concentration of the films in the first tunnel junction 108 is the same to reduce the complexity of the process. The specific doping concentration can be selected according to the actual design requirements, and this embodiment of the invention does not impose a specific limitation. The electron current input through the first Bragg reflector 102 is converted into the hole current of the conversion layer after passing through the first tunnel junction 108 and injected into the active layer 104. At the same time, the electron current output through the second Bragg reflector 106 is uniformly diffused through the current diffusion layer 107 and injected into the active layer 104. At this time, the hole current and the electron current combine in the active layer 104 to achieve light emission. At the same time, the setting of the N-type highly doped current diffusion layer 107 ensures uniform light output of the semiconductor laser 100. At this time, a third Bragg reflector 110 is provided in the semiconductor laser 100, and the first tunnel junction 108 is located away from the first barrier layer 103. At this time, the first tunnel junction 108 is far away from the active layer 104, which can effectively reduce the absorption of light energy by the first tunnel junction 108. At the same time, since the film structure in the first tunnel junction 108 is highly doped, it can prevent the highly doped impurities in the first tunnel junction 108 from diffusing to the active layer 104, affecting the combination effect of electron current and hole current in the active layer 104, and thus affecting the light output effect of the semiconductor laser 100.

[0047] Continue to refer to Figure 4-5When the second barrier layer 105 is a P-type barrier layer and the third Bragg reflector 110 is a P-type Bragg reflector, the third Bragg reflector 110 is located between the first tunnel junction 108 and the second barrier layer 105; when the first barrier layer 103 is a P-type barrier layer and the third Bragg reflector 110 is a P-type Bragg reflector, the third Bragg reflector 110 is located between the first barrier layer 103 and the first tunnel junction 108; that is, the third Bragg reflector 110 is located between the first tunnel junction 108 and the P-type barrier layer.

[0048] Optional, Figure 6 A schematic diagram of another semiconductor laser provided in an embodiment of the present invention is shown below. Figure 6 As shown, the semiconductor laser 100 also includes a second tunnel junction 112 located on the side of the second Bragg mirror 106 away from the substrate 101 and a fourth Bragg mirror 113 located on the side of the second tunnel junction 112 away from the substrate 101; the fourth Bragg mirror 113 is a P-type Bragg mirror.

[0049] Among them, such as Figure 6 As shown, the semiconductor laser 100 comprises, in sequence, a substrate 101, a first Bragg mirror 102, a first barrier layer 103, an active layer 104, a second barrier layer 105, a first tunnel junction 108, a second Bragg mirror 106, a second tunnel junction 112, a fourth Bragg mirror 113, a first oxide layer 109 disposed in the second barrier layer 105, and three current diffusion layers 107 disposed in the second Bragg mirror 106. The first barrier layer 103 is an N-type barrier layer, the second barrier layer 105 is a P-type barrier layer, and the current diffusion layers 107 are all N-type highly doped current diffusion layers. The fourth Bragg mirror 113 is a P-type Bragg mirror. The second tunnel junction 112... Located between the fourth Bragg reflector 113 and the second Bragg reflector 106, the surface of the second tunnel junction 112 away from the substrate 101 is in contact with the surface of the fourth Bragg reflector 113 near the substrate 101, and the surface of the second tunnel junction 112 near the substrate 101 is in contact with the surface of the second Bragg reflector 106 away from the substrate 101. The second Bragg reflector 106 is an N-type Bragg reflector. In this case, the second tunnel junction 112 comprises at least two layers: an N-type highly doped tunnel junction film layer 11 near the substrate 101 and a P-type highly doped tunnel junction film layer 10 away from the substrate 101. The doping concentration of the P-type highly doped tunnel junction film layer 10 ranges from 5 × 10⁻⁶. 18 ~4×10 20 cm -3 The doping concentration of the N-type highly doped tunnel junction layer 11 ranges from 5 × 10⁻⁶. 18 ~4×10 20 cm -3The doping concentration can be the same as that of the film layer in the first tunnel junction 108 to reduce the complexity of the process. The specific doping concentration can be selected according to the actual design requirements, and this embodiment of the invention does not impose a specific limitation. When the hole current injected from the side of the fourth Bragg reflector 113 is converted into an electron current through the second tunnel junction 112, and this electron current is diffused through the current diffusion layer 107 and then converted back into a hole current through the first tunnel junction 108 and injected into the active layer 104, while the electron current is injected into the active layer 104 through the first Bragg reflector 102, the hole current and the electron current combine in the active layer 104 to achieve light emission and ensure the uniformity of light emission of the semiconductor laser 100. At the same time, in the structure of this semiconductor laser 100, a fourth Bragg reflector 113 is introduced on the side away from the substrate 101. The fourth Bragg reflector 113 is a P-type Bragg reflector. Therefore, in the fabrication process of the semiconductor laser 100, the P-type ohmic metal can be kept unchanged without subsequent replacement with N-type ohmic metal, and the fabrication process of conventional semiconductor lasers in the prior art can be carried out, reducing the difficulty of the fabrication process and reducing the manufacturing cost.

[0050] Figure 7 A schematic diagram of another semiconductor laser provided in an embodiment of the present invention is shown below. Figure 7 As shown, Figure 7 and Figure 6 The structures are similar, but the difference lies in that the first barrier layer 103 is a P-type barrier layer, the second barrier layer 105 is an N-type barrier layer, and the first tunnel junction 108 is disposed between the first barrier layer 103 and the first Bragg reflector 102. The semiconductor laser 100 sequentially stacks a substrate 101, a first Bragg reflector 102, a first tunnel junction 108, a first barrier layer 103, an active layer 104, a second barrier layer 105, a second Bragg reflector 106, a second tunnel junction 112, and a fourth Bragg reflector 113. A first oxide layer 109 is disposed in the second barrier layer 105, and a three-layer current diffusion layer 107 is disposed in the second Bragg reflector 106. The first tunnel layer 108 is located at the first... Between the Bragg reflector 102 and the first barrier layer 103, that is, the surface of the first tunnel layer 108 away from the substrate 101 is in contact with the surface of the first barrier layer 103 near the substrate 101, and the surface of the first tunnel layer 108 near the substrate 101 is in contact with the surface of the first Bragg reflector 102 away from the substrate 101. The first Bragg reflector 102 is an N-type Bragg reflector. At this time, the first tunnel layer 108 includes at least two layers, including an N-type highly doped tunnel junction layer 11 near the substrate 101 and a P-type highly doped tunnel junction layer 10 away from the substrate 101. The doping concentration of the P-type highly doped tunnel junction layer 10 and the N-type highly doped tunnel junction layer 11 can be selected according to the... Figure 6The doping concentration of the films in the first tunnel junction 108 is the same to reduce the complexity of the process. The specific doping concentration can be selected according to the actual design requirements, and this embodiment of the invention does not impose a specific limitation. The electron current output from one side of the first Bragg reflector 102 is converted into hole current through the first tunnel layer 108 and then injected into the active layer 104. At the same time, the hole current injected from one side of the fourth Bragg reflector 113 is converted into electron current through the second tunnel junction 112. This electron current is diffused through the current diffusion layer 107 and then injected into the active layer 104. The hole current and electron current combine in the active layer 104 to achieve light emission.

[0051] Continue to refer to Figure 6 and Figure 7 When the second barrier layer 105 is a P-type barrier layer, the first tunnel junction 108 is located between the N-type second Bragg reflector 106 and the second barrier layer 105; when the first barrier layer 103 is a P-type barrier layer, the first tunnel junction 108 is located between the first barrier layer 103 and the N-type first Bragg reflector 102; that is, the first tunnel junction 108 is located between the N-type Bragg reflector and the P-type barrier layer.

[0052] Optionally, the material of the current diffusion layer 107 includes at least one of GaAs, AlGaAs, GaInAs, AlGaInAs, GaAsP, AlGaAsP, GaInAsP, GaInP, or AlGaInP, and the doping element of the current diffusion layer 107 includes at least one of tellurium, silicon, or germanium.

[0053] In the above embodiments, the current diffusion layer 107 is an N-type highly doped current diffusion layer, which is doped with at least one of tellurium, silicon, or germanium in GaAs, AlGaAs, GaInAs, AlGaInAs, GaAsP, AlGaAsP, GaInAsP, GaInP, or AlGaInP. By reasonably controlling the doping concentration, an N-type highly doped current diffusion layer 107 is formed. Compared with a P-type highly doped current diffusion layer 107, the N-type highly doped current diffusion layer 107 has a higher carrier mobility, which is usually greater than 1000 cm2 / Vs. For a semiconductor laser 100 with an N-type highly doped current diffusion layer 107, the current injection uniformity in the semiconductor laser 100 is effectively improved, ensuring the light output effect.

[0054] Optionally, the doping concentration M of the current diffusion layer 107 is M ≥ 5 × 10⁻⁶. 18 cm -3 .

[0055] The doping concentration of the current diffusion layer 107 is typically greater than or equal to 5 × 10⁻⁶. 18 cm -3In the semiconductor laser 100, the doping concentration of the current diffusion layer 107 can be alternated between high doping concentration and low doping concentration to form multiple high doping concentration films with spacing, thereby reducing the manufacturing cost while ensuring the current diffusion effect of the current diffusion layer 107.

[0056] Optionally, the number of current diffusion layers 107 is n, and the thickness of each current diffusion layer 107 is h, where 1≤n≤30 and 5≤h≤1000nm.

[0057] Among them, exemplary Figure 1 The current diffusion layer 107 is shown in three layers. The number of layers and the thickness of the current diffusion layer 107 can be selected according to actual design requirements. This embodiment of the invention does not impose specific limitations. By reasonably setting the number of layers and the thickness of each current diffusion layer 107, the diffusion effect of the current in the current diffusion layer 107 can be guaranteed, as well as the uniformity of current injection, thereby ensuring the uniformity of light emission of the semiconductor laser 100.

[0058] Figure 8 This is a schematic diagram of the structure of an optical device provided in an embodiment of the present invention, such as... Figure 8 As shown, the optical device includes the semiconductor laser 100 as described in any of the above embodiments.

[0059] Optical devices may include multiple arrays of semiconductor lasers 100 to achieve a large area light output effect. The optical devices have the same or similar technical effects as the semiconductor lasers 100 in the above embodiments, and will not be described in detail again.

[0060] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A semiconductor laser, characterized in that, include: Substrate; A first Bragg reflector is located on one side of the substrate; The first barrier layer is located on the side of the first Bragg mirror away from the substrate; The active layer is located on the side of the first barrier layer away from the substrate; The second barrier layer is located on the side of the active layer away from the substrate; A second Bragg reflector is located on the side of the second barrier layer away from the substrate, and the second Bragg reflector includes at least one current diffusion layer. Both the first and second Bragg reflectors are type N Bragg reflectors; One of the first barrier layer and the second barrier layer is a P-type barrier layer; It also includes a first tunnel junction located between the N-type Bragg reflector and the P-type barrier layer; when the second barrier layer is a P-type barrier layer, the first tunnel junction is located between the second Bragg reflector and the second barrier layer; when the first barrier layer is a P-type barrier layer, the first tunnel junction is located between the first barrier layer and the first Bragg reflector. Both the first tunnel junction and the current diffusion layer are located at the trough of the optical field, and the diffusion direction of the current in the current diffusion layer is parallel to the active layer. One of the first barrier layer and the second barrier layer is an N-type barrier layer; The semiconductor laser also includes a first oxide layer located in the second barrier layer; The first tunnel junction includes a P-type heavily doped tunnel junction film layer and an N-type heavily doped tunnel junction film layer, wherein the doping concentration of the P-type heavily doped tunnel junction film layer is in the range of 5 × 10⁻⁶. 18 ~4×10 20 cm -3 The doping concentration of the N-type highly doped tunnel junction layer ranges from 5 × 10⁻⁶. 18 ~4×10 20 cm -3 ; The at least one current diffusion layer is an N-type current diffusion layer; The material of the current diffusion layer includes at least one of GaAs, AlGaAs, GaInAs, AlGaInAs, GaAsP, AlGaAsP, GaInAsP, GaInP, or AlGaInP, and the doping element of the current diffusion layer includes at least one of tellurium, silicon, or germanium. The doping concentration M of the current diffusion layer is M≥5×10 18 cm -3 The current diffusion layer comprises a plurality of highly doped film layers spaced apart; The number of current diffusion layers is n, and the thickness of each current diffusion layer is h, where 1≤n≤30, 5≤h≤1000nm; The first oxide layer is used to form an effective light-emitting region for the light beam emitted from the active layer; The semiconductor laser further includes a third Bragg reflector located between the first barrier layer and the first tunnel junction or between the second barrier layer and the first tunnel junction, wherein the third Bragg reflector is a P-type Bragg reflector; when the second barrier layer is a P-type barrier layer and the third Bragg reflector is a P-type Bragg reflector, the third Bragg reflector is located between the first tunnel junction and the second barrier layer; when the first barrier layer is a P-type barrier layer and the third Bragg reflector is a P-type Bragg reflector, the third Bragg reflector is located between the first barrier layer and the first tunnel junction. The semiconductor laser also includes a second oxide layer located within the third Bragg mirror.

2. The semiconductor laser according to claim 1, characterized in that, The semiconductor laser further includes a second tunnel junction located on the side of the second Bragg mirror away from the substrate and a fourth Bragg mirror located on the side of the second tunnel junction away from the substrate; the fourth Bragg mirror is a P-type Bragg mirror.

3. The semiconductor laser according to claim 2, characterized in that, The second tunnel junction includes a P-type heavily doped tunnel junction film layer and an N-type heavily doped tunnel junction film layer, wherein the doping concentration of the P-type heavily doped tunnel junction film layer is in the range of 5 × 10⁻⁶. 18 ~4×10 20 cm -3 The doping concentration of the N-type highly doped tunnel junction layer ranges from 5 × 10⁻⁶. 18 ~4×10 20 cm -3 .

4. An optical device, characterized in that, Includes the semiconductor laser according to any one of claims 1-3.

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