Vertical cavity surface emitting laser, preparation method, laser radar system and light source of laser radar system

Abstract

The invention relates to the technical field of vertical-cavity surface-emitting lasers, and provides a vertical-cavity surface-emitting laser, a preparation method, a laser radar system and a light source of the laser radar system. The vertical cavity surface emitting laser comprises a device base body, the device base body comprises a substrate and a plurality of light emitting units arranged on the substrate, and the light emitting units are separated through grooves; each light-emitting unit comprises an epitaxial layer and an ohmic contact layer which are sequentially arranged on the substrate; the groove is formed in the epitaxial layer; a current blocking part embedded in the epitaxial layer is arranged below the ohmic contact layer corresponding to part or all of the light-emitting units; the current blocking part is configured to control the current of at least one light emitting unit injected into the epitaxial layer through the ohmic contact layer to be different from the current of the other light emitting units injected into the epitaxial layer through the ohmic contact layer; the phenomenon that the peripheral light-emitting hole has a high-order mode too early due to non-uniform injection current is avoided, the problem of a far-field divergence angle is improved, and the use performance of the vertical-cavity surface-emitting laser is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of vertical cavity surface emitting lasers, and particularly relates to a vertical cavity surface emitting laser and a preparation method thereof, a lidar system and a light source thereof. Background Art

[0002] In the design of vertical cavity surface emitting lasers, the far-field divergence angle and the optical power restrict each other, and these two indicators are very important for VCSELs. Usually, in order to pursue a small divergence angle, the vertical cavity surface emitting laser mostly reduces the far-field divergence angle at the cost of power. Conversely, in order to compensate for the loss of optical power of the vertical cavity surface emitting laser, it is necessary to increase the number of light-emitting holes on the vertical cavity surface emitting laser. The increased light-emitting holes will bring problems such as an increase in chip size and heat generation, and will also cause the phenomenon of uneven injection current, thereby increasing the loss of unit optical power of the light-emitting holes. Moreover, the uneven current injection leads to an increase in the far-field divergence angle, affecting the performance of the vertical cavity surface emitting laser. Summary of the Invention

[0003] An object of the present invention is to at least overcome one of the above-mentioned deficiencies of the prior art, and provide a vertical cavity surface emitting laser and a preparation method thereof, a lidar system and a light source thereof, so as to avoid an excessive far-field divergence angle of the vertical cavity surface emitting laser and ensure the performance of the vertical cavity surface emitting laser.

[0004] The technical solution of the present invention is as follows: A vertical cavity surface emitting laser includes a device substrate, and the device substrate includes a substrate and a plurality of light-emitting units disposed on the substrate, and each of the light-emitting units is separated by a trench; Each light-emitting unit includes an epitaxial layer and an ohmic contact layer disposed on the substrate in sequence; the trench is formed in the epitaxial layer; a current blocking portion embedded in the epitaxial layer is disposed below the ohmic contact layer corresponding to some or all of the light-emitting units; the current blocking portion is configured to control the current injected into the epitaxial layer through the ohmic contact layer of at least one of the light-emitting units to be different from the current injected into the epitaxial layer through the ohmic contact layer of the remaining light-emitting units.

[0005] Optionally, the device substrate has a light-emitting unit area, and the light-emitting unit area includes at least two light-emitting regions arranged away from the set position from a set position, and at least one light-emitting unit is disposed in each of the light-emitting regions; The set position is the center point of the light-emitting unit area, or the device substrate is provided with a first power supply access portion on one side of the light-emitting unit area, and the set position is a position away from the first power supply access portion.

[0006] Optionally, the thickness of the current blocking portion relatively far from the set position is greater than the thickness of the current blocking portion relatively close to the set position; Or / and, the width of the current blocking portion relatively far from the set position is greater than the width of the current blocking portion relatively close to the set position; Or / and, the conductivity of the material of the current blocking portion relatively far from the set position is less than the conductivity of the material of the current blocking portion relatively close to the set position.

[0007] Optionally, except for the light-emitting units in the light-emitting area close to the set position, the rest of the light-emitting units are provided with the current blocking portion. Optionally, the light-emitting area includes a first light-emitting area and a second light-emitting area. The first light-emitting area is closer to the center of the light-emitting unit area than the second light-emitting area. The second light-emitting area is provided on the outer periphery of the first light-emitting area, or the second light-emitting area is provided on the side of the first light-emitting area far from the set position; The current blocking portion is provided below each light-emitting unit in the first light-emitting area, and the total resistance value of the light-emitting units is R1. The current blocking portion is provided below each light-emitting unit in the second light-emitting area, and the total resistance value of the light-emitting units is R2, and R1 is less than R2. Optionally, each light-emitting unit includes a light-emitting hole and a current injection structure provided around the light-emitting hole; a first electrode is provided on one side of the device substrate, a second electrode is provided on the other side of the device substrate, the current injection structure includes a conductive channel provided between the first electrode and the second electrode, and a plurality of the conductive channels are provided around the periphery of each light-emitting hole; The current blocking portion is in contact with the ohmic contact layer; One end of the conductive channel is connected to the first electrode, and the ohmic contact layer is a P-type ohmic contact layer connected to the other end of the conductive channel. Optionally, one side of the P-type ohmic contact layer is in contact with the conductive channel, the current blocking portion is provided on the other side of the P-type ohmic contact layer, and the current blocking portion is in a layer shape and has a hollow hole, and the hollow hole is coaxially corresponding to the light-emitting hole. Optionally, the inner diameter of the hollow hole is greater than the aperture of the light-emitting hole, and the aperture of the hollow hole relatively close to the set position is greater than the aperture of the hollow hole relatively far from the set position. Optionally, the device substrate includes a passivation layer, the conductive channel penetrates through the passivation layer, the first electrode is provided on one side of the passivation layer and connected to the first end of the conductive channel, The ohmic contact layer is disposed on the other side of the passivation layer and connected to the second end of the conductive channel; The epitaxial layer includes a semiconductor contact layer, a P-DBR layer, an optical confinement layer, a multi-quantum well layer, and an N-DBR layer, which are sequentially arranged from top to bottom. Optionally, the current blocking portion is made of an insulating material or a semi-insulating material; Alternatively, and / or, the semiconductor contact layer is provided with an etching groove, and the current blocking portion is filled in the etching groove and is in contact with the ohmic contact layer.

[0008] The present invention also provides a method for manufacturing a vertical cavity surface emitting laser for manufacturing the above-mentioned vertical cavity surface emitting laser, including: When manufacturing the light emitting unit of the vertical cavity surface emitting laser, a current blocking portion embedded in the epitaxial layer is provided below the ohmic contact layer corresponding to some or all of the light emitting units; the current blocking portion is configured such that the current injected into the epitaxial layer by at least one of the light emitting units via the ohmic contact layer is different from the current injected into the epitaxial layer by the remaining light emitting units via the ohmic contact layer.

[0009] The present invention also provides a light source for a lidar system, including at least one of the above-mentioned vertical cavity surface emitting lasers.

[0010] The present invention also provides a lidar system, including a transmitting component for transmitting a light source and a receiving component for receiving the light source, and the transmitting component uses the above-mentioned light source for a lidar system.

[0011] In the vertical cavity surface emitting laser, manufacturing method, lidar system and its light source provided by the present invention, by setting a current blocking portion with a larger size / resistance value at a position relatively far from the set position, the overall resistance value of the light emitting units in the central part of the light emitting area is reduced, and the resistance value corresponding to the light emitting units at the central position is deliberately reduced, so that the current can be concentrated relatively towards the central part of the light emitting area, thereby achieving the purpose of adjusting the current injection uniformity of different light emitting units at different positions, and further avoiding the phenomenon that the peripheral light emitting holes prematurely appear high-order modes due to uneven injection current. The light emitting units with relatively small resistance values can carry higher current and power, while the light emitting units with relatively large resistance values carry relatively low current and power, avoiding the excessive light emitting angle of the light emitting units in the edge area from affecting the far-field divergence angle of the vertical cavity surface emitting laser. Moreover, the light emitting units with relatively small resistance values have a relatively longer path from the first power supply access part, and the light emitting units with relatively large resistance values have a relatively shorter path from the first power supply access part. Through resistance complementarity, it is also beneficial to make the injected current uniform. The problem of the far-field divergence angle can be improved by changing the resistance value of the light emitting units to adjust the current and power, and the far-field divergence angle can be reduced without sacrificing power, ensuring the use performance of the vertical cavity surface emitting laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0013] Figure 1 is a top view of a vertical cavity surface emitting laser provided by an embodiment of the present invention; Figure 2 is a schematic diagram showing the arrangement of light emitting units in the light emitting unit area of a vertical cavity surface emitting laser provided by an embodiment of the present invention; Figure 3 is Figure 1 a schematic cross-sectional view of the A-A section in Figure 4 is a partial cross-sectional view of a vertical cavity surface emitting laser provided by an embodiment of the present invention.

[0014] DESCRIPTION OF THE REFERENCE NUMERALS 100, device substrate; 101, light emitting unit area; 110, light emitting unit; 111, light emitting hole; 210, first power supply connection part; 110a, first light emitting area; 110b, second light emitting area; 120, first electrode; 112, conductive channel; 130, passivation layer; 140, ohmic contact layer; 150, semiconductor contact layer; 160, epitaxial layer; 161, P-DBR layer; 162, optical confinement layer; 163, multi-quantum well layer; 164, N-DBR layer; 170, second electrode; 190, current blocking part. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further details the present invention with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] It should be noted that the terms "arrangement" and "connection" should be understood in a broad sense. For example, it can be a direct arrangement or connection, or an indirect arrangement or connection through intermediate components or intermediate structures.

[0017] In addition, in the embodiments of the present invention, if there are terms indicating orientation or positional relationships such as "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., they are based on the orientation or positional relationships shown in the drawings or the conventional placement state or usage state. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the structures, features, devices or elements referred to must have a specific orientation or positional relationship, nor must they be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more than two.

[0018] In the various specific technical features and each embodiment described in the specific implementation manners, they can be combined in any suitable manner without contradiction. For example, different embodiments can be formed by combining different specific technical features / embodiments. To avoid unnecessary repetition, the various possible combination manners of the specific technical features / embodiments in the present invention will not be described separately.

[0019] As Figure 1 and Figure 2 As shown, a vertical cavity surface emitting laser provided by an embodiment of the present invention includes a device substrate 100. The device substrate 100 includes a substrate 200 and a plurality of light emitting units 110 disposed on the substrate 200. Each of the light emitting units 110 is separated by a trench. Each light emitting unit 110 includes an epitaxial layer 160 and an ohmic contact layer 140 disposed in sequence on the substrate 200. The trench is formed in the epitaxial layer 160. A current blocking portion 190 embedded in the epitaxial layer 160 is disposed below the ohmic contact layer 140 corresponding to some or all of the light emitting units 110. The current blocking portion 190 is configured to control the current injected from at least one of the light emitting units 110 into the epitaxial layer 160 via the ohmic contact layer 140 to be different from the current injected from the remaining light emitting units 110 into the epitaxial layer 160 via the ohmic contact layer 140. After the current blocking portion 190 is formed, each of the light emitting units 110 satisfies the following condition: the current injected from at least one light emitting unit 110 into the epitaxial layer 160 via the ohmic contact layer 140 is different from the current injected from the remaining light emitting units 110 into the epitaxial layer 160 via the ohmic contact layer 140. By adjusting the current passing ability of the light emitting units 110, it is beneficial to make the current passing abilities of the light emitting units 110 balanced and consistent, and avoid the emission angle of the light emitting units 110 in a local area (especially the edge area) from being too large and affecting the far-field divergence angle of the vertical cavity surface emitting laser.

[0020] Specifically, the device substrate 100 has a light-emitting unit region 101, and the light-emitting unit region 101 includes at least two light-emitting regions, and each light-emitting region is arranged away from the set position from the set position.

[0021] At least one light-emitting unit 110 is provided in each of the light-emitting regions; a current blocking portion (current blocking layer) 190 is correspondingly provided for some or all of the light-emitting units 110. Different sizes and / or conductivities of the current blocking portions make the overall resistance value of the light-emitting units 110 farther from the set position greater than the overall resistance value of the light-emitting units 110 relatively closer to the set position.

[0022] The overall resistance value of the light-emitting units 110 in the light-emitting region relatively closer to the set position is smaller than the overall resistance value corresponding to the light-emitting units 110 in the light-emitting region relatively farther from the set position. The set position may be the center point of the light-emitting unit region 101 (such as the O point shown in Figure 2 ), or the device substrate 100 is provided with a first power supply access portion 210 (which can be used to connect to the positive pole of the power supply) on one side of the light-emitting unit region 101, and the set position is a position away from the first power supply access portion 210, that is, the light-emitting units 110 away from the center point of the light-emitting unit region 101 or away from the first power supply access portion 210 have relatively small corresponding resistance values. Each light-emitting unit 110 can be regarded as a resistor connected in parallel between the positive pole and the negative pole of the power supply.

[0023] The light-emitting units 110 with relatively small resistance values can carry higher current and power, while the light-emitting units 110 with relatively large resistance values carry relatively low current and power, avoiding the problem that the emission angle of the light-emitting units 110 in the edge region is too large and affecting the far-field divergence angle of the vertical cavity surface emitting laser. Moreover, the light-emitting units 110 with relatively small resistance values are relatively farther from the first power supply access portion 210, and the light-emitting units 110 with relatively large resistance values are relatively closer to the first power supply access portion 210. Through resistance complementarity, it is also beneficial to make the injected current uniform. In this way, the resistance value of the current injection structure corresponding to the light-emitting units 110 near the set position is relatively small, and the resistance value of the current injection structure corresponding to the light-emitting units 110 far from the set position is relatively large, making the battery tend to flow to the light-emitting units 110 at the set position. In this embodiment, the set position is taken as the center of the light-emitting unit region 101. In this way, the current relatively tends to flow to the light-emitting units 110 in the central region, making the current and power carried by the light-emitting units 110 in the central region relatively large, and the current and power carried by the light-emitting units 110 in the peripheral region relatively small, thereby limiting the increase of the far-field divergence angle. The problem of the far-field divergence angle can be improved by changing the resistance value to adjust the current and power, and it is possible to ensure the use performance of the vertical cavity surface emitting laser without sacrificing power to reduce the far-field divergence angle.

[0024] In a specific application, the size or conductivity of the current blocking portion 190 relatively far from the set position is greater than that of the current blocking portion 190 relatively close to the set position, and it can be adjusted by adjusting the material or / and size of the current blocking portion 190.

[0025] In a specific application, as a first adjustment method, the thickness of the current blocking portion 190 relatively far from the set position is greater than that of the current blocking portion 190 relatively close to the set position, that is, for the current blocking portion 190 with a thicker axial dimension, the overall resistance value of the corresponding light-emitting unit 110 is greater.

[0026] As a second adjustment method, the width of the current blocking portion 190 relatively far from the set position is greater than that of the current blocking portion 190 relatively close to the set position, that is, for the current blocking portion 190 with a larger radial dimension, the overall resistance value of the corresponding light-emitting unit 110 is greater.

[0027] As a third adjustment method, the conductivity of the material of the current blocking portion 190 relatively far from the set position is less than that of the current blocking portion 190 relatively close to the set position, and the overall resistance value of the corresponding light-emitting unit 110 can be adjusted by using different materials. In a specific application, the above three resistance adjustment methods can be applied alone, or at least two of them can be applied simultaneously. Of course, the resistance adjustment method is not limited to the above examples.

[0028] In some alternative embodiments, except for the light-emitting units 110 in the light-emitting area close to the set position, the remaining light-emitting units 110 are all provided with the current blocking portion 190, that is, the light-emitting unit 110 closest to the set position may not be provided with the current blocking portion 190.

[0029] Specifically, as Figures 1 to 4 shown, the light-emitting area includes a first light-emitting area 110a and a second light-emitting area 110b. The first light-emitting area 110a is closer to the center of the light-emitting unit area 101 than the second light-emitting area 110b, and the second light-emitting area 110b is arranged on the outer periphery of the first light-emitting area 110a (as Figure 3as shown); alternatively, the second light-emitting region 110b is disposed on a side of the first light-emitting region 110a away from the set position. In a specific application, the first light-emitting region 110a may be circular or polygonal, and the second light-emitting region 110b may be circular ring-shaped or multi-sided ring-shaped. The second light-emitting region 110b is disposed around the periphery of the first light-emitting region 110a, that is, the light-emitting units 110 in the second light-emitting region 110b are relatively closer to the edge of the vertical cavity surface emitting laser than the light-emitting units 110 in the first light-emitting region 110a. Of course, in a specific application, a third light-emitting region may be further disposed around the periphery of the second light-emitting region 110b. Similarly, a fourth light-emitting region may be further disposed around the periphery of the third light-emitting region, and so on, which will not be elaborated herein.

[0030] Specifically, a current blocking portion 190 is disposed below each light-emitting unit 110 in the first light-emitting region 110a, and the total resistance value of the light-emitting units 110 is R1. A current blocking portion 190 is disposed below the second light-emitting region 110b, and the total resistance value of the light-emitting units is R2, and R1 is less than R2. In this way, the current and power of the light-emitting units 110 relatively closer to the set position (the center of the light-emitting unit area) are relatively greater.

[0031] In this embodiment, one light-emitting unit 110 is disposed in the first light-emitting region 110a, and the light-emitting unit 110 is disposed at the center point. Alternatively, a plurality of light-emitting units 110 are disposed in the first light-emitting region 110a, and each of the light-emitting units 110 is evenly distributed along the circumferential direction with the center point as the center; that is, one or more light-emitting units 110 may be disposed in the first light-emitting region 110a. In this embodiment, the light-emitting unit 110 in the first light-emitting region 110a is taken as an example. Of course, the number of light-emitting units 110 in the first light-emitting region 110a may also be three or four or other appropriate numbers. When a plurality of light-emitting units 110 are disposed in the first light-emitting region 110a, each of the light-emitting units 110 may be arranged according to a set rule or randomly arranged.

[0032] Specifically, a plurality of light-emitting units 110 are disposed in the second light-emitting region 110b. In this embodiment, the light-emitting units 110 in the second light-emitting region 110b are taken as six as an example. Of course, the number of light-emitting units 110 may also be 8 or 10 or other appropriate numbers, and each of the light-emitting units 110 is evenly distributed along the circumferential direction with the center point as the center around the periphery of the first light-emitting region 110a, and each of the light-emitting units 110 may be arranged according to a set rule or randomly arranged.

[0033] In specific applications, if more light-emitting units 110 or a vertical cavity surface emitting laser with a larger size is required, the light-emitting region further includes a third light-emitting region, and the third light-emitting region can be disposed around the periphery of the second light-emitting region 110b. A plurality of light-emitting units 110 are provided in the third light-emitting region, and each of the light-emitting units 110 is uniformly distributed in the circumferential direction around the second light-emitting region 110b with the center point as the center, forming a three-ring structure.

[0034] In specific applications, that is, each light-emitting unit 110 can adopt a double-ring or multi-ring arrangement. The inner ring can have one or more light-emitting units 110, and a plurality of light-emitting units 110 can be provided in the second ring and the third ring. Among them, the closer the light-emitting unit 110 is to the outer ring, the larger its corresponding resistance value is (the resistance value is adjusted by the current blocking portion 190), so as to reduce the current and power of the light-emitting unit 110 in the outer ring and prevent its emission angle from being too large.

[0035] Specifically, as Figures 1 to 4 shown, each light-emitting unit 110 includes a light-emitting hole 111 and a current injection structure, and the current injection structure can be disposed around the light-emitting hole 111; a first electrode 120 (which can be an Au layer for connecting to the positive electrode) is provided on one surface of the device substrate 100, and the first electrode 120 can be electrically connected to the first power supply access portion 210. A second electrode (which can be an Au layer for connecting to the negative electrode) is provided on the other surface of the device substrate 100. The current injection structure includes a conductive channel 112 electrically connected between the first electrode 120 and the second electrode. A plurality of the conductive channels 112 are provided around the periphery of each light-emitting hole 111. The conductive channel 112 can be a (circular) cylindrical metal-filled hole, and a plurality of conductive channels 112 can be correspondingly provided on the outer periphery of each light-emitting hole 111. Figure 2 Among them, 6 conductive channels 112 are correspondingly provided on the outer periphery of each light-emitting hole 111.

[0036] As Figure 3 and Figure 4As shown, the vertical cavity surface emitting laser includes an ohmic contact layer 140, and the current blocking portion 190 is in contact with the ohmic contact layer 140. One end of the conductive channel 112 is connected to the first electrode 120, and the ohmic contact layer 140 is a P-type ohmic contact layer connected to the other end of the conductive channel 112. A second electrode 170 (which can be a conductive metal layer for connecting to the negative electrode) is provided on the bottom surface of the substrate 180. In a specific application, the epitaxial layer 160 includes a semiconductor contact layer 150, a P-DBR layer 161, an optical confinement layer (OA layer) 162, a multi-quantum well layer (MQW layer) 163, and an N-DBR layer 164 arranged in sequence from top to bottom. The P-DBR layer 161, that is, a P-type distributed Bragg reflector, and the bottom N-DBR layer 164 together form an optical resonator to reflect light of a specific wavelength and enhance laser output. The P-DBR layer 161 can be composed of multiple layers of materials with different refractive indices and is usually P-type doped. The optical confinement layer 162 (OA layer) is used to confine the light emitting region of the vertical cavity surface emitting laser. It mainly oxidizes the high-aluminum component layer in the P-DBR through a wet oxidation process to obtain alumina, forming a refractive index difference with the high-aluminum component layer in the central region to achieve light confinement. Alumina itself is insulating, so current control can be achieved. The multi-quantum well layer 163 (MQW layer) serves as the active region, that is, the multi-quantum well active region (MQW Active Region), which is the region where laser is generated. The multi-quantum well structure is composed of alternating potential well layers and barrier layers. Carriers (electrons and holes) recombine in the potential well layers to generate photons and achieve stimulated emission. The N-DBR layer 164 is an N-type distributed Bragg reflector and serves as the bottom mirror, which together with the top P-DBR layer 161 forms an optical resonator to reflect light of a specific wavelength and enhance laser output. The N-DBR layer 164 can be composed of multiple layers of materials with different refractive indices and is usually N-type doped.

[0037] Specifically, the P-DBR layer 161 is located below the semiconductor contact layer 150, and the P-DBR layer 161, the optical confinement layer 162, the multi-quantum well layer 163, and the N-DBR layer 164 are arranged from top to bottom. In a specific application, the ohmic contact layer 140 can be a P-type ohmic contact layer or an N-type ohmic contact layer, corresponding to a front-emitting or back-emitting vertical cavity surface emitting laser. In this embodiment, the ohmic contact layer 140 is a P-type ohmic contact layer, and the vertical cavity surface emitting laser emits light from the front. When the ohmic contact layer 140 is an N-type ohmic contact layer, the N-type ohmic contact layer is arranged closer to the second electrode 170 relative to the conductive channel 112, and the vertical cavity surface emitting laser is a back-emitting vertical cavity surface emitting laser.

[0038] Specifically, the device substrate 100 further includes a passivation layer (which can be a SiN layer) 130. The conductive channel 112 penetrates through the passivation layer 130. The first electrode 120 (which can be a gold plating layer) is disposed on one side of the passivation layer 130 and connected to the first end of the conductive channel 112. The P-type ohmic contact layer is disposed on the other side of the passivation layer 130 and connected to the second end of the conductive channel 112.

[0039] Specifically, the ohmic contact layer 140 is a P-type ohmic contact layer. One side of the P-type ohmic contact layer is in contact with the conductive channel 112. The current blocking portion 190 is disposed on the other side of the P-type ohmic contact layer. The current blocking portion 190 is in a layer shape and has a hollow hole. The current blocking portion 190 can be in a circular ring shape or the like. The hollow hole is coaxially and correspondingly disposed with the light emitting hole 111. The inner diameter of the hollow hole is larger than the aperture of the light emitting hole 111. The aperture of the hollow hole relatively closer to the set position is larger than the aperture of the hollow hole relatively farther from the set position. The larger the inner diameter of the hollow hole, the easier it is for current to pass through the current blocking portion 190.

[0040] Specifically, the current blocking portion 190 is made of an insulating material or a semi-insulating material. In specific applications, the current blocking portion 190 can be fabricated by epitaxially growing an additional insulating material (such as silicon oxide, silicon nitride, or aluminum oxide), or by oxidizing the semiconductor contact layer 150 (AlGaAs system) to obtain aluminum oxide. The current blocking portion 190 can have the same material as the optical confinement layer 162.

[0041] Specifically, the semiconductor contact layer 150 is provided with an etching groove. The current blocking portion 190 is filled in the etching groove and is in contact with the ohmic contact layer 140. In this embodiment, the current blocking portion 190 is located below the ohmic contact layer 140 (P-type ohmic contact layer).

[0042] The embodiment of the present invention also provides a method for manufacturing a vertical cavity surface emitting laser for manufacturing the above-mentioned vertical cavity surface emitting laser, including: When fabricating the light-emitting unit 110 of the vertical cavity surface emitting laser, a current blocking portion 190 embedded in the epitaxial layer 180 is provided below part or all of the ohmic contact layer 140 corresponding to the light-emitting unit 110; the current blocking portion 190 is configured such that the current injected from at least one light-emitting unit 110 into the epitaxial layer 180 via the ohmic contact layer 140 is different from the current injected from the remaining light-emitting units 110 into the epitaxial layer 160 via the ohmic contact layer 140. When the current blocking portion 190 is provided corresponding to part or all of the light-emitting units 110, the overall resistance value of the light-emitting units 110 far from the set position is greater than the overall resistance value of the light-emitting units 110 relatively closer to the set position; wherein, the set position is the center point of the light-emitting unit area 101, or, the device substrate 100 is provided with a first power supply access portion 210 located on one side of the light-emitting unit area 101, and the set position is a position far from the first power supply access portion 210.

[0043] In a specific application, a light-emitting unit area 101 for arranging the light-emitting units 110 is divided on the device substrate 100, and the light-emitting unit area 101 is divided into at least two light-emitting regions, so that the light-emitting regions are arranged from the set position to a position far from the set position; by making the resistance values of the current blocking portions 190 in different light-emitting regions different, and by setting a current blocking portion 190 with a larger resistance value relatively far from the set position, the overall resistance value of the light-emitting units 110 in the central part of the light-emitting region is reduced, so as to deliberately reduce the resistance value corresponding to the light-emitting units 110 at the central position.

[0044] If the resistance values of all the light-emitting units 110 in the vertical cavity surface emitting laser are the same, due to reasons such as the length of the current path, in the actual current injection process, the distribution of the current of each light-emitting unit 110 is uneven, and for the light-emitting holes 111 on the periphery of the vertical cavity surface emitting laser, the higher the injection current. The more peripheral the light-emitting unit 110, the higher the injection current it bears, and its corresponding emission angle is large, which affects the far-field divergence angle. When the vertical cavity surface emitting laser operates stably, its injection current is constant. In this embodiment, by deliberately reducing the resistance value corresponding to the light-emitting units 110 at the central position, the current can be concentrated relatively towards the central part of the light-emitting region, so as to achieve the purpose of adjusting the current injection uniformity of different light-emitting units 110 at different positions, and further avoid the phenomenon that the high-order mode appears prematurely in the peripheral light-emitting holes due to uneven injection current. Of course, a similar effect can also be achieved by increasing the number of conductive channels 112 around the light-emitting holes 111 at the central position of the device or increasing the width of the P ohmic contact layer.

[0045] Such as Figure 3The arrow shown in [figure] is the current injection direction of the vertical cavity surface emitting laser. It can be seen that after the current passes through the conductive channel 112, it passes through the ohmic contact layer 140, the hollow hole of the current blocking portion 190, and the semiconductor contact layer 150, and then flows from the hole position of the optical confinement layer 162 to the multi-quantum well layer 163 to achieve laser excitation.

[0046] An embodiment of the present invention further provides a laser device, and the laser device includes the above-mentioned vertical cavity surface emitting laser.

[0047] An embodiment of the present invention further provides a light source for a lidar system, including at least one of the above-mentioned vertical cavity surface emitting lasers.

[0048] An embodiment of the present invention further provides a lidar system, including a transmitting component and a receiving component, and the transmitting component uses the above-mentioned light source for a lidar system.

[0049] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, or improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A vertical cavity surface emitting laser, characterized in that, It includes a device substrate, and the device substrate includes a substrate and a plurality of light-emitting units disposed on the substrate, and each of the light-emitting units is separated by a trench; Each light-emitting unit includes an epitaxial layer and an ohmic contact layer disposed on the substrate in sequence; the trench is formed in the epitaxial layer; a current blocking portion embedded in the epitaxial layer is disposed below the ohmic contact layer corresponding to some or all of the light-emitting units; the current blocking portion is configured to control the current injected into the epitaxial layer through the ohmic contact layer of at least one of the light-emitting units to be different from the current injected into the epitaxial layer through the ohmic contact layer of the remaining light-emitting units.

2. The vertical cavity surface emitting laser according to claim 1, characterized in that, The device substrate has a light-emitting unit region, and the light-emitting unit region includes at least two light-emitting regions arranged away from the set position from the set position, and at least one light-emitting unit is provided in each light-emitting region; The set position is the center point of the light-emitting unit region, or, the device substrate is provided with a first power supply access portion on one side of the light-emitting unit region, and the set position is a position away from the first power supply access portion.

3. The vertical cavity surface emitting laser according to claim 2, characterized in that, The thickness of the current blocking portion relatively far from the set position is greater than the thickness of the current blocking portion relatively close to the set position; Or / and, the width of the current blocking portion relatively far from the set position is greater than the width of the current blocking portion relatively close to the set position; Or / and, the conductivity of the material of the current blocking portion relatively far from the set position is less than the conductivity of the material of the current blocking portion relatively close to the set position.

4. The vertical cavity surface emitting laser according to claim 2, characterized in that, Except for the light-emitting units in the light-emitting region close to the set position, the remaining light-emitting units are all provided with the current blocking portion.

5. The vertical cavity surface emitting laser according to claim 2, characterized in that, The light-emitting region includes a first light-emitting region and a second light-emitting region. The first light-emitting region is closer to the center of the light-emitting unit region than the second light-emitting region. The second light-emitting region is provided on the outer periphery of the first light-emitting region, or, the second light-emitting region is provided on the side of the first light-emitting region away from the set position; The current blocking portion is provided below each light-emitting unit in the first light-emitting region, and the total resistance value of the light-emitting units is R1. The current blocking portion is provided below each light-emitting unit in the second light-emitting region, and the total resistance value of the light-emitting units is R2, and R1 is less than R2.

6. The vertical cavity surface emitting laser according to any one of claims 1 to 5, characterized in that, Each light-emitting unit includes a light-emitting hole and a current injection structure disposed around the light-emitting hole; a first electrode is provided on one side of the device substrate, and a second electrode is provided on the other side of the device substrate. The current injection structure includes a conductive channel disposed between the first electrode and the second electrode, and a plurality of the conductive channels are disposed around the periphery of each light-emitting hole; The current blocking portion is in contact with the ohmic contact layer; One end of the conductive channel is connected to the first electrode, and the ohmic contact layer is a P-type ohmic contact layer connected to the other end of the conductive channel.

7. The vertical cavity surface emitting laser according to claim 6, characterized in that, One side of the P-type ohmic contact layer is connected to the conductive channel, the current blocking portion is disposed on the other side of the P-type ohmic contact layer, and the current blocking portion is in a layered shape and has a hollow hole, and the hollow hole is coaxially and correspondingly disposed with the light emitting hole.

8. The vertical cavity surface emitting laser according to claim 7, characterized in that, The inner diameter of the hollow hole is larger than the aperture of the light emitting hole, and the aperture of the hollow hole relatively close to the set position is larger than the aperture of the hollow hole relatively far from the set position.

9. The vertical cavity surface emitting laser according to claim 6, characterized in that, The device substrate includes a passivation layer, the conductive channel penetrates through the passivation layer, and the first electrode is disposed on one side of the passivation layer and connected to the first end of the conductive channel. The ohmic contact layer is disposed on the other side of the passivation layer and connected to the second end of the conductive channel. The epitaxial layer includes a semiconductor contact layer, a P-DBR layer, a photoelectric confinement layer, a multi-quantum well layer, and an N-DBR layer sequentially arranged from top to bottom.

10. The vertical cavity surface emitting laser according to claim 6, characterized in that, The current blocking portion is made of an insulating material or a semi-insulating material. Or / and, an etching groove is provided in the semiconductor contact layer, and the current blocking portion is filled in the etching groove and is in contact with the ohmic contact layer.

11. A method for manufacturing a vertical cavity surface emitting laser, characterized in that, For manufacturing a vertical cavity surface emitting laser according to any one of claims 1 to 10, comprising: When manufacturing the light emitting unit of the vertical cavity surface emitting laser, a current blocking portion embedded in the epitaxial layer is provided below the ohmic contact layer corresponding to some or all of the light emitting units; the current blocking portion is configured such that the current injected into the epitaxial layer by at least one of the light emitting units via the ohmic contact layer is different from the current injected into the epitaxial layer by the remaining light emitting units via the ohmic contact layer.

12. A light source for a lidar system, characterized in that, Comprising at least one vertical cavity surface emitting laser according to any one of claims 1-10.

13. A lidar system, characterized in that, Comprising a transmitting component for emitting a light source and a receiving component for receiving the light source, and the transmitting component uses the light source for a lidar system according to claim 12.

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