VCSEL device and laser radar

Abstract

The utility model relates to the technical field of laser devices, and provides a VCSEL device and a laser radar, so as to solve the technical problem that the optical power is reduced in order to reduce the divergence angle of the existing VCSEL device. The VCSEL device comprises a substrate, a light-emitting epitaxial layer and a light-emitting layer, the light-emitting epitaxial layer is arranged on the substrate, the light-emitting epitaxial layer is used for emitting a light beam in a direction deviating from the substrate, and the light beam has an optical axis and a divergence angle deviating from the optical axis; the light-emitting layer is arranged on the light-emitting epitaxial layer; wherein the light-emitting layer comprises a light-emitting part and a restraining part, the restraining part is arranged on the periphery of the light-emitting part, the light-emitting part is used for transmitting light beams at least in the optical axis direction, and the restraining part is used for limiting light emission within at least partial range of the divergence angle. The suppression part is arranged on the periphery of the light emitting part, so that the effective light emitting area of the light emitting layer is reduced to the light emitting area of the light emitting part, and stray light of a light beam at a divergence angle is suppressed from being emitted out of the VCSEL device.

Description

Technical Field

[0001] This application relates to the field of laser device technology, specifically to a VCSEL device and a lidar. Background Technology

[0002] A vertical cavity surface emitting laser (VCSEL) is a type of semiconductor laser. Its emitted laser light features a narrow spectrum, low power consumption, and low temperature drift, making it widely used in optical communication, optical detection, and optical storage.

[0003] In the design of VCSEL devices, the far-field divergence angle and optical power of the emitted beam are two important performance indicators. In existing technologies, to reduce the far-field divergence angle of the emitted beam, the optical power of the VCSEL device is typically reduced directly. However, the reduced optical power often fails to meet the requirements of practical applications. Utility Model Content

[0004] This application provides a VCSEL device and a lidar, aiming to solve the technical problem of reduced optical power caused by existing VCSEL devices in order to reduce the divergence angle.

[0005] Some embodiments of this application provide a VCSEL device, including:

[0006] Substrate;

[0007] A light-emitting epitaxial layer is disposed on the substrate, the light-emitting epitaxial layer being used to emit a light beam in a direction away from the substrate, the light beam having an optical axis and a divergence angle deviating from the optical axis; and,

[0008] A light-emitting layer is disposed on the light-emitting epitaxial layer;

[0009] The light-emitting layer includes a light-emitting part and a suppression part. The suppression part is disposed around the light-emitting part. The light-emitting part is used to transmit the light beam at least in the direction of the optical axis, and the suppression part is used to limit the light emission within at least a portion of the divergence angle.

[0010] In some embodiments, the light-emitting portion has a thickness D1 along the optical axis, and the suppression portion has at least partially a thickness D2 that is thinner than the thickness D1.

[0011] In some embodiments, the light-emitting layer includes a protective layer and a contact layer, wherein the contact layer is disposed between the protective layer and the light-emitting epitaxial layer;

[0012] The protective layer has a suppression portion on its outer surface opposite to the contact layer, and a light-emitting portion is provided on the part of the protective layer opposite to the contact layer that has not been thinned. The centers of the light-emitting portion and the suppression portion are both located on the optical axis, and the thickness of the contact layer is set to the thickness that transmits the light beam.

[0013] In some embodiments, the thickness D1 of the light-emitting part is N*λ / 2, the thickness D2 of the suppression part is N*λ / 4, and the thickness of the contact layer is N*λ / 2; where N is a natural number and λ is the wavelength of the light beam in vacuum.

[0014] In some embodiments, the light-emitting layer includes a protective layer and a contact layer, wherein the contact layer is disposed between the protective layer and the light-emitting epitaxial layer;

[0015] The suppression portion is provided on the outer surface of the contact layer opposite to the light-emitting epitaxial layer, and the light-emitting portion is provided on the unthinned portion of the contact layer opposite to the light-emitting epitaxial layer. The centers of the light-emitting portion and the suppression portion are both located on the optical axis, and the thickness of the protective layer is set to the thickness that transmits the light beam.

[0016] In some embodiments, the thickness D1 of the light-emitting part is N*λ / 2, the thickness D2 of the suppression part is N*λ / 4, and the thickness of the protective layer is N*λ / 2; where N is a natural number and λ is the wavelength of the light beam in vacuum.

[0017] In some embodiments, a stepped surface is formed between the light-emitting portion and the suppression portion, the stepped surface being disposed along the extension direction of the optical axis and perpendicular to the surface of the light-emitting layer.

[0018] In some embodiments, the light-emitting epitaxial layer includes a first reflective layer, an active layer, a confinement layer, and a second reflective layer sequentially disposed on the substrate;

[0019] The light-emitting layer is disposed on the second reflective layer. The first reflective layer and the second reflective layer are used to reflect the light emitted by the active layer to the light-emitting layer. The confinement layer has a light-emitting hole for confining the light-emitting area of ​​the active layer. The cross-sectional dimension of the light-emitting part is less than or equal to the aperture of the light-emitting hole, and the cross-section is perpendicular to the optical axis.

[0020] In some embodiments, the VCSEL device further includes a first electrode and a second electrode;

[0021] One of the first electrode and the second electrode is electrically connected to the first reflective layer, and the other of the first electrode and the second electrode is electrically connected to the light-emitting layer.

[0022] Some embodiments of this application also provide a lidar, including:

[0023] A transmitting device includes multiple VCSEL chips, wherein multiple VCSEL devices as described in any of the above embodiments are integrated on the VCSEL chips; the transmitting device is used to emit a light beam toward an object under test; and...

[0024] A receiving device for receiving a light beam reflected by the object under test.

[0025] Based on the VCSEL device in the above embodiments, this application reduces the effective light-emitting area of ​​the light-emitting layer to the light-emitting area of ​​the light-emitting part by providing a suppression portion around the light-emitting portion, thereby suppressing stray light from escaping the VCSEL device at the divergence angle. Simultaneously, this application does not require altering the basic structure of the VCSEL device's substrate and emissive epitaxial layer, ensuring that the suppression portion does not affect the optical power of the VCSEL device. Therefore, this application enables the VCSEL device to reduce the divergence angle of the emitted beam while maintaining normal optical power, thus meeting the normal usage requirements of the VCSEL device. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the transmitting device structure of a lidar in one embodiment of this application;

[0027] Figure 2 for Figure 1 A schematic diagram of the structure of a VCSEL device emitting a light beam;

[0028] Figure 3 This is a cross-sectional view of a VCSEL device in one embodiment of this application;

[0029] Figure 4 for Figure 3 A schematic diagram of the structure of a VCSEL device emitting a light beam;

[0030] Figure 5 for Figure 3 A schematic diagram of an embodiment in which a suppression section is provided on a VCSEL device;

[0031] Figure 6 for Figure 3 A schematic diagram of another embodiment of a VCSEL device with a suppression section provided on it;

[0032] Figure 7 for Figure 3 A schematic diagram of another embodiment of a VCSEL device with a suppression section.

[0033] in:

[0034] 1-VCSEL device; 11-substrate; 12-light-emitting epitaxial layer; 121-first reflective layer; 122-active layer; 123-confining layer; 1230-light-emitting aperture; 124-second reflective layer; 13-light-emitting layer; 131-protective layer; 132-contact layer; 14-suppression part; 15-light-emitting part; 16-step surface; 17-first electrode; 18-second electrode; 2-conductive component; 3-pad; 4-optical axis. Detailed Implementation

[0035] The present application will be further described in detail below with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0036] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments, and the operational steps involved in each embodiment can also be rearranged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for clearly describing a particular embodiment and do not imply that they represent the necessary components and / or order.

[0037] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0038] This application provides a lidar system, which may include a transmitting device and a receiving device. The transmitting device emits a light beam towards an object to be measured, and the receiving device receives the light beam reflected by the object, thereby acquiring information about the object's three-dimensional shape, distance, orientation, velocity, height, attitude, etc. The transmitting device may include, for example, […]. Figure 1The diagram shows multiple VCSEL chips, each of which can integrate multiple VCSEL devices 1. For example, a VCSEL chip may include conductive elements 2 and pads 3. Multiple VCSEL devices 1 are electrically connected to conductive elements 2, and conductive elements 2 are electrically connected to pads 3. Pads 3 are used for electrical connection with wires, so that current is injected into multiple VCSEL devices 1 through the wires to excite the VCSEL chips to emit a light beam.

[0039] In some embodiments, multiple VCSEL devices 1 can be arranged in a ring array or a rectangular array on the VCSEL chip. Depending on the distribution of the multiple VCSEL devices 1, the VCSEL chip can be configured with a rectangular or circular cross-sectional shape, the cross-section of which is perpendicular to the optical axis of the beam emitted by the VCSEL devices 1. This application does not impose any special limitations on the number or distribution of VCSEL devices 1 integrated on the VCSEL chip.

[0040] When VCSEL device 1 emits a beam, such as Figure 2 As shown, the beam is conical in shape with an optical axis 4 and a divergence angle α away from the optical axis 4. When the beam illuminates the object under test, it forms a spot with a diameter of R1. To improve the accuracy of lidar detection of the object under test, it is usually required to reduce the divergence angle of the beam from α to β, thereby reducing the diameter of the spot on the object under test from R1 to R2, thus improving the collimation of the beam. In the prior art, to reduce the divergence angle of the beam, the optical power of the VCSEL device 1 is usually reduced directly. However, reducing the optical power makes it difficult for the VCSEL device 1 to meet the requirements of use. To increase the optical power, more VCSEL devices 1 need to be integrated on the VCSEL chip. However, increasing the number of VCSEL devices 1 will bring derivative problems such as larger VCSEL chip size, severe heat generation, and uneven injection current. Therefore, how to reduce the divergence angle of the beam emitted by the VCSEL device 1 has become one of the urgent technical problems to be solved.

[0041] To reduce the beam divergence angle, this application also provides a VCSEL device 1, such as... Figure 3 and Figure 4 As shown, the VCSEL device 1 may include a substrate 11, a light-emitting epitaxial layer 12, and a light-emitting layer 13. The light-emitting epitaxial layer 12 is disposed on the substrate 11 and can be used to emit a light beam in a direction away from the substrate 11. The light beam has an optical axis 4 and a divergence angle deviating from the optical axis 4. The light-emitting layer 13 is disposed on the light-emitting epitaxial layer 12. The light-emitting layer 13 may include a light-emitting portion 15 and a suppression portion 14. The suppression portion 14 is disposed around the light-emitting portion 15. The light-emitting portion 15 is used to transmit the light beam at least in the direction of the optical axis 4, and the suppression portion 14 is used to limit the light emission within at least a portion of the divergence angle.

[0042] When the VCSEL device 1 emits a light beam in a direction away from the substrate 11, because the suppression portion 14 is disposed around the light-emitting portion 15, most of the light emitted by the light-emitting epitaxial layer 12 is suppressed. Figure 3 The light (indicated by the hollow arrow) can be allowed to exit from the light-emitting section 15, and at least a portion of the light in the beam located at the divergence angle ( Figure 3 The light (indicated by the filled arrow) can be confined within the VCSEL device 1 by the suppression part 14, thereby reducing the divergence angle of the beam from α to β. Figure 4 (As shown).

[0043] This application reduces the effective light-emitting area of ​​the light-emitting layer 13 to the light-emitting area of ​​the light-emitting section 15 by providing a suppression section 14 around the light-emitting section 15, thereby suppressing stray light from the VCSEL device 1 at the divergence angle. Simultaneously, this application does not require altering the basic structure of the substrate 11 and the light-emitting epitaxial layer 12 of the VCSEL device 1, ensuring that the provision of the suppression section 14 does not affect the optical power of the VCSEL device 1. Therefore, this application enables the VCSEL device 1 to reduce the divergence angle of the emitted beam while maintaining normal optical power, thus meeting the normal operating requirements of the VCSEL device 1.

[0044] Among them, such as Figure 3 As shown, the light-emitting epitaxial layer 12 may include a first reflective layer 121, an active layer 122, a confinement layer 123, and a second reflective layer 124 sequentially disposed on the substrate 11; the light-emitting layer 13 is disposed on the second reflective layer 124, the first reflective layer 121 and the second reflective layer 124 are used to reflect the light emitted by the active layer 122 to the light-emitting layer 13, the confinement layer 123 has a light-emitting hole 1230 for confining the light-emitting area of ​​the active layer 122, the cross-sectional dimension of the light-emitting part 15 is less than or equal to the aperture of the light-emitting hole 1230, and the cross-section is perpendicular to the optical axis 4.

[0045] For example, the substrate 11 can be made of semiconductor materials such as gallium arsenide (GaAs), indium phosphide (InP), or gallium nitride (GaN). The first reflective layer 121 and the second reflective layer 124 can be configured as N-type distributed Bragg reflectors (DBR) and P-type DBRs, respectively, to form a resonant cavity. The active layer 122 can use a quantum well structure as the gain medium. When electrons are injected into the active layer 122, electrons and holes recombine in the quantum well structure to generate photons. The photons undergo multiple reflections within the resonant cavity to form a light beam, which exits the VCSEL device 1 in an orientation perpendicular to the light-emitting layer 13. The confinement layer 123 has a light-emitting aperture 1230 centered on the optical axis 4. The light-emitting aperture 1230 can be used to confine the light-emitting region of the quantum well structure to improve the electro-optical conversion efficiency and the stability of the beam output of the VCSEL device 1. This application sets the cross-sectional size of the light-emitting part 15 to be less than or equal to the aperture of the light-emitting aperture 1230, so that the light beam emitted by the light-emitting epitaxial layer 12 can be emitted from the VCSEL device 1 after being restricted by the confinement layer 123 and the suppression part 14, which helps to maintain the collimation of the light beam emitted by the VCSEL device 1 and thereby reduce the divergence angle of the light beam.

[0046] In addition, such as Figure 3 As shown, the VCSEL device 1 may further include a first electrode 17 and a second electrode 18; one of the first electrode 17 and the second electrode 18 is electrically connected to the first reflective layer 121, and the other of the first electrode 17 and the second electrode 18 is electrically connected to the light-emitting layer 13.

[0047] Depending on the polarity of the first reflective layer 121 and the second reflective layer 124, the first electrode 17 and the second electrode 18 can be made of metals with different work functions, such as titanium (Ti), platinum (Pt), gold (Au), nickel (Ni), and chromium (Cr). For example, when the first reflective layer 121 is an N-type DBR, the first electrode 17 can be made of nickel (Ni) with a low work function, thereby forming a good ohmic contact between the first electrode 17 and the VCSEL device 1, thus improving the efficiency of electron injection into the VCSEL device 1. When the second reflective layer 122 is a P-type DBR, the second electrode 18 can be made of titanium (Ti) with a high work function, thereby forming a good ohmic contact between the second electrode 18 and the VCSEL device 1, thus improving the efficiency of hole injection into the VCSEL device 1. This application does not impose any special restrictions on the specific materials and polarities of the first electrode 17 and the second electrode 18.

[0048] When electrons are injected into the light-emitting epitaxial layer 12, as Figure 3As shown, due to the confinement effect of the confinement layer 123, electrons tend to concentrate near the edge of the light-emitting aperture 1230 (as indicated by the solid arrow in the figure), resulting in an increase in the current density at the aperture edge. Consequently, the photon density generated by the quantum well structure at the aperture edge projection position also increases, causing the light beam formed after multiple reflections by the first reflective layer 121 and the second reflective layer 124 to have a larger divergence angle. This application addresses this by placing the suppression part 14 around the light-emitting part 15, effectively limiting the high-density photons generated by the quantum well structure at the aperture edge projection position from escaping the VCSEL device 1, thereby effectively suppressing stray light emission at the divergence angle.

[0049] The above embodiments describe the principle of reducing the divergence angle of the light beam using the suppression part 14 in this application. To better illustrate the content of this application, the following embodiments will provide a detailed description of the specific structure of the suppression part 14. In some embodiments, such as Figure 3 As shown, the light-emitting part 15 has a thickness D1 along the optical axis 4, and the suppression part 14 has at least partially a thickness D2 that is thinner than the thickness D1.

[0050] Based on the properties of light, by setting the suppression portion 14 and the light-emitting portion 15 to different thicknesses, a portion of the light emitted from the light-emitting epitaxial layer 12 can be transmitted through the light-emitting portion 15, while another portion of the light can be reflected by the suppression portion 14 to confine it within the VCSEL device 1. In this application, the thickness D1 of the light-emitting portion 15 allows light to be transmitted through it. By reducing the thickness of the suppression portion 14 from the thickness D1 of the light-emitting portion 15 to a thickness D2, the suppression portion 14 can suppress light at the divergence angle, thereby reducing the divergence angle of the beam. Furthermore, forming the suppression portion 14 by reducing its thickness simplifies the process and improves the production efficiency of the VCSEL device 1.

[0051] For example, when fabricating VCSEL device 1, the light-emitting epitaxial layer 12 can normally grow a light-emitting layer 13 with a thickness of D1 on the side facing away from the substrate 11. Subsequent processes only require thinning the thickness of the suppression part 14 to a thickness of D2 through processes such as etch back or etching to form the suppression part 14. Thus, the suppression part 14 provided in this application does not change the basic structure of the epitaxial layer (Epi) in VCSEL device 1, and the fabrication of the suppression part 14 can be completed through simple subsequent processes.

[0052] Of course, the method of providing the suppression portion 14 on the light-emitting layer 13 is not limited to reducing the thickness of the light-emitting layer 13. For example, in other embodiments, the suppression portion 14 can also be formed by providing a light-shielding layer or a reflective layer or other structures that restrict light transmission on the outer surface of the light-emitting layer 13 on the side opposite to the light-emitting epitaxial layer 12, so that the light beam at the divergence angle can be limited by the suppression portion 14, thereby reducing the divergence angle of the light beam. This application does not impose any special limitations on the specific formation method of the suppression portion 14.

[0053] When setting the structure of the light-emitting layer 13, such as Figure 5 As shown, the light-emitting layer 13 may include a protective layer 131 and a contact layer 132. The contact layer 132 is disposed between the protective layer 131 and the light-emitting epitaxial layer 12. A suppression portion 14 is provided on the outer peripheral surface of the protective layer 131 away from the contact layer 132. A light-emitting portion 15 is provided on the part of the protective layer 131 away from the contact layer 132 that has not been thinned. The centers of the light-emitting portion 15 and the suppression portion 14 are both located on the optical axis 4. The thickness of the contact layer 132 can be set to the thickness of the transmitted light beam.

[0054] Both the protective layer 131 and the contact layer 132 can be made of light-transmitting materials. For example, the contact layer 132 can be made of a highly doped P-type or N-type semiconductor material to reduce its resistance. Furthermore, a good ohmic contact can be formed between the first electrode 17 and the contact layer 132, allowing electrons to be more easily injected into the light-emitting epitaxial layer 12 to excite it to emit a light beam, thereby improving the electrical performance of the VCSEL device 1. For example, the protective layer 131 can be made of silicon nitride (Si3N4) or silicon dioxide (SiO2), and the contact layer 132 can be made of gallium arsenide (GaAs), indium phosphide (InP), or gallium nitride (GaN). This application does not impose any special limitations on the specific materials of the protective layer 131 and the contact layer 132.

[0055] When an electron is injected into the light-emitting epitaxial layer 12 to generate a light beam, the thickness of the contact layer 132 is the same as the thickness of the transmitted light beam, allowing the light beam to be transmitted to the protective layer 131 after reaching the contact layer 132. Most of the light beam within the protective layer 131 is directly transmitted outward through the light-emitting portion 15 to form the emitted light beam of the VCSEL device 1. A small portion of the light beam located at the divergence angle position within the protective layer 131 is reflected back into the VCSEL device 1 at the suppression portion 14, thereby limiting the light located at the divergence angle position from escaping from the VCSEL device 1 and reducing the divergence angle of the emitted light beam from the VCSEL device 1.

[0056] In order to improve the transmittance and reflectance of the light-emitting layer 13 to the light beam, the thickness D1 of the light-emitting part 15 can be set to N*λ / 2, the thickness D2 of the suppression part 14 can be set to N*λ / 4, and the thickness of the contact layer 132 can be set to N*λ / 2; where N is a natural number and λ is the wavelength of the light beam in vacuum.

[0057] When the thickness of the contact layer 132 is N*λ / 2, the contact layer 132 has the maximum transmittance. Similarly, when the thickness D1 of the light-emitting portion 15 is N*λ / 2, the light-emitting portion 15 has the maximum transmittance. In this way, the light beam generated by the light-emitting epitaxial layer 12 can pass through the contact layer 132 to the maximum extent and be transmitted from the light-emitting portion 15 to the outside of the VCSEL device 1, thereby reducing the light beam loss. When the thickness D2 of the suppression portion 14 is N*λ / 4, the suppression portion 14 has the maximum reflectivity, so that the light at the beam divergence angle can be reflected into the VCSEL device 1 to the maximum extent, thereby limiting the light at the divergence angle from escaping from the suppression portion 14.

[0058] When fabricating the VCSEL device 1, the contact layer 132 and the protective layer 131 are sequentially grown on the light-emitting epitaxial layer 12 with a thickness controlled to N*λ / 2. In subsequent processes, only the outer surface of the protective layer 131 facing away from the contact layer 132 needs to be thinned to N*λ / 4 by processes such as etch back or etching, while the rest of the surface remains unchanged. This allows the surface of the protective layer 131 facing away from the contact layer 132 to form the suppression part 14 and the light-emitting part 15.

[0059] It is understood that, depending on the materials used for the protective layer 131 and the contact layer 132, for example, when the protective layer 131 is made of silicon nitride (Si3N4) and the contact layer 132 is made of gallium arsenide (GaAs), the thickness D1 of the light-emitting portion 15 and the contact layer 132 can be set to N*λ / 2, and the thickness D2 of the suppression portion 14 can be set to N*λ / 4. When the materials used for the protective layer 131 and the contact layer 132 are other materials, the thicknesses of the light-emitting portion 15, the suppression portion 14, and the contact layer 132 can be adjusted according to different materials. This application does not impose any special restrictions on the specific thicknesses of the light-emitting portion 15, the suppression portion 14, and the contact layer 132.

[0060] The above embodiments provide a detailed description of the structure in which the suppression part 14 and the light-emitting part 15 are disposed on the protective layer 131. In some embodiments, the suppression part 14 and the light-emitting part 15 may also be disposed on the contact layer 132. Specifically, as... Figure 6As shown, the light-emitting layer 13 may include a protective layer 131 and a contact layer 132. The contact layer 132 is disposed between the protective layer 131 and the light-emitting epitaxial layer 12. A suppression portion 14 is provided on the outer peripheral surface of the contact layer 132 away from the light-emitting epitaxial layer 12. A light-emitting portion 15 is provided on the unthinned portion of the contact layer 132 away from the light-emitting epitaxial layer 12. The centers of the light-emitting portion 15 and the suppression portion 14 are both located on the optical axis 4. The thickness of the protective layer 131 can be set to the thickness of the transmitted light beam.

[0061] The materials of the protective layer 131 and the contact layer 132 can be the same as those in the above embodiment, and will not be repeated here. When an electron is injected into the light-emitting epitaxial layer 12 to generate a light beam, after the light beam reaches the contact layer 132, most of the light beam at the light-emitting part 15 can directly pass through the contact layer 132 and enter the protective layer 131. Since the thickness of the protective layer 131 is the thickness of the transmitted light beam, the light beam in the protective layer 131 can be directly transmitted outward to form the light-emitting beam of the VCSEL device 1. A small portion of the light beam located at the divergence angle position in the contact layer 132 can be reflected back into the VCSEL device 1 at the suppression part 14, thereby limiting the light located at the divergence angle position in the beam from exiting the VCSEL device 1, thereby reducing the divergence angle of the light beam emitted by the VCSEL device 1.

[0062] The suppression portion 14 and the light-emitting portion 15 are disposed on the contact layer 132, which thins the peripheral surface of the contact layer 132 on the side away from the light-emitting epitaxial layer 12. This also helps to reduce the resistance of the contact layer 132 at the suppression portion 14. The first electrode 17 is disposed at the suppression portion 14 of the contact layer 132, which makes it easier for electrons to be injected into the light-emitting epitaxial layer 12 to excite the light-emitting epitaxial layer 12 to emit a light beam, thereby improving the power supply efficiency of the VCSEL device 1.

[0063] In order to improve the transmittance and reflectance of the light-emitting layer 13 to the light beam, the thickness D1 of the light-emitting part 15 can be set to N*λ / 2, the thickness D2 of the suppression part 14 can be set to N*λ / 4, and the thickness of the protective layer 131 can be set to N*λ / 2; where N is a natural number and λ is the wavelength of the light beam in vacuum.

[0064] When the thickness of the protective layer 131 is N*λ / 2, the protective layer 131 has the maximum light transmittance. Similarly, when the thickness D1 of the light-emitting portion 15 is N*λ / 2, the light-emitting portion 15 has the maximum light transmittance. In this way, the light beam generated by the light-emitting epitaxial layer 12 can pass through the light-emitting portion 15 to the maximum extent and be transmitted from the protective layer 131 to the outside of the VCSEL device 1, thereby reducing the light beam loss. When the thickness D2 of the suppression portion 14 is N*λ / 4, the suppression portion 14 has the maximum reflectivity, so that the light at the beam divergence angle can be reflected into the VCSEL device 1 to the maximum extent, thereby limiting the light at the divergence angle from escaping from the suppression portion 14.

[0065] In fabricating the VCSEL device 1, the thickness of the contact layer 132 grown on the light-emitting epitaxial layer 12 is first controlled to N*λ / 2. In subsequent processes, only the outer surface of the contact layer 132 facing away from the light-emitting epitaxial layer 12 needs to be thinned to N*λ / 4 through processes such as etch back or etching, while the remaining surfaces remain unchanged. This forms the suppression portion 14 and the light-emitting portion 15 on the surface of the contact layer 132 facing away from the light-emitting epitaxial layer 12. Then, the thickness of the protective layer 131 grown on the contact layer 132 is controlled to N*λ / 2, that is, the thickness of the protective layer 131 above the suppression portion 14 and the light-emitting portion 15 is both N*λ / 2, so that the light beam with reduced divergence angle can directly pass through the protective layer 131 and be emitted.

[0066] The above embodiments provide a detailed description of a structure in which the suppression part 14 and the light-emitting part 15 are only disposed on the protective layer 131 or the contact layer 132. In some embodiments, the suppression part 14 and the light-emitting part 15 may also be disposed on both the protective layer 131 and the contact layer 132. Specifically, as Figure 7 As shown, the light-emitting layer 13 may include a protective layer 131 and a contact layer 132. The contact layer 132 is disposed between the protective layer 131 and the light-emitting epitaxial layer 12. A suppression portion 14 is provided on the outer peripheral surface of the contact layer 132 away from the light-emitting epitaxial layer 12. A light-emitting portion 15 is provided on the unthinned portion of the contact layer 132 away from the light-emitting epitaxial layer 12. A suppression portion 14 is provided on the outer peripheral surface of the protective layer 131 away from the contact layer 132. A light-emitting portion 15 is provided on the unthinned portion of the protective layer 131 away from the contact layer 132. The centers of the light-emitting portion 15 and the suppression portion 14 are both located on the optical axis 4.

[0067] The materials of the protective layer 131 and the contact layer 132 can be the same as those in the above embodiment, and will not be repeated here. When an electron is injected into the light-emitting epitaxial layer 12 to generate a light beam, the light beam first reaches the contact layer 132. Most of the light beam at the light-emitting portion 15 on the contact layer 132 can directly pass through the contact layer 132 and enter the protective layer 131. Since the thickness of the light-emitting portion 15 on the protective layer 131 is the thickness of the transmitted light beam, the light beam at the light-emitting portion 15 in the protective layer 131 can be directly transmitted outward to form the light-emitting beam of the VCSEL device 1. A small portion of the light beam located at the divergence angle position in the contact layer 132 is reflected back into the VCSEL device 1 at the suppression portion 14 position of the contact layer 132, thereby limiting the light located at the divergence angle position in the beam from escaping from the VCSEL device 1. Meanwhile, the suppression portion 14 on the protective layer 131 can further restrict the light at the divergence angle in the beam within the protective layer 131. Furthermore, the suppression portion 14 on the protective layer 131 can further restrict the beam that is not completely reflected in the suppression portion 14 on the contact layer 132, thereby further reducing the divergence angle of the beam emitted by the VCSEL device 1.

[0068] In order to improve the transmittance and reflectance of the light-emitting layer 13 to the light beam, the thickness D1 of the light-emitting part 15 on the protective layer 131 and the contact layer 132 can be set to N*λ / 2, and the thickness D2 of the suppression part 14 on the protective layer 131 and the contact layer 132 can be set to N*λ / 4; where N is a natural number and λ is the wavelength of the light beam in vacuum.

[0069] When the thickness of the light-emitting portion 15 is N*λ / 2, the light-emitting portion 15 has the maximum transmittance. This allows the light beam generated by the light-emitting epitaxial layer 12 to pass through the light-emitting portion 15 to the maximum extent and be transmitted from the protective layer 131 to the outside of the VCSEL device 1, thereby reducing beam loss. Conversely, when the thickness D2 of the suppression portion 14 is N*λ / 4, the suppression portion 14 has the maximum reflectivity, allowing light at the beam divergence angle to be reflected to the maximum extent into the VCSEL device 1, thus limiting the light at the divergence angle from escaping from the suppression portion 14.

[0070] When fabricating the VCSEL device 1, based on the embodiment where the suppression part 14 and the light-emitting part 15 are only provided on the contact layer 132, the outer surface of the protective layer 131 on the side away from the contact layer 132 is further thinned to N*λ / 4 by processes such as etch back or etching, while the remaining surfaces remain unchanged. This results in the formation of the suppression part 14 and the light-emitting part 15 on the surface of the contact layer 132 on the side away from the light-emitting epitaxial layer 12, and the formation of the suppression part 14 and the light-emitting part 15 on the surface of the protective layer 131 on the side away from the contact layer 132.

[0071] In some embodiments, such as Figure 3As shown, a stepped surface 16 is formed between the light-emitting part 15 and the suppression part 14. The stepped surface 16 is arranged along the extension direction of the optical axis 4 and is perpendicular to the surface of the light-emitting layer 13.

[0072] Whether the suppression portion 14 and the light-emitting portion 15 are provided on the protective layer 131, on the contact layer 132, or simultaneously on both the protective layer 131 and the contact layer 132, a stepped surface 16 perpendicular to the surface of the light-emitting layer 13 is provided between the light-emitting portion 15 and the suppression portion 14, making the cross-section (the cross-section perpendicular to the optical axis 4) between the suppression portion 14 and the light-emitting portion 15 change steeply. In this way, once the light in the beam located at the divergence angle exceeds the cross-sectional size of the light-emitting portion 15, that portion of the light will be immediately confined within the VCSEL device 1 by the suppression portion 14, thereby preventing light leakage at the divergence angle caused by a smooth transition between the suppression portion 14 and the light-emitting portion 15.

[0073] The VCSEL device 1 in any embodiment of this application is not limited to the field of lidar, but can also be applied to other technical fields. For example, it can be used in various application scenarios such as data communication, electronic terminal products (mobile phones, tablets, etc.), and 3D structured light detection. This application does not impose any special limitations on the specific application scenarios of the VCSEL device 1.

[0074] The above-described specific examples are for illustrative purposes only and are not intended to limit the scope of this invention. Those skilled in the art to which this invention pertains can make various simple deductions, modifications, or substitutions based on the concept of this invention.

Claims

1. A VCSEL device, characterized by The application relates to a vertical cavity surface emitting laser (VCSEL) device. The device comprises: a substrate; a light emitting epitaxial layer arranged on the substrate, the light emitting epitaxial layer being configured to emit a light beam in a direction away from the substrate, the light beam having an optical axis and a divergence angle deviating from the optical axis; and a light emitting layer arranged on the light emitting epitaxial layer; 2. The VCSEL device of claim 1, wherein, wherein the light emitting layer comprises a light emitting portion and a suppressing portion, the suppressing portion being arranged at a periphery of the light emitting portion, the light emitting portion being configured to transmit the light beam at least in the direction of the optical axis, and the suppressing portion being configured to limit light emission in at least part of the range of the divergence angle.

3. The VCSEL device of claim 2, wherein, The light emitting portion has a thickness D1 in the direction of the optical axis, and the suppressing portion at least partially has a thickness D2 which is thinned relative to the thickness D1. The light emitting layer comprises a protective layer and a contact layer, the contact layer being arranged between the protective layer and the light emitting epitaxial layer; 4. The VCSEL device of claim 3, wherein, a peripheral surface of the protective layer on a side away from the contact layer is provided with the suppressing portion, and a portion of the protective layer on the side away from the contact layer which is not thinned is provided with the light emitting portion, the centers of the light emitting portion and the suppressing portion are located on the optical axis, and the thickness of the contact layer is configured to transmit the light beam.

5. The VCSEL device of claim 2, wherein, The thickness D1 of the light emitting portion is N*lambda / 2, the thickness D2 of the suppressing portion is N*lambda / 4, and the thickness of the contact layer is N*lambda / 2; wherein N is a natural number, and lambda is the wavelength of the light beam in vacuum. The light emitting layer comprises a protective layer and a contact layer, the contact layer being arranged between the protective layer and the light emitting epitaxial layer; 6. The VCSEL device of claim 5, wherein, a peripheral surface of the contact layer on a side away from the light emitting epitaxial layer is provided with the suppressing portion, and a portion of the contact layer on the side away from the light emitting epitaxial layer which is not thinned is provided with the light emitting portion, the centers of the light emitting portion and the suppressing portion are located on the optical axis, and the thickness of the protective layer is configured to transmit the light beam.

7. The VCSEL device of any of claims 1 to 6, wherein, The thickness D1 of the light emitting portion is N*lambda / 2, the thickness D2 of the suppressing portion is N*lambda / 4, and the thickness of the protective layer is N*lambda / 2; wherein N is a natural number, and lambda is the wavelength of the light beam in vacuum.

8. The VCSEL device of any of claims 1 to 6, wherein, A step surface is formed between the light emitting portion and the suppressing portion, the step surface is arranged in the extension direction of the optical axis and is perpendicular to the surface of the light emitting layer. The light emitting epitaxial layer comprises a first reflective layer, an active layer, a confinement layer and a second reflective layer arranged in sequence on the substrate; 9. The VCSEL device of claim 8, wherein, the light emitting layer is arranged on the second reflective layer, the first reflective layer and the second reflective layer are configured to reflect light emitted by the active layer to the light emitting layer, the confinement layer has a light emitting hole for limiting the light emitting area of the active layer, the cross-sectional size of the light emitting portion is less than or equal to the aperture of the light emitting hole, and the cross section is perpendicular to the optical axis. The VCSEL device further comprises a first electrode and a second electrode; 10. A lidar, comprising: one of the first electrode and the second electrode is electrically connected with the first reflective layer, and the other of the first electrode and the second electrode is electrically connected with the light emitting layer. The application relates to a vertical cavity surface emitting laser (VCSEL) device. The device comprises: A transmitting device comprising a plurality of VCSEL chips, each of which is integrated with a plurality of VCSEL devices according to any one of claims 1 to 9, and configured to emit a light beam to a to-be-tested object; and A receiving device configured to receive a light beam reflected by the to-be-tested object.

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