Novel horizontal cavity vertical emission laser and array based on inner and outer grating double-mirror

Abstract

The application relates to the technical field of semiconductor lasers, in particular to a novel transverse-cavity vertical-emission laser and array based on an inner-outer grating double-reflector, the novel transverse-cavity vertical-emission laser based on an inner-outer grating double-reflector comprising: a substrate; a quantum well layer arranged on the upper end face of the substrate; a back ridge optical waveguide arranged on the upper end face of the quantum well layer, the right end face of the back ridge optical waveguide is processed into an oblique angle phi, and the left and right end faces of the back ridge optical waveguide are both provided with a high reflectivity HR layer. The application has the following beneficial effects: multi-layer superimposed grating + metal grating electrode cooperation, coupling efficiency is improved to 92%-95% (traditional 85%), line width is narrowed to 2-10 KHz (traditional >=100 KHz), mode suppression ratio >=30 dB; oblique angle mirror surface and double-face HR reflection cooperate, vertical surface emission is realized, and the beam divergence angle is <=8 degrees.

Description

Technical Field

[0001] This invention relates to the field of semiconductor laser technology, specifically to a novel horizontal cavity vertical laser and array based on internal and external grating double mirrors. Background Technology

[0002] DFB lasers, with their narrow linewidth and high stability, have become core light source devices in optical communication and optical computing. However, existing DFB laser and array designs have the following technical problems:

[0003] 1. Limitations of grating function: Traditional DFB only uses a single-layer grating to achieve filtering and mode selection. The effective grating length is limited by the physical size of the device (usually ≤100μm), resulting in a coupling efficiency of ≤85% and a linewidth of ≥10kHz, which is difficult to meet the narrow linewidth requirements of AI computing scenarios.

[0004] 2. End-face processing challenges: Traditional DFB uses a resonant cavity design of "one end HR (high reflection) coating + one end AR (anti-reflection) coating". In two-dimensional array scenarios, the end-face area of ​​a single unit is ≤1000μm². During coating, uneven film thickness and poor consistency are easy to occur, and the coating cost accounts for more than 40% of the total device cost.

[0005] 3. Conflict between emission mode and power: Traditional DFB emits from the end face and needs to be turned by lens group to achieve vertical light output, which increases the complexity of the system; although surface-emitting lasers (such as VCSELs) support vertical emission, due to structural design limitations, the output power of a single unit is ≤10mW, which cannot meet the needs of high-power computing scenarios.

[0006] 4. Lack of synergy between electrodes and gratings: In existing designs, metal electrodes only serve the function of conducting electricity and are separated from the grating structure. Furthermore, the grating edge roughness is ≥10nm, which easily leads to mode loss. The "filtering-coupling-conductivity" synergistic effect is not formed, resulting in a significant loss of light output efficiency.

[0007] 5. Bottlenecks in large-scale production: Traditional processes require individual cutting of the end face of each unit in the two-dimensional array (accuracy requirement ±1μm) and manual application of coating materials. The yield of a single batch of 6-inch wafers is ≤80%, making it difficult to adapt to the manufacturing of large-area arrays with ≥100 units. Summary of the Invention

[0008] The purpose of this invention is to provide a novel horizontal cavity vertical laser based on internal and external grating double mirrors to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A novel horizontal cavity vertical laser based on internal and external grating double mirrors includes:

[0011] Substrate;

[0012] A quantum well layer is disposed on the upper end face of the substrate;

[0013] A back ridge waveguide is disposed on the upper end face of the quantum well layer. The right end face of the back ridge waveguide is processed into an oblique angle φ. Both the left and right end faces of the back ridge waveguide are provided with a high reflectivity HR layer.

[0014] The back ridge waveguide includes at least one DFB grating layer, with a SiO2 cladding layer disposed above the DFB grating layer, and an etched metal grating disposed on the upper surface of the SiO2 cladding layer.

[0015] The etched metal grating includes a first-order grating and a second-order grating serving as passive regions for reflective filtering; the etched metal grating also includes a second-order grating serving as an active region for coupling upward-emitting laser light; the first-order grating and the second-order grating are respectively distributed on the left and right sides of the second-order grating.

[0016] The first first-order grating has a first grating spacing and a first metal electrode on its upper part; the second first-order grating has a second grating spacing and a second metal electrode on its upper part.

[0017] As a preferred embodiment of the above technical solution, the substrate is made of InP or GaAs material with a thickness of 300-500μm.

[0018] As a preferred embodiment of the above technical solution, the quantum well layer is an InGaAsP / InP multi-quantum well structure with 3-5 wells and a single well thickness of 5-8 nm.

[0019] As a preferred embodiment of the above technical solution, the lasing wavelength λ of the quantum well layer is 1310nm or 1550nm.

[0020] As a preferred embodiment of the above technical solution, the grating constant of the second-order grating is twice that of the grating constants of the first-order grating and the second-order grating.

[0021] As a preferred embodiment of the above technical solution, the first grating spacing and the second grating spacing are 0.

[0022] As a preferred embodiment of the above technical solution, the first grating spacing and the second grating spacing are λ / 4.

[0023] As a preferred embodiment of the above technical solution, the oblique angle φ is 10°-26°.

[0024] As a preferred embodiment of the above technical solution, the high reflectivity HR layer is a coating layer or an optical film.

[0025] The present invention also provides a novel horizontal cavity vertical laser array based on internal and external grating double mirrors, which is composed of a matrix distribution of novel horizontal cavity vertical lasers based on internal and external grating double mirrors. The high reflectivity HR layer includes vertical grooves for filling high reflectivity HR coating on the vertical end face of the back ridge waveguide and oblique grooves for filling high reflectivity HR coating on the oblique end face of the back ridge waveguide.

[0026] This invention provides a novel horizontal cavity vertical laser based on internal and external grating double mirrors, which has the following beneficial effects:

[0027] 1. Breakthrough in performance metrics:

[0028] Optical performance: Multi-layer stacked gratings + metal grating electrodes work together to improve coupling efficiency to 92%-95% (traditional 85%), narrow linewidth to 2-10KHz (traditional ≥100KHz), and mode suppression ratio ≥30dB; angled mirrors and double-sided HR reflections work together to achieve vertical surface emission with beam divergence angle ≤8°.

[0029] Electrical performance: Reduced sheet resistance of layered metal electrodes, current distribution uniformity ≥90%, single-unit output power ≥50mW (traditional VCSEL ≤10mW), power attenuation ≤3% from -40℃ to 85℃;

[0030] 2. Cost and process optimization: Reflective coatings replace optical coatings, reducing material costs by 60%; the metal grating electrodes adopt a "one-step evaporation + one-step etching" process, avoiding multi-step alignment errors (alignment accuracy ≤200nm); the processing time of the two-dimensional array end face is shortened to 1 / 3 of the traditional process, and the yield of a single batch of 6-inch wafers is improved to 95%-98%;

[0031] 3. Strong scene adaptability: The multi-layer grating supports flexible adjustment (0 layers adapt to basic scenes, 2-3 layers adapt to high-performance scenes), and the nxm array can be expanded to 8×8 and above to meet the multi-channel optical interconnection requirements of AI computing chips (when the number of channels is ≥32, the optical power consistency deviation is ≤5%).

[0032] 4. High structural stability: After plasma treatment, the reflective coating has an adhesion of ≥50MPa. After 1000 cycles of -40℃ to 85℃, the reflectivity decreases by ≤0.5%, meeting industrial-grade reliability requirements.

[0033] 5. A two-dimensional laser chip array can be constructed using a highly reflective HR coating, eliminating the need for separate slicing and end-face optical coating. This method is simple, low-cost, and solves the problem of difficult HR optical coating on the end face of a two-dimensional array of transverse cavity lasers. Attached Figure Description

[0034] Figure 1This is a schematic diagram of the structure of the novel horizontal cavity vertical laser based on internal and external grating double mirrors in this invention;

[0035] Figure 2 for Figure 1 The left view;

[0036] Figure 3 for Figure 1 Top view;

[0037] Figure 4 This is a schematic diagram of the structure of a novel horizontal cavity vertical laser array based on internal and external grating double mirrors in the invention.

[0038] In the figure: 1. Substrate; 2. Quantum well layer; 3. Back ridge waveguide; 31. DFB grating layer; 32. SiO2 cladding; 33. Etched metal grating; 331. First-order grating; 3311. First grating spacing; 3312. First metal positive electrode; 332. Second-order grating; 3321. Second grating spacing; 3322. Second metal positive electrode; 333. Second-order grating; 34. Bevel angle φ; 35. High reflectivity HR layer; 351. Vertical groove; 352. Bevel groove. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0040] Example 1

[0041] A novel horizontal cavity vertical laser based on internal and external grating double mirrors includes:

[0042] Substrate 1, wherein the substrate 1 is made of InP material and has a thickness of 300μm;

[0043] A quantum well layer 2 is disposed on the upper surface of the substrate 1. The quantum well layer 2 is an InGaAsP multi-quantum well structure with 3 wells and a single well thickness of 5 nm. The lasing wavelength λ of the quantum well layer 2 is 1310 nm.

[0044] A back ridge waveguide 3 is disposed on the upper end face of the quantum well layer 2. The right end face of the back ridge waveguide 3 is processed into an angled φ34, which is 10°. Both the left and right end faces of the back ridge waveguide 3 are provided with a high reflectivity HR layer 35, which is a coating layer.

[0045] The back ridge waveguide 3 includes at least one DFB grating layer 31, and a SiO2 cladding layer 32 is disposed above the DFB grating layer 31. An etched metal grating 33 is disposed on the upper end surface of the SiO2 cladding layer 32.

[0046] The etched metal grating 33 includes a first-order grating 331 and a second-order grating 332, which serve as passive regions for reflection and filtering; the etched metal grating 33 also includes a second-order grating 333, which serves as an active region for coupling upward-emitting laser light; the first-order grating 331 and the second-order grating 332 are respectively distributed on the left and right sides of the second-order grating 333; the grating constant of the second-order grating 333 is twice the grating constant of the first-order grating 331 and the second-order grating 332;

[0047] The first first-order grating 331 has a first grating spacing 3311, and a first metal electrode 3312 is disposed on the upper part of the first first-order grating 331; the second first-order grating 332 has a second grating spacing 3321, and a second metal electrode 3322 is disposed on the upper part of the second first-order grating 332; the first grating spacing 3311 and the second grating spacing 3321 are both 0.

[0048] The present invention also provides a novel horizontal cavity vertical laser array based on internal and external grating double mirrors, which is composed of a matrix distribution of novel horizontal cavity vertical lasers based on internal and external grating double mirrors. The high reflectivity HR layer 35 includes a vertical groove 351 for filling the vertical end face of the back ridge waveguide 3 with high reflectivity HR coating and an angled groove 352 for filling the angled end face of the back ridge waveguide 3 with high reflectivity HR coating.

[0049] Using readily available high-reflectivity HR coatings to construct two-dimensional laser chip arrays eliminates the need for separate slicing and end-face optical coating. This method is simple, low-cost, and solves the problem of difficult HR optical coating on the end face of two-dimensional arrays of transverse cavity lasers.

[0050] Example 2

[0051] A novel horizontal cavity vertical laser based on internal and external grating double mirrors includes:

[0052] Substrate 1, wherein the substrate 1 is made of GaAs material and has a thickness of 400 μm;

[0053] A quantum well layer 2 is disposed on the upper surface of the substrate 1. The quantum well layer 2 is an InP multi-quantum well structure with 4 wells and a single well thickness of 6 nm. The lasing wavelength λ of the quantum well layer 2 is 1550 nm.

[0054] A back ridge waveguide 3 is disposed on the upper end face of the quantum well layer 2. The right end face of the back ridge waveguide 3 is processed into an oblique angle φ34, which is 18°. Both the left and right end faces of the back ridge waveguide 3 are provided with a high reflectivity HR layer 35, which is an optical film.

[0055] The back ridge waveguide 3 includes at least one DFB grating layer 31, and a SiO2 cladding layer 32 is disposed above the DFB grating layer 31. An etched metal grating 33 is disposed on the upper end surface of the SiO2 cladding layer 32.

[0056] The etched metal grating 33 includes a first-order grating 331 and a second-order grating 332, which serve as passive regions for reflection and filtering; the etched metal grating 33 also includes a second-order grating 333, which serves as an active region for coupling upward-emitting laser light; the first-order grating 331 and the second-order grating 332 are respectively distributed on the left and right sides of the second-order grating 333; the grating constant of the second-order grating 333 is twice the grating constant of the first-order grating 331 and the second-order grating 332;

[0057] The first first-order grating 331 has a first grating spacing 3311, and a first metal electrode 3312 is disposed on the upper part of the first first-order grating 331; the second first-order grating 332 has a second grating spacing 3321, and a second metal electrode 3322 is disposed on the upper part of the second first-order grating 332; the first grating spacing 3311 and the second grating spacing 3321 are λ / 4.

[0058] The present invention also provides a novel horizontal cavity vertical laser array based on internal and external grating double mirrors, which is composed of a matrix distribution of novel horizontal cavity vertical lasers based on internal and external grating double mirrors. The high reflectivity HR layer 35 includes a vertical groove 351 for filling the vertical end face of the back ridge waveguide 3 with high reflectivity HR coating and an angled groove 352 for filling the angled end face of the back ridge waveguide 3 with high reflectivity HR coating.

[0059] Using readily available high-reflectivity HR coatings to construct two-dimensional laser chip arrays eliminates the need for separate slicing and end-face optical coating. This method is simple, low-cost, and solves the problem of difficult HR optical coating on the end face of two-dimensional arrays of transverse cavity lasers.

[0060] Example 3

[0061] A novel horizontal cavity vertical laser based on internal and external grating double mirrors includes:

[0062] Substrate 1, wherein the substrate 1 is made of GaAs material and has a thickness of -500μm;

[0063] A quantum well layer 2 is disposed on the upper surface of the substrate 1. The quantum well layer 2 is an InP multi-quantum well structure with 5 wells and a single well thickness of 8 nm. The lasing wavelength λ of the quantum well layer 2 is 1550 nm.

[0064] A back ridge waveguide 3 is disposed on the upper end face of the quantum well layer 2. The right end face of the back ridge waveguide 3 is processed into an oblique angle φ34, which is 26°. Both the left and right end faces of the back ridge waveguide 3 are provided with a high reflectivity HR layer 35, which is an optical film.

[0065] The back ridge waveguide 3 includes at least one DFB grating layer 31, and a SiO2 cladding layer 32 is disposed above the DFB grating layer 31. An etched metal grating 33 is disposed on the upper end surface of the SiO2 cladding layer 32.

[0066] The etched metal grating 33 includes a first-order grating 331 and a second-order grating 332, which serve as passive regions for reflection and filtering; the etched metal grating 33 also includes a second-order grating 333, which serves as an active region for coupling upward-emitting laser light; the first-order grating 331 and the second-order grating 332 are respectively distributed on the left and right sides of the second-order grating 333; the grating constant of the second-order grating 333 is twice the grating constant of the first-order grating 331 and the second-order grating 332;

[0067] The first first-order grating 331 has a first grating spacing 3311, and a first metal electrode 3312 is disposed on the upper part of the first first-order grating 331; the second first-order grating 332 has a second grating spacing 3321, and a second metal electrode 3322 is disposed on the upper part of the second first-order grating 332; the first grating spacing 3311 and the second grating spacing 3321 are λ / 4.

[0068] The present invention also provides a novel horizontal cavity vertical laser array based on internal and external grating double mirrors, which is composed of a matrix distribution of novel horizontal cavity vertical lasers based on internal and external grating double mirrors. The high reflectivity HR layer 35 includes a vertical groove 351 for filling the vertical end face of the back ridge waveguide 3 with high reflectivity HR coating and an angled groove 352 for filling the angled end face of the back ridge waveguide 3 with high reflectivity HR coating.

[0069] Using readily available high-reflectivity HR coatings to construct two-dimensional laser chip arrays eliminates the need for separate slicing and end-face optical coating. This method is simple, low-cost, and solves the problem of difficult HR optical coating on the end face of two-dimensional arrays of transverse cavity lasers.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel horizontal-cavity vertical-emitting laser based on internal and external grating double mirrors, characterized in that, include: Substrate (1); A quantum well layer (2) is disposed on the upper end face of the substrate (1); A back ridge waveguide (3) is disposed on the upper end face of the quantum well layer (2). The right end face of the back ridge waveguide (3) is processed into an oblique angle φ (34). Both the left and right end faces of the back ridge waveguide (3) are provided with a high reflectivity HR layer (35). The back ridge waveguide (3) includes at least one DFB grating layer (31), and a SiO2 cladding layer (32) is disposed above the DFB grating layer (31). An etched metal grating (33) is disposed on the upper surface of the SiO2 cladding layer (32). The etched metal grating (33) includes a first-order grating (331) and a second-order grating (332) serving as passive regions for reflective filtering; the etched metal grating (33) also includes a second-order grating (333) serving as an active region for coupling upward-emitting laser light; the first-order grating (331) and the second-order grating (332) are respectively distributed on the left and right sides of the second-order grating (333); The first first-order grating (331) has a first grating spacing (3311) and a first metal electrode (3312) is provided on the upper part of the first first-order grating (331); the second first-order grating (332) has a second grating spacing (3321) and a second metal electrode (3322) is provided on the upper part of the second first-order grating (332).

2. The novel horizontal cavity vertical laser based on internal and external grating double mirrors according to claim 1, characterized in that: The substrate (1) is made of InP or GaAs material with a thickness of 300-500μm.

3. The novel horizontal cavity vertical laser based on internal and external grating double mirrors according to claim 1, characterized in that: The quantum well layer (2) is an InGaAsP / InP multi-quantum well structure with 3-5 wells and a single well thickness of 5-8 nm.

4. The novel horizontal cavity vertical laser based on internal and external grating double mirrors according to claim 1, characterized in that: The lasing wavelength λ of the quantum well layer (2) is 1310 nm or 1550 nm.

5. The novel horizontal cavity vertical laser based on internal and external grating double mirrors according to claim 1, characterized in that: The grating constant of the second-order grating (333) is twice that of the first-order grating (331) and the second-order grating (332).

6. The novel horizontal cavity vertical laser based on internal and external grating double mirrors according to claim 4, characterized in that: The first grating spacing (3311) and the second grating spacing (3321) are both 0.

7. The novel horizontal cavity vertical laser based on internal and external grating double mirrors according to claim 4, characterized in that: The first grating spacing (3311) and the second grating spacing (3321) are λ / 4.

8. The novel horizontal cavity vertical laser based on internal and external grating double mirrors according to claim 1, characterized in that: The oblique angle φ (34) is 10°-26°.

9. The novel horizontal cavity vertical laser based on internal and external grating double mirrors according to claim 1, characterized in that: The high reflectivity HR layer (35) is a coating layer or an optical film.

10. A novel horizontal cavity vertical laser array based on internal and external grating double mirrors, characterized in that: The high reflectivity HR layer (35) is composed of a matrix distribution of a novel horizontal cavity vertical laser based on internal and external grating double mirrors according to any one of claims 1-9. The high reflectivity HR layer (35) includes a vertical groove (351) for filling the vertical end face of the back ridge waveguide (3) with high reflectivity HR coating and an angled groove (352) for filling the angled end face of the back ridge waveguide (3) with high reflectivity HR coating.

Images