Multi-junction VCSEL device, VCSEL chip, laser radar system and light source

Abstract

The present invention relates to a multi-junction VCSEL device, a VCSEL chip, a laser radar system and a light source thereof. The multi-junction VCSEL device comprises: a substrate; a bottom reflector structure and a top reflector structure sequentially arranged on the substrate; the bottom reflector structure and the top reflector structure define a resonant cavity structure for generating a standing wave; the resonant cavity structure comprises a plurality of stacked active regions and at least one photoelectric limiting layer, the photoelectric limiting layer is located on a side of the corresponding active region away from the substrate and at a trough of the standing wave, the photoelectric limiting layer is used to define a light-emitting region of the multi-junction VCSEL device; at least one light field regulation layer is arranged adjacent to the photoelectric limiting layer, the light field regulation layer comprises two regulation sublayers, the two regulation sublayers in the same light field regulation layer are respectively located on opposite sides of a corresponding photoelectric limiting layer, so as to divide the light field in the resonant cavity structure into at least two sections.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and in particular to a multi-junction VCSEL device, a VCSEL chip, a laser radar system and a light source thereof. Background Art

[0002] With the continuous development of semiconductor technology, Vertical-Cavity Surface-Emitting Laser (VCSEL) is widely used in optical communication, optical interconnection, optical sensing and other fields due to its easy integration characteristics. The main application scenario in the field of optical sensing is LiDAR. High-power VCSEL devices are the main technical direction for future applications in LiDAR. High-power VCSELs usually require cascading multiple active layers to achieve. However, the limiting factor of the oxide layer in the multi-junction VCSEL device with multiple active layers cascaded is relatively high, resulting in a larger divergence angle of the multi-junction VCSEL device, which limits the use scenarios of the multi-junction VCSEL device. Summary of the invention

[0003] Based on this, it is necessary to provide a multi-junction VCSEL device, a VCSEL chip, a laser radar system and a light source thereof to address the problem of a large divergence angle of the multi-junction VCSEL device in the prior art.

[0004] In a first aspect, the present application provides a multi-junction VCSEL device, comprising:

[0005] substrate;

[0006] A bottom reflector structure and a top reflector structure are sequentially arranged on the substrate; the bottom reflector structure and the top reflector structure define a resonant cavity structure for generating a standing wave;

[0007] The resonant cavity structure comprises a plurality of stacked active regions and at least one photoelectric limiting layer, wherein the photoelectric limiting layer is located on a side of the corresponding active region away from the substrate and at a trough of the standing wave, and the photoelectric limiting layer is used to limit a light-emitting region of the multi-junction VCSEL device;

[0008] At least one light field regulation layer is arranged adjacent to the photoelectric confinement layer, the light field regulation layer includes two regulation sublayers, and the two regulation sublayers in the same light field regulation layer are respectively located on two opposite sides of a corresponding photoelectric confinement layer, so as to divide the light field in the resonant cavity structure into at least two sections.

[0009] In one of the embodiments, the intensity peaks of each segment of the light field in the resonant cavity structure are the same or different.

[0010] In one of the embodiments, the light field intensity at the light field regulation layer and the photoelectric confinement layer is lower than the light field intensity of any adjacent active region.

[0011] In one of the embodiments, the regulating sublayer includes a photonic crystal structure or a periodically stacked DBR structure, and the material of the periodically stacked DBR structure includes a semiconductor material.

[0012] In one of the embodiments, when the regulation sublayer includes a periodically stacked DBR structure, the refractive index stacking order of the DBR structures of two regulation sublayers in the same light field regulation layer is opposite.

[0013] In one of the embodiments, the periodically stacked DBR structure includes a first DBR functional layer and a second DBR functional layer that are alternately stacked and have different refractive indices. When the refractive index of the first DBR functional layer of each of the regulating sublayers in the same light field regulation layer is the same, and the refractive index of the second DBR functional layer of each of the regulating sublayers is the same, the stacking number of DBR structures of the two regulating sublayers in the same light field regulation layer is different.

[0014] In one embodiment, the composition of the element affecting the refractive index in the first DBR functional layer of each of the regulating sublayers in the same light field regulating layer is the same, and the composition of the element affecting the refractive index in the second DBR functional layer of each of the regulating sublayers is the same.

[0015] In one embodiment, the number of stacking periods of each of the regulating sublayers is between 1 pair and 5 pairs.

[0016] In one embodiment, the number of the light field control layers is two, and in the direction away from the substrate, the stacking periods of the DBR structures of the four control sublayers are 1 pair, 3 pairs, 1 pair, 3 pairs, or 1 pair, 3 pairs, 3 pairs, 1 pair, or 4 pairs, 3 pairs, 4 pairs, 3 pairs, or 2 pairs, 3 pairs, 2 pairs, 3 pairs.

[0017] In one of the embodiments, when the stacking period numbers of the DBR structures of the regulating sublayers in the same light field regulating layer are the same, the refractive index of the first DBR functional layer of each regulating sublayer in the same light field regulating layer is different, and / or the refractive index of the second DBR functional layer of each regulating sublayer is different.

[0018] In one of the embodiments, the elements affecting the refractive index in the first DBR functional layer of each of the regulating sublayers in the same light field regulating layer are different; or the elements affecting the refractive index in the first DBR functional layer of each of the regulating sublayers in the same light field regulating layer are the same, but the components of the elements affecting the refractive index are different.

[0019] In one embodiment, the periodically stacked DBR structure is composed of Al x Ga （1-x） As / Al y Ga （1-y） As is formed by alternating stacking, where 0≤x<y≤1.

[0020] In one embodiment, the photoelectric confinement layer includes any one of an air column type photoelectric confinement layer, an oxidation confinement type photoelectric confinement layer, an ion implantation type photoelectric confinement layer and a tunnel junction type photoelectric confinement layer.

[0021] In one embodiment, the oxidation-limited photoelectric limiting layer includes an unoxidized region of AlGaAs material with a high aluminum component and an oxidized region of aluminum oxide material, wherein the oxidized region is located outside the unoxidized region, and the unoxidized region forms a light-emitting region for effective current injection.

[0022] In one embodiment, the tunnel junction type photoelectric confinement layer includes at least one highly doped N-type structure layer and at least one highly doped P-type structure layer.

[0023] In one embodiment, the material of the N-type structure layer and the P-type structure layer is Al x Ga 1-x As, the doping concentration of the N-type structure layer and the P-type structure layer is greater than 1e 18 cm -3 , where 0≤x≤1.

[0024] In one embodiment, the active region includes at least one multi-quantum well structure and at least one tunnel junction layer, and the tunnel junction layer is located between two adjacent multi-quantum well structures or between the regulation sublayer and the photoelectric confinement layer.

[0025] In one embodiment, the resonant cavity structure includes three active regions and three photoelectric confinement layers; the three active regions include a first active region, a second active region and a third active region sequentially arranged in a direction away from the substrate, and the three photoelectric confinement layers include a first photoelectric confinement layer, a second photoelectric confinement layer and a third photoelectric confinement layer;

[0026] The first photoelectric limiting layer is located between the first active region and the second active region, the second photoelectric limiting layer is located between the second active region and the third active region, and the third photoelectric limiting layer is located on a side of the third active region close to the top reflector structure.

[0027] In one embodiment, the first active region includes three multi-quantum well structures, the second active region includes two multi-quantum well structures, and the third active region includes two multi-quantum well structures; and adjacent multi-quantum well structures in each active region are connected via a tunnel junction layer.

[0028] In one embodiment, the bottom reflector structure includes a plurality of reflectors with an optical thickness of one quarter of the lasing wavelength, and the plurality of reflectors are arranged alternately according to high and low refractive indices;

[0029] The top reflector structure includes a plurality of reflectors with an optical thickness of one quarter of the lasing wavelength, and the plurality of reflectors are alternately arranged according to high and low refractive indices.

[0030] In a second aspect, the present application provides a VCSEL chip, wherein the VCSEL chip comprises an anode, a cathode and a multi-junction VCSEL device as described above;

[0031] Wherein, the positive electrode and the negative electrode are electrically connected to the bottom reflector structure and the top reflector structure of the multi-junction VCSEL device respectively; or

[0032] The positive electrode and the negative electrode are electrically connected to the top reflector structure and the bottom reflector structure of the multi-junction VCSEL device respectively;

[0033] The positive electrode and the negative electrode are located on the side opposite to the light emitting side of the VCSEL chip.

[0034] In a third aspect, the present application provides a VCSEL chip comprising at least one laser array; the laser array comprises a plurality of multi-junction VCSEL devices as described above; the laser array is a regularly arranged array, or a randomly arranged array, or an array with multiple addressable sub-arrays.

[0035] In a fourth aspect, the present application provides a light source for a lidar system, comprising at least one multi-junction VCSEL device as described above or at least one VCSEL chip as described above.

[0036] In a fifth aspect, the present application provides a laser radar system, including a transmitting component and a receiving component, wherein the transmitting component adopts the above-mentioned light source for the laser radar system.

[0037] The above-mentioned multi-junction VCSEL device can divide the light field in the resonant cavity structure into at least two sections by inserting at least one light field regulation layer in the resonant cavity structure of the multi-junction VCSEL device. By setting the structure or composition of the two regulation sublayers in the light field regulation layer, the light field intensity of each section of the light field can be flexibly adjusted. Since the photoelectric confinement layer is located at the trough of the standing wave, the electric field intensity at the photoelectric confinement layer can be made lower. Moreover, due to the segmented effect of the light field regulation layer on the light field, the light field intensity after the light passes through the light field regulation layer becomes lower. Placing the photoelectric confinement layer between the two regulation sublayers of the light field regulation layer can further reduce the light field intensity of the photoelectric confinement layer. Based on the positive correlation between the confinement factor of the film layer and the electric field intensity and the light field intensity where it is located, the above-mentioned setting method effectively reduces the confinement factor of the photoelectric confinement layer, thereby achieving the suppression of high-order modes and achieving the effect of low divergence angle. Therefore, the present application provides a multi-junction VCSEL device with a small confinement factor of the photoelectric confinement layer and a large confinement factor of the active region, thereby improving the performance of the multi-junction VCSEL device in terms of divergence angle and threshold current. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 This is one of the structural schematic diagrams of a multi-junction VCSEL device according to an embodiment;

[0040] Figure 2 One of the refractive index and light field intensity diagrams of a multi-junction VCSEL device of an embodiment;

[0041] Figure 3 The second diagram of the refractive index and light field intensity of a multi-junction VCSEL device of an embodiment;

[0042] Figure 4 The third diagram of the refractive index and light field intensity of a multi-junction VCSEL device of an embodiment;

[0043] Figure 5 The fourth diagram of the refractive index and light field intensity of a multi-junction VCSEL device of an embodiment;

[0044] Figure 6 This is the second structural schematic diagram of a multi-junction VCSEL device according to an embodiment.

[0045] Component number description:

[0046] Substrate: 100; bottom reflector structure: 200; top reflector structure: 300; active area: 400; multi-quantum well structure: 401; first active area: 410; second active area: 420; third active area: 430; photoelectric confinement layer: 500; first photoelectric confinement layer: 510; second photoelectric confinement layer: 520; third photoelectric confinement layer: 530; light field regulation layer: 600; regulation sublayer: 610; tunnel junction layer: 700. DETAILED DESCRIPTION

[0047] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0049] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to or coupled to other elements or layers, it may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. On the contrary, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there may be no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types and / or parts, these elements, components, regions, layers, doping types and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, doping type or part from another element, component, region, layer, doping type or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer, doping type or portion discussed below may be represented as a second element, component, region, layer or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0050] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0051] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, in this specification, the term "and / or" includes any and all combinations of the relevant listed items.

[0052] An embodiment of the present application provides a multi-junction VCSEL device, which refers to a vertical cavity surface emitting laser (VCSEL) having a multi-layer PN junction stacked structure. Figure 1 FIG. 1 is a schematic diagram of a multi-junction VCSEL device according to an embodiment of the present invention. Figure 1 The multi-junction VCSEL device includes a substrate 100 and a bottom reflector structure 200, a resonant cavity structure and a top reflector structure 300 sequentially arranged on the substrate 100. The resonant cavity structure is defined by the bottom reflector structure 200 and the top reflector structure 300, that is, the area between the bottom reflector structure 200 and the top reflector structure 300 is the resonant cavity. The resonant cavity is used to generate standing waves. Standing waves are waves formed by two coherent waves propagating in opposite directions on the same straight line and superimposed on each other. Specifically, when the two waves are in the same phase, their amplitudes are added to form an antinode (i.e., a crest). When the two waves are in opposite phases, their amplitudes are subtracted to form a node (i.e., a trough). Therefore, the positions of the crest and trough of the standing wave are fixed.

[0053] Among them, the material of the substrate 100 includes but is not limited to GaAs, InP, Si, etc. The bottom reflector structure 200 and the top reflector structure 300 may include a film layer with a periodic change in refractive index to achieve efficient reflection or transmission of light within a specific wavelength range. The film layer with a periodic change in refractive index can be composed of semiconductor materials, dielectric materials, metal-dielectric mixed materials, etc. For example, the bottom reflector structure 200 can be an N-type semiconductor layer, and the top reflector structure 300 can be a P-type semiconductor layer. For another example, the bottom reflector structure 200 can be a P-type semiconductor layer, and the top reflector structure 300 can be an N-type semiconductor layer. Optionally, the material of the N-type semiconductor layer and the P-type semiconductor layer can be but is not limited to GaAs, AlGaAs, etc., which is not limited here. As long as the definition of the resonant cavity can be achieved, it belongs to the protection scope of this embodiment. Specifically, the resonant cavity structure includes a plurality of active regions 400 stacked, at least one photoelectric confinement layer 500, and at least one light field regulation layer 600.

[0054] The number of active regions 400 may be, for example, 2, 3, 4, etc. Figure 1 Three active regions 400 in a multi-junction VCSEL device are shown, namely, a first active region 410, a second active region 420, and a third active region 430. The active region 400 is used to generate stimulated radiated photons, and the emitted photons are continuously reflected in the resonant cavity defined by the bottom reflector structure 200 and the top reflector structure 300, and are continuously enhanced during the reflection process, thereby finally emitting laser light at a specific wavelength and having sufficient energy. Multiple active regions 400 in a multi-junction VCSEL device can emit light simultaneously, so that the light field can be effectively superimposed between the multiple active regions 400, thereby optimizing the overall distribution of the light field.

[0055]

[0056] Furthermore, the above formula (1) is a calculation formula for the limiting factor of the target film layer. is the limiting factor of the target film layer, is the thickness of the target film layer in the z-axis direction, is the thickness of the entire light field in the z-axis direction, is the refractive index of the target film layer in the z-axis direction, is the refractive index of the entire light field in the z-axis direction, is the light field intensity in the z-axis direction. The z-axis direction refers to the light emission direction. It can be understood that, under the premise that the thickness, refractive index and light field intensity of the entire light field remain basically unchanged, the integral result of the denominator in the calculation formula (1) remains basically unchanged.

[0057] When the target film layer is the active region 400, since multiple active regions 400 are provided in the multi-junction VCSEL device, the thickness of the active region 400 in the z-axis direction is relatively large, so that the integral result of the numerator in the calculation formula (1) of the limitation factor will increase accordingly, thereby making the limitation factor of the active region 400 larger, which in turn helps the photons to obtain gain more fully, so that the multi-junction VCSEL device can achieve laser emission at a lower injection current.

[0058] The number of the photoelectric limiting layers 500 is not greater than the number of the active regions 400, for example, it may be 2, 3, 4, etc. Figure 1 Three photoelectric confinement layers 500 in a multi-junction VCSEL device are shown, namely, a first photoelectric confinement layer 510, a second photoelectric confinement layer 520, and a third photoelectric confinement layer 530. The photoelectric confinement layer 500 is used to limit the light-emitting area of ​​the multi-junction VCSEL device. Specifically, the photoelectric confinement layer 500 is located on the side of the corresponding active area 400 away from the substrate 100 to limit the flow of current so that the current only flows in the light-emitting area defined by the photoelectric confinement layer 500, thereby reducing unnecessary energy consumption, thereby reducing the threshold current, and increasing the current density. Moreover, the photoelectric confinement layer 500 can also confine the light field in the light-emitting area defined by the photoelectric confinement layer 500, reducing the scattering and diffraction of light, thereby optimizing the divergence angle of the VCSEL and improving the beam quality. Continuing to refer to calculation formula (1), when the target film layer is the photoelectric confinement layer 500, since the photoelectric confinement layer 500 is set at the trough of the standing wave, the electric field at the photoelectric confinement layer 500 is small, and the electric field strength is positively correlated with the light field strength. Therefore, the integral result of the numerator in the calculation formula (1) of the limitation factor will decrease accordingly. Since the integral result of the denominator remains basically unchanged, the limitation factor of the optoelectronic limitation layer 500 is small, which helps to reduce the divergence angle of the multi-junction VCSEL device.

[0059] The number of the light field control layers 600 is not greater than the number of the photoelectric confinement layers 500, for example, it may be 2, 3, 4, etc. The light field control layers 600 are used to divide the light field in the resonant cavity structure into at least two sections. Figure 1Two light field control layers 600 in a multi-junction VCSEL device are shown, and the two light field control layers 600 can divide the light field in the resonant cavity structure into three sections. The light field control layer 600 is arranged adjacent to the photoelectric confinement layer 500. The light field control layer 600 includes two control sublayers 610, and the two control sublayers 610 in the same light field control layer 600 are respectively located on opposite sides of a corresponding photoelectric confinement layer 500. It can be understood that the closer the distance between the photoelectric confinement layer 500 and the light field control layer 600 is, the greater the diffusion of the current on the surface of the active area 400 after passing through the photoelectric confinement layer 500 can be reduced. Therefore, in this embodiment, the light field control layer 600 is arranged between the photoelectric confinement layer 500 and the active area 400, and the confinement factor of the photoelectric confinement layer 500 can be effectively regulated under the premise of better reducing the current diffusion. By setting the structure and / or composition of the two control sublayers 610 in the light field control layer 600, the light field intensity of each section of the light field can be flexibly adjusted. Based on different light field distributions, different scene applications can be realized, thereby improving the applicability of multi-junction VCSEL devices to different scenes. It should be noted that the light field intensities on both sides of a light field control layer 600 can be the same or different, which can be determined according to the actual scene requirements and is not limited here. The intensity peaks of each light field in the resonant cavity structure can also be the same or different, which is not limited here.

[0060] In the embodiment of the application, by inserting at least one light field control layer 600 in the resonant cavity structure of the multi-junction VCSEL device, the light field in the resonant cavity structure can be divided into at least two sections. By setting the structure and / or composition of the two control sublayers 610 in the light field control layer 600, the light field intensity of each section of the light field can be flexibly adjusted. Since the photoelectric confinement layer 500 is located at the trough of the standing wave, the electric field intensity at the photoelectric confinement layer 500 can be made lower. Moreover, due to the segmentation effect of the light field control layer 600 on the light field, the light field intensity at the light field control layer 600 is also weak, so it is also possible to limit the light field intensity of the photoelectric confinement layer 200 located between the two control sublayers 610. Based on the positive correlation between the confinement factor of the film layer and the electric field intensity and light field intensity where it is located, the above-mentioned setting method effectively reduces the confinement factor of the photoelectric confinement layer 500, thereby suppressing the high-order mode and achieving the effect of low divergence angle. Therefore, the present application provides a multi-junction VCSEL device with a smaller confinement factor of the optoelectronic confinement layer 500 and a larger confinement factor of the active region 400, thereby improving the performance of the multi-junction VCSEL device in terms of divergence angle and threshold current.

[0061] In one embodiment, the light field intensity at the light field control layer 600 and the photoelectric confinement layer 500 is lower than the light field intensity of any adjacent active area 400. It can be understood that the light field intensity at each location in the resonant cavity is constantly changing with the film layer where it is located. Since the light field control layer 600, the photoelectric confinement layer 500 and the active area 400 can all include multiple film layers, it can be understood here that the average light field intensity of the light field control layer 600 and the photoelectric confinement layer 500 is lower than the average light field intensity of any adjacent active area 400. Specifically, through the differentiated arrangement of each control sublayer 610 in the light field control layer 600, different control sublayers 610 can have different light enhancement and light emission characteristics, so that the light field control layer 600 and the photoelectric confinement layer 500 are located at a position with low light field intensity, so that the light field intensity of each segment of the light field can not only decrease step by step in the direction away from the substrate, but also can selectively realize the flexible adjustment of the light field intensity in different light field segments.

[0062] In one embodiment, the regulating sublayer 610 includes a photonic crystal structure or a periodically stacked DBR structure. Specifically, the periodically stacked DBR (Distributed Bragg Reflector) structure achieves efficient reflection or transmission of light within a specific wavelength range by periodically stacking multiple layers of materials with different refractive indices. Among them, the optical thickness of each layer in the periodically stacked DBR structure is 1 / 4 of the lasing wavelength. The material of the periodically stacked DBR structure includes any one of semiconductor materials and metals. Exemplarily, the DBR structure of semiconductor materials is composed of alternating stacks of GaAs and AlGaAs with different refractive indices, or alternating stacks of InGaAs and GaAsP with different refractive indices, or alternating stacks of InGaAs and AlGaAs with different refractive indices. The metal DBR structure is composed of, for example, alternating stacks of silver and aluminum with different refractive indices. Photonic crystals can form photonic energy gaps because of their own periodic dielectric constant changes, so that the reflection or transmission of light within a specific wavelength range can be achieved by controlling the position and width of the energy gap. In some embodiments, the regulation sublayer 610 may also be made of dielectric materials, metal-dielectric mixed materials, etc., which is not limited here.

[0063] In one embodiment, when the regulation sublayer 610 includes a periodically stacked DBR structure, the refractive index stacking order of the DBR structures of the two regulation sublayers 610 in the same light field regulation layer 600 is opposite. For example, the film layer of the regulation sublayer 610 closest to the substrate 100 is a high refractive index film layer, and is stacked in a high-low-high-low order along the direction away from the substrate 100, while the film layer of the regulation sublayer 610 closest to the substrate 100 is a low refractive index film layer, and is stacked in a low-high-low-high order along the direction away from the substrate 100. For another example, the film layer of a regulation sublayer 610 close to the substrate 100 on the side closest to the substrate 100 is a low refractive index film layer, and is stacked in a low-high-low-high order along the direction away from the substrate 100, while the film layer of a regulation sublayer 610 far from the substrate 100 on the side closest to the substrate 100 is a high refractive index film layer, and is stacked in a high-low-high-low order along the direction away from the substrate 100. In the embodiment of the application, by adjusting the refractive index stacking order of the DBR structure of different regulation sublayers 610, the phases of light in two regulation sublayers 610 in the same light field regulation layer 600 can be opposite, so that the light field intensity at the light field regulation layer 600 and the optoelectronic confinement layer 500 is lower than the light field intensity of any adjacent active region 400.

[0064] In one embodiment, the periodically stacked DBR structure is composed of Al x Ga （1-x） As / Al y Ga （1-y） As is alternately stacked, where 0≤x<y≤1. Specifically, by adjusting the proportion of aluminum and gallium in the AlGaAs material system, the refractive index and band gap of the periodically stacked DBR structure can be precisely controlled, thereby achieving reflection or transmission of light of a specific wavelength. Furthermore, the number of stacking periods of each regulating sublayer 610 is between 1 pair and 5 pairs, where a pair includes two adjacent film layers with different refractive indices. For example, if the number of stacking periods of the regulating sublayer 610 is 2 pairs, then the DBR structure of one regulating sublayer 610 includes Al x Ga （1-x） As layer, Al y Ga （1-y） As layer, Al x Ga （1-x） As layer and Al y Ga （1-y）As layer. It can be understood that the more stacking periods of the DBR structure of the regulating sublayer 610, the lower the limitation factor of the photoelectric limiting layer 500 can be, but it will also aggravate the problem of current diffusion, thereby increasing the impact on the luminous efficiency of the active area 400 after the photoelectric limiting layer 500. Therefore, in this embodiment, each regulating sublayer 610 is configured to include 1 to 5 pairs of stacking periods, respectively, so that the limitation factor of the photoelectric limiting layer 500 can be lower under the premise that the current diffusion problem is controllable. It should be noted that the stacking period numbers of the DBR structure of each regulating sublayer 610 can be the same or different, and can be specifically set according to the requirements for the light field, which is not limited here.

[0065] In one of the embodiments, the periodically stacked DBR structure includes a first DBR functional layer and a second DBR functional layer that are alternately stacked and have different refractive indices. When the refractive index of the first DBR functional layer of each regulation sublayer in the same light field regulation layer is the same, and the refractive index of the second DBR functional layer of each regulation sublayer is the same, the stacking number of DBR structures of the two regulation sublayers in the same light field regulation layer is different.

[0066] Furthermore, the components of the elements affecting the refractive index in the first DBR functional layer of each regulating sublayer 610 in the same light field regulating layer 600 can be made the same, so that the refractive index of the first DBR functional layer of each regulating sublayer 610 is the same. Similarly, the components of the elements affecting the refractive index in the second DBR functional layer of each regulating sublayer 610 can be made the same, so that the refractive index of the second DBR functional layer of each regulating sublayer 610 is the same. x Ga （1-x） As, the second DBR functional layer is Al y Ga （1-y） As is taken as an example, where 0≤x<y≤1. The x value of the first DBR functional layer in one regulating sublayer 610 can be the same as the x value of the first DBR functional layer in another regulating sublayer 610, and the y value of the second DBR functional layer in one regulating sublayer 610 can be the same as the y value of the second DBR functional layer in another regulating sublayer 610. For example, both regulating sublayers 610 can be made of Al 0.25 Ga 0.75 As / Al 0.5 Ga 0.5 As are stacked alternately.

[0067] The stacking period numbers of the DBR structures of the two regulating sublayers 610 in the same light field regulating layer 600 are different. The stacking period number of the DBR structure of the regulating sublayer 610 close to the substrate 100 may be greater than the stacking period number of the DBR structure of the regulating sublayer 610 away from the substrate 100, or the stacking period number of the DBR structure of the regulating sublayer 610 away from the substrate 100 may be greater than the stacking period number of the DBR structure of the regulating sublayer 610 close to the substrate 100, which is not limited here. It can be understood that the larger the stacking period number of the DBR structure of the regulating sublayer 610, the more interfaces the photons will be reflected at, that is, the reflection coefficient of the regulating sublayer 610 will be changed. Therefore, the different stacking period numbers of the DBR structures of the two regulating sublayers 610 in the same light field regulating layer 600 means that the reflection coefficients of the two regulating sublayers 610 are different, so that the photons generated by the active region 400 are emitted from the regulating sublayer 610 on one side after obtaining the required gain, so as to realize flexible control of the light field intensity. In the embodiments of the application, by changing the number of stacking periods of the DBR structure of the two regulating sublayers 610 in the same light field regulating layer 600, the light field intensity in each section of the light field can be adjusted to meet different application scenarios. Four embodiments are provided below to specifically illustrate the adjustment of the light field intensity.

[0068] Figure 2 FIG. 1 is a diagram of the refractive index and light field intensity of a multi-junction VCSEL device according to an embodiment of the present invention. Figure 2 In this embodiment, in the direction away from the substrate 100, the stacking period numbers of the DBR structure of the four regulating sublayers 610 are 1 pair, 3 pairs, 1 pair, and 3 pairs respectively. The refractive index at the light field regulating layer 600 shows periodic changes, and the refractive index between the two regulating sublayers 610 in the same light field regulating layer 600 shows an intermediate value, and the intermediate value of the refractive index is related to the material of the photoelectric limiting layer 500. The light field intensity at the photoelectric limiting layer 500 and the light field regulating layer 600 is both at a lower value, while the active areas 400 located on both sides of the light field regulating layer 600 have a higher light field intensity, and the light field intensity of the active areas 400 on both sides is different, indicating that the light field regulating layer 600 realizes the effective division of the light field in the resonant cavity. When the stacking period numbers are 1 pair, 3 pairs, 1 pair, and 3 pairs respectively, along the direction away from the substrate 100, the three sections of the light field show a trend of low, medium, and high light field intensity.

[0069] Figure 3 FIG2 is a second diagram of the refractive index and light field intensity of a multi-junction VCSEL device according to an embodiment of the present invention, referring to FIG2 Figure 3In this embodiment, in the direction away from the substrate 100, the stacking period numbers of the DBR structure of the four regulating sublayers 610 are 1 pair, 3 pairs, 3 pairs, and 1 pair respectively. The refractive index at the light field regulating layer 600 also shows periodic changes, and the refractive index between the two regulating sublayers 610 in the same light field regulating layer 600 shows an intermediate value, and the intermediate value of the refractive index is related to the material of the photoelectric limiting layer 500. The light field intensity at the photoelectric limiting layer 500 and the light field regulating layer 600 is both at a lower value, while the active areas 400 located on both sides of the light field regulating layer 600 have a higher light field intensity, and the light field intensity of the active areas 400 on both sides is different, indicating that the light field regulating layer 600 realizes the effective division of the light field in the resonant cavity. When the stacking period numbers are 1 pair, 3 pairs, 3 pairs, and 1 pair respectively, along the direction away from the substrate 100, the three sections of the light field show a trend of medium, high, and low light field intensity.

[0070] Figure 4 The third diagram of the refractive index and light field intensity of a multi-junction VCSEL device of an embodiment is shown in FIG. Figure 4 In this embodiment, in the direction away from the substrate 100, the stacking period numbers of the DBR structure of the four regulating sublayers 610 are 4 pairs, 3 pairs, 4 pairs, and 3 pairs respectively. The refractive index at the light field regulating layer 600 also shows periodic changes, and the refractive index between the two regulating sublayers 610 in the same light field regulating layer 600 shows an intermediate value, and the intermediate value of the refractive index is related to the material of the photoelectric limiting layer 500. The light field intensity at the photoelectric limiting layer 500 and the light field regulating layer 600 is both at a lower value, while the active areas 400 located on both sides of the light field regulating layer 600 have a higher light field intensity, and the light field intensity of the active areas 400 on both sides is different, indicating that the light field regulating layer 600 realizes the effective division of the light field in the resonant cavity. When the stacking period numbers are 4 pairs, 3 pairs, 4 pairs, and 3 pairs respectively, along the direction away from the substrate 100, the three sections of the light field show a trend of high, medium, and low light field intensity.

[0071] Figure 5 FIG4 is a fourth diagram of the refractive index and light field intensity of a multi-junction VCSEL device according to an embodiment, referring to FIG4 Figure 5In this embodiment, in the direction away from the substrate 100, the stacking period numbers of the DBR structure of the four regulating sublayers 610 are 2 pairs, 3 pairs, 2 pairs, and 3 pairs respectively. The refractive index at the light field regulating layer 600 also shows periodic changes, and the refractive index between the two regulating sublayers 610 in the same light field regulating layer 600 shows an intermediate value, and the intermediate value of the refractive index is related to the material of the photoelectric limiting layer 500. The light field intensity at the photoelectric limiting layer 500 and the light field regulating layer 600 is both at a lower value, while the active areas 400 located on both sides of the light field regulating layer 600 have a higher light field intensity, and the light field intensity of the active areas 400 on both sides is different, indicating that the light field regulating layer 600 realizes the effective division of the light field in the resonant cavity. When the stacking period numbers are 2 pairs, 3 pairs, 2 pairs, and 3 pairs respectively, along the direction away from the substrate 100, the three segments of the light field show a trend of the same light field intensity.

[0072] It can be understood that the number of stacking periods in the above embodiment is only used for exemplary explanation, and the number of stacking periods of the DBR structure of each regulation sublayer 610 can also be different from each other. For example, in the direction away from the substrate 100, the number of stacking periods of the DBR structure of the four regulation sublayers 610 is 1 pair, 3 pairs, 2 pairs, and 4 pairs respectively. Moreover, the three-segment electric field also presents a trend of gradually decreasing light field intensity in the direction away from the substrate 100. The ratio of the electric field intensity of the three-segment electric field can be 4:3:2 or 4:2:1, and the above difference can also be achieved by adjusting the number of stacking periods of the DBR structure of each regulation sublayer 610. That is, different stacking period setting methods can make the light field intensity produce similar changing trends, but the ratio of the light field intensity between each light field can be different. In addition, the number of light field regulation layers 600 in the multi-junction VCSEL device can also be one, three, etc., so as to divide the light field in the resonant cavity structure into other number of segments, which can be set according to actual needs and is not limited here.

[0073] In one of the embodiments, when the stacking periods of the DBR structures of two regulating sublayers 610 in the same light field regulating layer 600 are the same, the refractive index of the first DBR functional layer of each regulating sublayer in the same light field regulating layer is different, and / or the refractive index of the second DBR functional layer of each regulating sublayer is different.

[0074] For example, the element composition of the first DBR functional layer of each regulation sublayer 610 in the same light field regulation layer 600 may be different, or the element composition of the second DBR functional layer of each regulation sublayer 610 in the same light field regulation layer 600 may be different, so as to achieve different refractive indices. For example, one regulation sublayer 610 in the same light field regulation layer 600 is composed of GaAs and AlGaAs alternately stacked, and another regulation sublayer 610 is composed of InGaAs and GaAsP alternately stacked.

[0075] In another exemplary embodiment, the first DBR functional layer of each regulating sublayer 610 in the same light field regulating layer 600 may have the same element composition, and the second DBR functional layer of each regulating sublayer 610 in the same light field regulating layer 600 may have the same element composition, but the composition of the element affecting the refractive index of at least one of the first DBR functional layer and the second DBR functional layer is different. x Ga （1-x） As / Al y Ga （1-y） As is alternately stacked as an example, the composition of the element affecting the refractive index in the first DBR functional layer of each regulating sublayer 610 may be different, but the composition of the element affecting the refractive index in the second DBR functional layer may be the same. For example, one regulating sublayer 610 is composed of Al 0.5 Ga 0.5 As / AlAs are alternately stacked, and the other regulating sublayer 610 is composed of Al 0.75 Ga 0.25 As / AlAs are alternately stacked. Alternatively, the first DBR functional layer of each regulating sublayer 610 may have different components of the element affecting the refractive index, and the second DBR functional layer may also have different components of the element affecting the refractive index. For example, a regulating sublayer 610 may be composed of Al 0.5 Ga 0.5 As / Al 0.6 Ga 0.4 As is alternately stacked, and the other regulating sublayer 610 is composed of Al 0.75 Ga 0.25 As / AlAs are alternately stacked. It is understandable that different proportions of elements will lead to different refractive indices of the film layers, thereby making the refractive index difference of adjacent film layers different, and the greater the refractive index difference, the higher the reflectivity of the regulation sublayer 610. Therefore, the layer reflectivity of the two regulators of different components in the same light field regulation layer 600 is different, so that the photons generated by the active area 400 are emitted from the regulation sublayer 610 on one side after obtaining the required gain, so as to achieve flexible control of the light field intensity.

[0076] It is understandable that in some embodiments, the DBR structures of the two regulating sublayers 610 in the same light field regulating layer 600 have different stacking periods and different components, so as to control the reflection coefficient of the regulating sublayer 610 from multiple aspects and achieve more flexible adjustment of the light field intensity of each light field. The influence of the setting of the stacking period number and the component on the reflection coefficient of the regulating sublayer 610 can be referred to the above embodiment, and will not be repeated here.

[0077] In one embodiment, one of the regulation sublayers 610 in the same light field regulation layer 600 is a periodically stacked DBR structure, and the other is a photonic crystal structure. That is, the specific type of each regulation sublayer 610 can be set as needed, and is not limited to the two regulation sublayers 610 in the same light field regulation layer 600 having the same structure, both being periodically stacked DBR structures or both being photonic crystal structures. By selecting the specific type of each regulation sublayer 610 respectively, it is easier to achieve the required reflection coefficient, thereby more flexibly realizing the required multi-segment light field.

[0078] It should be noted that the specific structures of different light field control layers 600 can be set as needed. Specifically, each control sublayer 610 in each light field control layer 600 can adopt any one of a photonic crystal structure and a periodically stacked DBR structure. In the case of a periodically stacked DBR structure, the refractive index of the first DBR functional layer of each control sublayer 610 in different light field control layers 600 can be the same or different, and the refractive index of the second DBR functional layer of each control sublayer 610 in different light field control layers 600 can be the same or different, which is not limited in the embodiments of the present application.

[0079] In one embodiment, the photoelectric confinement layer 500 includes any one of an air column type photoelectric confinement layer 500, an oxidation confinement type photoelectric confinement layer 500, an ion implantation type photoelectric confinement layer 500, and a tunnel junction type photoelectric confinement layer 500. The air column type photoelectric confinement layer 500 limits the current and light through the air column, which is a hollow structure formed by dry etching technology, and has a lower refractive index than the surrounding semiconductor material, thereby effectively limiting the light in the central area. The ion implantation type photoelectric confinement layer 500 changes the electrical properties of the semiconductor material by injecting ions into the semiconductor material to form a high resistance area, which can limit the flow of current, thereby indirectly limiting the light generation area.

[0080] In one embodiment, continue to refer to Figure 1, the oxidation-restricted photoelectric limiting layer 500 includes an unoxidized area of ​​AlGaAs material with a high aluminum component and an oxidized area of ​​aluminum oxide material, the oxidized area is located outside the unoxidized area, and the unoxidized area forms a light-emitting area for effective current injection. Among them, the semiconductor layer in the unoxidized area of ​​the photoelectric limiting layer 500 can be understood as an opening, and the opening is used to define the light-emitting area of ​​the multi-junction VCSEL device. When the current enters, the current can only flow to the active area 400 through the opening in the photoelectric limiting layer 500, thereby realizing the restriction of the current injection path and the optical mode field. Further, the AlGaAs layer with a high aluminum component can be converted into aluminum oxide through a selective oxidation process to form an unoxidized area on the periphery. Further, the opening sizes of different photoelectric limiting layers 500 can be the same or different. When the openings of multiple photoelectric limiting layers 500 are different, the light-emitting area defined by the photoelectric limiting layer 500 with the smallest opening is used as the light-emitting area of ​​the multi-junction VCSEL device.

[0081] In one embodiment, the tunnel junction type photoelectric confinement layer 500 includes at least one highly doped N-type structure layer and at least one highly doped P-type structure layer. Specifically, a potential barrier is formed between the highly doped N-type structure layer and the highly doped P-type structure layer, and electrons are allowed to pass through the potential barrier by tunneling, thereby achieving lateral confinement of the current. In one embodiment, the material of the N-type structure layer and the P-type structure layer is Al x Ga 1-x As, the doping concentration of the N-type structure layer and the P-type structure layer is greater than 1e 18 cm -3 , where 0≤x≤1.

[0082] Figure 6 FIG. 2 is a schematic diagram of a multi-junction VCSEL device structure according to an embodiment of the present invention. Figure 6 In one embodiment, the active region 400 includes at least one multi-quantum well structure 401. That is, the active region 400 may include only one multi-quantum well structure 401, or may include a composite structure consisting of a plurality of multi-quantum well structures 401 stacked in layers. The composite structure may be, but is not limited to, composed of GaAs and AlGaAs, InGaAs and GaAsP, or InGaAs and AlGaAs materials stacked in layers. The multi-quantum well structure 401 is used to convert electrical energy into light energy, thereby generating laser light.

[0083] It can be understood that the multi-quantum well structure 401 is where the laser gain amplification is generated, and the center position of the multi-quantum well structure 401 can be aligned with the position where the light field is the strongest, so as to achieve a greater amplification effect. Further, in the case where a segmented light field includes multiple multi-quantum well structures 401, the confinement factors of the multi-quantum well structures 401 in the same segment of the light field are within the same preset range, that is, the confinement factors of each multi-quantum well structure 401 are maintained at the same level, so that the contribution of each multi-quantum well structure 401 to luminescence is similar. It can be understood that similar luminescence contributions mean that the injection of current in each multi-quantum well structure 401 is more uniform, which helps to reduce the threshold current of the multi-junction VCSEL device, thereby reducing the power consumption of the multi-junction VCSEL device and extending its service life. Moreover, when the contribution of each multi-quantum well structure 401 to luminescence is similar, the distribution of carriers in each multi-quantum well structure 401 will be more uniform, which helps to reduce the recombination loss of carriers, thereby improving the overall luminescence efficiency of the multi-junction VCSEL device.

[0084] In one embodiment, the multi-junction VCSEL device further includes at least one tunnel junction layer 700. The tunnel junction layer 700 is located between two adjacent multi-quantum well structures 401 or between the regulation sublayer 610 and the photoelectric confinement layer 500. Specifically, the tunnel junction layer 700 can be located between the photoelectric confinement layer 500 and the regulation sublayer 610 on the side away from the substrate 100. As a path for current, the tunnel junction layer 700 can limit the flow position of the current, so that the current flows more in the central area near the central axis of the multi-junction VCSEL device, reducing the diffusion of the current from the central area to the outside, thereby facilitating the laser to be emitted from the center of the multi-junction VCSEL device. Moreover, the tunnel junction layer 700 can also reduce the non-radiative recombination of carriers at the tunnel junction layer 700, ensuring that more current is used to generate useful photons, thereby increasing the probability of radiative recombination and improving the quality of the light field.

[0085] In one embodiment, the resonant cavity structure includes three active regions 400 and three photoelectric confinement layers 500. The three active regions 400 include a first active region 410, a second active region 420 and a third active region 430 sequentially arranged in a direction away from the substrate 100, and the three photoelectric confinement layers 500 include a first photoelectric confinement layer 510, a second photoelectric confinement layer 520 and a third photoelectric confinement layer 530. The first photoelectric confinement layer 510 is located between the first active region 410 and the second active region 420, the second photoelectric confinement layer 520 is located between the second active region 420 and the third active region 430, and the third photoelectric confinement layer 530 is located on a side of the third active region 430 close to the top reflector structure 300. A tunnel junction layer 700 is provided between the first photoelectric confinement layer 510 and the control sublayer 610 of the first light field control layer 600 away from the substrate 100, and a tunnel junction layer 700 is also provided between the second photoelectric confinement layer 520 and the control sublayer 610 of the second light field control layer 600 away from the substrate 100. Further, the first active region 410 includes three multi-quantum well structures 401, the second active region 420 includes two multi-quantum well structures 401, and the third active region 430 includes two multi-quantum well structures 401. Among them, the adjacent multi-quantum well structures 401 in each active region 400 are connected by a tunnel junction layer 700.

[0086] Among them, by setting a tunnel junction layer 700 between the regulating sublayer 610 and the photoelectric confinement layer 500, the speed of change of the light field intensity at the photoelectric confinement layer 500 and the light field regulating layer 600 can be slowed down, so that the light field intensity at the photoelectric confinement layer 500 and the light field regulating layer 600 can be continuously located at a lower position. It can be understood that if the process causes a certain offset in the position of the photoelectric confinement layer 500 in the light field, it may cause the photoelectric confinement layer 500 to be unable to be located at the trough of the standing wave. Based on the positive correlation between the confinement factor and the light field intensity, when the offset causes the light field intensity at the photoelectric confinement layer 500 to increase, it will cause the confinement factor of the photoelectric confinement layer 500 to increase, thereby affecting the performance of the multi-junction VCSEL device. In addition, taking the tunnel junction layer 700 disposed adjacent to the first photoelectric confinement layer 510 as an example, since the multi-quantum well structure 410 in the first active region 410 far away from the substrate 100 is close to the first photoelectric confinement layer 510, a P-type heavy doping is used. In the tunnel junction layer 700 disposed adjacent to the first photoelectric confinement layer 510, the side close to the first photoelectric confinement layer 510 is also heavily doped with P-type. Therefore, if the tunnel junction layer 700 is disposed on the side of the first photoelectric confinement layer 510 close to the substrate 100, two P-type heavily doped regions will be too close, and the P-type heavily doped region has certain light absorption characteristics. The two P-type heavily doped regions that are close will further enhance light absorption, thereby causing the performance of the multi-junction VCSEL device to decrease. In the embodiment of the application, the tunnel junction layer 700 is disposed on the side of the first photoelectric confinement layer 510 that is away from the substrate 100, which can effectively improve the above-mentioned light absorption problem.

[0087] In one of the embodiments, the bottom reflector structure 200 includes a plurality of reflectors with an optical thickness of one quarter of the laser wavelength, and the plurality of reflectors are arranged alternately according to high and low refractive indices. The top reflector structure 300 includes a plurality of reflectors with an optical thickness of one quarter of the laser wavelength, and the plurality of reflectors are arranged alternately according to high and low refractive indices. That is, the bottom reflector structure 200 and the top reflector structure 300 can be understood as a Bragg reflector structure respectively. Among them, the material of the top reflector structure 300 and the bottom reflector structure 200 can be a dielectric material with electrical insulation, for example, silicon nitride, silicon oxide, aluminum oxide or titanium oxide. The material of the top reflector structure 300 and the bottom reflector structure 200 can also be a semiconductor material, for example, GaAs and AlGaAs.

[0088] The embodiment of the present application also provides a VCSEL chip, which can be a flip-chip VCSEL chip, and the VCSEL chip includes a positive electrode, a negative electrode and a multi-junction VCSEL device as described above. In an exemplary embodiment, the positive electrode and the negative electrode are electrically connected to the bottom reflector structure 200 and the top reflector structure 300 of the multi-junction VCSEL device, respectively, and the positive electrode and the negative electrode are located on the side opposite to the light-emitting side of the VCSEL chip. In another exemplary embodiment, the positive electrode and the negative electrode are electrically connected to the top reflector structure 300 and the bottom reflector structure 200 of the multi-junction VCSEL device, respectively, and the positive electrode and the negative electrode are located on the side opposite to the light-emitting side of the VCSEL chip. Based on the aforementioned multi-junction VCSEL device, the VCSEL chip of this embodiment can have better performance in terms of divergence angle and threshold current. In addition, the flip-chip VCSEL chip connects the chip to the substrate and the carrier through the bump, which can reduce the need for wire bonding, thereby not only simplifying the packaging technology, but also reducing the system inductance of the flip-chip VCSEL chip, which helps to improve the overall photoelectric conversion efficiency of the flip-chip VCSEL chip.

[0089] The embodiment of the present application also provides a VCSEL chip, which includes at least one laser array. The laser array includes a plurality of multi-junction VCSEL devices as described above, and the laser array is a regularly arranged array, or a randomly arranged array, or an array with multiple addressable sub-arrays. Based on the aforementioned multi-junction VCSEL device, the VCSEL chip of this embodiment can have better performance in terms of divergence angle and threshold current.

[0090] An embodiment of the present application also provides a light source for a laser radar system, comprising at least one multi-junction VCSEL device as described above or at least one VCSEL chip as described above.

[0091] An embodiment of the present application also provides a laser radar system, including a transmitting component and a receiving component, wherein the transmitting component adopts the above-mentioned light source for the laser radar system.

[0092] Embodiments of the invention are described herein with reference to cross-sectional views which are schematic diagrams of ideal embodiments (and intermediate structures) of the invention, such that variations in the shapes shown due to, for example, manufacturing techniques and / or tolerances are anticipated. Thus, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include deviations in shapes due to, for example, manufacturing techniques. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Thus, the regions shown in the figures are schematic in nature, their shapes do not represent the actual shape of the region of the device, and do not limit the scope of the invention.

[0093] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0094] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A multi-junction VCSEL device, characterized in that: include: substrate; A bottom reflector structure and a top reflector structure sequentially disposed on the substrate; The bottom reflector structure and the top reflector structure define a resonant cavity structure for generating a standing wave; The resonant cavity structure comprises a plurality of stacked active regions and at least one photoelectric limiting layer, wherein the photoelectric limiting layer is located on a side of the corresponding active region away from the substrate and at a trough of the standing wave, and the photoelectric limiting layer is used to limit a light-emitting region of the multi-junction VCSEL device; At least one light field regulation layer is arranged adjacent to the photoelectric confinement layer, the light field regulation layer includes two regulation sublayers, and the two regulation sublayers in the same light field regulation layer are respectively located on two opposite sides of a corresponding photoelectric confinement layer, so as to divide the light field in the resonant cavity structure into at least two sections.

2. The multi-junction VCSEL device according to claim 1, characterized in that: The intensity peaks of each segment of the light field in the resonant cavity structure are the same or different.

3. The multi-junction VCSEL device according to claim 1, characterized in that: The light field intensity at the light field regulating layer and the photoelectric limiting layer is lower than the light field intensity of any adjacent active region.

4. The multi-junction VCSEL device according to claim 3, characterized in that: The regulating sublayer includes a photonic crystal structure or a periodically stacked DBR structure, and the material of the periodically stacked DBR structure includes a semiconductor material.

5. The multi-junction VCSEL device according to claim 4, characterized in that: When the regulation sublayer includes a periodically stacked DBR structure, the refractive index stacking order of the DBR structures of two regulation sublayers in the same light field regulation layer is opposite.

6. The multi-junction VCSEL device according to claim 4, characterized in that: The periodically stacked DBR structure includes alternately stacked first DBR functional layers and second DBR functional layers with different refractive indices. When the refractive index of the first DBR functional layer of each of the regulating sublayers in the same light field regulation layer is the same, and the refractive index of the second DBR functional layer of each of the regulating sublayers is the same, the stacking number of DBR structures of the two regulating sublayers in the same light field regulation layer is different.

7. The multi-junction VCSEL device according to claim 6, characterized in that: The components of the elements affecting the refractive index in the first DBR functional layer of each of the regulating sublayers in the same light field regulating layer are the same, and the components of the elements affecting the refractive index in the second DBR functional layer of each of the regulating sublayers are the same.

8. The multi-junction VCSEL device according to claim 6, characterized in that: The number of stacking periods of each of the regulating sublayers is between 1 pair and 5 pairs.

9. The multi-junction VCSEL device according to claim 8, characterized in that: The number of the light field control layers is two. In the direction away from the substrate, the stacking periods of the DBR structures of the four control sublayers are 1 pair, 3 pairs, 1 pair, 3 pairs, or 1 pair, 3 pairs, 3 pairs, 1 pair, or 4 pairs, 3 pairs, 4 pairs, 3 pairs, or 2 pairs, 3 pairs, 2 pairs, 3 pairs.

10. The multi-junction VCSEL device according to claim 4, characterized in that: The periodically stacked DBR structure includes alternately stacked first DBR functional layers and second DBR functional layers with different refractive indices; when the stacking period numbers of the DBR structures of each of the regulating sublayers in the same light field regulation layer are the same, the refractive indices of the first DBR functional layers of each of the regulating sublayers in the same light field regulation layer are different, and / or the refractive indices of the second DBR functional layers of each of the regulating sublayers are different.

11. The multi-junction VCSEL device according to claim 10, characterized in that: The element composition of the first DBR functional layer of each of the regulating sub-layers in the same light field regulating layer is different; or the element composition of the first DBR functional layer of each of the regulating sub-layers in the same light field regulating layer is the same, but the components of the elements affecting the refractive index are different; The element composition of the second DBR functional layer of each regulating sublayer in the same light field regulating layer is different; or the element composition of the second DBR functional layer of each regulating sublayer in the same light field regulating layer is the same, but the components of the elements affecting the refractive index are different.

12. The multi-junction VCSEL device according to claim 4, characterized in that: The periodically stacked DBR structure is composed of Al x1 Ga （1-x1） As / Al y Ga （1-y） As is formed by alternating stacking, where 0≤x1<y≤1.

13. The multi-junction VCSEL device according to any one of claims 1 to 12, characterized in that: The photoelectric confinement layer includes any one of an air column type photoelectric confinement layer, an oxidation confinement type photoelectric confinement layer, an ion implantation type photoelectric confinement layer and a tunnel junction type photoelectric confinement layer.

14. The multi-junction VCSEL device according to claim 13, characterized in that: The oxidation-limited photoelectric limiting layer includes an unoxidized region of AlGaAs material with a high aluminum component and an oxidized region of aluminum oxide material. The oxidized region is located outside the unoxidized region, and the unoxidized region forms a light-emitting region for effective current injection.

15. The multi-junction VCSEL device according to claim 13, characterized in that: The tunnel junction type photoelectric limiting layer includes at least one highly doped N-type structure layer and at least one highly doped P-type structure layer.

16. The multi-junction VCSEL device according to claim 15, characterized in that: The material of the N-type structure layer and the P-type structure layer is selected as Al x2 Ga 1-x2 As, the doping concentration of the N-type structure layer and the P-type structure layer is greater than 1e 18 cm -3 , where 0≤x2≤1.

17. The multi-junction VCSEL device according to any one of claims 1 to 12, characterized in that: The active region includes at least one multi-quantum well structure, and the multi-junction VCSEL device also includes at least one tunnel junction layer, and the tunnel junction layer is located between two adjacent multi-quantum well structures or between the regulation sublayer and the photoelectric confinement layer.

18. The multi-junction VCSEL device according to claim 17, characterized in that: The resonant cavity structure includes three active regions and three photoelectric confinement layers; the three active regions include a first active region, a second active region and a third active region sequentially arranged in a direction away from the substrate, and the three photoelectric confinement layers include a first photoelectric confinement layer, a second photoelectric confinement layer and a third photoelectric confinement layer; The first photoelectric limiting layer is located between the first active region and the second active region, the second photoelectric limiting layer is located between the second active region and the third active region, and the third photoelectric limiting layer is located on a side of the third active region close to the top reflector structure.

19. The multi-junction VCSEL device according to claim 18, characterized in that: The first active region includes three multi-quantum well structures, the second active region includes two multi-quantum well structures, and the third active region includes two multi-quantum well structures; and adjacent multi-quantum well structures in each active region are connected via a tunnel junction layer.

20. The multi-junction VCSEL device according to any one of claims 1 to 12, characterized in that: The bottom reflector structure includes a plurality of reflectors with an optical thickness of one quarter of the lasing wavelength, and the plurality of reflectors are arranged alternately according to high and low refractive indices; The top reflector structure includes a plurality of reflectors with an optical thickness of one quarter of the lasing wavelength, and the plurality of reflectors are alternately arranged according to high and low refractive indices.

21. A VCSEL chip, characterized in that: The VCSEL chip comprises a positive electrode, a negative electrode and a multi-junction VCSEL device according to any one of claims 1 to 20; Wherein, the positive electrode and the negative electrode are electrically connected to the bottom reflector structure and the top reflector structure of the multi-junction VCSEL device respectively; or The positive electrode and the negative electrode are electrically connected to the top reflector structure and the bottom reflector structure of the multi-junction VCSEL device respectively; The positive electrode and the negative electrode are located on the side opposite to the light emitting side of the VCSEL chip.

22. A VCSEL chip, characterized in that: It comprises at least one laser array; the laser array comprises a plurality of multi-junction VCSEL devices as described in any one of claims 1 to 20; the laser array is a regularly arranged array, or a randomly arranged array, or an array with a plurality of addressable sub-arrays.

23. A light source for a laser radar system, characterized in that: The method comprises at least one multi-junction VCSEL device according to any one of claims 1 to 20 or at least one VCSEL chip according to claim 21 or 22.

24. A laser radar system, characterized in that: It comprises a transmitting component and a receiving component, and the transmitting component adopts the light source for the laser radar system as described in claim 23.

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