Dual-power-supply-driven vertical cavity surface emitting laser and use method thereof

Abstract

The invention relates to a dual-power-supply-driven vertical-cavity surface-emitting laser and a using method thereof, and belongs to the technical field of semiconductor lasers, the dual-power-supply-driven 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 comprises a cathode, an anode and a discharge cavity, low-temperature plasma generated when the cathode discharges to break down discharge gas in the discharge cavity serves as an electrode, the plasma electrode is located on the light emitting side of the vertical cavity surface emitting laser, an insulating layer is arranged on the side face, close to the substrate, of the plasma electrode, and flow leakage holes are evenly distributed in the insulating layer; the cathode and the anode are electrically connected with a discharge power source, the plasma electrode and the first face electrode or the plasma electrode and the second face electrode are electrically connected with a driving power source, and the technical problem that in the prior art, a large-caliber VCSEL cannot be achieved, and therefore the output power is limited can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor lasers, and in particular relates to a dual-power-source driven 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 various deficiencies in the prior art, a dual-power supply driven vertical cavity surface emitting laser and a method of using the same are proposed to solve the technical problem that the prior art cannot realize large-aperture VCSEL and thus the output power is limited.

[0005] To achieve the above object, the present invention provides the following technical solutions: A dual-power-driven vertical cavity surface emitting laser comprises, in sequence, a first surface electrode, a substrate, an N-type DBR, an active region, a P-type DBR and a second surface electrode, wherein the second surface electrode or the first surface electrode is a plasma electrode, wherein the plasma electrode comprises a cathode, an anode and a discharge cavity, wherein the plasma electrode uses low-temperature plasma generated by cathode discharge breaking through a discharge gas in the discharge cavity as an electrode, wherein the plasma electrode is located at a light-emitting side of the vertical cavity surface emitting laser, wherein an insulating layer is provided on a side of the plasma electrode close to the substrate, wherein leakage holes are uniformly distributed on the insulating layer, wherein the cathode and the anode are electrically connected to a discharge power supply respectively, and wherein the plasma electrode and the first surface electrode, or the plasma electrode and the second surface electrode, are electrically connected to a driving power supply respectively.

[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 discharge cavity is formed between the light exit window and the insulating layer, the cathode and the anode are both located inside the discharge cavity, and the discharge cavity is filled with a discharge gas.

[0008] The technical solution is further configured such that the side surfaces adjacent to the cathode and the anode are both 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 dual-power-source driven vertical cavity surface emitting laser, comprising: S100, a discharge power source is loaded between the cathode and the anode, a strong electric field is generated near the cathode, and the electrons in the cathode material are ejected from the material surface and accelerated under the action of the strong electric field. When the electrons move toward the anode, they collide with the molecules / atoms of the discharge gas, causing an avalanche effect, generating a large number of ions and electrons. When passing through the leakage hole, a very small number of electrons are injected into the active area through the leakage hole, and the vast majority of electrons continue to move toward the anode, forming a full-caliber plasma electrode; S200, a driving power source is loaded between the plasma electrode and the first surface electrode, or between the plasma electrode and the second surface electrode, and current is injected into the active region through the leakage hole, stimulated radiation occurs in the active region, and laser is output from one side of the plasma electrode under multiple reflections of the N-type DBR and the P-type DBR; S300, after the laser output is completed, the discharge power supply is turned off. The beneficial effects of the present invention are: The dual-power drive mode is adopted. By setting an insulating layer, discharge between the anode and the cathode is realized to generate a full-aperture plasma electrode. By setting leakage holes on the insulating layer, the uniformity of the injected current in the active area is achieved. The plasma electrode can be diffused to any aperture, so a large-aperture VCSEL can be realized. While improving the output power of the VCSEL, the spot quality of the output laser can be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of an implementation of a dual-power-source driven 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, the cathode and the anode in an embodiment of the present invention; Figure 3 It is a flow chart of the method for using the dual-power supply driven vertical cavity surface emitting laser in the present invention; Figure 4 is a schematic diagram of another implementation of a dual-power-source driven vertical cavity surface emitting laser in an embodiment of the present invention; Figure 5 is a schematic diagram of current transmission distribution in a longitudinal section of a VCSEL in an embodiment of the present invention; Figure 6 Schematic diagram of normalized current density distribution in the active region of a VCSEL 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. cathode; 7. anode; 8. discharge cavity; 9. light exit window; 10. insulating layer; 11. discharge power supply; 13. driving power supply; 14. leakage hole; 15. 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 dual-power supply driven 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 area 4, a P-type DBR 5 and a second surface electrode 15 in sequence, wherein the second surface electrode 15 or the first surface electrode 1 is a plasma electrode, wherein the plasma electrode comprises a cathode 6, an anode 7 and a discharge cavity 8, wherein the plasma electrode uses a low-temperature plasma generated by cathode discharge breaking through a discharge gas in the discharge cavity 8 as an electrode, wherein the plasma electrode is located on the light-emitting side of the vertical cavity surface emitting laser, an insulating layer 10 is provided on the side of the plasma electrode close to the substrate 2, and leakage holes 14 are evenly distributed on the insulating layer 10, wherein the cathode 6 and the anode 7 are electrically connected to a discharge power supply 11 respectively, and the plasma electrode and the first surface electrode 1, or the plasma electrode and the second surface electrode 15 are electrically connected to a driving power supply 13 respectively.

[0018] It should be noted that, by adopting the dual power drive mode and setting the insulating layer 10, discharge between the anode 7 and the cathode 6 is realized to generate a full-caliber plasma electrode; by setting the leakage hole 14 on the insulating layer 10, the uniformity of the injected current in the active area 4 is achieved, and the plasma electrode can be diffused to any caliber. Therefore, a large-caliber VCSEL can be realized, and the spot quality of the output laser can be guaranteed while improving the output power of the VCSEL.

[0019] In the dual-power-driven vertical-cavity surface-emitting laser of this embodiment, please refer to Figure 1 , Figure 2 as well as Figure 4 A light exit window 9 is provided on the side of the plasma electrode away from the substrate 2 .

[0020] In the dual-power-driven vertical-cavity surface-emitting laser of this embodiment, please refer to Figure 1 , Figure 2 as well as Figure 4The discharge cavity 8 is formed between the light exit window 9 and the insulating layer 10 , the cathode 6 and the anode 7 are both located inside the discharge cavity 8 , and the discharge cavity 8 is filled with a discharge gas.

[0021] It should be noted that the light exit window 9 , the cathode 6 , the anode 7 and the insulating layer 10 together form a discharge chamber 8 , and a discharge gas with a certain pressure is sealed inside the discharge chamber 8 .

[0022] In the dual-power-driven vertical-cavity surface-emitting laser of this embodiment, please refer to Figure 1 , Figure 2 as well as Figure 4 The side surfaces adjacent to the cathode 6 and the anode 7 are both configured to be serrated.

[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 the dual-power-driven vertical-cavity surface-emitting laser of this embodiment, please refer to 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 the dual-power-driven vertical-cavity surface-emitting laser of this embodiment, please refer to Figure 1 , Figure 2 as well as Figure 4 , the substrate 2 is a GaAs or GaN substrate.

[0026] In the dual-power-driven vertical-cavity surface-emitting laser of this embodiment, please refer to Figure 1 , Figure 2 as well as Figure 4 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.

[0027] Specifically, the dual-power-driven 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 10, 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.

[0028] In the simulation of a VCSEL with a light aperture of 55 μm, the leakage holes 14 are evenly distributed in the entire light aperture, with a diameter of 1 μm and a spacing of 10 μm. The current transmission distribution of the VCSEL longitudinal section is obtained as follows: Figure 5 As shown, Figure 5 The middle curve and arrow represent the current transmission path and direction respectively. The normalized current density distribution in the active area is shown in Figure 6 As shown, the PV value is 0.017, indicating that the injection current density distribution of the active region 4 is uniform, there is no current crowding effect, and a high-quality laser beam can be output. In addition, by optimizing the size, number and distribution of the leakage holes 14, a more uniform current density distribution can be obtained.

[0029] In the dual-power-driven vertical-cavity surface-emitting laser of this embodiment, please refer to Figure 1 , Figure 2 as well as Figure 4 The first surface electrode is a plasma electrode, the second surface electrode 15 is a P-surface electrode, and the P-surface electrode is a Ti / Au or Ti / Pt / Au structure.

[0030] Specifically, the dual-power-driven vertical cavity surface emitting laser includes a plasma electrode, an insulating layer 10, a substrate 2, an N-type DBR 3, an active region 4, a P-type DBR 5, and a second surface electrode 15 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.

[0031] According to an embodiment of the present invention, a method for using a dual power supply to drive a vertical cavity surface emitting laser is provided. Figures 1 to 4 ,include: S100, a discharge power source 11 is loaded between the cathode 6 and the anode 7, a strong electric field is generated near the cathode 6, and electrons in the cathode 6 material are ejected from the material surface and accelerated under the action of the strong electric field. When the electrons move toward the anode 7, they collide with the molecules / atoms of the discharge gas, and an avalanche effect occurs, generating a large number of ions and electrons. When passing through the leakage hole 14, a very small number of electrons are injected into the active area 4 through the leakage hole 14, and the vast majority of electrons continue to move toward the anode 7, forming a full-caliber plasma electrode; S200, a driving power source 13 is loaded between the plasma electrode and the first surface electrode 1, or between the plasma electrode and the second surface electrode 15, and current is injected into the active region 4 through the leakage hole 14, and the active region 4 generates stimulated radiation, and outputs laser light from one side of the plasma electrode under multiple reflections of the N-type DBR 3 and the P-type DBR 5; S300 , after the laser output is completed, the discharge power supply 11 is powered off.

[0032] It should be noted that when the plasma encounters the leakage hole 14 during diffusion, because the leakage hole 14 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%, and it has a high damage threshold and can withstand high-power and high-energy laser output. The entire light-transmitting aperture on the light-emitting side is covered by the plasma electrode, and the leakage holes 14 are evenly distributed on the insulating layer 10, so the injected current in the active area 4 is evenly distributed, there is no current crowding effect, and a higher-quality laser beam can be output.

[0033] 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 dual-power-driven 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, wherein the plasma electrode comprises a cathode, an anode and a discharge cavity, wherein the plasma electrode uses a low-temperature plasma generated by cathode discharge breaking through a discharge gas in the discharge cavity as an electrode, wherein the plasma electrode is located on the light-emitting side of a vertical cavity surface emitting laser, 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, wherein the cathode and the anode are electrically connected to a discharge power supply respectively, and the plasma electrode and the first surface electrode, or the plasma electrode and the second surface electrode are electrically connected to a driving power supply respectively.

2. A dual-power source driven 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 dual-power source driven vertical cavity surface emitting laser according to claim 2, characterized in that: The discharge cavity is formed between the light exit window and the insulating layer, the cathode and the anode are both located inside the discharge cavity, and the discharge cavity is filled with a discharge gas.

4. A dual-power source driven vertical cavity surface emitting laser according to claim 1 or 3, characterized in that: The side surfaces of the cathode and the anode adjacent to each other are both configured to be sawtooth-shaped.

5. The dual-power-driven 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 dual-power source driven vertical cavity surface emitting laser according to claim 1, characterized in that: The substrate is a GaAs or GaN substrate.

7. The dual-power-driven 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 dual-power-driven 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 a dual power source driven vertical cavity surface emitting laser according to any one of claims 1 to 8, characterized in that: include: S100, a discharge power source is loaded between the cathode and the anode, a strong electric field is generated near the cathode, and the electrons in the cathode material are ejected from the material surface and accelerated under the action of the strong electric field. When the electrons move toward the anode, they collide with the molecules / atoms of the discharge gas, causing an avalanche effect, generating a large number of ions and electrons. When passing through the leakage hole, a very small number of electrons are injected into the active area through the leakage hole, and the vast majority of electrons continue to move toward the anode, forming a full-caliber plasma electrode; S200, a driving power source is loaded between the plasma electrode and the first surface electrode, or between the plasma electrode and the second surface electrode, and current is injected into the active region through the leakage hole, stimulated radiation occurs in the active region, and laser is output from one side of the plasma electrode under multiple reflections of the N-type DBR and the P-type DBR; S300, after the laser output is completed, the discharge power supply is powered off.

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