Large-aperture high-power vertical cavity surface emitting laser and use method thereof

Abstract

The invention relates to a large-caliber high-power vertical-cavity surface-emitting laser and a using method thereof, and belongs to the technical field of semiconductor lasers, the large-caliber high-power vertical-cavity surface-emitting laser sequentially comprises a first surface electrode, a substrate, an N-type DBR, an active region, a P-type DBR and a second surface electrode, the second surface electrode or the first surface electrode is a plasma electrode, the plasma electrode takes low-temperature plasma generated by disrupting discharge gas by the annular discharge electrode as an electrode, the plasma electrode is positioned on the light emitting side of the vertical cavity surface emitting laser, an insulating layer is arranged on the side surface, close to the substrate, of the plasma electrode, and leakage holes are uniformly distributed in the insulating layer; according to the invention, the technical problems that a large-aperture VCSEL cannot be realized and high-power laser output is limited in the prior art can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor lasers, and in particular relates to a large-aperture high-power vertical cavity surface emitting laser and a use method thereof. Background Art

[0002] Semiconductor lasers are divided into two types: edge-emitting and vertical-emitting. That is, the direction of the laser emission is parallel to the substrate or perpendicular to the substrate. Vertical cavity surface emitting laser (VCSEL) is a type of vertical emission. It places two distributed Bragg reflectors (DBR) on the upper and lower sides of the laser active layer, and adjusts the reflectivity of the DBR by growing epitaxial materials, so that the laser cavity resonates in the vertical direction, thereby achieving the purpose of vertical emission. VCSEL is widely used in the field of optical fiber communication because of its high connection efficiency with optical fiber, its manufacturing process matches the traditional semiconductor process, low power consumption and fast output power adjustment speed.

[0003] The traditional VCSEL includes an N-type contact electrode, a substrate, an N-type DBR, an active area, a P-type DBR and a P-type contact electrode stacked in sequence. Due to the use of a ring electrode, the injection current distribution in the active area is uneven, the edge current is large, and the middle current is small, resulting in a current crowding effect. Especially at a large aperture, the current crowding effect is significant and the output spot quality is poor. In order to solve the above problems, on the basis of the ring electrode, some distributed metal filament electrodes are usually designed within the aperture, which can greatly reduce the current crowding effect. However, since the metal filament electrode is placed within the aperture, it will diffract the output laser. At the same time, the metal filament electrode has a damage threshold, which will be damaged when the high-power laser is emitted, limiting the output of the high-power laser. The low-temperature plasma generated by gas discharge has almost no effect on the passing laser and has a high damage threshold. The plasma electrode can diffuse to any aperture and is an ideal transparent electrode. However, when the plasma contacts the semiconductor during the diffusion process, the electrons in the plasma are transmitted through the semiconductor without colliding with the gas, resulting in the plasma being unable to continue to diffuse in space and unable to form a full-aperture plasma electrode. The effect produced is similar to that of a ring electrode. Summary of the invention

[0004] In view of the various deficiencies of the prior art, a large-aperture high-power vertical cavity surface emitting laser and a method of using the same are proposed to solve the technical problems that the prior art cannot realize large-aperture VCSEL and limits high-power laser output.

[0005] To achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a large-aperture high-power vertical cavity surface emitting laser, which comprises a first surface electrode, a substrate, an N-type DBR, an active region, a P-type DBR and a second surface electrode in sequence, wherein the second surface electrode or the first surface electrode is a plasma electrode, and the plasma electrode uses a low-temperature plasma generated by a ring-shaped discharge electrode breaking down a discharge gas as an electrode, and the plasma electrode is located on the light-emitting side of the vertical cavity surface emitting laser, and an insulating layer is provided on the side of the plasma electrode close to the substrate, and leakage holes are evenly distributed on the insulating layer.

[0006] The technical solution is further configured such that a light exit window is provided on a side of the plasma electrode away from the substrate.

[0007] The technical solution is further configured such that the annular discharge electrode is located between the light exit window and the insulating layer, the middle of the annular discharge electrode serves as a discharge cavity, and the discharge cavity is filled with a discharge gas.

[0008] The technical solution is further configured such that the inner ring of the annular discharge electrode is configured in a sawtooth shape.

[0009] The technical solution is further configured such that the active region is a quantum dot active region or a quantum well active region.

[0010] The technical solution is further configured such that the substrate is a GaAs or GaN substrate.

[0011] The technical solution is further configured as follows: the second surface electrode is a plasma electrode, the first surface electrode is an N-surface electrode, and the N-surface electrode is a Au / Ge / Ni, AuGeNi / Au, Au / Ge or Pt / Au / Ge structure.

[0012] The technical solution is further configured as follows: the first surface electrode is a plasma electrode, the second surface electrode is a P-surface electrode, and the P-surface electrode is a Ti / Au or Ti / Pt / Au structure.

[0013] In a second aspect, the present invention provides a method for using a large-aperture high-power vertical cavity surface emitting laser, comprising: S100, applying a driving voltage between the annular discharge electrode and the second surface electrode, or between the annular discharge electrode and the first surface electrode, so that the annular discharge electrode breaks down the discharge gas near it to generate low-temperature plasma; S200. Under the continuous action of the driving voltage, the low-temperature plasma diffuses from the surroundings of the discharge cavity to the middle thereof. During the diffusion process, when the low-temperature plasma passes through the leakage hole, a small part of the current is injected into the active area through the Bragg reflector. The low-temperature plasma continues to diffuse to form a full-aperture plasma electrode. At the same time, stimulated radiation occurs in the active area, and laser is output from one side of the plasma electrode under multiple reflections of the N-type DBR and the P-type DBR. The beneficial effects of the present invention are: By setting an insulating layer, dielectric barrier discharge can be used to produce a full-aperture plasma electrode. By setting leakage holes on the insulating layer, the uniformity of the injected current in the active area can be achieved. The plasma electrode can be diffused to any aperture, so a large-aperture VCSEL can be realized, which can improve the output power of the VCSEL while ensuring the spot quality of the output laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of an implementation method of a large-aperture high-power vertical-cavity surface-emitting laser in an embodiment of the present invention; Figure 2 is a schematic diagram of the assembly of the insulating layer and the annular discharge electrode in an embodiment of the present invention; Figure 3 It is a flowchart of a method for using a large-aperture high-power vertical cavity surface emitting laser in the present invention; Figure 4 is a schematic diagram of another implementation of a large-aperture high-power vertical-cavity surface-emitting laser in an embodiment of the present invention; Figure 5 Schematic diagram of the normalized current density distribution injected into the active region in an embodiment of the present invention.

[0015] In the accompanying drawings: 1. first surface electrode; 2. substrate; 3. N-type DBR; 4. active area; 5. P-type DBR; 6. annular discharge electrode; 7. discharge cavity; 8. light exit window; 9. insulating layer; 11. leakage hole; 12. second surface electrode. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making creative work should all fall within the scope of protection of this application. In addition, the directional words mentioned in the following embodiments, such as "up", "down", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional words used are used to illustrate rather than limit the invention.

[0017] According to an embodiment of the present invention, a large-aperture high-power vertical cavity surface emitting laser is provided. Figure 1 , Figure 2 as well as Figure 4 , comprising a first surface electrode 1, a substrate 2, an N-type DBR 3, an active region 4, a P-type DBR 5 and a second surface electrode 12 in sequence, wherein the second surface electrode 12 or the first surface electrode 1 is a plasma electrode, wherein the plasma electrode uses a low-temperature plasma generated by a ring-shaped discharge electrode 6 breaking down a discharge gas as an electrode, and the plasma electrode is located on the light-emitting side of a vertical cavity surface emitting laser, and an insulating layer 9 is provided on the side of the plasma electrode close to the substrate, and leakage holes 11 are evenly distributed on the insulating layer 9.

[0018] It should be noted that by providing the insulating layer 9 and the annular discharge electrode 6, dielectric barrier discharge is achieved to generate plasma; by providing the leakage hole 11 on the insulating layer 9, not only a full-aperture plasma electrode can be generated, but also the uniformity of the injected current in the active area 4 can be achieved, and the plasma electrode can be diffused to any aperture, so that a large-aperture VCSEL can be realized, and the output power of the VCSEL can be improved while ensuring the beam quality of the output laser.

[0019] In this embodiment, the large-aperture high-power vertical cavity surface emitting laser is shown in Figure 1 , Figure 2 as well as Figure 4 A light exit window 8 is provided on the side of the plasma electrode away from the substrate 2 .

[0020] In this embodiment, the large-aperture high-power vertical cavity surface emitting laser is shown in Figure 1 , Figure 2 as well as Figure 4 The annular discharge electrode 6 is located between the light exit window 8 and the insulating layer 9 , and the middle of the annular discharge electrode 6 serves as a discharge cavity 7 , and the discharge cavity 7 is filled with a discharge gas.

[0021] It should be noted that the light exit window 8 , the annular discharge electrode 6 and the insulating layer 9 together form a discharge cavity 7 , and a discharge gas with a certain pressure is sealed inside the discharge cavity 7 .

[0022] In this embodiment, the large-aperture high-power vertical cavity surface emitting laser is shown in Figure 1 , Figure 2 as well as Figure 4 The inner ring of the annular discharge electrode 6 is configured to be sawtooth-shaped.

[0023] It should be noted that the serration shape can enhance the electric field near the electrode, making it easier for the discharge gas to be broken down.

[0024] In this embodiment, the large-aperture high-power vertical cavity surface emitting laser is shown in Figure 1 , Figure 2 as well as Figure 4 The active region 4 is a quantum dot active region or a quantum well active region. Specifically, the active region 4 is a periodic multiple quantum well structure of InGaAs / GaAsP, GaAs / AlGaAs, InGaAs / GaAs or AlGaN / InGaN.

[0025] In this embodiment, the large-aperture high-power vertical cavity surface emitting laser is shown in Figure 1 , Figure 2 as well as Figure 4 , the substrate 2 is a GaAs or GaN substrate.

[0026] In this embodiment, the large-aperture high-power vertical cavity surface emitting laser is shown in Figure 1 , Figure 2 as well as Figure 4 The P-type DBR5 and the N-type DBR3 are both GaAs or AlAs structures.

[0027] In this embodiment, the large-aperture high-power vertical cavity surface emitting laser is shown in Figure 1 to Figure 2 The second surface electrode is a plasma electrode, the first surface electrode 1 is an N-surface electrode, and the N-surface electrode is a Au / Ge / Ni, AuGeNi / Au, Au / Ge or Pt / Au / Ge structure.

[0028] Specifically, the large-aperture high-power vertical cavity surface emitting laser includes a first surface electrode 1, a substrate 2, an N-type DBR 3, an active region 4, a P-type DBR 5, an insulating layer 9, and a plasma electrode in sequence. The plasma electrode uses a low-temperature plasma generated by the discharge of a discharge gas as an electrode, and the plasma electrode is located on the light-emitting side of the laser. That is, in this embodiment, the plasma electrode serves as a P-surface electrode, and the vertical cavity surface emitting laser is a typical top-emitting VCSEL.

[0029] In the simulation of a VCSEL with a light aperture of 55 μm, the leakage holes 11 are evenly distributed in the entire light aperture, the diameter of the leakage holes 11 is 1 μm, each leakage hole 11 has 6 adjacent leakage holes 11, and the spacing between adjacent leakage holes 11 is 10 μm. The normalized current density distribution injected into the active area 4 is obtained as follows: Figure 5 As shown, from Figure 5 It can be seen that the current density in most of the central area is relatively uniform, with only a slight fluctuation at the edge. The current density PV value in the central φ50um aperture is calculated to be 0.185, indicating that the injection current density distribution of the active area 4 is uniform, and a high-quality laser beam can be output. In addition, by optimizing the size, number and distribution of the leakage holes 11, a more uniform current density distribution can be obtained.

[0030] In this embodiment, the large-aperture high-power vertical cavity surface emitting laser is shown in Figure 1 as well as Figure 4 The first surface electrode is a plasma electrode, the second surface electrode 12 is a P-surface electrode, and the P-surface electrode is a Ti / Au or Ti / Pt / Au structure.

[0031] Specifically, the large-aperture high-power vertical cavity surface emitting laser includes a plasma electrode, an insulating layer 9, a substrate 2, an N-type DBR 3, an active region 4, a P-type DBR 5, and a second surface electrode 12 in sequence. The plasma electrode uses a low-temperature plasma generated by discharge gas discharge as an electrode, and the plasma electrode is located on the light-emitting side of the laser. That is, in this embodiment, the plasma electrode serves as an N-surface electrode, and the vertical cavity surface emitting laser is a typical bottom-emitting VCSEL.

[0032] According to an embodiment of the present invention, a method for using a large-aperture high-power vertical cavity surface emitting laser is provided. Figures 1 to 4 ,include: S100, applying a driving voltage between the annular discharge electrode 6 and the second surface electrode 12, or between the annular discharge electrode 6 and the first surface electrode 1, so that the annular discharge electrode 6 breaks down the discharge gas near it to generate low-temperature plasma; S200. Under the continuous action of the driving voltage, the low-temperature plasma diffuses from the surroundings of the discharge cavity 7 to the middle thereof. During the diffusion process, when the low-temperature plasma passes through the leakage hole 11, a small part of the current is injected into the active area 4 through the Bragg reflector. The low-temperature plasma continues to diffuse to form a full-aperture plasma electrode. At the same time, stimulated radiation occurs in the active area 4, and laser is output from one side of the plasma electrode under multiple reflections of the N-type DBR3 and the P-type DBR5.

[0033] It should be noted that a driving voltage is applied between the annular discharge electrode 6 and the second surface electrode 12, or between the annular discharge electrode 6 and the first surface electrode 1, and there is an insulating layer 9 between the annular discharge electrode 6 and the second surface electrode 12, or between the annular discharge electrode 6 and the first surface electrode 1, so a dielectric barrier discharge occurs, and the discharge gas near the annular discharge electrode 6 is broken down to form a low-temperature plasma. Under the continuous action of the external driving voltage, the low-temperature plasma diffuses from the surroundings of the discharge chamber 7 to the middle. When encountering the leakage hole 11, because the leakage hole 11 is very small, only a small part of the current is injected into the semiconductor, so it does not affect the diffusion of the low-temperature plasma, and finally forms a full-caliber plasma electrode. The transmittance of low-temperature plasma to laser is close to 100%, has a high damage threshold, and can withstand high-power and high-energy laser output. The entire light aperture on the light-emitting side is covered by the plasma electrode, and the leakage holes 11 are evenly distributed on the insulating layer 9, so the injected current in the active area 4 is evenly distributed, there is no current crowding effect, and a high-quality laser beam can be output.

[0034] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made within the scope of this application should still fall within the scope of the present invention.

Claims

1. A large-aperture high-power vertical cavity surface emitting laser, characterized in that: The invention comprises a first surface electrode, a substrate, an N-type DBR, an active area, a P-type DBR and a second surface electrode in sequence, wherein the second surface electrode or the first surface electrode is a plasma electrode, and the plasma electrode uses a low-temperature plasma generated by a ring-shaped discharge electrode breaking down a discharge gas as an electrode, and the plasma electrode is located on the light-emitting side of a vertical cavity surface emitting laser, and an insulating layer is arranged on the side of the plasma electrode close to the substrate, and leakage holes are evenly distributed on the insulating layer.

2. A large-aperture high-power vertical cavity surface emitting laser according to claim 1, characterized in that: A light exit window is arranged on the side of the plasma electrode away from the substrate.

3. A large-aperture high-power vertical cavity surface emitting laser according to claim 2, characterized in that: The annular discharge electrode is located between the light exit window and the insulating layer. The middle of the annular discharge electrode serves as a discharge cavity, and the discharge cavity is filled with a discharge gas.

4. A large-aperture high-power vertical cavity surface emitting laser according to claim 1 or 3, characterized in that: The inner ring of the annular discharge electrode is configured to be sawtooth-shaped.

5. The large-aperture high-power vertical cavity surface emitting laser according to claim 1, characterized in that: The active region is a quantum dot active region or a quantum well active region.

6. A large-aperture high-power vertical cavity surface emitting laser according to claim 1, characterized in that: The substrate is a GaAs or GaN substrate.

7. The large-aperture high-power vertical cavity surface emitting laser according to claim 1, characterized in that: The second surface electrode is a plasma electrode, the first surface electrode is an N-surface electrode, and the N-surface electrode is a Au / Ge / Ni, AuGeNi / Au, Au / Ge or Pt / Au / Ge structure.

8. The large-aperture high-power vertical cavity surface emitting laser according to claim 1, characterized in that: The first surface electrode is a plasma electrode, the second surface electrode is a P-surface electrode, and the P-surface electrode is a Ti / Au or Ti / Pt / Au structure.

9. A method for using the large-aperture high-power vertical cavity surface emitting laser according to any one of claims 1 to 8, characterized in that: include: S100, applying a driving voltage between the annular discharge electrode and the second surface electrode, or between the annular discharge electrode and the first surface electrode, so that the annular discharge electrode breaks down the discharge gas near it to generate low-temperature plasma; S200. Under the continuous action of the driving voltage, the low-temperature plasma diffuses from the surroundings of the discharge cavity to the middle thereof. During the diffusion process, when the low-temperature plasma passes through the leakage hole, a small part of the current is injected into the active area through the Bragg reflector. The low-temperature plasma continues to diffuse to form a full-aperture plasma electrode. At the same time, stimulated radiation occurs in the active area, and laser is output from one side of the plasma electrode under multiple reflections of the N-type DBR and the P-type DBR.

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