Multi-dimensional coupling resonant semiconductor laser

Abstract

The invention provides a multi-dimensional coupling resonance semiconductor laser, which comprises a waveguide layer comprising an active area, and the active area is used for generating laser; the first emission structure is arranged on the lower side of the waveguide layer and is used for modulating the laser and then outputting edge emission laser; the second emitting structure is arranged on the upper side surface of the waveguide layer, the second emitting structure is used for modulating the laser and then outputting surface emitting laser, and the direction of the edge emitting laser is perpendicular to the direction of the surface emitting laser. Coupling resonance of the same laser chip in the plane dimension and the out-of-plane vertical direction dimension can be achieved, the laser chip has the functions of changing output light spots and regulating and controlling the output proportion of different coupling channels, the laser chip can be used for multi-dimensional space information utilization of laser, and multiple functions are achieved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a semiconductor laser with multi-dimensional coupled resonance. Background Art

[0002] Semiconductor lasers have many advantages such as high power, strong reliability, long life, small size, and low cost, and are widely used in fields such as pumping, medical treatment, and communication. Among them, surface-emitting lasers have low power consumption, are easy to integrate, have high beam quality, and flexible wavelength selection, and have excellent performance in fields such as optical communication, lidar, sensing measurement, and biomedicine.

[0003] The periodic structure of the photonic crystal layer has a specific bandgap. By adjusting parameters such as the period of the photonic crystal, the refractive index of the material, and the duty cycle, the specific position of its bandgap can be changed, which can inhibit light of certain specific modes and allow light of other modes to pass through, thereby achieving the effect of modulating the output mode of the edge-emitting laser.

[0004] However, currently, the composite cavity design is mainly used to test and optimize the single-dimensional output performance, and there are few studies that take into account both edge-emitting and surface-emitting applications. There are few means to achieve multi-dimensional coupled resonance in the composite cavity, and few of them focus on combining the cavity structure designs of edge-emitting and surface-emitting. Even if the current structure design combines edge-emitting and surface-emitting, it is mostly a fundamental change in the output dimension, sacrificing the light output of the original dimension, and there are few studies that take into account the output performance of both. Summary of the Invention

[0005] In view of this, one of the main purposes of the present invention is to provide a semiconductor laser with multi-dimensional coupled resonance to achieve the coupled resonance of the same laser chip in the planar dimension and the out-of-plane vertical dimension.

[0006] The semiconductor laser with multi-dimensional coupled resonance provided by the embodiment of the present invention includes: a waveguide layer including an active region for generating laser light; a first emission structure disposed on the lower side of the waveguide layer for modulating and outputting edge-emitting laser light after modulating the laser light; a second emission structure disposed on the upper surface of the waveguide layer, and the second emission structure is used for modulating and outputting surface-emitting laser light after modulating the laser light, and the direction of the edge-emitting laser light is perpendicular to the direction of the surface-emitting laser light.

[0007] According to the embodiment of the present invention, the first emission structure includes a photonic crystal layer, and the photonic crystal layer outputs edge-emitting laser light after modulating the laser light based on total internal reflection and evanescent field coupling of the lateral light-emitting mode in the photonic crystal layer.

[0008] According to the embodiment of the present invention, the photonic crystal layer includes multiple groups of alternately stacked first material layers and second material layers, the refractive index of the first material layer is higher than that of the second material layer, and the active region is close to the first material layer at the uppermost layer of the photonic crystal layer.

[0009] According to an embodiment of the present invention, the thickness of the first material layer is greater than the thickness of the second material layer.

[0010] According to an embodiment of the present invention, the laser structure further includes: a light field confinement layer, located on the lower side of the second material layer at the bottommost layer of the photonic crystal layer.

[0011] According to an embodiment of the present invention, the second emission structure includes a ridge waveguide having a surface emission structure, and the type of the surface emission structure includes one of a second-order Bragg grating, a metasurface, or a two-dimensional photonic crystal. The second emission structure realizes the output of surface emission laser through the folding of the energy band of the photonic crystal by the surface emission structure.

[0012] According to an embodiment of the present invention, the ridge waveguide includes a cladding layer, a P-type transition layer, and an ohmic contact layer.

[0013] According to an embodiment of the present invention, the relative distance between the active region and the first emission structure in the waveguide layer deviates from the peak position of the optical field distribution of the semiconductor laser.

[0014] According to an embodiment of the present invention, the lasing wavelength, gain magnitude, and internal quantum efficiency of the semiconductor laser are related to the type of the active region, and the type of the active region includes a quantum well or a tunnel junction.

[0015] According to an embodiment of the present invention, the semiconductor laser includes an electrode window; the semiconductor laser is configured to inject currents of different magnitudes through the electrode window to change the output light spot, select the output mode, and regulate the output ratio of different-dimensional coupling channels.

[0016] According to the multi-dimensional coupled resonance semiconductor laser provided by the embodiment of the present invention, different-dimensional emission structures are adopted, so that the coupled resonance in the plane dimension and the out-of-plane vertical dimension can be realized on the same laser chip. By changing the injected current, the functions of changing the output light spot and modulating the output ratio of different coupling channels can be achieved, and it can be used for the multi-dimensional space information utilization of the laser to realize multi-functions. The surface emission formed by this laser, compared with the traditional vertical cavity surface emission laser, does not require an oxidation aperture, so there is no need for zoned injection, which is beneficial to the formation of a large-area single-chip high-power surface emission output. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Through the following description of the embodiments of the present invention with reference to the accompanying drawings, the above and other objects, features, and advantages of the present invention will become clearer. In the drawings:

[0018] Figure 1 is a schematic structural diagram of a semiconductor laser according to an embodiment of the present invention;

[0019] Figure 2 is a schematic structural diagram of a semiconductor laser according to another embodiment of the present invention;

[0020] Figure 3 is Figure 2 a schematic cross-sectional view of the semiconductor laser perpendicular to the epitaxial direction as shown;

[0021] Figure 4 is Figure 2 a schematic diagram of the far-field distribution of the edge emission of the semiconductor laser when different gains are applied as shown;

[0022] Figure 5 is Figure 2 a schematic diagram of the far-field distribution of the surface emission of the semiconductor laser when different gains are applied as shown;

[0023] Figure 6 is Figure 2 a schematic diagram of the near-field distribution of the edge emission of the semiconductor laser as shown;

[0024] Figure 7 is Figure 2 a schematic diagram of the field distributions of the fundamental mode and the high-order modes under the influence of the photonic crystal layer of the semiconductor laser as shown. Detailed implementation manners

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In the following detailed description, for the sake of explanation, numerous specific details are set forth in order to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments can be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of the present invention.

[0026] The terms used herein are merely for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising", etc. used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0027] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0028] As Figure 1 shown, in an embodiment of the present invention, the multi-dimensional coupled-resonant semiconductor laser 100 may include: a first emission structure 110, a second emission structure 120, and a waveguide layer 130 including an active region 131.

[0029] The active region 131 can be used to generate laser light, and the waveguide layer 130 can guide the laser light to the first emission structure 110 and the second emission structure 120. The first emission structure 110 is disposed on the lower side of the waveguide layer 130 and can be used to modulate the laser light and output edge-emitting laser light; the second emission structure 120 is disposed on the upper surface of the waveguide layer 130 including the active region 131, and the second emission structure 120 can be used to modulate the laser light and output surface-emitting laser light, and the direction of the edge-emitting laser light is perpendicular to the direction of the surface-emitting laser light. By integrating emission structures with different modulation functions on the same laser chip, coupling resonance in the plane dimension and the out-of-plane vertical direction dimension can be achieved on the same laser chip.

[0030] Figure 2 Schematic structural diagram of a semiconductor laser according to another embodiment of the present invention; Figure 3 is Figure 2 Cross-sectional schematic diagram of the semiconductor laser shown perpendicular to the epitaxial direction. Figure 2 and Figure 3 In [reference], the waveguide layer 260 and the active region 261 can be the same as Figure 1 the waveguide layer 130 and the active region 131 in [reference].

[0031] In this embodiment, the photonic crystal layer 250 can serve as Figure 1 the first emission structure 110 in [reference]. Based on total internal reflection and evanescent field coupling of the lateral light-emitting mode therein, the photonic crystal layer 250 modulates the laser light and outputs edge-emitting laser light. Compared with the transverse Bragg resonance mechanism supported by a general Distributed Bragg reflector (DBR) structure, the lateral leakage loss of the fundamental mode of the structure in this embodiment is small.

[0032] As Figure 3 shown, the photonic crystal layer 250 can include multiple groups of alternately stacked first material layers 251 and second material layers 252, and the refractive index of the first material layer 251 is higher than that of the second material layer 252. That is to say, a material with a high refractive index can be selected for the first material layer 251, for example, it can be Al 0.2 GaAs, and a material with a low refractive index can be selected for the second material layer 252, for example, it can be Al 0.3 GaAs. As an example, the number of pairs of alternately stacked first material layers 251 and second material layers 252 is set to 6 pairs. It should be noted that the number of stacked pairs can be reasonably set according to actual needs, and the present invention does not limit the specific number of stacked pairs.

[0033] As Figure 2As shown, the bottom layer of the photonic crystal layer 250 is the second material layer 252, and the top layer is the first material layer 251. The top first material layer 251 is in contact with the waveguide layer 260. In other words, the first material layer 251 is close to the active region 261. The bottom second material layer 252 is connected to the optical field confinement layer 240. The optical field confinement layer 240 can better confine the optical field in the photonic crystal layer 250 and improve the emission power. In some specific embodiments, the optical field confinement layer 240 can be simplified and deleted according to research and process requirements, and the present invention does not make specific limitations.

[0034] In some embodiments, the thickness of the first material layer 251 can be greater than the thickness of the second material layer 252. For example, the thickness of the first material layer 251 can be 610 nm, and the thickness of the second material layer 252 can be 90 nm. By using a photonic crystal layer with an appropriate thickness, output with a lower divergence angle can be achieved while ensuring the laser efficiency; the thicker first material layer can increase the confinement factor of the active region; by optimizing individual photonic crystal layers, adding a low refractive index capping layer to confine the expansion of the optical field, and then thickening its first material layer to ensure an ideal output mode, the selection and control of the lateral output mode can be realized.

[0035] Please continue to refer to Figure 2 and Figure 3 , in this embodiment, the ridge waveguide 280 with a surface emission structure can be used as Figure 1 the second emission structure 120. The surface emission structure type of the ridge waveguide 280 includes but is not limited to a second-order Bragg grating, a metasurface, or a two-dimensional photonic crystal. The second emission structure 120 realizes the output of surface emission laser through the folding of the energy band of the photonic crystal by the surface emission structure. As Figure 2 and Figure 3 shown, the surface structure of the ridge waveguide 280 can use a second-order grating to achieve surface emission. The ridge waveguide 280 can include a cladding layer 281, a P-type transition layer 282, and an ohmic contact layer 283. As an example, the periodic dimension of the ridge waveguide 280 can be 287.3 nm, the number of periods N can be 100, and the duty cycle can be 50%.

[0036] The relative distance between the active region 261 in the waveguide layer 260 and the first emission structure 110 deviates from the peak position of the optical field distribution of the semiconductor laser. By changing the relative position of the active region 261 in the waveguide layer 260 and the first emission structure 110 (specifically, it can be the second material layer 252), it can be appropriately deviated from the peak position of the optical field distribution to reduce device damage. As an example, the position of the active region 261 in the waveguide layer 260 can be offset 105 nm downward from the center of the waveguide layer 260. Further, the lasing wavelength, gain magnitude, internal quantum efficiency, etc. of the semiconductor laser can be determined by changing the type of the active region 261 in the waveguide layer 260. The types of the active region 261 include but are not limited to quantum wells, tunnel junctions, etc. Different types of active regions 261 can adopt different material systems, and the present invention does not make specific limitations.

[0037] As Figure 2 and Figure 3 shown, the semiconductor laser 200 may further include an N-side electrode 210, a substrate layer 220, an N-type transition layer 230, a P-side electrode 290. The lower part of the P-side electrode 290 covers the insulating layer 270, and the uncovered part is an electrode window. The semiconductor laser 200 can change the output spot, select the output mode, and regulate the output ratio of different-dimensional coupling channels by changing the magnitude of the injection current.

[0038] Figure 4 For Figure 2 the schematic diagram of the field distribution of the edge-emitting far field of the semiconductor laser shown when different gains are applied; Figure 5 For Figure 2 the schematic diagram of the field distribution of the surface-emitting far field of the semiconductor laser shown when different gains are applied; Figure 6 For Figure 2 the schematic diagram of the field distribution of the edge-emitting near field of the semiconductor laser shown; Figure 7 For Figure 2 the schematic diagram of the field distribution of the fundamental mode and high-order modes under the influence of the photonic crystal layer of the semiconductor laser shown.

[0039] For the semiconductor laser 200 according to the above embodiments, a series of simulation experiments were carried out in the present invention. The simulation results can be as Figures 4 to 7 shown. In the simulation process, the finite difference time domain method (FDTD) was used, and the injection current effect was realized by adding an imaginary part of the refractive index to the active region material. Figure 4 and Figure 5 (a), (b), and (c) in respectively correspond to the imaginary part k being 4.76×10 -6 , -0.005, and -0.01, where 4.76×10 -6 is only considering the internal loss α of the device iThe value of the imaginary part k at this time, when edge emission dominates. As the gain continues to increase, the far-field spot of edge emission gradually becomes larger, and conversely, the far-field spot of surface emission gradually becomes smaller. Further increasing the gain, the imaginary part k is set to -0.03, at which time the output mode changes from the fundamental mode to the high-order mode, and the surface emission intensity increases significantly. The field distribution diagram of the near-field of edge emission in this embodiment can be as shown in Figure 6 shown. The influence of the photonic crystal layer on the field distributions of the fundamental mode and the high-order mode in this embodiment can be as shown in Figure 7 shown. The photonic crystal layer can well confine the fundamental mode near the active region and pull the high-order mode into the photonic crystal layer, ensuring single-mode output.

[0040] In summary, the multi-dimensional coupled-resonant semiconductor laser provided by the present invention adopts an N-side photonic crystal layer epitaxial structure and a P-side surface emission structure, enabling the realization of coupled resonance in the planar dimension and the out-of-plane vertical dimension on the same laser chip, and having the functions of changing the output spot and regulating the output ratio of different coupling channels by changing the injection current, which can be used for the multi-dimensional spatial information utilization of lasers to achieve multiple functions. The surface emission formed by this laser, compared with the traditional vertical-cavity surface-emitting laser, does not require an oxidation aperture, so there is no need for zoned injection, which is conducive to forming a large-area single-chip high-power surface emission output.

[0041] The embodiments of the present invention have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present invention.

Claims

1. A multi-dimensional coupled resonant semiconductor laser, characterized in that: include: a waveguide layer including an active region for generating laser light; A first emitting structure is disposed on the lower side of the waveguide layer, and the first emitting structure is used to modulate the laser and then output edge-emitting laser; A second emitting structure is arranged on the upper surface of the waveguide layer, and the second emitting structure is used to modulate the laser and output a surface-emitting laser. The direction of the edge-emitting laser is perpendicular to the direction of the surface-emitting laser, so as to realize adjustable coupling resonance of the same laser chip in the plane dimension and the out-of-plane vertical direction.

2. The semiconductor laser according to claim 1, characterized in that The first emitting structure comprises a photonic crystal layer, and the photonic crystal layer modulates the laser and outputs the edge-emitting laser based on total internal reflection and evanescent field coupling in a lateral light emission mode in the photonic crystal layer.

3. The semiconductor laser according to claim 2, characterized in that The photonic crystal layer includes a plurality of groups of first material layers and second material layers stacked alternately, the refractive index of the first material layer is higher than the refractive index of the second material layer, and the active region is close to the uppermost first material layer of the photonic crystal layer.

4. The semiconductor laser according to claim 3, characterized in that The thickness of the first material layer is greater than the thickness of the second material layer.

5. The semiconductor laser according to claim 2, characterized in that Also includes: The light field limiting layer is located at the lower side of the second material layer at the bottom of the photonic crystal layer.

6. The semiconductor laser according to claim 1, characterized in that The second emission structure includes a ridge waveguide with a surface emission structure, and the surface emission structure type includes one of a second-order Bragg grating, a metasurface or a two-dimensional photonic crystal. The second emission structure realizes the output of the surface emission laser by folding the energy band of the photonic crystal through the surface emission structure.

7. The semiconductor laser according to claim 6, characterized in that The ridge waveguide includes a cladding layer, a P-type transition layer and an ohmic contact layer.

8. The semiconductor laser according to claim 1, characterized in that The relative distance between the active region in the waveguide layer and the first emitting structure deviates from the peak position of the light field distribution of the semiconductor laser.

9. The semiconductor laser according to claim 1, characterized in that The lasing wavelength, gain size and internal quantum efficiency of the semiconductor laser are related to the type of the active region, which includes a quantum well or a tunnel junction.

10. The semiconductor laser according to claim 1, characterized in that The semiconductor laser comprises an electrode window; the semiconductor laser is configured to inject currents of different magnitudes through the electrode window to change the output light spot, select the output mode and regulate the output ratio of coupling channels of different dimensions.

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