Laser, optical module, and electronic device

Abstract

The application provides a laser, an optical module and an electronic device. The laser comprises a first electrode, an active layer, a photonic crystal and a second electrode which are stacked. The active layer is configured to generate laser light with a gain spectrum peak wavelength in response to current injected by the first electrode and the second electrode. The gain spectrum peak wavelength is different when the current is different. The photonic crystal is configured to receive and allow laser light with at least two different gain spectrum peak wavelengths to be emitted at different angles. The application can reduce the cost of the laser and improve the reliability of the laser while meeting the requirements of simultaneously realizing light emission and laser steering.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a laser, an optical module, and an electronic device. Background Technology

[0002] In applications such as radar or facial recognition, lasers are often required as the light source, and the direction of laser emission needs to be directional to identify and detect objects over a large area. Therefore, in related technologies, a beam deflector is installed on the laser's output side. The laser can emit laser light in a unique direction towards the beam deflector, which then redirects the laser light upon receiving it, thereby achieving laser output at different angles.

[0003] However, this solution is complex and bulky, resulting in high costs. Moreover, the beam deflector can be implemented using mechanical structures or micro-electro-mechanical systems (MEMS). When the mechanical structure or MEMS is damaged, it will result in the inability to emit laser light or the emitted laser light being in the wrong direction, thus leading to low reliability. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a laser, an optical module, and an electronic device that can reduce the cost and improve the reliability of the laser while simultaneously achieving laser emission and laser steering.

[0005] A first aspect of this application provides a laser, comprising: a first electrode, an active layer, a photonic crystal, and a second electrode stacked together. The active layer is used to generate laser light with a gain spectrum peak wavelength in response to current injected into the first and second electrodes. The photonic crystal is used to receive and allow laser light with at least two different gain spectrum peak wavelengths to be emitted at different angles. Specifically:

[0006] Current can be injected into both the first and second electrodes. The current injected from the first electrode originates from the first electrode and flows into the active layer. The current injected from the second electrode originates from the second electrode and flows into the active layer. The active layer generates charge carriers, which interact to form laser light. The laser light can then be emitted through a photonic crystal.

[0007] Photonic crystals are periodic dielectric structures with wavelength selectivity, allowing light of a certain wavelength to pass through while blocking light of other wavelengths. Furthermore, different wavelengths of light passing through a photonic crystal have different exit angles.

[0008] When the injected current on the first and second electrodes is increased, the concentration of charge carriers generated in the active layer increases, and the peak wavelength of the gain spectrum shifts to a longer wavelength. When the peak wavelength of the gain spectrum increases to within a certain wavelength band allowed by the photonic crystal, laser light at that peak wavelength can be emitted from the photonic crystal at a specific angle. When the injected current on the first and second electrodes is decreased, the concentration of charge carriers generated in the active layer decreases, and the peak wavelength of the gain spectrum shifts to a shorter wavelength. When the peak wavelength of the gain spectrum decreases to within a certain wavelength band allowed by the photonic crystal, laser light at that peak wavelength can be emitted from the photonic crystal at a specific angle. In other words, increasing the current increases the wavelength of the laser light selected by the photonic crystal, while decreasing the current decreases the wavelength of the laser light selected by the photonic crystal. Therefore, under different currents, the output laser wavelength and the emission angle are different.

[0009] Because the wavelength of the output laser differs under different currents, and different wavelengths correspond to different emission angles, the direction of the output laser can be changed by altering the magnitude of the current. In other words, the laser can simultaneously emit light and redirect the laser beam.

[0010] Furthermore, in this application, the laser itself can realize the function of laser steering, so there is no need to set up an additional steering mechanism. This avoids the mechanical structure of laser steering schemes in related technologies, thereby simplifying the structure, reducing costs and improving reliability.

[0011] In some embodiments of this application, the laser further includes a reflective structure located on one side of the photonic crystal. During the emission of the laser beam from the photonic crystal, a portion of the beam is emitted along a first direction perpendicular to the surface of the photonic crystal facing away from the substrate, while another portion is emitted from other directions at a certain angle to the first direction. When the reflective structure is located on one side of the photonic crystal, the portion of the beam emitted from other directions illuminates the reflective structure, which reflects this portion, thereby changing its direction and allowing it to exit from the first direction. This improves the laser emission efficiency. Furthermore, the reflective structure can provide high reflectivity for lasers of specific wavelengths. Moreover, the reflective structure exhibits different reflectivities for different modes in the laser; for example, it has a higher reflectivity for the target mode (fundamental mode) and a lower reflectivity for higher-order modes deviating from the target wavelength. This provides differentiated compensation for losses in different modes, ensuring that the quality factor of the fundamental mode in a specific laser is essentially the same, ultimately achieving stable output of a single-mode laser or a single-mode laser.

[0012] Furthermore, the photonic crystal has reflection structures on its four sides. These four reflection structures can reflect most of the light beams emitted from the photonic crystal except in the first direction, thus ensuring that the quality factor of the laser light at each wavelength is essentially the same. Therefore, under each current, a single wavelength of laser light can be output. Consequently, the output laser has a wide wavelength range and a wide directional range.

[0013] In some embodiments of this application, the first surface of the photonic crystal is higher than or flush with the first surface of the reflective structure, and the second surface of the photonic crystal is lower than or flush with the second surface of the reflective structure. The first surface is the surface facing away from the first electrode, and the second surface is the surface facing the first electrode. In this way, the reflective structure can cover a wider range of the beam emitted by the photonic crystal, thereby enabling more comprehensive reflection of the laser emitted by the photonic crystal, further improving the efficiency of the laser and enhancing the consistency of the quality factor.

[0014] In some embodiments of this application, at least one reflective structure includes a first reflective portion and a second reflective portion alternately stacked along a first direction. The first reflective portion and the second reflective portion have different refractive indices, and the first direction is perpendicular to the stacking direction of the first electrode and the active layer. Both the first reflective portion and the second reflective portion can be dielectric films. Therefore, in this application, the reflective structure can be considered to be formed by sequentially stacking multiple dielectric films. Multiple dielectric films can achieve high reflectivity for lasers of specific wavelengths, thereby reducing the loss of laser propagation to the location of the reflective structure and improving the quality factor. Furthermore, the reflection spectrum of this reflective structure has wavelength selectivity, providing high reflectivity for the target mode (such as the fundamental mode) in the laser, while having lower reflectivity for higher-order modes deviating from the target wavelength, thereby suppressing the oscillation of higher-order modes. In this way, lasers of specific wavelengths can operate on the fundamental mode, and the laser spot is a solid circle or ellipse, with more concentrated energy and better laser quality.

[0015] In some embodiments of this application, the laser further includes a first cladding layer located between the second electrode and the active layer, and a photonic crystal disposed on the surface of the first cladding layer facing away from the active layer. Thus, the laser light generated by the active layer can reach the photonic crystal disposed on the first cladding layer via the first cladding layer, and be emitted by the photonic crystal.

[0016] In some embodiments of this application, a groove is formed on the surface of the first cladding layer opposite to the first electrode, and the groove is located on one side of the photonic crystal; a portion of the second electrode is located within the groove, and the second electrode covering the sidewall of the groove forms a reflective structure. That is, a portion of the second electrode forms a reflective structure. Thus, this partial structure enables the function of the second electrode. Furthermore, since the second electrode needs to be conductive, the material of the second electrode is typically metal. Therefore, this application can also utilize the high reflectivity of metal to suppress radiation loss of the laser in both the vertical and horizontal directions. This reflective structure has a higher reflectivity for transverse magnetic modes (the interface where the electric field is perpendicular to the reflective structure) in the laser, and can also selectively enhance the confinement of transverse magnetic modes. Since metal has a stronger absorption of transverse electric waves (the interface where the electric field is parallel to the reflective structure) in the laser, transverse electric waves can be suppressed. Thus, transverse electric waves can be filtered out, while transverse magnetic modes are retained, resulting in an emitted laser with a fixed vibration direction and better laser quality.

[0017] In some embodiments of this application, the second electrode includes a first ridge and a second ridge disposed opposite to each other, located on opposite sides of the photonic crystal. Adjusting the geometry of the first and second ridges can enhance the confinement of lateral modes in the laser (such as those perpendicular to the stacking direction of the first electrode and the active layer), thereby reducing radiation loss of higher-order modes. Furthermore, when the widths of the first and second ridges match the wavelength of the target mode, strong reflection of the laser light from the fundamental mode can be provided, while for higher-order modes, the loss increases due to the mismatch between the widths of the first and second ridges and the wavelengths of the higher-order modes.

[0018] Therefore, in this application, the first and second ridges can restrict the lateral mode, the reflective structure formed by the second electrode covering the sidewall portion of the groove can suppress vertical and horizontal laser radiation, and the reflective structure including the alternating layers of the first and second reflective parts can enhance the fundamental mode feedback. The combination of these three elements achieves a high quality factor for the fundamental mode while suppressing radiation loss in higher-order modes. Furthermore, by adjusting the dimensions of the first and second ridges, the thickness of the reflective structure formed by the second electrode covering the sidewall portion of the groove, and the reflectivity of the reflective structure including the alternating layers of the first and second reflective parts, differential compensation can be made for the loss of different laser modes, ultimately achieving stable output of single-mode lasing or a single-mode laser, and enabling unidirectional vibration of the output laser.

[0019] Furthermore, the surface of the reflective structure facing away from the first electrode is higher than the surface of the photonic crystal facing away from the first electrode. In this way, the reflective structure can reflect the laser emitted by the photonic crystal, thereby further improving the efficiency of the laser and promoting greater consistency in the quality factor.

[0020] In some embodiments of this application, a first hollow portion is formed on the second electrode, through which the photonic crystal is exposed. Thus, the laser emitted by the photonic crystal can exit the laser generator through the first hollow portion.

[0021] In some embodiments of this application, the laser further includes an ohmic contact layer located between the first cladding layer and the second electrode. The first cladding layer can be made of a semiconductor material, and the second electrode can be made of a metal. Therefore, by providing an ohmic structure layer between the first cladding layer and the second electrode, the current between the first cladding layer and the second electrode can flow smoothly.

[0022] Furthermore, a second hollow portion is formed on the ohmic contact layer, surrounding the first hollow portion; a portion of the second electrode is located within the second hollow portion, and this portion of the second electrode covers the side of the ohmic contact layer facing the photonic crystal and the surface away from the first electrode. The surface of the reflective structure away from the first electrode is flush with the surface of the portion of the second electrode on the ohmic contact layer. Thus, the portion of the second electrode covering the side of the ohmic contact layer facing the photonic crystal is located on one side of the photonic crystal, thereby enabling this portion of the structure to reflect the laser emitted from the photonic crystal. In addition, the height of the surface of the second electrode away from the substrate can be increased, making this surface higher than the surface of the photonic crystal away from the substrate, thereby enabling the reflective structure to provide more comprehensive reflection of the laser emitted from the photonic crystal.

[0023] In some embodiments of this application, the laser further includes an isolation layer located between the first cladding and the second electrode, covering the area of ​​the first cladding except for the grooves. Thus, the portion of the first cladding not covered by the isolation layer can directly contact the second electrode or the ohmic contact layer, thereby allowing current to be injected onto the second electrode where the isolation layer is not present, and the injected current can be injected into the first cladding from that portion of the second electrode. This improves the current injection efficiency.

[0024] Furthermore, the projection of the insulating layer onto the first cladding layer does not overlap with the projection of at least a portion of the ohmic contact layer onto the first cladding layer. Thus, current injected from the second electrode can be injected into the first cladding layer via the ohmic contact layer where the projection of the insulating layer onto the first cladding layer does not overlap. This avoids the insulating layer's isolation effect on current injection.

[0025] In some embodiments of this application, the two reflective structures located on opposite sides of the photonic crystal have identical structures. Therefore, the reflective structures on opposite sides of the photonic crystal can produce substantially the same reflection effect on the light beam emitted from the photonic crystal, thereby ensuring that the confinement ability of the light beam reflected by the reflective structures is substantially consistent. This results in substantially the same quality factor for both parts of the light beam, which is more conducive to the consistency of the quality factor.

[0026] In some embodiments of this application, the photonic crystal has at least two discrete energy levels. Each energy level indicates that the photonic crystal allows a laser of a certain wavelength to exit at a certain angle. The photonic crystal includes a plurality of holes arranged in an array, and the lattice of the plurality of holes (the arrangement of the holes) is arranged in a finite periodic pattern, and its energy band can be considered discrete. The discrete portions of the energy band are energy levels, and different energy levels correspond to different frequencies and different wave vectors. Discreteness can refer to a gap between the wavelengths of the lasers corresponding to two adjacent energy levels, or, when represented on an energy level diagram, a certain distance between the two energy levels on the same energy band. Different frequencies mean different wavelengths. Different wave vectors mean different angles of deviation from the normal, i.e., different exit angles. In other words, different energy levels correspond to different wavelengths and different exit angles, and a certain energy level means that the laser of the wavelength corresponding to that energy level can exit from the photonic crystal at the corresponding angle. In this way, when a current that meets the preset conditions is injected into the first electrode and the second electrode, the peak wavelength of the gain spectrum generated in the active region can correspond to an energy level of the photonic crystal, so that the photonic crystal can select the laser of that wavelength and emit it at the corresponding angle.

[0027] In some embodiments of this application, the number of periods of the holes in the photonic crystal in both dimensions ranges from 50 to 125. This allows for a small number of periods of holes, which is beneficial for the photonic crystal to have at least two discrete energy levels, i.e., for achieving bandgap discreteness.

[0028] In some embodiments of this application, the quality factor of lasers emitted from different angles by the photonic crystal is the same. This ensures stable output of different lasers. It is understood that the same quality factor can include theoretically identical values, or it can include small deviations caused by factors such as processing errors. For example, the quality factor of lasers emitted from any two directions may differ by about 5%.

[0029] A second aspect of this application also provides an optical module, including a detector and a laser according to any of the above embodiments; the laser is used to emit a first optical signal toward a target object; the detector is used to receive a second optical signal formed after the target object reflects the first optical signal. After receiving the second optical signal, the detector can analyze the second optical signal, thereby achieving the detection function of the target object. The optical module can achieve all the effects of a laser.

[0030] A third aspect of this application also provides an electronic device, including a circuit board and the aforementioned optical module, the optical module being disposed on the circuit board. The electronic device is capable of achieving all the effects of the optical module. Alternatively, the electronic device includes a circuit board and a laser according to any of the above embodiments, the laser being disposed on the circuit board. The electronic device is capable of achieving all the effects of the laser. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the laser structure in the first related technology;

[0033] Figure 2 This is a schematic diagram of the laser structure in the second related technology;

[0034] Figure 3 This is a schematic diagram of the laser structure in the first embodiment of this application;

[0035] Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure at point AA;

[0036] Figure 5 for Figure 3 The diagram shows the structure of the photonic crystal in the laser.

[0037] Figure 6 This is an energy level diagram of a large-period photonic crystal.

[0038] Figure 7 This is the energy level diagram of a small-scale photonic crystal;

[0039] Figure 8 for Figure 3 The diagram shown illustrates how a laser emits a laser beam to detect an object.

[0040] Figure 9 for Figure 3 A schematic diagram of the cross-sectional structure at point BB;

[0041] Figure 10 This is a schematic diagram of the laser structure in the second embodiment of this application;

[0042] Figure 11 for Figure 10 Schematic diagram of the cross-sectional structure at point CC;

[0043] Figure 12 This is a schematic diagram of the laser structure in the third embodiment of this application;

[0044] Figure 13 This is a schematic diagram of the laser structure in the fourth embodiment of this application;

[0045] Figure 14 This is a schematic diagram of the laser structure in the fifth embodiment of this application;

[0046] Figure 15 for Figure 14 A schematic diagram of the cross-sectional structure at DD;

[0047] Figure 16 This is a cross-sectional structural diagram of the laser in the fifth embodiment of this application;

[0048] Figure 17 This is a schematic diagram illustrating the relationship between the Q value and wavelength of a laser in related technologies.

[0049] Figure 18 for Figure 10 A schematic diagram showing the relationship between the Q value and wavelength of the laser in the illustrated embodiment;

[0050] Figure 19 for Figure 10 A schematic diagram showing the relationship between the intensity, current, and wavelength of the laser emitted by the laser in the illustrated embodiment;

[0051] Figure 20 To be under different currents, Figure 10 A schematic diagram showing the change in the direction of laser emission from a hole in the laser in the illustrated embodiment;

[0052] Figure 21 for Figure 10 A schematic diagram showing the relationship between the peak wavelength, angle Φ, and angle θ of the laser emitted by the laser 100 in the illustrated embodiment;

[0053] Figure 22 To be under different currents, Figure 10 A schematic diagram showing the relationship between the angles Φ and θ of the laser emitted by the laser 100 in the illustrated embodiment.

[0054] Icons: 100-Laser; 101-Laser unit; 10-First electrode; 20-Substrate; 30-Second cladding; 40-Active layer; 50-First cladding; 51-Groove; 511-Bottom wall; 512-Side wall; 60-Second electrode; 61-First hollow portion; 62-First ridge; 63-Second ridge; 70-Photonic crystal; 71-Aperture; 80-Reflective structure; 81-First reflective portion; 82-Second reflective portion; 90-Ohmic contact layer; 91-Second hollow portion; 92-Side side; 93-Surface; 110-Isolation layer; 120-Buffer layer; 200-Beam deflector. Detailed Implementation

[0055] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0056] In this article, the term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item)" refers to one or more, while "more" refers to two or more. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0057] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order of objects. For example, "first target object" and "second target object," etc., are used to distinguish different target objects, not to describe a specific order of target objects.

[0058] Terms such as “connected” and “linked” are used to express the interconnection or interaction between different components, which may include direct connection or indirect connection through other components. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or apparatus is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Terms such as “upper,” “lower,” “left,” and “right” are used only relative to the orientation of components in the accompanying drawings. These directional terms are relative concepts used for relative description and clarification, and may vary accordingly depending on the orientation of the components in the drawings.

[0059] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0060] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more. For example, multiple processing units means two or more processing units; multiple systems means two or more systems.

[0061] This application provides an electronic device, which can be, for example, a consumer electronics product, a home electronics product, an in-vehicle electronics product, a financial terminal product, a communication electronics product, a testing electronics product, etc., and this application does not limit the scope of the application. For example, the aforementioned consumer electronics products can be mobile phones, tablet computers, laptops, personal computers (PCs), personal digital assistants (PDAs), smart wearable products (e.g., smartwatches, smart bracelets), virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, drones, cameras, projectors, televisions, etc. Home electronics products can be smart door locks, televisions, smart speakers, refrigerators, robot vacuum cleaners, etc. In-vehicle electronics products can be in-vehicle navigation systems, in-vehicle displays, head-up display (HUD) systems, etc. Financial terminal products can be automated teller machines (ATMs), self-service electronic devices, etc. Communication electronics products can be servers, storage devices, radar, base stations, and other communication equipment. Detection-related electronic products can include devices such as gas detectors and sports and health monitoring devices. Electronic devices can also be vehicles. For example, vehicles can include cars, trains, and airplanes.

[0062] The aforementioned electronic device typically includes an optical module and a circuit board, with the optical module mounted on the circuit board. The optical module may include a detector and a laser, wherein the laser sends a first optical signal to the object being detected, which can be a detection signal. After the first optical signal propagates to the object being detected, it is reflected to generate a second optical signal, which can propagate to the detector. The detector may specifically be a photodetector, which receives the second optical signal, performs photoelectric conversion on it, and further analyzes and processes it to achieve the detection of the object being detected.

[0063] In applications, lasers often require the emitted laser light to follow the direction of the object being detected. Therefore, in a related technology, such as... Figure 1 As shown, a beam deflector 200 is provided on the light-emitting side of the laser 100. The laser 100 can emit laser L1 towards the beam deflector 200. After receiving the laser L1, the beam deflector 200 changes the propagation direction of the laser L1 to obtain laser L2 or laser L3. The propagation directions of laser L2 and laser L3 are different from those of laser L1, and there is an angle α between laser L2 and laser L3.

[0064] Because this technology incorporates a beam deflector 200, the overall product structure is relatively complex and bulky, resulting in higher costs. The beam deflector 200 can be implemented using a mechanical structure or a MEMS. Damage to either the mechanical structure or the MEMS will prevent the entire product from emitting laser light or cause the emitted laser light to be in the wrong direction, thus leading to low reliability of this technology.

[0065] To simplify the overall product structure and improve reliability, another related technology, such as Figure 2 As shown, the laser 100 includes a plurality of laser units 101, and the laser L emitted by each laser unit 101 has a different direction. For example, the angle α between the laser L emitted by each laser unit 101 and the surface of the laser unit 101 is different.

[0066] Since this related technology lacks a beam deflector 200, therefore, compared to Figure 1 The related technology shown has a simpler structure and higher reliability. However, because it incorporates multiple laser units 101, its cost is higher.

[0067] Based on this, embodiments of this application provide a laser 100 that can reduce the cost and improve the reliability of the laser 100 while satisfying the requirements of laser emission and laser steering. This laser 100 can be a photonic crystal surface emitting laser (PCSEL).

[0068] For ease of description, such as Figure 3 As shown, three directions are first defined: X, Y, and Z. X represents the length direction of laser 100, Y represents the width direction of laser 100, and Z represents the thickness direction of laser 100. Furthermore, X, Y, and Z are all perpendicular to each other.

[0069] like Figure 3 and Figure 4 As shown, the laser 100 includes: a first electrode 10, a substrate 20, a second cladding layer 30, an active layer 40, a first cladding layer 50, and a second electrode 60, which are stacked sequentially.

[0070] Regarding the types of substrate 20, second cladding 30, and first cladding 50, in one example, substrate 20 can be an N-type substrate, second cladding 30 can be an N-type cladding, and first cladding 50 can be a P-type cladding. In another example, substrate 20 can be a P-type substrate, second cladding 30 can be a P-type cladding, and first cladding 50 can be an N-type cladding.

[0071] The substrate 20, the second cladding layer 30, and the first cladding layer 50 can all be made of semiconductor materials, such as gallium nitride (GaN) or indium phosphide (InP). Furthermore, the materials of the substrate 20, the second cladding layer 30, and the first cladding layer 50 may be the same, partially the same, or all different.

[0072] In one example, such as Figure 3 As shown, a first hollow portion 61 is formed on the second electrode 60, and the first hollow portion 61 may be located at the middle position of the second electrode 60. There is a gap between the sidewall of the first hollow portion 61 and the sidewall of the second electrode 60. In another example, the second electrode 60 may be a transparent electrode.

[0073] like Figure 4 As shown, a photonic crystal 70 is formed on the first cladding layer 50. (As illustrated...) Figure 5 As shown, the photonic crystal 70 includes a plurality of pillars arranged in an array. These pillars can be hollow or solid. For example, holes 71 can be formed in the first cladding 50 to create hollow pillars, or other dielectric materials can be filled into the hollow pillars to create solid pillars. The following section uses pillars as an example. Figure 4 The following explanation uses hole 71 as an example.

[0074] like Figure 5As shown, multiple holes 71 extend along the Z-direction and are arranged periodically or quasi-periodically in two dimensions (X and Y directions). The number of periods N of the holes 71 can be in the range of 50-125. For example, 50, 60, 70...125, etc. Here, the number of periods N is the number of holes 71 arranged in the X or Y direction. To simplify the structure, this embodiment uses an example where the number of periods N of the holes 71 along both the X and Y directions is 6. In practical applications, the number of periods N is still taken within the range of 50-125.

[0075] like Figure 5 As shown, the photonic crystal 70 also has the following parameters: side length L, lattice constant a, radius r, height h, refractive index ratio, and lattice type. The lattice constant a represents the center-to-center distance between two adjacent holes 71. The refractive index ratio can refer to the ratio between the refractive index of the medium within the hole 71 and the refractive index of the first cladding 50. Furthermore, the medium within the hole 71 is typically air.

[0076] The lattice type may include the arrangement and shape of the holes 71. Specifically, the arrangement may be a rectangular array, a circular array, or a triangular array. For example, ... Figure 5 As shown, the multiple holes 71 can be arranged in a rectangular array. In other embodiments, the multiple holes 71 can be arranged in a circular array or a triangular array, etc.

[0077] The photonic crystal 70 can be a one-dimensional photonic crystal 70 or a two-dimensional photonic crystal 70. The shape of the two-dimensional photonic crystal 70 can be a circular air column, an elliptical air column, a triangular air column, a quadrilateral air column, or a combination of the above shapes.

[0078] Regarding the formation method of the photonic crystal 70, in one example, a substrate 20, a second cladding layer 30, an active layer 40, and a first cladding layer 50 can be sequentially fabricated. A first electrode 10 is fabricated on the first cladding layer 50 using processes such as vapor deposition, and a second electrode 60 is fabricated on the side of the substrate 20 opposite to the second cladding layer 30. A first cutout portion 61 is formed on the second electrode 60. Then, the photonic crystal 70 is etched onto the first cladding layer 50. In another example, a substrate 20, a second cladding layer 30, and an active layer 40 can be sequentially fabricated, a first cladding layer 50 is fabricated, and the photonic crystal 70 is etched onto the first cladding layer 50. The first cladding layer 50 with the photonic crystal 70 formed is then bonded to the active layer 40. Next, a second electrode 60 is fabricated on the first cladding layer 50, and a first electrode 10 is fabricated on the side of the substrate 20 opposite to the second cladding layer 30.

[0079] like Figure 4As shown, the photonic crystal 70 is exposed from the first cutout portion 61. In application, the laser 100 of this embodiment can inject current into the first electrode 10 and the second electrode 60 respectively. The current injected from the first electrode 10 originates from the first electrode 10, passes through the substrate 20 and the second cladding 30, and is injected into the active layer 40. The current injected from the second electrode 60 originates from the second electrode 60, passes through the first cladding 50, and is injected into the active layer 40. The active layer 40 can generate charge carriers. A resonant cavity can be formed between the second cladding 30 and the first cladding 50. The charge carriers move within the resonant cavity and interact to form multiple laser beams of different wavelengths. There is a gap between the wavelengths of two adjacent laser beams. The multiple laser beams of different wavelengths can reach the photonic crystal 70 formed on the first cladding 50. The photonic crystal 70 can select a specific wavelength of laser beam from the multiple different wavelengths and emit it, thereby outputting laser beams in one direction.

[0080] When the injected current on the first electrode 10 and the second electrode 60 is increased, the concentration of charge carriers generated in the active layer 40 increases, and the peak wavelength of the gain spectrum shifts to a longer wavelength. When the peak wavelength of the gain spectrum increases to within a certain wavelength range allowed by the photonic crystal 70, laser light at that peak wavelength can be emitted from the photonic crystal 70 at a specific angle. When the injected current on the first electrode 10 and the second electrode 60 is decreased, the concentration of charge carriers generated in the active layer 40 decreases, and the peak wavelength of the gain spectrum shifts to a shorter wavelength. When the peak wavelength of the gain spectrum decreases to within a certain wavelength range allowed by the photonic crystal 70, laser light at that peak wavelength can be emitted from the photonic crystal 70 at a specific angle. In other words, increasing the current increases the wavelength of laser light selected by the photonic crystal 70, and decreasing the current decreases the wavelength of laser light selected by the photonic crystal 70. Therefore, under different currents, the output laser wavelength and the emission angle are different.

[0081] Figure 6 This is the energy level diagram of a large-period photonic crystal. When the period number N of aperture 71 is large-period (infinite-period), that is, when the side length L of photonic crystal 70 tends to infinity, as shown... Figure 6 As shown, the wave vector, i.e. the value of horizontal momentum, tends to be continuous, that is, the energy levels are continuous.

[0082] In this embodiment, the number of periods N of the aperture 71 is in the range of 50-125, therefore, the number of periods N of the aperture 71 is a finite number of periods. The photonic crystal 70 only supports lasers in a limited number of propagation directions. Figure 7 This is an energy level diagram of a short-period photonic crystal. Figure 7In the diagram, the horizontal axis represents the wave vector (propagation direction), and the vertical axis represents the laser frequency. TEA, TEB, TEC, and TED represent different energy bands. The solid black dots on the energy bands represent different energy levels. For example... Figure 7 As shown, Figure 5 The photonic crystal 70 shown has at least two discrete energy levels. That is, the wave vector takes discrete values, i.e., Figure 7 In the energy level diagram shown, any two adjacent black solid dots have a certain distance between their components on the horizontal axis. This can also be described as energy level splitting. Here, an energy level can refer to different laser beams (black solid dots) within an energy band, and energy level splitting refers to the certain distance between the components of different laser beams on the horizontal axis within the energy band. Furthermore, the energy band can be considered discrete, with different laser wave vectors corresponding to different angles of deviation from the normal. In addition, lasers of different frequencies correspond to different energy levels, and therefore also to different wave vectors, i.e., different angles of deviation from the normal. In other words, lasers of different wavelengths correspond to different angles of deviation from the normal.

[0083] Furthermore, the side length L and period number N of the photonic crystal 70 affect the number and distribution of optical modes in the laser. The lattice constant a influences the band gap and the distribution of optical modes. The ratio between the radius r and the lattice constant a is the fill factor, which affects the radiation constant of the mode. The refractive index ratio affects the band gap and the distribution of optical modes. The height h can change the structural parameters of the aperture 71, adjusting the spatial distribution of the dielectric constant, and thus affecting the position and width of the band gap. A larger height h may lead to a larger refractive index ratio, resulting in a wider band gap or a different frequency response. The lattice type affects the energy level diagram.

[0084] Because the wavelength of the output laser differs under different currents, and different wavelengths correspond to different deviations from the normal, i.e., different emission angles, the wavelength of the output laser can be changed by altering the current, thereby changing the direction of the output laser. Therefore, laser 100 can generate laser light in different directions under different currents. In other words, laser 100 can simultaneously achieve both light emission and laser direction redirection. For example, as... Figure 3 and Figure 4 As shown in the figure, three laser beams in different directions are represented as L1, L2, and L3.

[0085] like Figure 8 As shown, when the laser 100 detects the object being detected, if the object is at position W1, the laser 100 can emit laser L1 towards the object. When the object is at position W2, the laser 100 can emit laser L2 towards the object, and there is an angle α between laser L1 and laser L2. Here, the object being detected can be a gas, a human body, or other objects.

[0086] Furthermore, in this embodiment, the laser 100 itself can realize the function of laser steering, so there is no need to set up an additional laser steering device, thereby reducing the mechanical structure in the related technology, simplifying the structure, and thus reducing costs and improving reliability.

[0087] like Figure 4 As shown, there is a spacing d between the aperture 71 and the active layer 40. In this way, when the light beam is emitted from the active layer 40, the coupling coefficient between its optical field and the aperture 71 can be optimized, thereby improving the output power.

[0088] like Figure 3 As shown, the laser 100 also includes at least one reflective structure 80, which is located on one side of the photonic crystal 70. During the emission of the laser beam from the photonic crystal 70, part of the beam is emitted along the Z-direction, while another part is emitted from other directions at a certain angle to Z. When the reflective structure 80 is located on one side of the photonic crystal 70, the portion of the beam emitted from other directions will illuminate the reflective structure 80, which can reflect this portion of the beam, thereby changing its direction and enabling it to be emitted from the Z-direction. This improves the laser emission efficiency of the laser 100. Furthermore, the reflective structure 80 can provide high reflection for lasers of specific wavelengths. Moreover, the reflective structure 80 has different reflectivities for different modes in the laser; for example, it has a higher reflectivity for the target mode (fundamental mode) and a lower reflectivity for higher-order modes deviating from the target wavelength. This provides differentiated compensation for the loss of different modes in the laser, ensuring that the quality factor of the fundamental mode in a specific laser is essentially the same, ultimately achieving stable output of single-mode lasing or a single-mode laser.

[0089] Furthermore, in this embodiment, the laser 100 includes four reflective structures 80, which are respectively disposed on the four sides of the photonic crystal 70. For ease of description, the four reflective structures 80 can be named reflective structures 80a, 80b, 80c, and 80d. Thus, the four reflective structures 80a, 80b, 80c, and 80d can reflect most of the light beam emitted from the photonic crystal 70 except in the Z-direction, thereby ensuring that the Q value of the laser at each wavelength is basically the same, and thus, under each current, a laser of one wavelength can be output. Therefore, the output laser has a wide wavelength range and a wide directional range. For example, the laser output in this embodiment can cover the deep ultraviolet band to the far-infrared band.

[0090] It is understood that in other embodiments, the laser 100 may include three reflective structures 80, which are respectively located on three sides of the photonic crystal 70. Alternatively, the laser 100 may include two reflective structures 80, which are respectively located on two sides of the photonic crystal 70. The laser 100 may also include one reflective structure 80, which is respectively located on one side of the photonic crystal 70.

[0091] like Figure 4 and Figure 9 As shown, the first surface of the photonic crystal 70 is higher than or flush with the first surface of the reflective structure 80, and the second surface of the photonic crystal 70 is lower than or flush with the second surface of the reflective structure 80. The first surface may be a surface facing away from the first electrode 10, and the second surface may be a surface facing the first electrode 10. For example, as... Figure 4 As shown, the surfaces of reflective structures 80c and 80d facing away from substrate 20 are both higher than the surface of photonic crystal 70 facing away from substrate 20. In this way, reflective structures 80c and 80d can reflect the laser emitted from photonic crystal 70, thereby further improving the efficiency of laser 100 and promoting greater consistency in Q-value. Figure 9 As shown, the surfaces of the reflective structures 80a and 80b facing away from the substrate 20 are flush with the surface of the photonic crystal 70 facing away from the substrate 20.

[0092] In this embodiment, as Figure 4 As shown, the surfaces of reflective structures 80c and 80d facing the substrate 20 are lower than the surface of the photonic crystal 70 facing the substrate 20, as... Figure 9 As shown, the surfaces of reflective structures 80a and 80b facing the substrate 20 are flush with the surface of the photonic crystal 70 facing the substrate 20. Alternatively, in other embodiments, the surfaces of reflective structures 80a, 80b, 80c, and 80d facing the substrate 20 are all flush with the surface of the photonic crystal 70 facing the substrate 20. In this way, reflective structures 80a, 80b, 80c, and 80d can cover a wider range of the beam emitted by the photonic crystal 70, thereby enabling more comprehensive reflection of the beam emitted by the photonic crystal 70, further improving the efficiency of the laser 100, and promoting greater consistency in the Q-value.

[0093] Regarding the structure of each reflective structure 80, in one possible implementation, some reflective structures 80 differ from other reflective structures 80. For example, in this embodiment, such as... Figure 3 As shown, the two reflective structures 80 located on opposite sides of the photonic crystal 70 are identical. For example, as Figure 9 As shown, reflective structures 80a and 80b are identical, as follows: Figure 4As shown, reflection structures 80c and 80d are identical. Therefore, when the reflection structures 80 on opposite sides of the photonic crystal 70 are identical, they can form essentially the same reflection effect on the light beam emitted from the photonic crystal 70, which is more conducive to the consistency of the Q value.

[0094] Specifically, such as Figure 9 As shown, both reflective structures 80a and 80b include a first reflective portion 81 and a second reflective portion 82 alternately stacked along the Y direction. The refractive indices of the first reflective portion 81 and the second reflective portion 82 are different; for example, the refractive index of the first reflective portion 81 is higher than that of the second reflective portion 82. For example, the material of the first reflective portion 81 with the higher refractive index may include at least one of titanium nitride (TiN), magnesium fluoride (MgF2), and other media with high refractive indices. The material of the second reflective portion 82 with the lower refractive index may include at least one of silicon oxide (SiO2), air, and other media with low refractive indices.

[0095] Both the first reflective portion 81 and the second reflective portion 82 can be dielectric films. Therefore, in this embodiment, the reflective structures 80a and 80b can be considered to be formed by sequentially stacking multiple dielectric films. The multiple dielectric films enable high reflectivity of lasers at specific wavelengths, thereby reducing the loss of laser propagation to the location of the reflective structure and improving the quality factor (Q value). Furthermore, the reflection spectra of the reflective structures 80a and 80b are wavelength selective, providing high reflectivity for the target mode (such as the fundamental mode) in the laser while exhibiting lower reflectivity for higher-order modes deviating from the target wavelength, thus suppressing the oscillation of higher-order modes. In this way, lasers of specific wavelengths can operate on the fundamental mode, resulting in a solid circular or elliptical laser spot with more concentrated energy and better laser quality.

[0096] like Figure 4 As shown, both reflective structures 80c and 80d are part of the second electrode 60. Specifically, two grooves 51 are formed on the surface of the first cladding 50 facing away from the first electrode 10, and the two grooves 51 are located on opposite sides of the photonic crystal 70. Regarding the structure of the grooves 51, in one example, as... Figure 4 As shown, the groove 51 can be a groove 51 having a bottom wall 511 and two side walls 512. In another example, as Figure 10 and Figure 11 As shown, the groove 51 can be a groove 51 having a bottom wall 511 and a side wall 512. A portion of the second electrode 60 is located within the groove 51, and the second electrode 60 covering the side wall portion of the groove 51 forms reflective structures 80c and 80d, thereby enabling the reflective structures 80c and 80d to perform the function of the second electrode 60.

[0097] Furthermore, since the second electrode 60 needs to be conductive, its material is typically metal. Therefore, this embodiment can also utilize the high reflectivity of metal to suppress radiation loss of the laser in the vertical (i.e., Z-direction) and horizontal (i.e., X-direction) directions. The reflective structures 80c and 80d have higher reflectivity for transverse magnetic wave (TM) modes (where the electric field is perpendicular to the interface of the reflective structure) in the laser, and can also selectively enhance the confinement of the TM mode. Since metal has stronger absorption of transverse electric mode (TE) modes (where the electric field is parallel to the interface of the reflective structure) in the laser, the TE mode can be suppressed. Thus, transverse electric waves can be filtered out while the transverse magnetic mode is retained, resulting in an emitted laser with a fixed vibration direction and better laser quality.

[0098] Regarding the structure of each reflective structure 80, in another possible implementation, such as Figure 12 As shown, reflective structures 80a, 80b, 80c, and 80d are all identical, and reflective structures 80a and 80b each include a first reflective portion 81 and a second reflective portion 82 that are alternately stacked along the Y direction. Reflective structures 80c and 80d each include a first reflective portion 81 and a second reflective portion 82 that are alternately stacked along the X direction.

[0099] Regarding the structure of each reflective structure 80, in another possible implementation, such as Figure 13 As shown, reflective structures 80a, 80b, 80c and 80d are all part of the second electrode 60.

[0100] It is understood that in other possible embodiments, the following scheme may also be adopted: the reflective structure 80a includes a first reflective portion 81 and a second reflective portion 82 alternately stacked along the Y direction, and the reflective structures 80b, 80c and 80d are all part of the second electrode 60. Alternatively, the reflective structures 80a, 80b and 80c each include a first reflective portion 81 and a second reflective portion 82 alternately stacked, and the reflective structure 80d is part of the second electrode 60.

[0101] like Figure 15As shown, the second electrode 60 includes a first ridge 62 and a second ridge 63, which are located on opposite sides of the photonic crystal 70. Both the first ridge 62 and the second ridge 63 extend along the Y direction and are arranged along the X direction. The side of the first ridge 62 facing away from the photonic crystal 70 is connected to the reflective structure 80c, and the side of the second ridge 63 facing away from the photonic crystal 70 is connected to the reflective structure 80d. The confinement of transverse modes (such as those perpendicular to the Z direction, for example, the X direction) in the laser can be enhanced by adjusting the geometry of the first ridge 62 and the second ridge 63, thereby reducing the radiation loss of higher-order modes. Moreover, when the width of the first ridge 62 and the second ridge 63 matches the wavelength of the target mode, strong reflection of the laser light of the fundamental mode can be provided. However, for higher-order modes, the loss increases due to the mismatch between the width of the first ridge 62 and the second ridge 63 and the wavelength of the higher-order mode.

[0102] Therefore, in this embodiment, the first ridge 62 and the second ridge 63 can restrict the lateral mode, the reflective structures 80c and 80d can suppress vertical and horizontal laser radiation, and the reflective structures 80a and 80b can enhance the fundamental mode feedback. The combination of these three elements can achieve high Q-value resonance of the fundamental mode while suppressing radiation losses of higher-order modes. By adjusting the dimensions of the first ridge 62 and the second ridge 63, the thickness of the reflective structures 80c and 80d, and the reflectivity of the reflective structures 80a and 80b, differential compensation can be made for the losses of different laser modes, ultimately achieving stable output of single-mode lasing or a single-mode laser, and enabling unidirectional vibration of the output laser.

[0103] like Figure 14 and Figure 15 As shown, the laser 100 also includes an ohmic contact layer 90, which is located between the first cladding layer 50 and the second electrode 60. The first cladding layer 50 can be made of a semiconductor material, and the second electrode 60 can be made of a metal. Therefore, by providing an ohmic structure layer between the first cladding layer 50 and the second electrode 60, the current between the first cladding layer 50 and the second electrode 60 can flow smoothly. The ohmic contact layer 90 can be made of materials such as silver, gold, copper, nickel, or cobalt.

[0104] Figure 15As shown, a second cutout 91 is formed on the ohmic contact layer 90, which surrounds the first cutout 61. Regarding the structure of the ohmic contact layer 90, in one possible embodiment, a portion of the ohmic contact layer 90 is located within the groove 51, and the ohmic contact layer 90 extends from the surface away from the substrate 20 to both sides, with the extended structure located on the side of the first cladding layer 50 away from the substrate 20. Specifically, a portion of the ohmic structure layer 90 is located between the first cladding layer 50 and the first ridge 62, and a portion of the ohmic structure layer 90 is located between the first cladding layer 50 and the second ridge 63. The second electrode 60, located within the second hollow portion 91, covers the first cladding layer 50. The first ridge 62 and the second ridge 63 cover the side 92 of the ohmic contact layer 90 facing the photonic crystal 70 and the surface 93 facing away from the substrate 20. The surfaces of the reflective structures 80c and 80d facing away from the substrate 20 are flush with the surfaces of the portion of the second electrode 60 on the ohmic contact layer 90 (i.e., the first ridge 62 and the second ridge 63). Thus, the portion of the second electrode 60 covering the side 92 of the ohmic contact layer 90 facing the photonic crystal 70 is located on one side of the photonic crystal 70, allowing this portion of the structure to reflect the laser emitted from the photonic crystal 70. Furthermore, the height of the surfaces of the first ridge 62 and the second ridge 63 facing away from the substrate 20 can be increased, making these surfaces higher than the surface of the photonic crystal 70 facing away from the substrate 20. Therefore, the reflective structures 80c and 80d can provide more comprehensive reflection of the laser emitted from the photonic crystal 70. In another possible embodiment, as... Figure 16 As shown, the ohmic contact layer 90 may be located within the groove 51.

[0105] like Figure 14 and Figure 15 As shown, the laser 100 also includes an isolation layer 110, which is located between the first cladding 50 and the second electrode 60, and covers the area of ​​the first cladding 50 except for the groove 51. Thus, the portion of the first cladding 50 not covered by the isolation layer 110 can contact the ohmic contact layer 90. Therefore, current can be injected into the second electrode 60 where the isolation layer 110 is not located, and the injected current can be injected into the first cladding 50 from this portion of the second electrode 60, thereby achieving directional current injection and improving the current injection efficiency.

[0106] Furthermore, such as Figure 15 As shown, the projection of the insulating layer 110 onto the first sheath 50 does not overlap with the projection of at least a portion of the ohmic contact layer 90 onto the first sheath 50. Exemplarily, in one example, the projection of the insulating layer 110 onto the first sheath 50 does not overlap with the projection of the portion of the ohmic contact layer 90 onto the first sheath 50. For example, as... Figure 15As shown, the isolation layer 110 is disposed on the first cladding 50 in the area excluding the groove 51. A portion of the ohmic contact layer 90 is disposed within the groove 51 of the first cladding 50, and the remainder is disposed on the isolation layer 110. In another example, the projection of the isolation layer 110 onto the first cladding 50 does not overlap with the projection of the entire structure of the ohmic contact layer 90 onto the first cladding 50. For example, as... Figure 16 As shown, the isolation layer 110 is disposed on the first cladding 50 in the area excluding the groove 51, and the ohmic contact layer 90 is located within the groove 51. Thus, current injected from the second electrode 60 can be injected into the first cladding 50 through the ohmic contact layer 90, whose projection on the first cladding 50 does not overlap with the isolation layer 110. This avoids the isolation effect of the isolation layer 110 on current injection.

[0107] like Figure 14 and Figure 15 As shown, the laser 100 may further include a buffer layer 120 located between the substrate 20 and the second cladding layer 30. During the fabrication of the laser 100, the buffer layer 120 can be fabricated on the substrate 20, followed by the second cladding layer 30. Due to fabrication errors, the surface of the substrate 20 often has some defects; for example, the surface of the substrate 20 may actually be uneven rather than perfectly flat. Therefore, by fabricating the buffer layer 120 on the substrate 20, the buffer layer 120 can eliminate such defects to a certain extent, thereby improving the interface characteristics between the second cladding layer 30, the buffer layer 120, and the substrate 20, and preventing defects in the substrate 20 from affecting the growth of epitaxial layers, such as the second cladding layer 30.

[0108] The following discusses related technologies and... Figure 10 Simulation experiments were conducted on the laser 100 of the illustrated embodiment to obtain... Figures 17-22 The experimental results are shown. Figure 17 A schematic diagram illustrating the relationship between the Q value and wavelength of a laser 100 in a related art is shown. For example... Figure 17 As shown, because the photonic crystal 70 has different binding forces on light beams of different wavelengths, the Q values ​​corresponding to light beams of different wavelengths are different. For example, the Q value at point A is 1700, the Q value at point B is 1000, and the Q values ​​at points C and D are 500.

[0109] Figure 18 It shows Figure 10 A schematic diagram illustrating the relationship between the Q value and wavelength of the laser 100 in the illustrated embodiment. (See diagram below.) Figure 18 As shown, the Q values ​​corresponding to beams of different wavelengths are basically the same. It can be understood that the same quality factor can include theoretical similarity, or it can include small deviations caused by factors such as processing errors. For example, the quality factors of lasers from any two emission directions may differ by about 5%.

[0110] Figure 19 It shows Figure 10 A schematic diagram showing the relationship between the intensity, current, and wavelength of the laser emitted by the laser 100 in the illustrated embodiment. From... Figure 19 As can be seen, the wavelength of the output laser also changes with the change of current.

[0111] Figure 20 This shows the results under different currents. Figure 10 The diagram illustrates the change in the direction of laser emission from a hole 71 in the laser 100 of the illustrated embodiment. Furthermore, the laser can be redirected within the planes containing the Z and Y axes, or within the planes containing the X and Z axes.

[0112] Figure 21 It shows Figure 10 A schematic diagram showing the relationship between the peak wavelength, angle Φ, and angle θ of the laser emitted by the laser 100 in the illustrated embodiment. Wherein, as... Figure 20 As shown, angle Φ represents the angle when turning in the plane containing the Z and Y directions, and angle θ represents the angle when turning in the plane containing the Z and X directions. Figure 21 As shown, the peak wavelength of the laser differs under different currents. For any point a, there are unique angles Φ and θ.

[0113] Figure 22 It shows that under different currents, Figure 10 The diagram illustrates the relationship between the angles Φ and θ of the laser emitted by the laser 100 in the illustrated embodiment, where each dashed circle represents a laser point under a given current. The current range is 350 mA to 980 mA. Figure 22 As can be seen, the angles Φ and θ of each laser beam are different. It is evident that as the current increases, the emission direction of the laser changes in the direction indicated by the dashed arrow.

[0114] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A laser characterized by, include: A first electrode, an active layer, a photonic crystal, and a second electrode are stacked together. The active layer is used to generate laser light with a gain spectrum peak wavelength in response to the current injected into the first electrode and the second electrode; the gain spectrum peak wavelength is different when the current is different. The photonic crystal is used to receive and allow at least two different laser beams with peak gain wavelengths to be emitted at different angles.

2. The laser of claim 1, wherein, The laser also includes a reflective structure located on one side of the photonic crystal.

3. The laser of claim 2, wherein, The photonic crystal has the reflective structure on each of its four sides.

4. The laser of claim 2 or 3, wherein, The first surface of the photonic crystal is higher than or flush with the first surface of the reflective structure, and the second surface of the photonic crystal is lower than or flush with the second surface of the reflective structure. The first surface is the surface away from the first electrode, and the second surface is the surface facing the first electrode.

5. The laser of any of claims 2-4, wherein, At least one of the reflective structures includes a first reflective portion and a second reflective portion that are alternately stacked along a first direction, wherein the first reflective portion and the second reflective portion have different refractive indices, and the first direction is perpendicular to the stacking direction of the first electrode and the active layer.

6. The laser of any of claims 2-5, wherein, The second electrode includes a first ridge and a second ridge disposed opposite to each other, the first ridge and the second ridge being located on opposite sides of the photonic crystal.

7. The laser of any of claims 2-6, wherein, The laser further includes a first cladding layer located between the second electrode and the active layer, and the photonic crystal is disposed on the surface of the first cladding layer opposite to the active layer.

8. The laser of claim 7, wherein, A groove is formed on the surface of the first cladding layer opposite to the first electrode, and the groove is located on one side of the photonic crystal; A portion of the second electrode is located within the groove, and the portion of the second electrode covering the sidewall of the groove forms the reflective structure.

9. The laser of claim 7 or 8, wherein, The surface of the reflective structure facing away from the first electrode is higher than the surface of the photonic crystal facing away from the first electrode.

10. The laser according to claim 8 or 9, characterized in that, The material of the first cladding layer includes a semiconductor material, and the material of the second electrode includes a metal; The laser also includes an ohmic contact layer located between the first cladding and the second electrode.

11. The laser according to claim 10, characterized in that, A second hollow portion is formed on the ohmic contact layer; The second electrode is located within the second cutout portion, and the second electrode covers the side of the ohmic contact layer facing the photonic crystal and the surface away from the first electrode.

12. The laser according to claim 8, characterized in that, The laser also includes an isolation layer located between the first cladding and the second electrode, and the isolation layer covers the area on the first cladding except for the groove.

13. The laser according to claim 10 or 11, characterized in that, The laser also includes an isolation layer, the projection of which onto the first cladding layer does not overlap with the projection of at least a portion of the ohmic contact layer onto the first cladding layer.

14. The laser according to any one of claims 2-13, characterized in that, The two reflective structures located on opposite sides of the photonic crystal have the same structure.

15. The laser according to any one of claims 1-14, characterized in that, The photonic crystal has at least two discrete energy levels, each energy level indicating that the photonic crystal allows a laser of a certain wavelength to be emitted at a certain angle.

16. The laser according to any one of claims 1-15, characterized in that, The number of periods of holes in the photonic crystal in both dimensions ranges from 50 to 125.

17. The laser according to any one of claims 1-16, characterized in that, The quality factor of the laser emitted from the photonic crystal at different angles is the same.

18. The laser according to any one of claims 1-17, characterized in that, A first hollow portion is formed on the second electrode, and the photonic crystal is exposed from the first hollow portion.

19. An optical module, characterized in that, Includes the detector and the laser as described in any one of claims 1-18; The laser is used to emit a first optical signal toward the object being detected; The detector is used to receive a second optical signal formed after the object being detected reflects the first optical signal.

20. An electronic device, characterized in that, The device includes a circuit board and the optical module as described in claim 19, wherein the optical module is disposed on the circuit board; Alternatively, the electronic device may include a circuit board and a laser as described in any one of claims 1-18, the laser being disposed on the circuit board.

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