Z-Cavity Surface Emitting Semiconductor Laser

Abstract

The present invention relates to the field of semiconductor laser technology, and in particular to a Z-type cavity surface emitting semiconductor laser, comprising at least two inclined substrates, each of which is provided with an inclined epitaxial structure, the inclined directions of two adjacent inclined epitaxial structures are opposite, the two adjacent inclined epitaxial structures form a Z-type resonant cavity, a spacer layer is provided between the two adjacent inclined epitaxial structures, a reflective coating is provided on the sides of all the inclined epitaxial structures, a reflective structure and a P-type electrode are provided on the top surface of the inclined epitaxial structure at the top, the P-type electrode covers the surface of the inclined epitaxial structure and the non-reflective surface of the reflective structure, and an N-type electrode is provided on the bottom surface of the inclined substrate at the bottom. The present invention can narrow the line width of the laser and increase the output power.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor lasers, and in particular relates to a Z-type cavity surface emitting semiconductor laser. Background Art

[0002] In the field of semiconductor lasers, the linewidth narrowing and mode controllability of VCSEL are crucial to improving signal quality, system stability and frequency modulation. Narrow linewidth can improve spectral purity and reduce coherent noise, thereby improving the accuracy and efficiency of optical communications, sensors, spectroscopy, laser processing, quantum communications and medical applications. These characteristics make VCSELs excellent in high data rate transmission and high-sensitivity detection, promoting the advancement and widespread application of optoelectronic technology. The controllability of mode output makes it possible to select or suppress specific laser modes, avoid interference caused by multi-mode oscillation, and improve the working efficiency of VCSELs.

[0003] In order to achieve narrow line width and mode controllability of VCSEL, an external resonant cavity is usually added to the output end of VCSEL to effectively narrow the line width. By adjusting the parameters of the external resonant cavity, the output mode of the laser can be selected and controlled. However, this method does not improve the laser output power, and the parameters are determined after the device is prepared, and the mode adjustability is poor. Summary of the invention

[0004] In view of this, the present invention aims to provide a Z-cavity surface emitting semiconductor laser to solve the technical problems that increasing the external resonant cavity pressure to narrow the line width cannot increase the laser output power and the mode adjustability is poor.

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0006] A Z-type cavity surface emitting semiconductor laser comprises at least two inclined substrates, each of which is provided with an inclined epitaxial structure, the inclined directions of two adjacent inclined epitaxial structures are opposite, the two adjacent inclined epitaxial structures form a Z-type resonant cavity, a spacing layer is provided between the two adjacent inclined epitaxial structures, a reflective coating is provided on the side surfaces of all the inclined epitaxial structures, a reflective structure and a P-type electrode are provided on the top surface of the inclined epitaxial structure at the top, the P-type electrode covers the surface of the inclined epitaxial structure and the non-reflective surface of the reflective structure, and an N-type electrode is provided on the bottom surface of the inclined substrate at the bottom.

[0007] Furthermore, a reflective coating is provided on the reflective surface of the reflective structure.

[0008] Furthermore, the reflective structure is a pseudo-prism, one surface of the pseudo-prism is used as a reflective surface, and the other surfaces of the pseudo-prism are used as non-reflective surfaces.

[0009] Furthermore, the pseudo-prism is a pyramid, a prism, a prism or a wedge.

[0010] Furthermore, each inclined epitaxial structure includes, from bottom to top, an inclined N-type DBR layer, an inclined active layer, an inclined oxide layer and an inclined P-type DBR layer, and an oxidation hole is formed inside the inclined oxide layer.

[0011] Furthermore, the diameter of the oxidation holes of each inclined epitaxial structure is different.

[0012] Furthermore, the diameter of the oxide holes in the inclined epitaxial structure gradually increases from top to bottom.

[0013] Furthermore, the reflective structure is made of a deformable material, and the deformable material is an electroactive polymer or a conductive polymer.

[0014] Furthermore, the electroactive polymer is polyurethane or polyimide, and the conductive polymer is polyaniline or polypyrimidine.

[0015] Furthermore, the isolation layer is made of a deformable material or a microelectronic device filling material, the deformable material is polyurethane, polyimide, polyaniline or polypyrimidine, and the microelectronic device filling material is BCB or epoxy resin.

[0016] Compared with the prior art, the invention can achieve the following beneficial effects:

[0017] (1) The resonant cavity is set to a Z-shape, which extends the propagation path of the laser and increases the effective cavity length of the resonant cavity, thereby achieving line width narrowing and power improvement of the laser.

[0018] (2) The material of each tilted epitaxial structure can be different, forming different laser modes, thereby realizing multi-modal output of the laser.

[0019] (3) The isolation layer uses deformable materials, which can further control the cavity length of the Z-type resonant cavity, thereby achieving mode adjustment and beam quality optimization.

[0020] (4) The reflective structure uses deformable materials, which can control the light emission direction of the laser.

[0021] (5) The Z-type resonant cavity can utilize a larger surface area for heat exchange with the surrounding environment, effectively dissipating the generated heat.

[0022] (6) By controlling the size of the oxide holes of each inclined epitaxial structure, the size of the oxide holes gradually increases from top to bottom, thereby achieving layer-by-layer filtering of the laser mode and improving the quality of the laser mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0024] Figure 1 2 is a schematic structural diagram of a Z-type cavity surface emitting semiconductor laser according to Embodiment 1 of the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of the Z-type cavity surface emitting semiconductor laser described in Example 2 of the present invention.

[0026] Description of reference numerals:

[0027] A first inclined substrate 1, a first inclined epitaxial structure 2, a first inclined N-type DBR layer 21, a first inclined active layer 22, a first inclined oxide layer 23, a first inclined P-type DBR layer 24, a first inclined oxide hole 25, a second inclined substrate 3, a second inclined epitaxial structure 4, a second inclined N-type DBR layer 41, a second inclined active layer 42, a second inclined oxide layer 43, a second inclined P-type DBR layer 44, a second inclined oxide hole 45, a spacer layer 5, a reflective structure 6, a P-type electrode 7, an N-type electrode 8, a first reflective coating 9, and a second reflective coating 10. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying 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 a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0031] In the description of the 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 indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0032] The present invention will be described in detail below with reference to the drawings and in combination with embodiments.

[0033] Example 1

[0034] like Figure 1 As shown, the present invention creates an embodiment 1 that provides a Z-type cavity surface emitting semiconductor laser, including a first inclined substrate 1, a first inclined epitaxial structure 2, a second inclined substrate 3, a second inclined epitaxial structure 4, a spacer layer 5, a reflective structure 6, a P-type electrode 7, an N-type electrode 8, a first reflective coating 9 and a second reflective coating 10; wherein the first inclined epitaxial structure 2 is deposited on the top surface of the first inclined substrate 1, the spacer layer 5 is deposited on the top surface of the first inclined epitaxial structure 2, the second inclined substrate 3 is deposited on the top surface of the spacer layer 5, and the second inclined epitaxial structure 4 is deposited on the top surface of the spacer layer 5. The inclined epitaxial structure 4 is deposited on the top surface of the second inclined substrate 3, the reflective structure 6 and the P-type electrode 7 are deposited on the top surface of the second inclined epitaxial structure 4, the N-type electrode 8 is deposited on the bottom surface of the first inclined epitaxial structure 2, the first inclined substrate 1, the first inclined epitaxial structure 2, the second inclined substrate 3, the second inclined epitaxial structure 4, the spacer layer 5, the reflective structure 6, the P-type electrode 7, and the N-type electrode 8 constitute a laser as a whole, the first reflective coating 9 is deposited on the side of the laser, and the second reflective coating 10 is deposited on the reflective surface of the reflective structure 6.

[0035] The bottom surface of the first inclined substrate 1 is a plane, and the top surface is an inclined surface. The first inclined epitaxial structure 2 is deposited on the top surface of the first inclined substrate 1, and the spacer layer 5 is used to fill the upper surface of the first inclined epitaxial structure 2. Then, the second inclined substrate 3 is deposited on the upper surface of the spacer layer 5, and the second inclined epitaxial structure 4 is deposited on the second inclined substrate 3.

[0036] The first inclined epitaxial structure 2 includes, from bottom to top, a first inclined N-type DBR layer 21 , a first inclined active layer 22 , a first inclined oxide layer 23 , and a first inclined P-type DBR layer 24 . A first inclined oxide hole 25 is formed inside the first inclined oxide layer 23 .

[0037] The second inclined epitaxial structure 4 includes from bottom to top a second inclined N-type DBR layer 41 , a second inclined active layer 42 , a second inclined oxide layer 43 , and a second inclined P-type DBR layer 44 , and a second inclined oxide hole 45 is formed inside the second inclined oxide layer 43 .

[0038] Since the first inclined epitaxial structure 2 and the second inclined epitaxial structure 4 are inclined in opposite directions, the first inclined N-type DBR layer 21 and the first inclined P-type DBR layer 24 of the first inclined epitaxial structure 2 and the second inclined N-type DBR layer 41 and the second inclined P-type DBR layer 44 of the second inclined epitaxial structure 4 form a folding reflector, that is, according to the propagation path of the laser, the resonant cavity of the laser is a Z-type resonant cavity.

[0039] The Z-type resonant cavity design allows the propagation path of the laser to be extended. This design achieves a longer cavity length in a limited space, thereby increasing the output power of the laser and narrowing the line width of the laser.

[0040] The Z-type resonant cavity can utilize a larger surface area for heat exchange with the surrounding environment, effectively dissipating the generated heat. In this way, the laser can maintain a lower operating temperature during long-term operation, thereby improving reliability and service life and reducing performance degradation due to overheating.

[0041] The design of the Z-type resonant cavity structure allows for a more compact modular layout, which is easy to integrate with optical fibers, optical waveguides or other optical components. This simplified integration can significantly reduce the complexity and manufacturing costs of the system, and adapt to the requirements of modern optoelectronic devices for miniaturization and high performance. The flexibility of the manufacturing process, the Z-type cavity design may allow a variety of material selection and configuration during the manufacturing process to meet different technical requirements. For example, the cavity performance can be optimized through different reflector materials and coatings to improve the efficiency and stability of the laser.

[0042] The apertures of the first inclined oxidation hole 25 and the second inclined oxidation hole 45 may be the same or different. When the aperture of the first inclined oxidation hole 25 is larger than the aperture of the second inclined oxidation hole 45, the laser mode is filtered to improve the quality of the laser mode.

[0043] The first inclined epitaxial structure 2 and the second inclined epitaxial structure 4 can adopt the same material system or different material systems. When the same material system is adopted, the output power of the laser can be increased, and when different material systems are adopted, multi-wavelength output can be achieved.

[0044] The first reflective coating 9 is used to reflect the laser light to ensure that the laser light is emitted from the surface of the laser.

[0045] The reflective structure 6 is a pseudo-prism, such as a pyramid, a prism, a prism or a wedge, one surface of the pseudo-prism is used as the reflective surface of the reflective structure 6, and the other surfaces of the pseudo-prism are used as non-reflective surfaces of the reflective structure 6. The second reflective coating 10 is deposited on the reflective surface of the reflective structure 6 to change the light emitting direction of the laser so that the laser emits light perpendicular to the surface of the laser.

[0046] In order to achieve the regulation of the light emission direction of the laser, the reflective structure 6 is made of a deformable material, which includes but is not limited to electroactive polymers and conductive polymers. Electroactive polymers are materials that can change shape and size under the action of an electric field, such as polyurethane and polyimide, which can be deformed when an electric field is applied. Conductive polymers are materials that change shape and size after an electric current is applied, such as polyaniline and polypyrimidine, which expand or shrink in volume after an electric current is applied.

[0047] When the reflective structure 6 is made of deformable material, the P-type electrode 7 covers the top surface of the second inclined epitaxial structure 4 and the non-reflective surface of the reflective structure 6. The P-type electrode 7 should be closely attached to the non-reflective surface of the reflective structure 6. The contraction or relaxation of the reflective structure 6 is controlled by controlling the magnitude of the injected current, thereby adjusting the inclination angle of the reflective surface of the reflective structure 6, and then changing the light emitting direction of the laser. When the reflective structure 6 is made of non-deformable material, the P-type electrode 7 may not be in electrical contact with the reflective structure 6.

[0048] The first reflective coating 9 and the second reflective coating 10 are made of materials having a light beam reflection function such as AlGaAs / GaAs / TiO.

[0049] The spacer layer 5 can be made of deformable material or microelectronic device filling material. When the spacer layer 5 is made of microelectronic device filling material (such as BCB or epoxy resin), the spacer layer 5 only plays a filling role. When the spacer layer 5 is made of deformable material (such as polyurethane, polyimide, polyaniline or polypyrimidine), the contraction or relaxation of the spacer layer 5 is controlled by controlling the size of the injected current, and the cavity length of the Z-type resonant cavity is further regulated, thereby achieving mode regulation and beam quality optimization.

[0050] Z-cavity surface emitting semiconductor lasers are suitable for existing VCSEL material systems, but are not limited to GaAs, GaN, InP, etc.

[0051] The method for preparing a Z-type cavity surface emitting semiconductor laser comprises the following steps:

[0052] S1: a first inclined N-type DBR layer 21 , a first inclined active layer 22 , a first inclined oxide layer 23 , and a first inclined P-type DBR layer 24 are sequentially deposited on the top surface of the first inclined substrate 1 to form a first inclined epitaxial structure 2 .

[0053] S2: performing mesa etching on the first inclined epitaxial structure 2 and performing side oxidation to form a first inclined oxidation hole 25 .

[0054] S3 : depositing a spacer layer 5 on the top surface of the first inclined epitaxial structure 2 .

[0055] S4 : depositing a second inclined substrate 3 on the top surface of the spacer layer 5 .

[0056] S5: a second inclined N-type DBR layer 41 , a second inclined active layer 42 , a second inclined oxide layer 43 , and a second inclined P-type DBR layer 44 are sequentially deposited on the top surface of the second inclined substrate 3 to form a second inclined epitaxial structure 4 .

[0057] S6: performing mesa etching on the second inclined epitaxial structure 4 and performing side oxidation to form a second inclined oxidation hole 45 .

[0058] S7: depositing a first reflective coating 9 on the side surfaces of the first inclined substrate 1 , the first inclined epitaxial structure 2 , the second inclined substrate 3 , the second inclined epitaxial structure 4 , and the spacer layer 5 as a whole.

[0059] S8 : depositing a reflective structure 6 and a P-type electrode 7 on the top surface of the second inclined P-type DBR layer 44 , and depositing a second reflective coating 10 on the reflective surface of the reflective structure 6 .

[0060] S9: Thinning and polishing the bottom surface of the first inclined substrate 1 , and then depositing an N-type electrode 8 .

[0061] Example 2

[0062] like Figure 2 As shown, the difference between the Z-type cavity surface emitting semiconductor laser provided by Example 2 of the present invention and Example 1 is that the number of Z-type resonant cavities of the laser is different. Example 2 has two Z-type resonant cavities, which further extends the propagation path of the laser compared with Example 1, so that the effective cavity length of the Z-type resonant cavity is further increased, and higher laser power and narrower laser line width can be achieved.

[0063] Similarly, more inclined epitaxial structures can be stacked according to demand to form multiple Z-type resonant cavities. Each inclined epitaxial structure can use different material systems to output different laser modes, ultimately achieving multi-modal output of the same laser. By controlling the oxidation time and temperature of the oxide layer, the size of the oxide hole of each inclined epitaxial structure can be controlled so that the size of the oxide hole gradually increases from top to bottom, achieving layer-by-layer filtering of the laser mode and improving the quality of the laser mode.

[0064] The structural design of multiple Z-type resonant cavities can achieve a longer cavity length within the limited space of the laser, which is beneficial to improving the beam quality and mode controllability of the laser. It also has many advantages such as simple manufacturing process, high stability, good heat dissipation, and strong integration, providing a new design idea for the new laser structure.

[0065] Due to the above advantages, Z-type cavity surface emitting semiconductor lasers have a wide range of applications. In laser communications, Z-type cavity surface emitting semiconductor lasers can provide high-power and high-quality laser output, which is suitable for long-term data transmission needs. In medical equipment, Z-type cavity surface emitting semiconductor lasers can be used to generate accurate wavelengths and modes to achieve efficient optical imaging or treatment. In industrial sensors, through efficient multi-modal output, Z-type cavity surface emitting semiconductor lasers can support multiple sensing modes and improve measurement accuracy and reliability.

[0066] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0067] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A Z-cavity surface emitting semiconductor laser, characterized in that: The invention comprises at least two inclined substrates, each of which is provided with an inclined epitaxial structure, the inclined directions of two adjacent inclined epitaxial structures are opposite, the two adjacent inclined epitaxial structures form a Z-type resonant cavity, a spacer layer is provided between the two adjacent inclined epitaxial structures, a reflective coating is provided on the side surfaces of all the inclined epitaxial structures, a reflective structure and a P-type electrode are provided on the top surface of the inclined epitaxial structure at the top, the P-type electrode covers the surface of the inclined epitaxial structure and the non-reflective surface of the reflective structure, and an N-type electrode is provided on the bottom surface of the inclined substrate at the bottom.

2. The Z-cavity surface emitting semiconductor laser according to claim 1, characterized in that: A reflective coating is arranged on the reflective surface of the reflective structure.

3. The Z-cavity surface emitting semiconductor laser according to claim 1 or 2, characterized in that: The reflective structure is a pseudo-cylindrical body, one surface of the pseudo-cylindrical body is used as a reflective surface, and the other surfaces of the pseudo-cylindrical body are used as non-reflective surfaces.

4. The Z-cavity surface emitting semiconductor laser according to claim 3, characterized in that: A pseudo-prism is a pyramid, a prism, a prism or a wedge.

5. The Z-cavity surface emitting semiconductor laser according to claim 1, characterized in that: Each inclined epitaxial structure includes, from bottom to top, an inclined N-type DBR layer, an inclined active layer, an inclined oxidation layer and an inclined P-type DBR layer, and oxidation holes are formed inside the inclined oxidation layer.

6. The Z-cavity surface emitting semiconductor laser according to claim 5, characterized in that: The diameter of the oxide pores in each inclined epitaxial structure is different.

7. The Z-cavity surface emitting semiconductor laser according to claim 6, characterized in that: The diameter of the oxide holes in the inclined epitaxial structure gradually increases from top to bottom.

8. The Z-cavity surface emitting semiconductor laser according to claim 1, characterized in that: The reflective structure is made of a deformable material, and the deformable material is an electroactive polymer or a conductive polymer.

9. The Z-cavity surface emitting semiconductor laser according to claim 8, characterized in that: The electroactive polymer is polyurethane or polyimide, and the conductive polymer is polyaniline or polypyrimidine.

10. The Z-cavity surface emitting semiconductor laser according to claim 1, characterized in that: The isolation layer is made of a deformable material or a microelectronic device filling material. The deformable material is polyurethane, polyimide, polyaniline or polypyrimidine. The microelectronic device filling material is BCB or epoxy resin.

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