VCSEL (Vertical Cavity Surface Emitting Laser) with uniform light emission and laser equipment

Abstract

The utility model belongs to the technical field of semiconductors, and particularly relates to a VCSEL (vertical cavity surface emitting laser) uniform in light emitting, which comprises a plurality of light emitting arrays, each light emitting array comprises a plurality of light emitting units arranged in sequence, and each light emitting unit comprises a substrate layer with a top surface and a bottom surface; a first Bragg reflector on the top surface of the substrate layer; the active region is positioned on one side, far away from the substrate layer, of the first Bragg reflector; the electrical limiting layer provides optical and electrical limitation for the VCSEL laser, and the electrical limiting layer is provided with a light-emitting hole for current and laser to pass through; the second Bragg reflector is positioned on one side, far away from the first Bragg reflector, of the active region; wherein the apertures of the plurality of light-emitting holes in the light-emitting array are gradually increased along the current flowing direction.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductors, and particularly relates to a VCSEL laser with uniform light emission and a laser device. BACKGROUND

[0002] VCSEL (Vertical-Cavity Surface-Emitting Laser) is a new type of semiconductor laser that emits laser light along the direction perpendicular to the substrate. It has the advantages of low threshold current, small size, easy two-dimensional integration, etc. In practical applications, multiple VCSELs are usually integrated together to form a VCSEL array to improve the output power and beam quality.

[0003] By inputting current to the VCSEL array, the VCSEL array is lit. At present, when powering the VCSEL array, power is usually supplied from one side of the VCSEL array. However, this power supply method results in high current near the power source and low current farther away from the power source. The reduction in current leads to a reduction in the light emission power of the corresponding VCSEL, which affects the uniformity of the light emitted by the VCSEL array. Therefore, a new VCSEL structure design scheme is needed to improve the performance of the VCSEL laser. CONTENT OF THE INVENTION

[0004] One advantage of the application is to provide a VCSEL laser with uniform light emission. In order to achieve uniform light emission, the aperture of the light emission hole on the light emission array is changed, and the corresponding size of the light emission hole aperture is adapted according to the intensity of the current to keep the intensity of the light emitted by each light emission hole consistent, thereby keeping the laser of the VCSEL laser uniform.

[0005] In order to achieve the above at least one advantage or other advantages and purposes, according to one aspect of the application, a VCSEL laser with uniform light emission is provided, which comprises a plurality of light emission arrays, each of which comprises a plurality of sequentially arranged light emission units, wherein the light emission unit comprises

[0006] a substrate layer having a top surface and a bottom surface;

[0007] a first Bragg reflector located on the top surface of the substrate layer;

[0008] an active region located on the side of the first Bragg reflector away from the substrate layer;

[0009] an electrical confinement layer providing optical and electrical confinement, the electrical confinement layer having a light emission hole for current and laser to pass through;

[0010] a second Bragg mirror located on a side of the active region away from the first Bragg mirror;

[0011] wherein a plurality of the light emitting holes on the light emitting array have an aperture that gradually increases along a direction of current flow.

[0012] In the VCSEL laser with uniform light emission according to the application, the light emitting unit further comprises a first electrode as a cathode of the light emitting unit and a second electrode as an anode of the light emitting unit, and the resistive layer is in contact with a bottom surface of the second electrode.

[0013] In the VCSEL laser with uniform light emission according to the application, a distance between two adjacent light emitting holes on the light emitting array gradually decreases along a direction of current flow.

[0014] In the VCSEL laser with uniform light emission according to the application, the light emitting hole is one of a circular light emitting hole and a polygonal light emitting hole.

[0015] In the VCSEL laser with uniform light emission according to the application, two adjacent light emitting holes on the light emitting array partially overlap.

[0016] In the VCSEL laser with uniform light emission according to the application, two adjacent light emitting holes on the light emitting array are tangent to each other.

[0017] In the VCSEL laser with uniform light emission according to the application, two adjacent light emitting holes on the light emitting array share the same etching groove.

[0018] In the VCSEL laser with uniform light emission according to the application, the first Bragg mirror is an N-DBR, and the second Bragg mirror is a P-DBR.

[0019] In the VCSEL laser with uniform light emission according to the application, the first Bragg mirror is a P-DBR, and the second Bragg mirror is an N-DBR.

[0020] According to yet another aspect of the application, the application provides an electronic device comprising:

[0021] a laser projection device for projecting a laser, wherein the laser projection device comprises any of the VCSEL lasers with uniform light emission as described above;

[0022] a laser receiving device for receiving a laser signal; and

[0023] a processor communicably connected to the laser projection device and the laser receiving device.

[0024] These and other objects, features, and advantages of the present application will become apparent with reference to the following description and drawings.

[0025] These and other objects, features, and advantages of the present application will become apparent with reference to the following description and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A top view of a VCSEL laser with uniform light emission for which current is input from one side of the light emitting array.

[0027] Figure 2 A top view of a VCSEL laser with uniform light emission for which current is input from both sides of the light emitting array.

[0028] Figure 3 An example diagram of a light emitting cell layer structure of a VCSEL laser with uniform light emission.

[0029] Figure 4 A cross-sectional view of a light emitting cell of a VCSEL laser with uniform light emission.

[0030] Figure 5 An example diagram of a light emitting cell layer structure of another VCSEL laser with uniform light emission. DETAILED DESCRIPTION

[0031] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used to enable a clear and consistent in understanding of the application. Therefore, it should be apparent to those skilled in the art that the following description of various embodiments of the present application is provided for illustration purpose only and not for the purpose of limiting the application as defined by the appended claims and their equivalents.

[0032] It is to be understood that the terms "one", "another", "an", "a", "another", "one or more", "at least one", and "one or more" are understood not to limit the number of objects to one or more unless the context clearly indicates otherwise. The term "plurality" is understood to imply two or more of an object unless the context clearly indicates otherwise.

[0033] Although ordinal numbers such as "first", "second", etc., will be used to describe various components, the components are not limited by the ordinal numbers. The ordinal numbers are used merely to distinguish a component from another. For example, a first component can be termed as a second component, and likewise, a second component can also be termed as a first component without departing from the teachings of the present application. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0034] The terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "has," when used in this specification, specify the presence of stated features, numbers, steps, operations, components, elements, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, elements, or combinations thereof.

[0035] SUMMARY

[0036] After the pump source current enters the VCSEL laser array, the current is lost when flowing through each light emitting unit 10. This results in the light emitting unit 10 far from the input end receiving a smaller current, and thus emitting a lower light power; while the light emitting unit 10 close to the input end receives a larger current, and thus emits a higher light power. This uneven current distribution ultimately leads to the uneven light emission of the VCSEL laser array.

[0037] Based on the above problem analysis, in order to solve the uneven light emission of the VCSEL laser array, and improve the light power of the VCSEL laser array. The present application proposes to improve the aperture size of the light emitting hole on the light emitting array, so as to keep the light intensity of each light emitting hole on the light emitting array consistent, thereby realizing the uniform light emission of the VCSEL laser array.

[0038] Correspondingly, the present application proposes a VCSEL laser with uniform light emission, comprising a plurality of light emitting arrays, each of the light emitting arrays comprising a plurality of light emitting units arranged in sequence, wherein the light emitting unit comprises a substrate layer having a top surface and a bottom surface; a first Bragg reflector located on the top surface of the substrate layer; an active region located on the side of the first Bragg reflector away from the substrate layer; an electrical confinement layer providing optical and electrical confinement for the VCSEL laser, the electrical confinement layer having a light emitting hole for current and laser to pass through; a second Bragg reflector located on the side of the active region away from the first Bragg reflector; wherein the apertures of the plurality of light emitting holes on the light emitting array gradually increase in the direction of current flow.

[0039] After introducing the basic principles of the present application, various non-limiting embodiments of the present application will be specifically introduced below with reference to the accompanying drawings.

[0040] Schematic VCSEL laser

[0041] As Figures 1-5As shown, the present application discloses a VCSEL laser with uniform light emission. The VCSEL laser is composed of a plurality of light emission arrays 1, which are arranged in order along the transverse or longitudinal direction. Each light emission array 1 further comprises a plurality of light emission units 10. In the design, the current of the pump source is input from one end of the light emission array 1, and then sequentially lights up each light emission unit 10. Alternatively, in other examples, in order to improve the light emission efficiency of the VCSEL laser, the current of the pump source is synchronously input from both ends of the light emission array 1.

[0042] Referring to Figure 3 and Figure 4 , according to the VCSEL laser disclosed in the embodiments of the present application, the light emission units 10 of the light emission array 1 on each of the VCSEL lasers sequentially comprise, from bottom to top, a substrate layer 11, a first Bragg reflector 12, an active region 13, an electrical confinement layer 14, and a second Bragg reflector 15. The substrate layer 11 serves as the base of the light emission unit 10, and the first Bragg reflector 12 is stacked on the upper surface of the substrate layer 11. The substrate layer 11 is an N-doped gallium arsenide substrate, or alternatively, in other embodiments, the substrate layer 11 is a P-doped gallium arsenide substrate; of course, in other embodiments, the material of the substrate layer 11 can be an InP, GaN, GaAs, etc. doped material. The substrate layer 11 has a top surface and a bottom surface, and the bottom surface of the substrate layer 11 is provided with a first electrode 19, which serves as the cathode of the light emission unit 10.

[0043] The first Bragg reflector 12 is grown on the top surface of the substrate layer 11 by a vapor phase epitaxy technique (MOCVD), and the first Bragg reflector 12 is an N-DBR formed by the alternative stacking of N-doped high-aluminum-content AlxGaAs and N-doped low-aluminum-content AlxGaAs. It is worth mentioning that the material selection of the alternative layers depends on the operating wavelength of the laser emitted by the light emission unit 10, and the optical thickness of the alternative layers is equal to or approximately equal to 1 / 4 of the operating wavelength of the laser.

[0044] The active region 13 is grown on the top surface of the first Bragg reflector 12 by a vapor phase epitaxy technique (MOCVD), and the active region 13 is sandwiched between the first Bragg reflector 12 and the second Bragg reflector 15 to form a resonant cavity. After being excited, the photons repeatedly amplify in the resonant cavity to form laser oscillation, thereby forming a laser.

[0045] The second Bragg mirror 15 is located above the first Bragg mirror 12, and is grown on the top surface of the active region 13 by a vapor phase epitaxy (MOCVD) technique. The second Bragg mirror 15 is a P-DBR formed by an alternating stack of P-type doped high-aluminum-content AlxGaAs and P-type doped low-aluminum-content AlxGaAs.

[0046] In the embodiment, the second Bragg mirror 15 is provided with an insulating protective layer 18 on the side away from the active region 13. The protective layer 18 protects the second Bragg mirror 15 from damage during operation and adjusts the laser emitted by the active region 13 to improve the divergence angle and optical power of the light-emitting unit 10. In the embodiment, the protective layer 18 is preferably Si3N4 (silicon nitride) with insulating and optical modulation properties. In other variant embodiments, the protective layer can be any one of SiO2, Al2O3, and AlN. Alternatively, in another variant embodiment, the protective layer can be a combination of SiO2, Si3N4, Al2O3, and AlN.

[0047] A second electrode 16 is stacked on the side of the second Bragg mirror 15 away from the active region 13. The second electrode 16 is gold deposited on the top surface of the second Bragg mirror 15 by evaporation. An anode electrode 17 is deposited on the top surface of the second electrode 16. The anode electrode 17 is copper-gold or gold deposited.

[0048] The electrical confinement layer 14 is formed on the lower part of the second Bragg mirror 15 or on the upper part of the active region 13. The electrical confinement layer 14 has a high resistivity to guide the flow of electric charges from the middle region of the VCSEL laser into the active region 13. The electrical confinement layer 14 has a ring structure, and the area enclosed by the electrical confinement layer 14 forms a light-emitting hole 141 for the laser emitted by the active region 13. From the view direction of the second Bragg mirror 15 toward the first Bragg mirror 12, the light-emitting hole 141 is a circular or polygonal structure. As shown in Figure 2

[0049] In the embodiment, the electrical confinement layer 14 is formed by oxidizing the second Bragg mirror 15 or the active region 13. Of course, in other embodiments, the electrical confinement layer 14 can also be formed by ion implantation on the second Bragg mirror 15 or the active region 13. The implanted ions can be one or more of the following: H+, O+, and B+.

[0050] As shown in Figure 1 ​The number of light emitting holes 141 on the light emitting array 1 is multiple, and the aperture size of each of the multiple light emitting holes 141 on the light emitting array 1 is different. Specifically, the aperture size of the light emitting hole 141 gradually decreases along the direction of current flow. The closer the light emitting unit 10 corresponding to the light emitting hole 141 to the Pad, the smaller the aperture size of the light emitting hole 141, and the farther the light emitting hole 141 from the Pad, the larger the aperture size of the light emitting hole 141.

[0051] The distance between the two adjacent light emitting holes 141 on the light emitting array 1 gradually decreases along the direction of current flow. As shown in Figure 3 In other embodiments, in order to increase the light power of the light emitting array and reduce the volume of the VCSEL laser, the two adjacent light emitting holes 141-3 partially overlap. Alternatively, as shown in Figure 4 In another embodiment, the two adjacent light emitting holes 141-4 share the same etching hole 14, which makes the adjacent edges of the two light emitting holes 141-4 partially overlap, i.e., the distance between the two light emitting holes 141-4 is zero.

[0052] In summary, the VCSEL laser based on the embodiments of the present application is illustrated, which provides a feasible design scheme for uniform current flow through the light emitting hole, can change the current flow direction, reduce the current density at the edge of the light emitting hole, reduce the heat generated during the operation of the VCSEL laser, improve the reliability of the VCSEL laser, and improve the uniformity of the light spot emitted by the VCSEL laser during operation, i.e., form a light spot with the same brightness in the outer ring and the middle.

[0053] Schematic laser device

[0054] According to another aspect of the present application, a laser device is also provided. The working principle of the laser device is to emit laser to the measured target and receive the reflected laser from the measured target, and based on the time difference between the emitted laser and the received laser pulse (or the phase difference between the emitted laser and the reflected laser), the relative position and distance between the measured target and the laser device are obtained, so as to realize the detection, tracking and identification of the measured object in the target area.

[0055] It should be noted that in the device and method of the present application, each component or each step in different embodiments can be decomposed and / or recombined without departing from the principle of the present application. These decompositions and / or recombination should be considered as included in the application concept of the present application.

[0056] The basic principles of the present application are described above in conjunction with specific embodiments, but it should be noted that the advantages, advantages, effects and the like mentioned in the present application are only examples and are not limiting, and these advantages, advantages, effects and the like cannot be considered as the must-have of each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of example and for the purpose of understanding, and the above details do not limit the present application to the must-use of the above specific details to realize.

Claims

1. A VCSEL laser with uniform light emission, characterized in that The light-emitting array comprises a plurality of light-emitting arrays, each of the light-emitting arrays comprising a plurality of light-emitting units arranged in sequence, wherein the light-emitting units comprise a substrate layer having a top surface and a bottom surface; a first Bragg reflector on the top surface of the substrate layer; an active region on a side of the first Bragg reflector away from the substrate layer; an electrical confinement layer providing optical and electrical confinement for the VCSEL laser, the electrical confinement layer having a light-emitting aperture for current and laser to pass through; a second Bragg reflector on a side of the active region away from the first Bragg reflector; wherein the aperture of the plurality of light-emitting apertures on the light-emitting array gradually increases along a direction of current flow.

2. A uniform emitting VCSEL laser according to claim 1, wherein, The pitch of the plurality of adjacent two light-emitting apertures on the light-emitting array gradually decreases along the direction of current flow.

3. A uniform emitting VCSEL laser as claimed in claim 1, wherein, The light-emitting aperture is one of a circular light-emitting aperture and a polygonal light-emitting aperture.

4. The uniform emitting VCSEL laser of claim 1, wherein, The adjacent two light-emitting apertures on the light-emitting array partially overlap.

5. The uniform emitting VCSEL laser of claim 1, wherein, The adjacent two light-emitting apertures on the light-emitting array are tangent to each other.

6. A uniform emitting VCSEL laser as claimed in claim 1, wherein, The adjacent two light-emitting apertures on the light-emitting array share the same etching groove.

7. A uniform emitting VCSEL laser as claimed in claim 1, wherein, The first Bragg reflector is an N-DBR, and the second Bragg reflector is a P-DBR.

8. A uniform emitting VCSEL laser as claimed in claim 1, wherein, The first Bragg reflector is a P-DBR, and the second Bragg reflector is an N-DBR.

9. An electronic device, comprising: The light-emitting array comprises: a laser projection device for projecting laser, wherein the laser projection device comprises the VCSEL laser with uniform light emission as claimed in any one of claims 1 to 8; a laser receiving device for receiving laser signals; and a processor communicably connected to the laser projection device and the laser receiving device.

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