Vertical cavity surface-emitting laser

Abstract

To provide a vertical cavity surface emitting laser having a plurality of reflecting mirrors.SOLUTION: The vertical cavity surface emitting laser Z1 according to the present invention is provided with a plurality of reflectors. To be specific, the vertical cavity surface emitting laser Z1 of the present invention has a first resonance cavity C1 and a second resonance cavity C2, the second resonance cavity C2 is far away from the current limiting layer 13, and the light beam is mainly emitted after resonating in the second resonance cavity C2. With this structure, the influence of beam scattering caused by the current limiting layer 13 is solved, and the light emitting effect is improved.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vertical cavity surface emitting laser having a plurality of reflectors. [Background Art]

[0002] A conventional vertical cavity surface emitting laser includes a current confinement layer. This current confinement layer is generally made of an oxide. When a beam resonates in the resonance chamber, the beam is often scattered under the influence of the current confinement layer, which affects the light emission efficiency of the laser.

[0003] In the prior art, to solve the above problem, narrowing the confinement aperture of the current confinement layer has been implemented. As a result, the electrical resistance of the laser increases, which is disadvantageous for light emission of the laser device and requires more electrical energy for light emission. [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] Therefore, improving the light emission efficiency of a vertical cavity surface emitting laser and overcoming the above-mentioned drawbacks through improvement of structural design has become one of the important problems to be solved by those skilled in the art. [Means for Solving the Problem]

[0005] The problem to be solved by the present invention is to provide a vertical cavity surface emitting laser comprising an active light emitting layer, a first reflector, a current confinement layer, a second reflector, and a third reflector.

[0006] In the vertical-cavity surface-emitting laser according to the present invention, the opposing sides of the active emission layer are defined as the first side and the second side, respectively. The first reflector is located on the first side of the active emission layer and has a first reflective surface. The current-limiting layer is located on the second side of the active emission layer and has limiting holes. The second reflector is located on the second side, and the current-limiting layer is located between the second reflector and the active emission layer. The two opposing surfaces of the second reflector are defined as the transmitting surface and the second reflective surface, respectively. The transmitting surface faces the current-limiting layer, and the second reflective surface is away from the current-limiting layer. A first resonant chamber is formed between the second reflector and the first reflector. The third reflector is located on the second side, and the second reflector is located between the current-limiting layer and the third reflector. The third reflector has an opposing third reflective surface and a light-emitting surface, the third reflective surface facing the second reflector, and a second resonance chamber is formed between the second reflector and the third reflector.

[0007] When current is injected from the limiting hole into the active luminescence layer, a first beam and a second beam are generated on the first and second sides of the active luminescence layer. After the first beam is reflected by the first mirror, a first reflected beam is generated. When the first reflected beam passes through the active luminescence layer, the active luminescence layer absorbs a portion of the first reflected beam and is further excited to generate a first beam and a second beam. The portion of the first reflected beam that has passed through the active luminescence layer is defined as the first transmitted beam. The second beam and the portion of the first transmitted beam that has been reflected by the second mirror are defined as the second reflected beam. When the second reflected beam passes through the active luminescence layer, the active luminescence layer is excited again by the second reflected beam to generate a first beam and a second beam. Of the second beam and the first transmitted beam, the beam that passes through the second reflector and enters the second resonant chamber is defined as the second transmitted beam. The second transmitted beam reciprocates between the second reflector and the third reflector to generate a laser beam, which is emitted from the light-emitting surface of the third reflector.

[0008] Furthermore, in the vertical-cavity surface-emitting laser according to the present invention, the current-limiting layer is an oxide layer.

[0009] Furthermore, in the vertical-cavity surface-emitting laser according to the present invention, the first mirror, the second mirror, and the third mirror are Bragg reflectors.

[0010] Furthermore, in the vertical-cavity surface-emitting laser according to the present invention, the reflectivity of the first mirror is 99.9% or higher.

[0011] Furthermore, in the vertical-cavity surface-emitting laser according to the present invention, the distance between the second reflector and the third reflector is greater than the distance between the first reflector and the second reflector. [Effects of the Invention]

[0012] The vertical-cavity surface-emitting laser having multiple mirrors according to the present invention forms a first resonant chamber and a second resonant chamber with the first, second, and third mirrors. As a result, the beam resonates mainly in the second resonant chamber, which is separated from the current limiting layer. Therefore, with the vertical-cavity surface-emitting laser according to the present invention, the beam is relatively unaffected by the current limiting layer, and the laser beam can be generated and emitted after resonance in the second resonant chamber, thereby improving the light emission effect.

[0013] Furthermore, according to the vertical-cavity surface-emitting laser of the present invention, the thickness design of the second mirror causes the second transmitted beam in the second resonant chamber to be reflected almost 100% when it comes into contact with the second reflective surface of the second mirror. This makes it possible to resonate the transmitted beam so that it is concentrated within the second resonant chamber, and ultimately, laser light can be emitted from the light-emitting surface of the third mirror, which has a relatively low reflectivity. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic diagram showing the usage state of a vertical-cavity surface-emitting laser according to the present invention. [Modes for carrying out the invention]

[0015] To further understand the features and technical details of the present invention, please refer to the detailed description and drawings of the vertical-cavity surface-emitting laser according to the present invention. However, the provided drawings are for reference and illustrative purposes only and do not limit the scope of the claims of the present invention.

[0016] The features of the vertical-cavity surface-emitting laser according to the present invention will be described below with more specific embodiments. Those skilled in the art will be able to understand the advantages and effects of the vertical-cavity surface-emitting laser according to the present invention based on the disclosures herein. Furthermore, the characteristic configurations described in this specification can also be implemented or applied in other different specific embodiments. In addition, various modifications and changes can be made to each detail described in this specification, based on different viewpoints and applications, as long as they do not deviate from the concept of the present invention. Furthermore, the accompanying drawings described in this specification are merely simplified schematics and are not drawn to actual size. The technical details of the vertical-cavity surface-emitting laser according to the present invention will be described in detail based on the following embodiments, but the disclosures are not intended to limit the scope of protection of the present invention.

[0017] In this specification, various elements or signals may be described using terms such as “first,” “second,” and “third,” but these elements or signals are not limited by these terms. These terms are primarily used to distinguish one element from another, or one signal from another. Furthermore, the term “or” as used in this specification may include any one or a combination of the items listed in relation to the actual situation.

[0018] Figure 1 is a schematic diagram showing the usage state of the vertical-cavity surface-emitting laser according to the present invention. Note that the circuit board and metal electrodes are omitted in Figure 1. The vertical-cavity surface-emitting laser Z1 has multiple reflectors. Specifically, it includes an active light-emitting layer 10, a first reflector 11, a current-limiting layer 13, a second reflector 14, and a third reflector 12. The opposing sides of the active light-emitting layer 10 are defined as the first side S1 and the second side S2, respectively. The first reflector 11 is located on the first side S1 of the active light-emitting layer 10. The first reflector 11 has a first reflective surface 111. The current limiting layer 13 is located on the second side S2 of the active light-emitting layer 10, between the second reflector 14 and the active light-emitting layer 10. The current limiting layer 13 has limiting holes 131. The second reflector 14 is located on the second side S2 between the current limiting layer 13 and the third reflector 12. The two opposing surfaces of the second reflector 14 are defined as the transmissive surface 141 and the second reflective surface 142, respectively. The transmissive surface 141 faces the current limiting layer 13. The second reflective surface 142 is away from the current limiting layer 13, and a first resonant chamber C1 is formed between the second reflector 14 and the first reflector 11. The third reflector 12 is located on the second side S2. The third reflector 12 has a third reflective surface 121 and a light-emitting surface 122 facing each other. The third reflective surface 121 faces the second reflector 14, and a second resonance chamber C2 is formed between the second reflector 14 and the third reflector 12.

[0019] When current is injected into the active light-emitting layer 10 through the restriction hole 131, a first beam L1 and a second beam L2 are respectively generated on a first side S1 and a second side S2 of the active light-emitting layer 10. After the first beam L1 is reflected by the first reflecting mirror 11, a first reflected beam L11 is generated. When the first reflected beam L11 passes through the active light-emitting layer 10, the active light-emitting layer 10 absorbs a part of the first reflected beam L11, and is further excited by the first reflected beam L11 to generate the first beam L1 and the second beam L2. A part of the first reflected beam L11 that transmits through the active light-emitting layer 10 is defined as a first transmitted beam L12. A beam reflected by the second reflecting mirror 14 among the second beam L2 and the first transmitted beam L12 is defined as a second reflected beam L21. When the second reflected beam L21 passes through the active light-emitting layer 10, the active light-emitting layer 10 is excited again by the second reflected beam L21 to generate the first beam L1 and the second beam L2. A beam that transmits through the second reflecting mirror 14 among the second beam L2 and the first transmitted beam L12 and further enters the second resonance chamber C2 is defined as a second transmitted beam L22. When the second transmitted beam L22 reciprocates and resonates between the second reflecting mirror 14 and the third reflecting mirror 12, a laser beam L3 is generated. This laser beam L3 is emitted from the light exit surface 122 of the third reflecting mirror 12.

[0020] Here, the second reflected beam L21 is a part of the beam reflected by the second reflecting mirror 14 among the second beam L2 and the first transmitted beam L12. The active light-emitting layer 10 is excited by the second reflected beam L21 to generate the first beam L1 and the second beam L2 again. In this way, the inside of the first resonance chamber C1 has beams generated successively.

[0021] On the other hand, the second transmitted beam L22 is most of the beam that transmits through the second reflecting mirror 14 among the second beam L2 and the first transmitted beam L12. When this beam enters the second resonance chamber C2 and reciprocates for resonance, the laser beam L3 is generated and emitted from the light exit surface 122.

[0022] Furthermore, in the present embodiment, the second reflecting mirror 14 having different thicknesses may be designed. In this case, after the second transmitted beam L22 in the second resonance chamber C2 reaches the second reflecting surface 142 of the second reflecting mirror 14, it can be reflected in a form close to substantially 100%, and the second transmitted beam L22 is caused to reciprocally resonate within the second resonance chamber C2, whereby the laser beam L3 can be finally generated.

[0023] It should be noted that the active light-emitting layer 10 includes multilayer film layers for forming multiple quantum wells (for example, alternatingly stacked undoped multilayer well layers and barrier layers). The materials of the well layer and the barrier layer are determined according to the wavelength of the beam to be generated. For example, when the beam to be generated is red light, the well layer and the barrier layer are respectively gallium arsenide layer and aluminum gallium arsenide (Al x Ga (1-x) As) layer, which is preferable. When the beam to be generated is blue light, it is preferable that the barrier layer and the well layer are respectively a gallium nitride (GaN) layer and an indium gallium nitride (InGaN) layer.

[0024] Furthermore, in the present embodiment, the current confinement layer 13 may be an oxide layer.

[0025] Furthermore, in the present embodiment, the first reflecting mirror 11, the second reflecting mirror 14, and the third reflecting mirror 12 may be Bragg reflectors. In other words, the first reflecting mirror 11, the third reflecting mirror 12, and the second reflecting mirror 14 may be Distributed Bragg Reflectors (DBR) formed by alternately stacking two types of thin films with different refractive indices, whereby a beam having a predetermined wavelength can be reflected and resonated. Furthermore, in the present embodiment, it is preferable that the reflectance of the first reflecting mirror 11 is 99.9% or more.

[0026] Furthermore, in this embodiment, the second reflector 14 may be constructed by stacking film layers containing multiple materials with different refractive indices. In addition, the number of stacked layers and their thickness may be adjusted according to the phase angle and interference requirements to obtain the necessary reflection effect.

[0027] Furthermore, in this embodiment, the distance H1 between the second reflector 14 and the third reflector 12 may be made larger than the distance H2 between the first reflector 11 and the second reflector 14, so that the vertical-cavity surface-emitting laser Z1 having multiple reflectors can output (emit, emit) purer laser light (stable mode).

[0028] Of particular note is that, of the two beams L2 emitted when the active luminescence layer 10 is excited by an electric current, the proportion of the second beam L2 is greater than the proportion of the first beam L1. Furthermore, under certain conditions, the amount of the second beam L2 that passes through the second mirror 14 may be far greater than the amount of the beam reflected by the second mirror 14.

[0029] [Beneficial effects of this embodiment] The vertical-cavity surface-emitting laser having multiple mirrors according to the present invention forms a first resonant chamber and a second resonant chamber with the first, second, and third mirrors. As a result, the beam resonates mainly in the second resonant chamber, which is separated from the current limiting layer. Therefore, with the vertical-cavity surface-emitting laser according to the present invention, the beam is relatively unaffected by the current limiting layer, and the laser beam can be generated and emitted after resonance in the second resonant chamber, thereby improving the light emission effect.

[0030] Furthermore, according to the vertical-cavity surface-emitting laser of the present invention, the thickness design of the second mirror causes the second transmitted beam in the second resonant chamber to be reflected almost 100% when it comes into contact with the second reflective surface of the second mirror. This makes it possible to resonate the transmitted beam so that it is concentrated within the second resonant chamber, and ultimately, laser light can be emitted from the light-emitting surface of the third mirror, which has a relatively low reflectivity.

[0031] The information disclosed above represents only preferred embodiments of the present invention and does not limit the scope of the claims. Therefore, all equivalent technical modifications made based on the specifications and accompanying drawings of the present invention are included within the scope of the claims. [Explanation of Symbols]

[0032] Z1 Vertical Cavity Surface Emitting Laser 10 Active luminescence layer 11. First reflecting mirror 111 First reflective surface 12. The third reflecting mirror 121 Third Reflecting Surface 122 Idemitsu surface 13 Current Limiting Layer 131 Restriction holes 14. The second reflecting mirror 141 Transparent surface 142 Second Reflecting Surface C1 First Resonance Chamber C2 Second Resonant Chamber H1 distance H2 distance L1 First beam L11 First reflected beam L12 First transmitted beam L2 Second beam L21 Second reflected beam L22 Second transmitted beam L3 laser beam S1 First side S2 Second side

Claims

1. An active light-emitting layer, with opposing sides defined as the first side and the second side, A first reflector having a first reflective surface is located on the first side of the active light-emitting layer, A current limiting layer is located on the second side of the active light-emitting layer, with a gap between it and the active light-emitting layer, and has limiting holes. A second reflector located on the second side, A third reflector located on the second side, Includes, The current limiting layer is located between the second reflector and the active light-emitting layer, and the two opposing surfaces of the second reflector are defined as the transmitting surface and the second reflecting surface, respectively, the transmitting surface facing the current limiting layer, and the second reflecting surface away from the current limiting layer, and a first resonance chamber is formed in the space between the second reflector and the first reflector. The second reflector is located between the current limiting layer and the third reflector, the third reflector has a third reflective surface and a light-emitting surface facing each other, the third reflective surface facing the second reflector, and a second resonance chamber is formed in the space between the second reflector and the third reflector. A gap is provided between the activated light-emitting layer and the first reflector, and a gap is provided between the current-limiting layer and the second reflector. The distance between the second reflector and the third reflector is greater than the distance between the first reflector and the second reflector. When current is injected into the active light-emitting layer through the limiting hole, a first beam and a second beam are generated on the first and second sides of the active light-emitting layer, respectively. After the first beam is reflected by the first reflector, a first reflected beam is generated. When the first reflected beam passes through the active light-emitting layer, the active light-emitting layer absorbs a portion of the first reflected beam and is further excited to generate the first beam and the second beam. The portion of the first reflected beam that has passed through the active light-emitting layer is defined as the first transmitted beam. The second beam and the first transmitted beam, the beam reflected by the second reflector, are defined as the second reflected beam. When the second reflected beam passes through the active light-emitting layer, the active light-emitting layer is excited again by the second reflected beam to generate the first beam and the second beam. The second beam and the first transmitted beam, the beam that passes through the second reflector and enters the second resonance chamber, are defined as the second transmitted beam, and a laser beam is generated by the reciprocating resonance of the second transmitted beam between the second reflector and the third reflector, and the laser beam is emitted from the light-emitting surface of the third reflector. A vertical-cavity surface-emitting laser characterized by the following features.

2. The current limiting layer is an oxide layer. The vertical cavity type surface-emitting laser according to feature 1.

3. The first reflector, the second reflector, and the third reflector are Bragg reflectors. The vertical cavity type surface-emitting laser according to feature 1.

4. The reflectance of the first reflector is 99.9% or higher. The vertical cavity type surface-emitting laser according to feature 1.

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