Tunable surface emitting laser array and manufacturing method

Abstract

The invention discloses a tunable surface emitting laser array and a manufacturing method, comprising an N-surface electrode layer; an active epitaxial component is arranged on the N-surface electrode layer, two opposite sides of the top of the active epitaxial component are etched to form a ridge waveguide, the ridge waveguide comprises a convex portion located in the middle of the active epitaxial component and a concave portion located on both sides of the convex portion; an electrical isolation layer is grown on the upper surface of the concave portion and on both sides of the convex portion; and a P-surface electrode layer is grown on the active epitaxial component and the electrical isolation layer, the P-surface electrode layer is provided with a light-emitting hole, a plurality of photonic crystal holes are arranged in the light-emitting hole, and the plurality of photonic crystal holes are distributed in an array and penetrate the ridge waveguide; wherein the N-surface electrode layer, the active epitaxial component, the electrical isolation layer and the P-surface electrode layer form a plurality of array-distributed crystal units, the P-surface electrode layer at adjacent positions of two crystal units is etched to form an electrical isolation region, the spacings of the photonic crystal holes of different crystal units are different, so as to realize tunable wavelength output and provide a large-scale high-efficiency light source.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular to a tunable surface emitting laser array and a manufacturing method thereof. Background Art

[0002] In recent years, the development of information transmission and sensing has provided new opportunities for the development of artificial intelligence technology. The development of artificial intelligence technology depends on the iterative progress of advanced sensing systems. Lasers, as the core of precision sensing systems, are the most basic elements for solving future artificial intelligence automation.

[0003] Photonic crystal surface emitting lasers are an important research direction for new laser chip structures. Photonic crystal surface emitting lasers use photonic crystal structures to combine the advantages of high output power, low divergence angle, and narrow linewidth of edge-emitting lasers with the advantages of 2D on-chip arrays and low-cost packaging of vertical cavity surface emitting lasers, forming a laser with tunable output wavelength and providing large-scale high-efficiency light sources, improving the concurrent scale and flexibility of sensing, reducing power consumption, and opening up new directions for artificial intelligence architectures. Summary of the invention

[0004] The present invention provides a tunable surface emitting laser array and a manufacturing method thereof, which are used to at least partially solve the above technical problems, realize output of tunable wavelength and provide a large-scale high-efficiency light source.

[0005] In order to achieve the above object, the present invention provides a tunable surface emitting laser array, comprising:

[0006] N-side electrode layer;

[0007] An active epitaxial component is arranged above the N-side electrode layer, and two opposite sides of the top of the active epitaxial component are etched to form a ridge waveguide, wherein the ridge waveguide includes a raised portion located in the middle of the active epitaxial component and recessed portions located on both sides of the raised portion;

[0008] an electrical isolation layer, grown on the upper surface of the recessed portion and on both sides of the raised portion; and

[0009] A P-side electrode layer is grown and covers the upper surface of the active epitaxial component and the electrical isolation layer, the P-side electrode layer located at the raised portion is provided with a light-emitting hole formed by etching, a plurality of photonic crystal holes are provided in the light-emitting hole, the plurality of photonic crystal holes are distributed in a rectangular array, and the plurality of photonic crystal holes penetrate the ridge waveguide of the active epitaxial component;

[0010] Among them, the N-side electrode layer, the active epitaxial component, the electrical isolation layer and the P-side electrode layer form a plurality of crystal units, the plurality of crystal units are distributed in an array, the P-side electrode layers adjacent to two adjacent crystal units are etched to form electrical isolation regions, and the spacings between the photonic crystal holes of different crystal units are different.

[0011] According to an embodiment of the present disclosure, the active epitaxial component includes an N-type substrate, an N-type highly doped layer, an N-type cap layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type cap layer and a P-type highly doped layer, which are stacked in sequence from bottom to top.

[0012] According to an embodiment of the present disclosure, the light emitting hole is located at the center of the raised portion of the ridge waveguide.

[0013] According to an embodiment of the present disclosure, the diameter of the light-emitting hole ranges from 80 to 380 microns.

[0014] According to an embodiment of the present disclosure, the spacing between adjacent photonic crystal holes ranges from 450 to 550 nanometers.

[0015] According to an embodiment of the present disclosure, the photonic crystal hole is filled with gas or solid medium.

[0016] According to an embodiment of the present disclosure, the N-side electrode layer and the active epitaxial component are 500 microns in length and 500 microns in width.

[0017] According to an embodiment of the present disclosure, the length of the ridge waveguide is equal to the length of the active epitaxial component, and the width of the protruding portion of the ridge waveguide is in the range of 100-400 microns.

[0018] According to an embodiment of the present disclosure, the length of the electrical isolation region is equal to the length of the edge of the active epitaxial component, and the width of the electrical isolation region is in the range of 10-100 microns.

[0019] An embodiment of the present invention also provides a method for manufacturing a tunable surface emitting laser array, comprising:

[0020] Etching two opposite sides of the top of the active epitaxial component to form a ridge waveguide, wherein the ridge waveguide includes a raised portion located in the middle and recessed portions located on both sides of the raised portion;

[0021] growing an electrical isolation layer on the upper surface of the recessed portion and on both sides of the raised portion of the ridge waveguide;

[0022] Growing and covering a P-side electrode layer on the upper surfaces of the active epitaxial component and the electrical isolation layer;

[0023] Etching a light-emitting hole at the center of the P-side electrode layer of the raised portion;

[0024] Etching a plurality of photonic crystal holes distributed in a rectangular array in the light-emitting hole, wherein the plurality of photonic crystal holes penetrate the raised portion of the ridge waveguide;

[0025] Growing an N-side electrode layer at the bottom of the active epitaxial component;

[0026] The P-side electrode layer adjacent to the crystal unit is etched to form an electrical isolation region.

[0027] According to the tunable surface emitting laser array provided by the present invention, the ridge waveguide is used to limit the lateral diffusion of current and form a weak refractive index guiding mechanism, thereby limiting the mode field distribution within the entire laser; the photonic crystal hole can form a mode oscillation with a narrow spectral width, a high side mode suppression ratio and a low divergence angle; in addition, by injecting electricity into the crystal units separately, due to the different spacings between the photonic crystal holes of different crystal units, tunable wavelength output can be achieved under different injection conditions and a large-scale high-efficiency light source can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a three-dimensional schematic diagram of a crystal unit of a tunable surface-emitting laser array according to an embodiment of the present invention;

[0029] Figure 2 is a three-dimensional schematic diagram of a tunable surface-emitting laser array according to an embodiment of the present invention;

[0030] Figure 3 is a top view of a tunable surface emitting laser array according to an embodiment of the present invention.

[0031] Reference numerals

[0032] 1. N-side electrode layer;

[0033] 2. Active epitaxial components;

[0034] 21. N-type substrate;

[0035] 22. N-type high-doped layer;

[0036] 23. N-type cap layer;

[0037] 24. N-type waveguide layer;

[0038] 25. Active layer;

[0039] 26. P-type waveguide layer;

[0040] 27. P-type cap layer;

[0041] 28. P-type high-doped layer;

[0042] 3. Ridge waveguide;

[0043] 31. Raised part;

[0044] 32. Depression;

[0045] 4. Electrical isolation layer;

[0046] 5. P-side electrode layer;

[0047] 6. Light-emitting hole;

[0048] 7. Photonic crystal hole;

[0049] 8. Electrical isolation area;

[0050] 9. Crystal unit. DETAILED DESCRIPTION

[0051] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0052] The description of the structural embodiments and methods of the present invention is disclosed herein. It should be understood that this is not intended to limit the present invention to the specific disclosed embodiments, and the present invention can be implemented by using other features, elements, methods and embodiments. Similar elements in different embodiments are usually marked with similar numbers.

[0053] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0054] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0055] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0056] Figure 1 is a three-dimensional schematic diagram of a crystal unit of a tunable surface-emitting laser array according to an embodiment of the present invention; Figure 2 is a schematic three-dimensional diagram of a tunable surface emitting laser array according to an embodiment of the present invention.

[0057] The embodiment of the present invention provides a tunable surface emitting laser array, including an N-surface electrode layer 1 , an active epitaxial component 2 , an electrical isolation layer 4 and a P-surface electrode layer 5 . The N-side electrode layer 1 is suitable for injecting current; the active epitaxial component 2 is arranged above the N-side electrode layer 1, and the two opposite sides of the top of the active epitaxial component 2 are etched to form a ridge waveguide 3, and the ridge waveguide 3 includes a raised portion 31 located in the middle of the active epitaxial component 2 and a recessed portion 32 located on both sides of the raised portion 31; the electrical isolation layer 4 is grown on the upper surface of the recessed portion 32 and on both sides of the raised portion 31; and the P-side electrode layer 5 is grown and covered on the upper surface of the active epitaxial component 2 and the electrical isolation layer 4, and the P-side electrode layer 5 located at the raised portion 31 is provided with a light-emitting hole 6 formed by etching, and a plurality of photonic crystal holes 7 are arranged in the light-emitting hole 6, and the plurality of photonic crystal holes 7 are distributed in a rectangular array, and the plurality of photonic crystal holes 7 penetrate the ridge waveguide 3 of the active epitaxial component 2; wherein, the N-side electrode layer 1, the active epitaxial component 2, the electrical isolation layer 4 and the P-side electrode layer 5 are arranged in a rectangular array, and the plurality of photonic crystal holes 7 penetrate the ridge waveguide 3 of the active epitaxial component 2; wherein, the N-side electrode layer 1, the active epitaxial component 2, the electrical isolation layer 4 and the P-side electrode layer 5 are arranged in a rectangular array, and the plurality of photonic crystal holes 7 penetrate the ridge waveguide 3 of the active epitaxial component 2 The surface electrode layer 5 forms a plurality of crystal units 9, and the plurality of crystal units 9 are distributed in an array. The P-surface electrode layer 5 adjacent to two adjacent crystal units 9 is etched to form an electrical isolation region 8, and the spacings between the photonic crystal holes 7 of different crystal units 9 are different.

[0058] In an exemplary embodiment, see Figure 1The active epitaxial component 2 includes an N-type substrate 21, an N-type high-doped layer 22, an N-type cap layer 23, an N-type waveguide layer 24, an active layer 25, a P-type waveguide layer 26, a P-type cap layer 27 and a P-type high-doped layer 28, which are stacked and distributed from bottom to top. The N-type substrate 21 is located above the N-side electrode layer 1; the N-type high-doped layer 22 is used for effective current injection to reduce device resistance; the N-type cap layer 23 is used to limit the light field and current injection; the N-type waveguide layer 24 is used to expand the light field generated in the active area, and the active layer 25 is used to form optical gain, which can be a quantum dot, a quantum well or a quantum cascade structure; the P-type waveguide layer 26 is used to expand the light field generated in the active area; the P-type cap layer 27 is used to limit the light field, and the refractive index is lower than that of the P-type waveguide layer 26, and the P-type high-doped layer 28 is located above the P-type waveguide layer 26.

[0059] The ridge waveguide 3 includes a raised portion 31 located in the middle of the active epitaxial component 2 and a recessed portion 32 located on both sides of the raised portion 31. The recessed portion 32 is a structure formed by etching the two opposite sides of the top of the P-type waveguide layer 26 to form a recessed structure on both sides, and the raised portion 31 is formed by sequentially covering the middle raised portion of the P-type waveguide layer 26 with a P-type cap layer 27 and a P-type high-doped layer 28. The ridge waveguide 3 is used to limit the lateral diffusion of the current and form a weak refractive index guiding mechanism to limit the internal mode field distribution of the entire tunable laser.

[0060] Specifically, the etching can be ultraviolet optical lithography and dry etching.

[0061] In an exemplary embodiment, the electrical isolation layer 4 is grown on the upper surface of the recessed portion 32 and on both sides of the raised portion 31 ; the P-side electrode layer 5 is grown and covers the upper surface of the active epitaxial component 2 and the electrical isolation layer 4 , and the P-side electrode layer 5 forms an ohmic contact with the top surface of the P-type high-doped layer 28 .

[0062] In an exemplary embodiment, see Figure 1 and 2 , the N-side electrode layer 1, the active epitaxial component 2, the electrical isolation layer 4 and the P-side electrode layer 5 form a plurality of crystal units 9, the plurality of crystal units 9 are distributed in a rectangular array and contact each other, the P-side electrode layer 5 at the adjacent positions of two adjacent crystal units 9 is etched to form an electrical isolation region 8, and the spacing of the photonic crystal holes 7 of different crystal units 9 is different. The P-side electrode layer 5 at the raised portion 31 is provided with a light-emitting hole 6 formed by etching; the plurality of photonic crystal holes 7 are located in the light-emitting hole 6, the plurality of photonic crystal holes 7 are distributed in a rectangular array, and the plurality of photonic crystal holes 7 penetrate the ridge waveguide 3 of the active epitaxial component 2, that is, penetrate the P-type waveguide layer 26, the P-type cap layer 27 and the P-type high-doping layer 28.

[0063] According to the tunable surface emitting laser array of the above embodiment, the ridge waveguide 3 is used to limit the lateral diffusion of current and form a weak refractive index guiding mechanism, thereby limiting the mode field distribution within the entire laser; the photonic crystal hole 7 can form a mode oscillation with a narrow spectral width, a high side mode suppression ratio and a low divergence angle; in addition, by injecting electricity into the crystal units 9 separately, due to the different spacings between the photonic crystal holes 7 of different crystal units 9, tunable wavelength output can be achieved under different injection conditions and a large-scale high-efficiency light source can be provided.

[0064] In an exemplary embodiment, see Figure 1 and 2 The length of the N-side electrode layer 1 and the active epitaxial component 2 is about 500 microns, and the width is about 500 microns. The length of the ridge waveguide 3 is equal to the length of the active epitaxial component 2, and the width of the protrusion 31 of the ridge waveguide 3 is in the range of 100-400 microns, for example, 100 microns, 140 microns, 180 microns, 220 microns, 260 microns, 300 microns, 340 microns, 380 microns or 400 microns.

[0065] In an exemplary embodiment, the light-emitting hole 6 is located at the center of the raised portion 31 of the ridge waveguide 3. The light-emitting hole 6 is realized by electron beam exposure and inductively coupled plasma etching. The diameter of the light-emitting hole 6 is in the range of 80-380 microns, for example, it can be 80 microns, 120 microns, 160 microns, 200 microns, 240 microns, 280 microns, 320 microns, 360 microns or 380 microns. The light-emitting hole 6 is a reserved area for the subsequent formation of a photonic crystal hole 7.

[0066] Figure 3 is a top view of a tunable surface emitting laser array according to an embodiment of the present invention.

[0067] In an exemplary embodiment, the photonic crystal hole 7 is also realized by electron beam exposure and inductively coupled plasma etching, and the depth of the photonic crystal hole 7 is greater than the thickness of the ridge waveguide 3 to achieve a sufficient refractive index difference, thereby regulating the distribution and propagation of the light field therein. In this embodiment, the photonic crystal hole 7 is a circular hole, the aperture of the photonic crystal hole 7 is 200 nanometers, and the spacing between adjacent photonic crystal holes 7 ranges from 450 to 550 nanometers. The spacing of the photonic crystal holes 7 of different crystal units 9 is different, see Figure 3, the spacing between adjacent photonic crystal holes 7 is a, and the spacing between the photonic crystal holes 7 of each crystal unit 9 is different, namely a1, a2, a3 and a4, a1, a2, a3 and a4 are all different, and the differences between a1, a2, a3 and a4 can be equal or unequal. The photonic crystal hole 7 can form a mode oscillation with a narrow spectrum width, a high side mode suppression ratio and a low divergence angle; in addition, by injecting electricity into the crystal units 9 separately, due to the different spacings between the photonic crystal holes 7 of different crystal units 9, tunable wavelength output can be achieved under different injection conditions and a large-scale high-efficiency light source can be provided.

[0068] In an exemplary embodiment, the photonic crystal hole 7 is filled with a gas or a solid medium, such as air.

[0069] In an exemplary embodiment, the electrical isolation region 8 is realized by corroding the metal deposited above the P-side electrode layer 5 adjacent to the crystal unit 9. The length of the electrical isolation region 8 is equal to the length of the edge of the active epitaxial component 2. The width of the electrical isolation region 8 ranges from 10 to 100 microns. For example, it can be 10 microns, 20 microns, 30 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns or 100 microns. The electrical isolation region 8 separates each crystal unit 9.

[0070] An embodiment of the present invention also provides a method for manufacturing a tunable surface emitting laser array, comprising:

[0071] Etching is performed on two opposite sides of the top of the active epitaxial component 2 by ultraviolet optical lithography and dry etching to form a ridge waveguide 3, wherein the ridge waveguide 3 includes a raised portion 31 located in the middle and recessed portions 32 located on both sides of the raised portion 31;

[0072] An electrical isolation layer 4 is grown on the upper surface of the concave portion 32 and on both sides of the convex portion 31 of the ridge waveguide 3;

[0073] A P-side electrode layer 5 is grown on and covers the upper surface of the active epitaxial component 2 and the electrical isolation layer 4;

[0074] A light emitting hole 6 is formed at the center of the P-side electrode layer 5 of the protrusion 31 by electron beam exposure and inductively coupled plasma etching;

[0075] A plurality of photonic crystal holes 7 distributed in a rectangular array are etched in the light-emitting hole 6 by electron beam exposure and inductively coupled plasma, and the plurality of photonic crystal holes 7 penetrate the raised portion 31 of the ridge waveguide 3, and the depth of the photonic crystal holes 7 is greater than the thickness of the ridge waveguide 3;

[0076] Growing an N-side electrode layer 1 at the bottom of the active epitaxial component 2;

[0077] The P-side electrode layer 5 adjacent to the crystal unit 9 is etched to form an electrical isolation region 8 .

[0078] According to the tunable surface emitting laser array disclosed in the present invention, the ridge waveguide 3 is used to limit the lateral diffusion of current and form a weak refractive index guiding mechanism, thereby limiting the mode field distribution within the entire laser; the photonic crystal hole 7 can form a mode oscillation with a narrow spectral width, a high side mode suppression ratio and a low divergence angle; in addition, by injecting electricity into the crystal units 9 separately, due to the different spacings between the photonic crystal holes 7 of different crystal units 9, tunable wavelength output can be achieved under different injection conditions and a large-scale high-efficiency light source can be provided.

[0079] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A tunable surface emitting laser array, characterized in that: include: N-side electrode layer (1); An active epitaxial component (2) is arranged above the N-side electrode layer (1), and two opposite sides of the top of the active epitaxial component (2) are etched to form a ridge waveguide (3), wherein the ridge waveguide (3) comprises a raised portion (31) located in the middle of the active epitaxial component (2) and recessed portions (32) located on both sides of the raised portion; An electrical isolation layer (4) grown on the upper surface of the recessed portion (32) and on both sides of the raised portion (31); as well as A P-surface electrode layer (5) is grown and covers the upper surfaces of the active epitaxial component (2) and the electrical isolation layer (4); the P-surface electrode layer (5) located on the protruding portion (31) is provided with a light-emitting hole (6) formed by etching; a plurality of photonic crystal holes (7) are arranged in the light-emitting hole (6); the plurality of photonic crystal holes (7) are distributed in a rectangular array, and the plurality of photonic crystal holes (7) penetrate the ridge waveguide (3) of the active epitaxial component (2); The N-side electrode layer (1), the active epitaxial component (2), the electrical isolation layer (4) and the P-side electrode layer (5) form a plurality of crystal units (9), the plurality of crystal units (9) are distributed in an array, the P-side electrode layers adjacent to two adjacent crystal units (9) are etched to form an electrical isolation region (8), and the spacings of the photonic crystal holes (7) of different crystal units (9) are different.

2. The tunable surface emitting laser array according to claim 1, characterized in that: The active epitaxial component (2) comprises an N-type substrate (21), an N-type highly doped layer (22), an N-type cap layer (23), an N-type waveguide layer (24), an active layer (25), a P-type waveguide layer (26), a P-type cap layer (27) and a P-type highly doped layer (28), which are stacked in sequence from bottom to top.

3. The tunable surface emitting laser array according to claim 1, characterized in that: The light-emitting hole (6) is located at the center of the raised portion (31) of the ridge waveguide (3).

4. The tunable surface emitting laser array according to claim 1, characterized in that: The diameter of the light-emitting hole (6) ranges from 80 to 380 micrometers.

5. The tunable surface emitting laser array according to claim 1, characterized in that: The spacing between adjacent photonic crystal holes (7) is in the range of 450-550 nanometers.

6. The tunable surface emitting laser array according to claim 1, characterized in that: The photonic crystal hole (7) is filled with gas or solid medium.

7. The tunable surface emitting laser array according to claim 1, characterized in that: The N-side electrode layer (1) and the active epitaxial component (2) are 500 micrometers in length and 500 micrometers in width.

8. The tunable surface emitting laser array according to claim 1, characterized in that: The length of the ridge waveguide (3) is equal to the length of the active epitaxial component (2), and the width of the protruding portion (31) of the ridge waveguide (3) is in the range of 100-400 microns.

9. The tunable surface emitting laser array according to claim 1, characterized in that: The length of the electrical isolation region (8) is equal to the length of the edge of the active epitaxial component (2), and the width of the electrical isolation region (8) is in the range of 10-100 microns.

10. A method for manufacturing a tunable surface emitting laser array according to any one of claims 1 to 9, characterized in that: include: Etching is performed on two opposite sides of the top of the active epitaxial component (2) to form a ridge waveguide (3), wherein the ridge waveguide (3) comprises a raised portion (31) located in the middle and recessed portions (32) located on both sides of the raised portion; Growing an electrical isolation layer (4) on the upper surface of the recessed portion (32) of the ridge waveguide (3) and on both sides of the raised portion (31); Growing and covering a P-side electrode layer (5) on the upper surfaces of the active epitaxial component (2) and the electrical isolation layer (4); Etching a light-emitting hole (6) at the center of the P-side electrode layer (5) of the protruding portion (31); Etching a plurality of photonic crystal holes (7) distributed in a rectangular array in the light-emitting hole (6), wherein the plurality of photonic crystal holes (7) penetrate the raised portion (31) of the ridge waveguide (3); Growing an N-side electrode layer (1) at the bottom of the active epitaxial component (2); The P-side electrode layer (5) adjacent to the crystal unit (9) is etched to form an electrical isolation region (8).

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