阅读说明：本技术 垂直腔面发射激光器阵列及改善其该阵列性能的方法 (Vertical cavity surface emitting laser array and method for improving performance of array ) 是由 李�浩 于 2021-09-14 设计创作，主要内容包括：本发明公开了一种垂直腔面发射激光器阵列及改善其该阵列性能的方法,属于垂直腔面发射激光器技术领域。解决了现有技术存在的功率转换效率、输出功率和出光均匀性较差的技术问题。该垂直腔面发射激光器阵列,包括半导体层及形成于一个半导体层上的若干阵列单元,每个阵列单元均存在氧化沟槽、台面、环以及出光面,出光面存在有电极,台面中设有氧化层,氧化层内存在出光孔,阵列单元中至少部分阵列单元的氧化沟槽、台面、环、电极四者中的任意一者或多者的形状为不规则形状以使出光孔的形成不规则形状,至少一部分阵列单元中不同的阵列单元的出光孔的形状彼此不同。本发明用于提高垂直腔面发射激光器阵列的功率转换效率、输出功率和出光均匀性。(The invention discloses a vertical cavity surface emitting laser array and a method for improving the performance of the array, and belongs to the technical field of vertical cavity surface emitting lasers. The technical problems of poor power conversion efficiency, output power and light emitting uniformity in the prior art are solved. The vertical cavity surface emitting laser array comprises a semiconductor layer and a plurality of array units formed on the semiconductor layer, wherein each array unit is provided with an oxidation groove, a table top, a ring and a light-emitting surface, electrodes are arranged on the light-emitting surface, an oxidation layer is arranged in the table top, light-emitting holes are formed in the oxidation layer, the shape of any one or more of the oxidation groove, the table top, the ring and the electrodes of at least part of the array units in the array units is irregular so that the light-emitting holes form irregular shapes, and the shapes of the light-emitting holes of different array units in at least part of the array units are different from one another. The invention is used for improving the power conversion efficiency, the output power and the light-emitting uniformity of the vertical cavity surface emitting laser array.)

1. A vertical cavity surface emitting laser array is characterized by comprising a semiconductor layer and a plurality of array units formed on the semiconductor layer, wherein each array unit is provided with an oxidation groove, a table top, a ring and a light-emitting surface, the light-emitting surface is provided with an electrode, an oxidation layer is arranged in the table top, a light-emitting hole is formed in the oxidation layer, the shape of any one or more of the oxidation groove, the table top, the ring and the electrode of at least part of the array units in the array units is irregular, so that the light-emitting holes are irregularly shaped, and the shapes of the light-emitting holes of different array units are different from one another.

2. The VCSEL array of claim 1, wherein the irregular shape is an asymmetrical shape.

3. The VCSEL array of claim 1, wherein an inner peripheral profile of the oxidation trench and/or the mesa of at least one of the array units is an irregular ring shape.

4. The VCSEL array of claim 1, wherein the oxidation trench is a continuous ring shape and an inner peripheral profile of the oxidation trench is an irregular ring shape.

5. The VCSEL array of claim 1, wherein a local region of the oxide trench on a same array cell has a shape different from a shape of the remaining region.

6. The VCSEL array of claim 1, wherein the oxide trench is generally annular and includes a plurality of segments spaced apart, at least two of the segments having different shapes.

7. A vertical cavity surface emitting laser array according to claim 5 or 6, wherein said difference in shape includes a difference in size and a difference in ratio of a length dimension to a width dimension.

8. The VCSEL array of claim 1, wherein the oxide trench is generally annular and includes a plurality of segments spaced apart from each other, at least one segment having a different distance from two adjacent segments.

9. The VCSEL array of claim 1, wherein at least two adjacent array units have the same structure and each have a center line extending in a radial direction, and center lines extending in the radial direction of each other are not parallel to each other.

10. The VCSEL array of claim 1, wherein any one or more of the oxide trenches, mesas, rings, and electrodes of at least two adjacent array units are different in shape from each other.

11. A method of improving the performance of an array of vertical cavity surface emitting lasers as claimed in any of claims 1 to 10, comprising the steps of:

adjusting the shape and/or size of the light exit hole by adjusting at least the shape and/or size of any one or more of the oxide trench, mesa, ring, and electrode of at least one array unit in the VCSEL array of any of claims 1-10, thereby improving the power conversion efficiency, output power, and/or light exit uniformity of the VCSEL device.

12. The method for improving the performance of an array of vertical cavity surface emitting lasers of claim 11, further comprising the steps of:

and adjusting the shape and/or size of the electrode on the light-emitting surface of the corresponding array unit according to the shape and/or size of the light-emitting hole so as to match the electrode with the light-emitting surface of the corresponding array unit.

Technical Field

The present invention relates to a laser, and more particularly, to a vertical-cavity surface-emitting laser (VCSEL) array and a method for improving performance of the VCSEL array.

Background

Vertical cavity surface emitting lasers are a new type of active semiconductor laser devices that have rapidly developed in recent years.

In recent years, the vertical cavity surface emitting laser has been rapidly developed and is favored by the optical communication field because of its advantages such as low threshold current, high modulation frequency and low power loss. At present, the application of the vertical cavity surface emitting laser is mainly focused on low power occasions, such as optical communication, optical interconnection, computer and optical information processing, etc., but in fact, the high power application field of the vertical cavity surface emitting laser is wider, such as laser ranging, laser radar, laser fuse, laser medical treatment, etc. In order to increase the output power of a semiconductor laser, a method of integrating a plurality of light emitting cells is generally used. Compared with the traditional edge-emitting semiconductor laser, the vertical cavity surface-emitting laser array is simpler to manufacture.

The prior art at least has the following technical problems:

referring to fig. 1, 2 and 3, the conventional vertical cavity surface emitting laser includes a p-metal (top p-metal)1, a mesa (mesa) 2, a mesa (mesa) 3, a substrate 8 and an n-type metal (n-metal) 9 sequentially arranged in a direction, a p-type DBR (p-type top DBR)4 and an n-type DBR (n-type DBR, DBR is named as Distributed Bragg Reflector)5 are respectively arranged in the table top 2 and the table top 3, oxide layers (oxide layers) 11, 12 are provided in the table-board 2 and the table-board 3, light-emitting holes (oxide apertures) 10 are formed in the oxide layers, meanwhile, an Active region 7 and a resonant cavity 6 formed by quantum wells QWs are distributed in the table top 3. Wherein, the mesa is formed by opening an oxide trench (trench for oxidation) on the epitaxial structure of the VCSEL. Since the laser light exits from the top of the VCSEL, the optical mode (light mode) and profile (profile) strongly depend on the shape of the p-metal, the shape of the light exit hole, which in turn is determined by the mesa and oxide trench shapes.

There is a great demand for vertical cavity surface emitting laser arrays in the market at present, and higher requirements are also put on the miniaturization of the device density and size. It has long been generally accepted by those skilled in the art that: ensuring the consistency of the shapes of the channels of different light-emitting points is one of the important factors for guaranteeing the density of the device.

As shown in fig. 4-5, all the array units in the vcsel array are identical and uniformly distributed. The applicant finds out after creative work that: there is a need for a vertical cavity surface emitting laser array that better controls the emission of a single vertical cavity surface emitting laser array in the light mode. Without management and control of the optical mode, it can create interference in the far field, causing power variations at certain emitter mode transitions, reducing far field uniformity.

As shown in FIG. 6, in the prior art, VCSEL arrays are formed by processing epitaxial layers based on III-V materials. More specifically, in the manufacturing process, a mesa and an oxidation channel may be formed by etching to the GaAs layer, and then the AlGaAs layer in the epitaxial layer may be oxidized in an oxidation reaction apparatus using the oxidation channel to form an oxide layer and the light exit hole 10, wherein the mesa 2, the oxidation channel, and the upper electrode (e.g., the p-electrode 1) are all circular, and the light exit hole 10 is circular.

In summary, each array unit of the conventional vertical cavity surface emitting laser has a symmetrical shape, and different array units have the same structure and are uniformly distributed, so that the array units with different structures interfere in a far field, and the far field uniformity is reduced, thereby resulting in poor Power conversion efficiency (hereinafter, referred to as PCE), output Power and light-emitting uniformity.

Disclosure of Invention

The invention provides a vertical cavity surface emitting laser array and a method for improving the performance of the vertical cavity surface emitting laser array. The technical problems of poor power conversion efficiency, output power and light emitting uniformity in the prior art are solved.

The embodiment of the invention at least provides the following technical scheme:

the vertical cavity surface emitting laser array provided by the embodiment of the invention comprises a semiconductor layer and a vertical cavity surface emitting laser array formed on the semiconductor layer

The array comprises a plurality of array units, each array unit is provided with an oxidation groove, a table top, a ring and a light-emitting surface, the light-emitting surface is provided with an electrode, an oxidation layer is arranged in the table top, a light-emitting hole is arranged in the oxidation layer, the shape of any one or more of the oxidation groove, the table top, the ring and the electrode of at least part of the array units in the array units is irregular, so that the light-emitting hole is irregularly formed, and the shapes of the light-emitting holes of the different array units are different from each other.

Preferably or optionally, the irregular shape is an asymmetric shape.

Preferably or optionally, the inner peripheral profile of the oxidation trench and/or the mesa of at least one of the array units is an irregular ring shape.

Preferably or optionally, the oxidation trench is a continuous ring shape, and an inner circumferential profile of the oxidation trench is an irregular ring shape.

Preferably or alternatively, the shape of a local region of the oxide trench located on the same array cell is different from the shape of the remaining region.

Preferably or optionally, the oxidation trench is annular in shape and comprises a plurality of segments arranged at intervals, wherein at least two segments have different shapes.

Preferably or alternatively, the difference in shape comprises a difference in size, a difference in ratio of length dimension to width dimension.

Preferably or optionally, the oxidation trench is annular and comprises a plurality of segments arranged at intervals, wherein the distance between at least one segment and two segments adjacent to the segment is different.

Preferably or alternatively, at least two adjacent array units have the same structure and each have a centerline extending in the radial direction, and the centerlines extending in the radial direction of each other are not parallel to each other.

Preferably or optionally, any one or more of the four oxidation trenches, mesas, rings and electrodes of at least two adjacent array units are different in shape from each other.

The method for improving the performance of the vertical cavity surface emitting laser array provided by any technical scheme of the invention comprises the following steps: at least adjusting the shape and/or size of any one or more of the oxidation trench, the mesa, the ring and the electrode of at least one array unit in the vertical cavity surface emitting laser array to adjust the shape and/or size of the light emitting hole, so as to improve the power conversion efficiency, the output power and/or the light emitting uniformity of the VCSEL device.

Preferably or optionally, further comprising the steps of:

and adjusting the shape and/or size of the electrode on the light-emitting surface of the corresponding array unit according to the shape and/or size of the light-emitting hole so as to match the electrode with the light-emitting surface of the corresponding array unit.

Any one of the above technical solutions can produce at least the following technical effects:

in the invention, because the light-emitting holes are irregular and the shapes of the light-emitting holes of different array units in at least one part of array units are different from each other, different array units are not easy to generate interference in a far field, the far field has better uniformity, the power conversion efficiency and the output power are higher, and the light-emitting uniformity is more uniform, thereby solving the technical problem of poorer power conversion efficiency, output power and light-emitting uniformity in the prior art.

Drawings

FIG. 1 is a schematic view of a conventional sectioning structure of a VCSEL;

FIG. 2 is a schematic cross-sectional view of a conventional VCSEL;

FIG. 3 is a top view of a conventional VCSEL;

FIG. 4 is a photograph taken by a Scanning Electron Microscope (SEM) of a conventional VCSEL;

FIG. 5 is a photograph taken by a Scanning Electron Microscope (SEM) of another conventional VCSEL;

FIG. 6 is a top view of a conventional VCSEL;

FIG. 7 is a top view of another conventional VCSEL;

FIG. 8 is a top view of a VCSEL provided by an embodiment of the present invention;

FIG. 9 is a top view of another VCSEL provided by an embodiment of the invention;

FIG. 10 is a top view of yet another VCSEL provided by an embodiment of the invention;

FIG. 11 is a top view of yet another VCSEL provided by an embodiment of the invention;

FIG. 12 is a top view of yet another VCSEL provided by an embodiment of the invention;

FIG. 13 is a top view of yet another VCSEL array provided by an embodiment of the present invention;

FIG. 14 is a top view of yet another VCSEL array provided by an embodiment of the present invention;

FIG. 15 is a top view of yet another VCSEL array provided by an embodiment of the present invention;

in the figure: 1. a p-metal; 2. a table top; 3. a table top; 4. a p-type DBR; 5. an n-type DBR; 6. a resonant cavity; 7. an active region; 8. a substrate; 9. an n-type metal; 10. a light exit hole; 11. an oxide layer; 12. an oxide layer; 13. and oxidizing the trench.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail with reference to fig. 1 to 15. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

As shown in fig. 6 to 15, the vcsel array according to the embodiment of the invention includes a semiconductor layer and a plurality of array units formed on the semiconductor layer, each array unit includes an oxide trench, a mesa 2, a ring and a light-emitting surface, an electrode is disposed on the light-emitting surface (for example, P-metal 1 is illustrated in fig. 7), an oxide layer is disposed in the mesa 2, a light-emitting hole 10 is disposed in the oxide layer, and at least one or more of the oxide trench, the mesa 2, the ring and the electrode of some of the array units in the array unit is irregular (for example, the shape may be an asymmetric shape between a circle and a square) so that the light-emitting hole 10 is irregular, and the light-emitting holes 10 of different array units in at least some of the array units are different from each other.

In the invention, because the light-emitting holes 10 are irregular in shape and the shapes of the light-emitting holes 10 of different array units in at least one part of array units are different from each other, different array units are not easy to generate interference in a far field, the far field has better uniformity, the power conversion efficiency and the output power are higher, and the light-emitting uniformity is more uniform.

As an alternative embodiment, the irregular shape may be a non-rotationally symmetric shape, preferably a (fully) asymmetric shape. The optical mode can be controlled, regulated and controlled by adjusting the shape of any one or more of the oxidation trench, the mesa 2, the ring and the electrode, and a stable optical mode is provided. Of course, the present invention can also determine the size and position of the inner peripheral region of the oxide trench to be adjusted according to actual needs, and finally adjust the shape of the light exit hole 10.

As an alternative embodiment, the inner circumferential profile of the oxidation trench and/or mesa 2 of at least one of the array cells is an irregular ring shape. In the case where a plurality of array cells are present, the inner peripheral profile of the oxidation trench and/or the mesa 2 of part of the array cells may be an irregular ring shape, and part may be a regular ring shape. As shown in fig. 7, the processing conditions of the oxidation trench and the mesa 2 are slightly adjusted, so that different parts of the inner periphery of the oxidation trench have different shapes, the inner periphery of the oxidation trench is in an irregular ring shape, and the shape of the light exit hole 10 is irregular.

As an alternative embodiment, the oxidation trench is a continuous ring shape, and the inner circumferential profile of the oxidation trench is an irregular ring shape. The invention can make the lengths and the intervals of different segments of the oxidation channel different by slightly regulating and controlling the processing conditions of the oxidation channel and the table-board 2, thereby making the inner circumference of the oxidation channel present an irregular ring shape, further making the shape of the light-emitting hole 10 irregular, for example, making the local area of the outer circumference convex to a thorn-shaped circle. Also, by adopting such a design, the optical mode can be controlled, regulated, and a stable optical mode can be provided. The specific shape of the irregular ring shape may be a combination or a split of a plurality of regular shapes, such as a combination of an arc and a polygon, a shape between an ellipse and a square, or a shape between a circle and a rectangle or a pentagon.

As an alternative embodiment, the shape of a local region of the oxide trench on the same array cell is different from the shape of the remaining region. The oxide trenches formed in the same array unit in this structure are irregular.

As shown in fig. 9, the mesa 2 and the oxidation channel can be formed by etching to the GaAs layer, and the AlGaAs layer in the epitaxial layer can be oxidized in the oxidation reaction device by using the oxidation channel, thereby forming the oxidation layer and the light exit hole 10. Wherein, the mesa 2 and the oxidation channel are annular as a whole but formed by combining a plurality of segments arranged at intervals, the upper electrode (such as a p electrode) is annular, and the light-emitting hole 10 is approximately circular.

As an alternative embodiment, the oxidation trench is annular as a whole and comprises a plurality of segments arranged at intervals, wherein at least two segments have different shapes. As shown in fig. 10, at least a portion of the segments constituting the oxidation channel may also be irregularly shaped, so that the light exit opening 10 is also irregular. The difference in shape in the present invention includes a difference in size and a difference in the ratio of the length dimension to the width dimension.

As an alternative embodiment, the oxidation trench is annular as a whole and comprises a plurality of segments arranged at intervals, wherein the distance between at least one segment and two segments adjacent to the segment is different. As shown in fig. 9, the main structure of the vcsel of the present invention can also be fabricated by a process known to those skilled in the art, and the processing conditions of the oxide trench and the mesa 2 can be slightly adjusted, so that the lengths and the intervals of different segments of the oxide trench are different, the inner periphery of the oxide trench is in an irregular ring shape, and the shape of the light exit hole 10 is also irregular.

As an alternative embodiment, several array units formed on one semiconductor layer in the present invention may be the same as each other and uniformly distributed as shown in fig. 13. Or may not be uniformly distributed.

As an alternative embodiment, at least two adjacent array units have the same structure and each have a centerline extending in the radial direction, and the centerlines extending in the radial direction of each other are not parallel to each other. This structure can also be understood as two array units having center lines extending in the radial direction oriented differently.

As shown in fig. 14, the problem of interference between array units in a uniform array during operation can be eliminated in the present invention by rotating some array units in the vcsel array shown in fig. 13 at a certain angle around their center points.

As an alternative embodiment, any one or more of the four of the oxidation trench, the mesa 2, the ring and the electrode of at least two adjacent array units are different in shape from each other. As shown in fig. 15, in the present invention, the structure, distribution position, etc. of each array unit in the VCSEL array shown in fig. 13 can be adjusted simultaneously according to the above embodiments while rotating some array units, so that the problem of interference between array units in a uniform array during operation can be eliminated more effectively.

The method for improving the performance of the vcsel array provided in any of the technical solutions of the present invention adjusts the shape and/or size of the light exit hole 10 by at least adjusting the shape and/or size of any one or more of the oxide trench, the mesa 2, the ring, and the electrode of at least one array unit in the vcsel array provided in any of the technical solutions of the present invention, so as to improve the power conversion efficiency, the output power, and/or the light exit uniformity of the vcsel.

The shape and/or size of any one or more of the oxidation trench, the mesa 2, the ring, and the electrode is changed to adjust the shape and/or size of the light exit aperture 10, and the power conversion efficiency, the output power, and/or the light exit uniformity of the VCSEL device can be improved by adjusting the shape and/or size of the light exit aperture 10.

As an alternative embodiment, the present invention further comprises the steps of:

according to the shape and/or size of the light-emitting hole 10, the shape and/or size of the electrode on the light-emitting surface of the corresponding array unit is adjusted to match the two.

As shown in fig. 11, the shape of the electrode (p-metal) 1 in fig. 11 is also adjusted adaptively according to the shape of the light exit hole 10, and at least the inner peripheral profile thereof is an irregular ring shape matching the light exit hole 10. By adjusting the shape of the upper electrode, the current injection efficiency is improved, the optical mode jump is reduced, and the series resistance of the device is reduced. This will effectively increase the PCE, output power, and uniformity. For the VCSEL shown in FIG. 10, the electrodes may also be adjusted, and the adjusted VCSEL may have the structure shown in FIG. 11.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.