Photonic crystal surface-emitting laser and preparation method therefor, optical module, and optical device

Abstract

A photonic crystal surface-emitting laser (PCSEL) and a preparation method therefor, an optical module, and an optical device, relating to the technical field of lasers. The laser is a PCSEL, and comprises a first electrode layer (101), a first cladding layer (102), a first photonic crystal layer (103), a second photonic crystal layer (104), a second cladding layer (105), a second electrode layer (106), and at least one of a first active layer (107) and a second active layer (108); the first electrode layer (101), the first cladding layer (102), the first photonic crystal layer (103), the second photonic crystal layer (104), the second cladding layer (105), and the second electrode layer (106) are sequentially arranged; the first active layer (107) is located between the first cladding layer (102) and the first photonic crystal layer (103); the second active layer (108) is located between the second cladding layer (105) and the second photonic crystal layer (104); and the first photonic crystal layer (103) is bonded to the second photonic crystal layer (104). The problem of the laser emitting performance of PCSELs being affected due to the fact that the materials of other film layers fall into the air holes in the photonic crystal layers can be solved.

Description

Photonic crystal surface emitting laser and its preparation method, optical module, and optical equipment

[0001] This application claims priority to Chinese patent application filed on March 1, 2024, with application number 202410239945.2, entitled “Photonic crystal surface emitting laser and its preparation method, optical module, and optical equipment”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of laser technology, and in particular to a photonic crystal surface emitting laser and a preparation method thereof, an optical module, and an optical device. Background Art

[0003] A laser is a device that can emit laser light. There are many types of lasers, such as photonic crystal surface emitting laser (PCSEL), vertical cavity surface emitting laser (VCSEL), and distributed feedback laser (DFB). Among them, PCSEL is widely used due to its four major characteristics: high power, narrow divergence angle, single-mode light output, and surface emission.

[0004] A PCSEL typically consists of two opposing cladding layers, an active layer and a photonic crystal layer stacked between them, and two electrode layers stacked on either side of the cladding layers. Applying an electric field to the active layer through these two electrode layers causes it to emit laser light, which is then emitted perpendicularly to the active layer under the influence of the photonic crystal layer.

[0005] When manufacturing PCSELs, each film layer is typically grown sequentially in one direction using epitaxy. Since the photonic crystal layer is located between these layers, other film layers must be grown on top of it using epitaxy after the photonic crystal layer is formed. However, the photonic crystal layer often has multiple pores. When other film layers are formed on top of the photonic crystal layer, material may fall into these pores, affecting the properties of the photonic crystal layer and, consequently, the luminescence performance of the PCSEL. Summary of the Invention

[0006] The present application provides a photonic crystal surface emitting laser and its preparation method, optical module, and optical equipment, which can solve the problem that materials from other film layers fall into the pores in the photonic crystal layer and affect the luminescence performance of PCSEL.

[0007] In a first aspect, the present application provides a PCSEL comprising: a first electrode layer, a first cladding layer, a first photonic crystal layer, a second photonic crystal layer, a second cladding layer, a second electrode layer, and at least one of a first active layer and a second active layer; wherein the first electrode layer, the first cladding layer, the first photonic crystal layer, the second photonic crystal layer, the second cladding layer, and the second electrode layer are arranged in sequence, and the first photonic crystal layer is bonded to the second photonic crystal layer. The first active layer is located between the first cladding layer and the first photonic crystal layer, and the second active layer is located between the second cladding layer and the second photonic crystal layer.

[0008] When preparing a PCSEL, a first structure and a second structure can be prepared first. The first structure can also be called a first wafer, and the second structure can also be called a second wafer. The first structure includes a first electrode layer, a first cladding layer, a first active layer, and a first photonic crystal layer arranged in sequence. The first photonic crystal layer is the last film layer prepared in the first structure; the second structure includes a second electrode layer, a second active layer, a second cladding layer, and a second photonic crystal layer arranged in sequence. The second photonic crystal layer is the last film layer prepared in the second structure. Afterwards, the first photonic crystal layer and the second photonic crystal layer are bonded to obtain a PCSEL. Here, the PCSEL including the first active layer and the second active layer is taken as an example. It can be understood that the PCSEL may not include the first active layer or the second active layer. Accordingly, the first structure may not include the first active layer, or the second structure may not include the second active layer.

[0009] According to the above preparation process, since the PCSEL provided in the embodiment of the present application has the first electrode layer, the first cladding layer, the first photonic crystal layer, the second photonic crystal layer, the second cladding layer, and the second electrode layer arranged in sequence, the first active layer is located between the first cladding layer and the first photonic crystal layer, and the second active layer is located between the second cladding layer and the second photonic crystal layer. In addition, the first photonic crystal layer is bonded to the second photonic crystal layer. Therefore, the PCSEL supports the use of the photonic crystal layer as the last film layer prepared when preparing the above-mentioned first structure and second structure. Finally, the first photonic crystal layer and the second photonic crystal layer are bonded to obtain the PCSEL. Since the photonic crystal layer is the last film layer prepared in the first structure and the second structure, no other materials will be epitaxially grown on the photonic crystal layer. Therefore, there is no problem of other materials falling into the pores in the photonic crystal layer, so it will not affect the luminescence performance of the PCSEL. It can be seen that the preparation difficulty of the PCSEL is relatively low.

[0010] Furthermore, the first surface of the first photonic crystal layer close to the second photonic crystal layer may have a first alignment mark, and the second surface of the second photonic crystal layer close to the first photonic crystal layer may have a second alignment mark; the first alignment mark and the second alignment mark overlap. In this way, when the first photonic crystal layer and the second photonic crystal layer are bonded, the first surface of the first photonic crystal layer and the second surface of the second photonic crystal layer can be bonded, and the first alignment mark and the second alignment mark can be used to achieve precise bonding between the first surface and the second surface. Optionally, the first surface may not have the first alignment mark, and the second surface may not have the second alignment mark, which is not limited in this embodiment of the present application.

[0011] In the photonic crystal layer of the embodiment of the present application, the material of the first photonic crystal layer and the material of the second photonic crystal layer can be the same or different, and the embodiment of the present application does not limit this. When the material of the first photonic crystal layer and the material of the second photonic crystal layer are different, the wavelength of the laser applicable to the first photonic crystal layer and the wavelength of the laser applicable to the second photonic crystal layer can be different. In this way, the PCSEL can be used to control lasers of multiple wavelengths, improving the control dimension and applicability of the PCSEL.

[0012] Optionally, the PCSEL provided in this application further includes a first substrate and a second substrate, wherein the first structure includes the first substrate, and the second structure includes the second substrate. The first substrate is located between the first electrode layer and the first cladding layer, and the second substrate is located between the second electrode layer and the second cladding layer. Optionally, the first substrate may be located on the side of the first electrode layer away from the first cladding layer, and the second substrate may be located on the side of the second electrode layer away from the second cladding layer. The PCSEL may also not include the first substrate and the second substrate, and this application does not limit this.

[0013] The PCSEL provided in the embodiments of the present application may further include a first buffer layer and a second buffer layer. The first structure includes the first buffer layer, and the second structure includes the second buffer layer. The first buffer layer is located between the first active layer and the first photonic crystal layer, and the second buffer layer is located between the second active layer and the second photonic crystal layer. Optionally, the PCSEL may not include the first buffer layer and the second buffer layer, and this application does not limit this.

[0014] Furthermore, in the PCSEL provided by the present application, the first photonic crystal layer and the second photonic crystal layer form a UGR structure. The UGR structure can radiate laser light only in one direction perpendicular to the active layer through optical resonance, and will not radiate laser light in another direction perpendicular to the active layer. In this way, the first photonic crystal layer and the second photonic crystal layer will transmit the laser light emitted by the active layer of the PCSEL to the direction of one of the first electrode layer and the second electrode layer, and will not transmit the laser light to the direction of the other electrode layer, thereby reducing the waste of optical power. Moreover, since the UGR structure can reduce the waste of optical power, the PCSEL does not need to be provided with a reflective structure such as a DBR, thereby avoiding a series of problems caused by the provision of these reflective structures, and can also reduce the thickness of the PCSEL, which is conducive to the miniaturization of the PCSEL. In addition, the first photonic crystal layer and the second photonic crystal layer in the embodiment of the present application are bonded, so the method of preparing the UGR structure formed by the first photonic crystal layer and the second photonic crystal layer is also relatively simple.

[0015] The first photonic crystal layer and the second photonic crystal layer can form a UGR structure in any of a variety of achievable methods, two of which will be used as examples for explanation below.

[0016] In a first possible implementation, the first photonic crystal layer has a plurality of first through holes arranged in an array, and the second photonic crystal layer has a plurality of second through holes arranged in an array; the angle between the row direction of the first through holes and the row direction of the second through holes is greater than zero and not equal to 90 degrees.

[0017] In a second possible implementation, the first photonic crystal layer has a plurality of first through holes arranged in an array, and the second photonic crystal layer has a plurality of second through holes arranged in an array; the diameter of the circumscribed circle of the opening surface of the first through hole is smaller than the diameter of the circumscribed circle of the opening surface of the second through hole.

[0018] Furthermore, in this second possible implementation, the plurality of first through holes correspond one-to-one with the plurality of second through holes, and the first through holes are connected to the corresponding second through holes. Of course, the plurality of first through holes and the plurality of second through holes may not correspond one-to-one, and the first through holes may not be connected to the corresponding second through holes, and this application does not limit this.

[0019] In a second aspect, the present application provides a method for preparing a PCSEL, which can be used to prepare the PCSEL described in any design of the first aspect, the method comprising: preparing a first structure and a second structure, wherein the first structure comprises a first electrode layer, a first cladding layer, and a first photonic crystal layer arranged in sequence, and the first photonic crystal layer is the last film layer prepared in the first structure; the second structure comprises a second electrode layer, a second cladding layer, and a second photonic crystal layer arranged in sequence, and the second photonic crystal layer is the last film layer prepared in the second structure; the first structure comprises a first active layer, and / or the second structure comprises a second active layer; the first active layer is located between the first cladding layer and the first photonic crystal layer, and the second active layer is located between the second cladding layer and the second photonic crystal layer. Finally, bonding the first photonic crystal layer to the second photonic crystal layer to obtain the PCSEL.

[0020] Optionally, the first surface of the first photonic crystal layer has a first alignment mark, and the second surface of the second photonic crystal layer has a second alignment mark; when bonding the first photonic crystal layer to the second photonic crystal layer, the first surface of the first photonic crystal layer can be bonded to the second surface of the second photonic crystal layer so that the first alignment mark and the second alignment mark overlap.

[0021] Optionally, the first structure further includes a first substrate, and the second structure further includes a second substrate, the first substrate is located between the first electrode layer and the first cladding layer, and the second substrate is located between the second electrode layer and the second cladding layer.

[0022] In a third aspect, the present application provides an optical module comprising: a controller, and the PCSEL described in any one of the designs in the first aspect; the driver is used to control the PCSEL to emit laser light.

[0023] In a fourth aspect, the present application provides an optical device, comprising: a power supply module and the optical module provided in the third aspect, wherein the power supply module is used to supply power to the optical module.

[0024] The effects of the second to fourth aspects mentioned above can refer to the effects of the corresponding designs in the first aspect, and this application will not go into details here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic diagram of a PCSEL provided in an embodiment of the present application;

[0026] FIG2 is a schematic diagram of a VCSEL provided in an embodiment of the present application;

[0027] FIG3 is a schematic diagram of a DFB provided in an embodiment of the present application;

[0028] FIG4 is a schematic diagram of various film layers in a PCSEL provided in an embodiment of the present application;

[0029] FIG5 is a schematic diagram of a reflective structure in a PCSEL provided in an embodiment of the present application;

[0030] FIG6 is a schematic diagram of another PCSEL provided in an embodiment of the present application;

[0031] FIG7 is a schematic diagram of a PCSEL preparation process provided in an embodiment of the present application;

[0032] FIG8 is a schematic diagram of a through hole in a photonic crystal layer provided in an embodiment of the present application;

[0033] FIG9 is a schematic diagram of another through hole in a photonic crystal layer provided in an embodiment of the present application;

[0034] FIG10 is a schematic diagram of a corresponding relationship between a first through hole and a second through hole provided in an embodiment of the present application;

[0035] FIG11 is a schematic diagram of a PCSEL used as a light source for optical communication according to an embodiment of the present application;

[0036] FIG12 is a schematic diagram of another PCSEL used as a light source for optical communication according to an embodiment of the present application;

[0037] FIG13 is a schematic diagram of another PCSEL used as a light source for optical communication according to an embodiment of the present application;

[0038] FIG14 is a schematic diagram of a PCSEL used as a laser radar light source according to an embodiment of the present application;

[0039] FIG15 is a flow chart of a method for preparing a PCSEL provided in an embodiment of the present application;

[0040] FIG16 is a schematic diagram of an optical module provided in an embodiment of the present application;

[0041] FIG17 is a schematic diagram of an optical device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The embodiments of the present application provide a laser. Currently, there are many types of lasers, which can be mainly divided into three types: PCSEL, VCSEL and DFB.

[0043] As shown in Figure 1, PCSEL can emit laser light with a divergence angle less than 1 degree (°) × 1° from a direction perpendicular to its active layer. PCSEL supports the emission of laser light of one wavelength (called single-mode light emission), and the power of the laser light emitted by PCSEL is in the watt (W) range.

[0044] As shown in Figure 2, VCSEL can emit laser light with a divergence angle less than 20°×20° from a direction perpendicular to its active layer. VCSEL only supports the emission of laser light with multiple wavelengths (called multi-mode light output). The power of the laser light emitted by VCSEL is in the milliwatt (mW) range (e.g., several mW).

[0045] As shown in FIG3 , the DFB can emit a laser with a divergence angle less than 20°×40° from a direction parallel to the active layer, and the DFB supports the emission of laser light of one wavelength (called single-mode emission). The power of the laser light emitted by the DFB is in the milliwatt (mW) range (e.g., tens of mW).

[0046] When a laser emits laser light perpendicular to its active layer, it is called surface emission. When a laser emits laser light parallel to its active layer, it is called edge emission. The packaging and testing cost of surface emission is lower than that of edge emission. The power of laser light emitted by a laser in single-mode light-emitting mode is higher than that of laser light emitted by a laser in multi-mode light-emitting mode. Therefore, the laser light emitted by a laser in single-mode light-emitting mode can support transmission over longer distances (such as greater than or equal to 200 meters). The smaller the divergence angle of the laser light emitted by the laser, the higher the collimation of the laser light, the longer the transmission distance supported by the laser light, the longer the lifespan, and the higher the stability.

[0047] Comparing PCSEL, VCSEL and DFB, it can be seen that the laser emitted by PCSEL has four major characteristics: high power, small divergence angle, single-mode light output and surface emission. Therefore, lasers mainly evolve towards PCSEL.

[0048] Figure 4 shows the structure of a PCSEL. A PCSEL typically consists of two opposing cladding layers, an active layer and a photonic crystal layer stacked between them, and two electrode layers stacked on either side of the cladding layers. Applying an electric field to the active layer through these two electrode layers causes it to emit laser light, which is then emitted perpendicular to the active layer under the influence of the photonic crystal layer.

[0049] In the related art, when fabricating a PCSEL, an electrode layer, a cladding layer, an active layer, a photonic crystal layer, another cladding layer, and another electrode layer are typically formed in sequence through epitaxy. However, when forming the second cladding layer on the photonic crystal layer, due to the multiple pores in the photonic crystal layer, material may fall into these pores during the fabrication of the second cladding layer, affecting the properties of the photonic crystal layer and, consequently, the luminescence performance of the PCSEL. Therefore, the second cladding layer is difficult to fabricate, and the fabrication of PCSELs is quite challenging.

[0050] Furthermore, the PCSEL uses surface emission, emitting light in the directions of both electrode layers. However, only the light emitted in the direction of one electrode layer is actually utilized, and the light emitted in the direction of the other electrode layer is wasted, resulting in 50% optical power waste.

[0051] In the related art, as shown in FIG5 , in order to reduce the waste of optical power, a reflective structure such as a metal reflector or a distributed Bragg reflector (DBR) is set between another cladding and the other electrode layer. However, the precision requirement for the thickness of the other cladding in setting the reflective structure is relatively strict to ensure that in the light emitted by the PCSEL, the laser reflected by the reflective structure and the laser not reflected by the reflective structure are in the same phase, thereby producing a constructive interference effect. If the thickness deviation is large, the laser reflected by the reflective structure and the laser not reflected by the reflective structure in the light emitted by the PCSEL will be in different phases, resulting in destructive interference, affecting the light extraction efficiency of the PCSEL. In addition, when the reflective structure is a DBR, the DBR is usually formed by alternating two materials with different refractive indices, and the more material layers in the DBR, the higher the reflectivity of the DBR. For lasers in some special wavelength bands, the DBR often requires more material layers to achieve effective reflection of such lasers. For example, for 1550 nanometer (nm) lasers (optical communications, frequency modulated continuous wave (FMCW) laser radars use this type of laser), the two materials with different refractive indices in the DBR are both doped with indium phosphide (InP). Since the refractive index difference of the material obtained by doping with indium phosphide is usually very small, it is difficult to meet the reflection requirements of 1550 nanometer lasers. Therefore, it is necessary to set more layers of these two materials in the DBR to alternate. However, due to the large lattice mismatch rate, these multilayer materials in the DBR are difficult to grow. In addition, the overall thickness of the PCSEL has certain limitations, and therefore the thickness of the DBR in the PCSEL also has certain limitations. Therefore, in some cases, the DBR cannot achieve effective reflection of the laser.

[0052] The present invention provides a PCSEL that reduces the difficulty of manufacturing by splitting a photonic crystal layer into two layers and bonding the two layers together. Furthermore, the PCSEL can form a unidirectional guided-mode resonance (UGR) structure between the two photonic crystal layers, reducing optical power waste. Therefore, there is no need to add a reflective structure to the PCSEL, thus avoiding the problems associated with reflective structures.

[0053] For example, FIG6 is a schematic diagram of the structure of a PCSEL provided in an embodiment of the present application. As shown in FIG6 , the PCSEL includes: a first electrode layer 101, a first cladding layer 102, a first photonic crystal layer 103, a second photonic crystal layer 104, a second cladding layer 105, a second electrode layer 106, and at least one of a first active layer 107 and a second active layer 108. FIG6 illustrates the PCSEL including the first active layer 107 and the second active layer 108 as an example. It is understood that the PCSEL may also include the first active layer 107 but not the second active layer 108, or the PCSEL may include the second active layer 108 but not the first active layer 107. The shapes of the first electrode layer 101 and the second electrode layer 106 may vary, for example, the first electrode layer 101 may be rectangular and the second electrode layer 106 may be annular.

[0054] The first electrode layer 101, the first cladding layer 102, the first photonic crystal layer 103, the second photonic crystal layer 104, the second cladding layer 105 and the second electrode layer 106 are arranged in sequence, the first active layer 107 is located between the first cladding layer 102 and the first photonic crystal layer 103, and the second active layer 108 is located between the second cladding layer 105 and the second photonic crystal layer 104; the first photonic crystal layer 103 is bonded to the second photonic crystal layer 104.

[0055] When fabricating a PCSEL, as shown in Figure 7, a first structure and a second structure can be prepared first. The first structure can also be referred to as a first wafer, and the second structure can also be referred to as a second wafer. The first structure includes a first electrode layer 101, a first cladding layer 102, a first active layer 107, and a first photonic crystal layer 103, arranged in sequence. The first photonic crystal layer 103 is the last layer fabricated in the first structure. The second structure includes a second electrode layer 106, a second active layer 108, a second cladding layer 105, and a second photonic crystal layer 104, arranged in sequence. The second photonic crystal layer 104 is the last layer fabricated in the second structure. Subsequently, the first photonic crystal layer 103 and the second photonic crystal layer 104 are bonded to form a PCSEL. Here, the PCSEL including the first active layer 107 and the second active layer 108 is taken as an example. It can be understood that the PCSEL may not include the first active layer 107 or the second active layer 108. Accordingly, the first structure may not include the first active layer 107, or the second structure may not include the second active layer 108.

[0056] According to the above preparation process, since the PCSEL provided in the embodiment of the present application has the first electrode layer, the first cladding layer, the first photonic crystal layer, the second photonic crystal layer, the second cladding layer, and the second electrode layer arranged in sequence, the first active layer is located between the first cladding layer and the first photonic crystal layer, and the second active layer is located between the second cladding layer and the second photonic crystal layer. In addition, the first photonic crystal layer is bonded to the second photonic crystal layer. Therefore, the PCSEL supports the use of the photonic crystal layer as the last film layer prepared when preparing the above-mentioned first structure and second structure. Finally, the first photonic crystal layer and the second photonic crystal layer are bonded to obtain the PCSEL. Since the photonic crystal layer is the last film layer prepared in the first structure and the second structure, no other materials will be epitaxially grown on the photonic crystal layer. Therefore, there is no problem of other materials falling into the pores in the photonic crystal layer, so it will not affect the luminescence performance of the PCSEL. It can be seen that the preparation difficulty of the PCSEL is relatively low.

[0057] Optionally, the photonic crystal layer in the embodiment of the present application may include: a first portion having a plurality of through holes arranged in an array. Of course, these through holes may also be filled with a second portion, and the first portion and the second portion may be made of different materials, which is not limited in the embodiment of the present application.

[0058] Furthermore, the first surface of the first photonic crystal layer 103 close to the second photonic crystal layer 104 may have a first alignment mark (not shown in the drawings), and the second surface of the second photonic crystal layer 104 close to the first photonic crystal layer 103 may have a second alignment mark (not shown in the drawings); the first alignment mark and the second alignment mark overlap. In this way, when the first photonic crystal layer 103 and the second photonic crystal layer 104 are bonded, the first surface of the first photonic crystal layer 103 and the second surface of the second photonic crystal layer 104 can be bonded, and the first alignment mark and the second alignment mark can be used to achieve precise bonding between the first surface and the second surface. Optionally, the first surface may not have the first alignment mark, and the second surface may not have the second alignment mark, which is not limited in this embodiment of the present application.

[0059] When bonding the first photonic crystal layer 103 and the second photonic crystal layer 104 , a flip chip bonding method may be used.

[0060] In the photonic crystal layer in the embodiment of the present application, the material of the first photonic crystal layer 103 and the material of the second photonic crystal layer 104 can be the same or different, and the embodiment of the present application does not limit this. The material of the first photonic crystal layer 103 and the material of the second photonic crystal layer 104 can be any material such as indium phosphide (InP), gallium arsenide (GaAs), lithium niobate (LN) or silicon (Si). When the material of the first photonic crystal layer 103 and the material of the second photonic crystal layer 104 are different, the wavelength of the laser applicable to the first photonic crystal layer 103 and the wavelength of the laser applicable to the second photonic crystal layer 104 can be different. In this way, the PCSEL can be used to control lasers of multiple wavelengths, thereby improving the control dimension and applicability of the PCSEL.

[0061] Optionally, referring to Figure 6 , the PCSEL provided in this embodiment of the present application further includes a first substrate 109 and a second substrate 110. The first structure described above includes the first substrate 109, and the second structure includes the second substrate 110. The first substrate 109 is located between the first electrode layer 101 and the first cladding layer 102, and the second substrate 110 is located between the second electrode layer 106 and the second cladding layer 105. Optionally, the first substrate 109 may be located on the side of the first electrode layer 101 away from the first cladding layer 102, and the second substrate 110 may be located on the side of the second electrode layer 106 away from the second cladding layer 105. The PCSEL may also not include the first substrate 109 and the second substrate 110, and this embodiment of the present application is not limited to this.

[0062] Continuing with FIG6 , the PCSEL provided in the embodiment of the present application may further include a first buffer layer 111 and a second buffer layer 112. The first structure described above includes the first buffer layer 111, and the second structure includes the second buffer layer 112. The first buffer layer 111 is located between the first active layer 107 and the first photonic crystal layer 103, and the second buffer layer 112 is located between the second active layer 108 and the second photonic crystal layer 104. Optionally, the PCSEL may not include the first buffer layer 111 and the second buffer layer 112, and this is not limited in the embodiment of the present application.

[0063] Furthermore, in the PCSEL provided in the embodiment of the present application, the first photonic crystal layer 103 and the second photonic crystal layer 104 form a UGR structure. The UGR structure can radiate laser light only in one direction perpendicular to the active layer through optical resonance, and will not radiate laser light in another direction perpendicular to the active layer. In this way, the first photonic crystal layer 103 and the second photonic crystal layer 104 will transmit the laser light emitted by the active layer of the PCSEL to the direction of one of the first electrode layer 101 and the second electrode layer 102, and will not transmit the laser light to the direction of the other electrode layer, thereby reducing the waste of optical power. Moreover, since the UGR structure can reduce the waste of optical power, the PCSEL does not need to be provided with a reflective structure such as a DBR, thereby avoiding a series of problems caused by the provision of these reflective structures, and can also reduce the thickness of the PCSEL, which is conducive to the miniaturization of the PCSEL. In addition, in the embodiment of the present application, the first photonic crystal layer 103 and the second photonic crystal layer 104 are bonded together. Therefore, the method for preparing the UGR structure formed by the first photonic crystal layer 103 and the second photonic crystal layer 104 is also relatively simple.

[0064] The first photonic crystal layer 103 and the second photonic crystal layer 104 can form a UGR structure in any of a variety of achievable methods, two of which will be used as examples for explanation below.

[0065] (1) In a first possible implementation, as shown in FIG8 , the first photonic crystal layer 103 has a plurality of first through holes 1031 arranged in an array, and the second photonic crystal layer 104 has a plurality of second through holes 1041 arranged in an array; FIG8 shows a top view of the first photonic crystal layer 103 and the second photonic crystal layer 104 in FIG6 . The angle between the row direction of the first through holes 1031 (such as the x1 direction in FIG8 ) and the row direction of the second through holes 1041 (such as the x2 direction in FIG8 ) is greater than zero and is not equal to 90 degrees. It can be seen that the angle a is not 0 degrees or 90 degrees. In this case, the first photonic crystal layer 103 and the second photonic crystal layer 104 form a UGR structure.

[0066] The row direction of the first through holes 1031 is perpendicular to the column direction of the first through holes 1031, and the row direction of the second through holes 1041 is perpendicular to the column direction of the second through holes 1041. In the embodiment of the present application, the angle between the column direction of the first through holes 1031 (such as the y1 direction in FIG. 8 ) and the column direction of the second through holes 1041 (such as the y2 direction in FIG. 8 ) is not 0 degrees or 90 degrees.

[0067] (2) In a second possible implementation, as shown in FIG9 , the first photonic crystal layer 103 has a plurality of first through holes 1031 arranged in an array, and the second photonic crystal layer 104 has a plurality of second through holes 1041 arranged in an array. FIG9 shows a top view of the first photonic crystal layer 103 and the second photonic crystal layer 104 in FIG6 . The diameter of the circumscribed circle of the opening surface of the first through hole 1031 is smaller than the diameter of the circumscribed circle of the opening surface of the second through hole 1041. In this case, the first photonic crystal layer 103 and the second photonic crystal layer 104 form a UGR structure.

[0068] It can be understood that the embodiment of the present application does not limit the shape of the opening surface of the first through hole 1031 and the opening surface of the second through hole 1041. Figure 9 takes the two opening surfaces as circles as an example. The two opening surfaces can also be other shapes (such as squares, rectangles, triangles, irregular shapes, etc.), and the shapes of the two opening surfaces can be the same or different.

[0069] Furthermore, in this second possible implementation, as shown in FIG10 , the plurality of first through holes 1031 correspond one-to-one with the plurality of second through holes 1041, and the first through holes 1031 are connected to the corresponding second through holes 1041. Of course, the plurality of first through holes 1031 and the plurality of second through holes 1041 may not correspond one-to-one, and the first through holes 1031 and the corresponding second through holes 1041 may not be connected, and this is not limited in this embodiment of the present application.

[0070] When multiple first through holes 1031 correspond to multiple second through holes 1041 one by one, and the first through holes 1031 are connected to the corresponding second through holes 1041, if the diameter of the circumscribed circle of the opening surface of the first through hole 1031 is smaller than the diameter of the circumscribed circle of the opening surface of the second through hole 1041, then the PCSEL can emit laser light toward the side where the first photonic crystal layer 103 or the second photonic crystal layer 104 is located.

[0071] The first photonic crystal layer 103 and the second photonic crystal layer 104 may also form a UGR structure using other feasible methods different from the first and second feasible methods described above. For example, the first photonic crystal layer 103 may have a plurality of first through holes 1031 arranged in an array, and the second photonic crystal layer 104 may have a plurality of second through holes 1041 arranged in an array; the angle a between the row direction of the first through holes 1031 and the row direction of the second through holes 1041 may be an acute angle or an obtuse angle; and the diameter of the circumscribed circle of the opening surface of the first through holes 1031 may be smaller than the diameter of the circumscribed circle of the opening surface of the second through holes 1041.

[0072] The first photonic crystal layer 103 and the second photonic crystal layer 104 may not form a UGR structure, which is not limited in this embodiment of the present application.

[0073] The cladding layer in the embodiment of the present application serves to protect the photonic crystal layer. For example, both the first cladding layer 102 and the second cladding layer 105 can be made of silicon dioxide. If the first photonic crystal layer 103 and the second photonic crystal layer 104 do not form a UGR structure, one of the first cladding layer 102 and the second cladding layer 105 can also be made of a special material to allow the PCSEL to emit light toward the side of the first cladding layer 102 or the second cladding layer 105 where the other cladding layer is located.

[0074] The laser light emitted by a PCSEL can be used in a variety of applications, such as optical communications, optical sensing, and optical displays. When the laser light emitted by a PCSEL is used for optical communications, the PCSEL can be used as a light source for optical transmission networks, optical access networks, data centers, and satellite optical communications. When the laser light emitted by a PCESL is used for optical sensing, the PCSEL can be used as a light source for lidar, fiber optic sensing, and optical gas sensors. When the laser light emitted by a PCESL is used for optical displays, the PCSEL can be used as a light source for heads-up displays (HUDs), augmented reality (AR), virtual reality (VR), and mixed reality (MR). Furthermore, the laser light emitted by a PCSEL can be used for lighting, laser processing, and atomic clock light sources. For example, the PCSEL can be used as a light source for automotive headlights.

[0075] The laser light emitted by the PCSEL provided in the embodiments of the present application has a relatively high power. Therefore, there is no need for an optical amplifier to amplify the laser light, thereby reducing the cost and power consumption of the device in which the PCSEL is located. Furthermore, the laser light emitted by the PCSEL itself has a narrow divergence angle. Therefore, there is no need for a beam shaping device (such as a complex lens system) to shape and collimate the laser light emitted by the PCSEL. Therefore, the size of the device in which the PCSEL is located can be reduced. In addition, laser light with high power and narrow divergence angle can support a longer detection distance and higher resolution.

[0076] For example, when PCSEL is used as a light source for optical communication, as shown in Figure 11, PCSEL can be part of an optical transmitter. After the laser emitted by the PCSEL is modulated into an optical signal by the modulator, it is coupled to the optical fiber through a coupler and can be transmitted to the optical receiver through an optical splitter on the optical fiber. The modulator can modulate the optical signal based on the electrical signal, and the electrical signal can be a 50 GHz non-return to zero code (not return to zero, NRZ), and the modulation bandwidth can be 30 GHz. After that, the optical signal is converted into an electrical signal in the photoelectric converter (avalanche photodiode, APD) in the optical receiver. After the electrical signal is amplified by an electrical signal amplifier (trans-impedance amplifier, TIA), it is demodulated at the decider. The PCSEL provided in the embodiment of the present application has the advantage of reducing cost / power consumption by about two times compared to the non-PCSEL light source used in optical communication in the related art.

[0077] As another example, when the PCSEL is used as a light source for optical communication, as shown in FIG12 , the PCSEL can be used as a co-packaged optics (CPO) light source. The laser emitted by the PCSEL is transmitted to each CPO module after passing through the optical splitter. FIG12 takes 8 CPO modules as an example. The power of the laser emitted by the PCSEL can be greater than 400 milliwatts, and the divergence angle of the laser can be less than 1°. Compared with the CPO light source in the related art, the PCSEL provided in the embodiment of the present application has the advantages of high power, no need for an optical amplifier, narrow divergence angle, no need for a beam shaping device, high coupling efficiency with optical fiber, and more CPOs supported (more than twice).

[0078] As another example, when a PCSEL is used as a light source for optical communication, as shown in FIG13 , the PCSEL can be used as a wireless free space optical communication (FSO) light source. The laser emitted by the PCSEL is modulated by a wireless signal and then converted into an electrical signal by a photoelectric converter, which is then demodulated by a demodulator. The power of the laser emitted by the PCSEL can be approximately 1 watt, and the divergence angle of the laser can be less than 1°. Compared with the FSO light source in the related art, the PCSEL provided in the embodiment of the present application has the advantages of high power, no need for an optical amplifier, a narrow divergence angle, and no need for a beam shaping device.

[0079] As another example, when the laser emitted by the PCSEL is used for light perception, the PCSEL can be used as a laser radar light source. As shown in Figure 14, the laser emitted by the PCSEL can be output after passing through a scanner. The scanner is used to change the transmission direction of the laser. The power of the laser emitted by the PCSEL can be about 100 milliwatts, and the divergence angle of the laser can be less than 1°. Compared with the non-PCSEL light source used in the laser radar in the related art, the PCSEL provided in the embodiment of the present application has the advantages of narrow divergence angle, high transmission power, no need for optical amplifier, and small size of the laser radar.

[0080] As another example, when a PCSEL is used as a laser processing light source, the PCSEL provided by the embodiment of the present application has advantages such as not requiring a shaping lens system compared to non-PCSEL light sources used in laser processing in related technologies.

[0081] For example, when PCSEL is used as an array light source for face recognition, AR gestures, etc., the PCSEL provided in the embodiment of the present application has the advantages of high power, narrow divergence angle, support for a longer detection distance and higher resolution compared to the non-PCSEL light source used in the array light source in the related art.

[0082] Furthermore, the materials of the various film layers in the PCSEL provided in the embodiments of the present application can be set as needed. The PCSEL shown in FIG. 6 is used as an example to illustrate the materials of these film layers. As shown in FIG. 6 , the first electrode layer 101 and the second electrode layer 106 can both be made of metal materials, such as gold, silver, or copper. The first substrate 109 and the second substrate 110 can be made of materials such as indium phosphide (InP), gallium arsenide (GaAs), or silicon (Si). The first cladding layer 102 and the second cladding layer 105 can be made of materials such as indium phosphide, indium gallium arsenide (InGaAs), or gallium arsenide. The first active layer 107 and the second active layer 108 can be made of materials such as indium phosphide, indium gallium arsenide, or gallium arsenide. The first buffer layer 111 and the second buffer layer 112 can be made of materials such as indium phosphide, indium gallium arsenide, or aluminum indium gallium arsenide (InAlGaAs). The first photonic crystal layer 103 and the second photonic crystal layer 104 can be made of materials such as aluminum indium gallium arsenide, indium gallium arsenide, or gallium arsenide.

[0083] The present invention also provides a method for preparing a PCSEL, which is used to prepare any of the PCSELs provided in the present invention (the PCSEL shown in FIG6 ). As shown in FIG15 , the preparation method includes:

[0084] S1501, preparing a first structure, the first structure comprising a first electrode layer, a first cladding layer, and a first photonic crystal layer arranged in sequence, and the first photonic crystal layer is the last film layer prepared in the first structure;

[0085] S1502. Prepare a second structure, where the second structure includes a second electrode layer, a second cladding layer, and a second photonic crystal layer arranged in sequence, and the second photonic crystal layer is the last film layer prepared in the second structure; the first structure includes a first active layer, and / or the second structure includes a second active layer; the first active layer is located between the first cladding layer and the first photonic crystal layer, and the second active layer is located between the second cladding layer and the second photonic crystal layer.

[0086] S1503 , bonding the first photonic crystal layer and the second photonic crystal layer to obtain a PCSEL.

[0087] Optionally, the first surface of the first photonic crystal layer has a first alignment mark, and the second surface of the second photonic crystal layer has a second alignment mark. In S1503, the first surface of the first photonic crystal layer can be bonded to the second surface of the second photonic crystal layer so that the first alignment mark and the second alignment mark overlap.

[0088] Optionally, the first structure further includes a first substrate, and the second structure further includes a second substrate. The first substrate is located between the first electrode layer and the first cladding layer, and the second substrate is located between the second electrode layer and the second cladding layer.

[0089] The preparation method of the PCSEL provided in the embodiments of the present application can refer to the relevant description in the aforementioned PCSEL embodiments, and the embodiments of the present application will not be described in detail here.

[0090] Furthermore, an embodiment of the present application also provides an optical module, as shown in FIG16 , which includes a controller 1601 and any one of the PCSELs 1602 provided in the embodiment of the present application (such as the PCSEL shown in FIG6 ). Controller 1601 is connected to PCSEL 1602 and is used to control PCSEL 1602 to emit laser light.

[0091] The PCSEL can also include other structures besides the controller and PCSEL. For example, when the laser light emitted by the PCSEL is used for optical communication, the optical module can also include a modulator, an electrical signal processor, and an optoelectronic converter. The modulator is used to modulate the laser light emitted by the PCSEL according to the modulated electrical signal to generate an optical signal. This optical signal can be transmitted to other devices via optical fiber for communication. In addition, the optoelectronic converter can receive the optical signal transmitted on the optical fiber, convert it into an electrical signal, and transmit it to the electrical signal processor, which processes the electrical signal.

[0092] The present application also provides an optical device, as shown in FIG17 . The optical device includes a power supply module 1701 and an optical module 1702 provided in the present application. The power supply module 1701 is configured to supply power to the optical module 1702. The power supply module may be a battery or a charger. The optical device may also include components other than the power supply module and the optical module, such as a housing.

[0093] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "at least one" refers to one or more, and "a plurality" refers to two or more, unless otherwise expressly defined.

[0094] The various different types of embodiments provided in the embodiments of this application can be referenced with each other, and the embodiments of this application are not limited thereto. In the corresponding embodiments provided in this application, it should be understood that the disclosed PCSEL, optical module, optical device, etc. can be implemented through other configurations. In the corresponding embodiments provided in this application, it should be understood that the disclosed structure can be implemented through other configurations. For example, the embodiments described above are merely illustrative.

[0095] The above are merely optional embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A photonic crystal surface emitting laser PCSEL, characterized in that: include: a first electrode layer, a first cladding layer, a first photonic crystal layer, a second photonic crystal layer, a second cladding layer, a second electrode layer, and at least one active layer of the first active layer and the second active layer; The first electrode layer, the first cladding, the first photonic crystal layer, the second photonic crystal layer, the second cladding and the second electrode layer are arranged in sequence, the first active layer is located between the first cladding and the first photonic crystal layer, and the second active layer is located between the second cladding and the second photonic crystal layer; the first photonic crystal layer is bonded to the second photonic crystal layer.

2. The PCSEL according to claim 1, wherein: The first photonic crystal layer and the second photonic crystal layer form a single-side radiation guided mode resonance (UGR) structure.

3. The PCSEL according to claim 2, wherein: The first photonic crystal layer has a plurality of first through holes arranged in an array, and the second photonic crystal layer has a plurality of second through holes arranged in an array; An included angle between a row direction of the first through holes and a row direction of the second through holes is greater than zero and not equal to 90 degrees.

4. The PCSEL according to claim 2, wherein: The first photonic crystal layer has a plurality of first through holes arranged in an array, and the second photonic crystal layer has a plurality of second through holes arranged in an array; The diameter of the circumscribed circle of the opening surface of the first through hole is smaller than the diameter of the circumscribed circle of the opening surface of the second through hole.

5. The PCSEL according to claim 4, wherein: The plurality of first through holes correspond to the plurality of second through holes on a one-to-one basis, and the first through holes are communicated with the corresponding second through holes.

6. The PCSEL according to any one of claims 1 to 5, characterized in that: The material of the first photonic crystal layer is the same as the material of the second photonic crystal layer.

7. The PCSEL according to any one of claims 1 to 5, characterized in that: The material of the first photonic crystal layer is different from the material of the second photonic crystal layer.

8. The PCSEL according to any one of claims 1 to 7, wherein: The PCSEL further includes a first substrate and a second substrate. The first substrate is located between the first electrode layer and the first cladding layer, and the second substrate is located between the second electrode layer and the second cladding layer.

9. The PCSEL according to any one of claims 1 to 8, wherein: A first surface of the first photonic crystal layer close to the second photonic crystal layer has a first alignment mark, and a second surface of the second photonic crystal layer close to the first photonic crystal layer has a second alignment mark; the first alignment mark and the second alignment mark overlap.

10. A method for preparing a photonic crystal surface emitting laser (PCSEL), characterized in that: For preparing the PCSEL according to any one of claims 1 to 9, the method comprises: Prepare a first structure, wherein the first structure includes a first electrode layer, a first cladding layer, and a first photonic crystal layer arranged in sequence, and the first photonic crystal layer is the last film layer prepared in the first structure; Prepare a second structure, the second structure comprising a second electrode layer, a second cladding layer, and a second photonic crystal layer arranged in sequence, the second photonic crystal layer being the last film layer prepared in the second structure; the first structure comprising a first active layer, and / or the second structure comprising a second active layer; the first active layer being located between the first cladding layer and the first photonic crystal layer, and the second active layer being located between the second cladding layer and the second photonic crystal layer; The first photonic crystal layer and the second photonic crystal layer are bonded to obtain the PCSEL.

11. The method according to claim 10, characterized in that The first surface of the first photonic crystal layer has a first alignment mark, and the second surface of the second photonic crystal layer has a second alignment mark; Bonding the first photonic crystal layer to the second photonic crystal layer includes: The first surface of the first photonic crystal layer is bonded to the second surface of the second photonic crystal layer so that the first alignment mark and the second alignment mark overlap.

12. The method according to claim 10 or 11, characterized in that The first structure further includes a first substrate, and the second structure further includes a second substrate. The first substrate is located between the first electrode layer and the first cladding layer, and the second substrate is located between the second electrode layer and the second cladding layer.

13. An optical module, characterized in that: include: A controller and a PCSEL according to any one of claims 1 to 9; wherein the driver is used to control the PCSEL to emit laser light.

14. An optical device, characterized in that: include: A power supply module and the optical module according to claim 13, wherein the power supply module is used to supply power to the optical module.

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