Bent waveguide face emitting semiconductor laser

Abstract

The application relates to a curved waveguide surface-emitting semiconductor laser. The curved waveguide surface-emitting semiconductor laser comprises, in sequence, an upper cladding layer, an upper waveguide layer, an active layer, a lower waveguide layer and a lower cladding layer, the active layer emits light when carriers are injected into the active layer, at least one of the upper cladding layer, the upper waveguide layer, the active layer, the lower waveguide layer and the lower cladding layer is a curved waveguide structure with a spatially coiled expansion feature, the curved waveguide structure has an extension path composed of circular arcs with different radii of curvature and / or circular arcs with different centers; and the curved waveguide surface-emitting semiconductor laser further comprises a second-order or higher-order periodic optical modulation layer, which is located in at least one of the upper cladding layer, the upper waveguide layer, the lower waveguide layer and the lower cladding layer in the curved waveguide structure, and the period of the optical modulation layer is designed to meet the Bragg diffraction condition to realize surface emission. The curved waveguide surface-emitting semiconductor laser can maintain single-mode output while increasing the device area, and realizes high-power and high-brightness laser output.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor lasers, in particular to a curved waveguide surface-emitting semiconductor laser. BACKGROUND

[0002] In the field of semiconductor lasers, it has been an important research direction to realize high-power and high-brightness laser output. In the traditional technology, grating-coupled surface-emitting lasers (GCSELs) and photonic crystal surface-emitting lasers (PCSELs) use flat waveguide structures to limit the light field to a single mode in the z direction, and use grating / photonic crystal structures to generate z-direction diffraction components to realize surface emission.

[0003] For PCSELs, a double-lattice structure is used to reduce the in-plane feedback. However, this scheme has an upper limit on the size of the device, and the larger the device area, the smaller the threshold gain difference between the fundamental mode and the high-order mode, i.e., it is more difficult to maintain single-mode emission at a large size. For wide GCSELs, the device technology is relatively mature due to the proximity to the F-P structure, but due to the long strip-shaped structure, the far field of surface emission is eye-shaped, the divergence angle in the strip width direction is large, and an optical system needs to be set at the back end for shaping.

[0004] Therefore, how to increase the device area while maintaining single-mode output and realizing high-power and high-brightness laser output is a technical problem that needs to be solved in the field. SUMMARY

[0005] Therefore, it is necessary to provide a curved waveguide surface-emitting semiconductor laser that can increase the device area while maintaining single-mode output, improve heat dissipation performance, and realize high-power and high-brightness laser output.

[0006] A curved waveguide surface-emitting semiconductor laser includes an upper cladding layer, an upper waveguide layer, an active layer, a lower waveguide layer, and a lower cladding layer arranged in sequence, the active layer emits light when carriers are injected into the active layer, at least one of the upper cladding layer, the upper waveguide layer, the active layer, the lower waveguide layer, and the lower cladding layer is a curved waveguide structure having a spatially coiled expansion feature, the curved waveguide structure has an extension path composed of circular arcs with different radii of curvature and / or circular arcs with different centers.

[0007] The curved waveguide surface-emitting semiconductor laser further includes a second-order or higher-order periodic optical modulation layer, the optical modulation layer is located in at least one of the upper cladding layer, the upper waveguide layer, the lower waveguide layer, and the lower cladding layer in the curved waveguide structure, and the period of the optical modulation layer is designed to satisfy the Bragg diffraction condition to realize surface emission.

[0008] The curved waveguide surface emitting semiconductor laser can maintain single-mode output while increasing the device area, and realizes high-power and high-brightness laser output.

[0009] (1) Mode control can be simplified. Since it is a curved waveguide structure, the physical model of the device is similar to a one-dimensional waveguide device, avoiding the problem that PCSEL needs to control the coupling in x-y two directions to realize single-mode lasing. Therefore, only the in-plane feedback strength of the grating / photonic crystal needs to be controlled, which is more conducive to the fundamental mode surface emission of large-size devices.

[0010] (2) It is conducive to heat dissipation of large-size devices. Compared with PCSEL, the electric injection area of the high-power device is lower, which is conducive to heat lateral diffusion and better heat dissipation.

[0011] (3) Reduce the influence of non-uniformity of epitaxial wafer material on the device. Semiconductor lasers usually use MOCVD equipment for material epitaxial growth, which is affected by the airflow field and temperature field. The material components grown in different areas of the epitaxial wafer have certain deviations, resulting in different refractive indexes and different light emitting wavelengths, which limits the length of the long strip-shaped laser cavity. By setting the curved waveguide structure, a longer and higher-power laser can be made in a relatively uniform area.

[0012] In one of the embodiments, the curved waveguide structure includes the upper cladding layer, the upper waveguide layer, the active layer, the lower waveguide layer and the lower cladding layer.

[0013] In one of the embodiments, the extension path of the curved waveguide structure is spiral.

[0014] In one of the embodiments, the width of the curved waveguide structure is D, and the minimum curvature radius of the curved waveguide structure is R, and R / D is greater than or equal to 10.

[0015] In one of the embodiments, the optical modulation layer is a grating structure or a hole structure.

[0016] In one of the embodiments, the grating structure is a second-order grating, and the hole structure is a second-order hole.

[0017] In one of the embodiments, along the width direction of the curved waveguide structure, the grating structure penetrates through the curved waveguide structure.

[0018] In one of the embodiments, the basic unit of the grating structure is a long strip, a triangle or a trapezoid, and the basic unit of the hole structure is a circle, an isosceles triangle, an equilateral triangle, a double-hole structure, etc.

[0019] In one embodiment, the curved waveguide structure has at least two ends.

[0020] In one embodiment, the curved waveguide structure is a closed structure.

[0021] In one embodiment, the curved waveguide structure comprises a seed light generating structure and a curved waveguide light amplifying structure.

[0022] In one embodiment, the seed light generating structure has a first order grating or a first order hole at both ends.

[0023] In one embodiment, the curved waveguide surface emitting semiconductor laser further comprises an upper electrode, which is located on the side of the upper cladding layer away from the upper waveguide layer, and is offset from the center of the curved waveguide structure and disposed on the outer edge of the curved waveguide structure. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 FIG. 1 is a cross-sectional view of a curved waveguide surface emitting semiconductor laser according to an embodiment of the present application;

[0025] Figure 2 FIG. 2 is a schematic view of a spiral-shaped curved waveguide of a curved waveguide surface emitting semiconductor laser according to an embodiment of the present application;

[0026] Figure 3 FIG. 3 is a schematic view of a second order grating of a curved waveguide surface emitting semiconductor laser according to an embodiment of the present application;

[0027] Figure 4 FIG. 4 is a schematic view of a second order hole of a curved waveguide surface emitting semiconductor laser according to an embodiment of the present application;

[0028] Figure 5 FIG. 5 is a closed curved waveguide of a curved waveguide surface emitting semiconductor laser according to an embodiment of the present application;

[0029] Figure 6 (a) FIG. 6 is a schematic view of a curved waveguide surface emitting semiconductor laser according to an embodiment of the present application, which comprises a master oscillator power amplifier structure;

[0030] Figure 6 (b) FIG. 7 is a schematic view of a curved waveguide surface emitting semiconductor laser according to another embodiment of the present application, which comprises a master oscillator power amplifier structure;

[0031] Figure 7 FIG. 8 is a distribution of an electric field along the width direction of a waveguide at different bending radii in a curved waveguide surface emitting semiconductor laser according to an embodiment of the present application;

[0032] Figure 8FIG. 1 is a cross-sectional view of a bent waveguide surface emitting semiconductor laser according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the above objects, features and advantages of the present application more clear, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art, that the present application can be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present application. The purpose of the above-mentioned description and specific embodiments is to describe and explain the present application in detail. The present application is not limited to the specific embodiments described herein, but is only limited by the claims.

[0034] It is understood that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it is understood that when an element is referred to as being "connected to" another element, it can be directly connected to the other element or intervening elements can also be present. As used herein the terms "vertical", "horizontal", "left", "right" and the like are merely used for the purpose of explanation and are not intended to limit the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0036] Referring to Figure 1 and Figure 2 A bent waveguide surface emitting semiconductor laser 100 according to an embodiment of the present application includes an upper cladding layer 110, an upper waveguide layer 120, an active layer 130, a lower waveguide layer 140, and a lower cladding layer 150, which are sequentially arranged, i.e., an epitaxial layer includes the upper cladding layer 110, the upper waveguide layer 120, the active layer 130, the lower waveguide layer 140, and the lower cladding layer 150. The epitaxial layer structure forms a horizontal cavity, and most of the laser light field energy is confined in the upper waveguide layer 120, the active layer 130, and the lower waveguide layer 140. When carriers are injected into the active layer 130, the active layer 130 emits light.

[0037] In the bent waveguide surface emitting semiconductor laser 100, at least one of the upper cladding layer 110, the upper waveguide layer 120, the active layer 130, the lower waveguide layer 140, and the lower cladding layer 150 is a bent waveguide structure having a spatially meandering extension feature, and the bent waveguide structure has an extension path composed of a combination of circular arcs having different radii of curvature and / or different centers.

[0038] Wherein, at least one of the upper cladding layer 110, upper waveguide layer 120, active layer 130, lower waveguide layer 140, and lower cladding layer 150 refers to any one or any two or more of the upper cladding layer 110, upper waveguide layer 120, active layer 130, lower waveguide layer 140, and lower cladding layer 150 being a curved waveguide structure. Preferably, along the thickness direction, the structure of the 1st to nth layers is a curved waveguide structure, where n is an integer less than or equal to 5. Specifically, in the direction from the upper cladding 110 to the lower cladding 150, when n is 1, the upper cladding 110 is a curved waveguide structure; when n is 2, the upper cladding 110 and the upper waveguide layer 120 are curved waveguide structures as a whole; when n is 3, the upper cladding 110, the upper waveguide layer 120, and the active layer 130 are curved waveguide structures as a whole; when n is 4, the upper cladding 110, the upper waveguide layer 120, the active layer 130, and the lower waveguide layer 140 are curved waveguide structures as a whole; and when n is 5, the upper cladding 110, the upper waveguide layer 120, the active layer 130, the lower waveguide layer 140, and the lower cladding 150 are curved waveguide structures as a whole. Alternatively, from the direction of the lower cladding 150 to the upper cladding 110, when n is 1, the lower cladding 150 is a curved waveguide structure; when n is 2, the lower waveguide layer 140 and the lower cladding 150 are curved waveguide structures as a whole; when n is 3, the active layer 130, the lower waveguide layer 140 and the lower cladding 150 are curved waveguide structures as a whole; when n is 4, the upper waveguide layer 120, the active layer 130, the lower waveguide layer 140 and the lower cladding 150 are curved waveguide structures as a whole; when n is 5, the upper cladding 110, the upper waveguide layer 120, the active layer 130, the lower waveguide layer 140 and the lower cladding 150 are curved waveguide structures as a whole.

[0039] The extension path of the curved waveguide structure can be composed of arcs with different radii of curvature, arcs with different centers, or arcs with different centers and different radii of curvature.

[0040] The curved waveguide surface-emitting semiconductor laser 100 of this embodiment further includes a second-order or higher-order periodic optical modulation layer. The optical modulation layer is located in at least one of the upper cladding layer 110, upper waveguide layer 120, lower waveguide layer 140 and lower cladding layer 150 in the curved waveguide structure, and the periodic design of the optical modulation layer satisfies the Bragg diffraction condition to achieve surface emission.

[0041] Among them, the curved waveguide structure has spatial winding and expansion characteristics, which can increase the waveguide cavity length and increase the device size within a limited wafer size.

[0042] The optical modulation layer is made in a direction perpendicular to the curved waveguide structure, which forms a band edge / defect mode on the curved waveguide structure and produces a diffraction component in a direction perpendicular / inclined to the epitaxial layer to realize surface emission. The band edge / defect mode formed in the cavity length direction is a fundamental mode, i.e., the near field is a fundamental mode. By using the curved waveguide structure, the device size is increased, and the output power is increased, so that the application can realize high-power surface emission.

[0043] The curved waveguide surface emission semiconductor laser can maintain single-mode output while increasing the device area, and realize high-power and high-brightness laser output.

[0044] The curved waveguide structure of the embodiment can obtain the largest possible light-emitting area in a limited area by coiling. Figure 1 Taking the spiral-shaped curved waveguide structure as an example, the waveguide width is D, and the distance between adjacent curved waveguides is G. The light-emitting area is the electrical injection area, i.e., the area where the waveguide width is located. The ratio of the distance G and the width D is controlled, the larger the G / D is, the smaller the light-emitting area ratio is, and at the same time, the more the heat is laterally diffused through the heat sink, and the better the heat dissipation of the device is.

[0045] On the basis of the foregoing embodiment, the curved waveguide structure includes an upper cladding layer 110, an upper waveguide layer 120, an active layer 130, a lower waveguide layer 140, and a lower cladding layer 150. In the embodiment, the upper cladding layer 110, the upper waveguide layer 120, the active layer 130, the lower waveguide layer 140, and the lower cladding layer 150 are all curved waveguide structures. The refractive index difference between the semiconductor material and air can be fully utilized to confine the optical field. It should be noted that the curved waveguide structure of the application is not limited to this. In a feasible embodiment, the upper cladding layer 110 is a curved waveguide structure; in a feasible embodiment, the upper cladding layer 110 and the upper waveguide layer 120 are curved waveguide structures; in a feasible embodiment, the upper cladding layer 110, the upper waveguide layer 120, and the active layer 130 are curved waveguide structures; in a feasible embodiment, the upper cladding layer 110, the upper waveguide layer 120, the active layer 130, and the lower waveguide layer 140 are curved waveguide structures; in a feasible embodiment, the lower cladding layer 150 is a curved waveguide structure; in a feasible embodiment, the lower waveguide layer 140 and the lower cladding layer 150 are curved waveguide structures; in a feasible embodiment, the active layer 130, the lower waveguide layer 140, and the lower cladding layer 150 are curved waveguide structures; in a feasible embodiment, the upper waveguide layer 120, the active layer 130, the lower waveguide layer 140, and the lower cladding layer 150 are curved waveguide structures.

[0046] On the basis of the foregoing embodiment, the extension path of the curved waveguide structure is spiral-shaped, as shown in Figure 1As shown. In this embodiment, a helical curved waveguide structure composed of arcs with a radius of curvature R1 is used. The width of the curved waveguide structure is D, and the two ends are T1 and T2, with a spacing of G. To prevent light leakage from the two ends T1 and T2, a reflective film can be deposited on the end faces of T1 and T2, or a first-order grating structure of DFB (distributed feedback laser) or DBR (distributed Bragg reflector laser) can be fabricated on the T1 and T2 segments. Preferably, the first-order grating / aperture structure is fabricated on T1 and T2, which can be carried out simultaneously with the second-order or higher-order grating / aperture fabrication.

[0047] Based on the aforementioned implementation, the width of the curved waveguide structure is D, the minimum radius of curvature of the curved waveguide structure is R, and R / D is greater than or equal to 10. Controlling the minimum value of the radius of curvature R1 of the curved waveguide makes the optical field Gaussian distributed or with less oscillation, and reduces the intensity of the optical field at the outer edge, resulting in excessive leakage and increased loss.

[0048] Based on the aforementioned embodiments, the optical modulation layer is a grating structure or a hole structure.

[0049] Based on the aforementioned implementation method, the grating structure is a second-order grating, and the aperture structure is a second-order aperture. The second-order grating is as follows... Figure 3 As shown, the width of the second-order grating in the waveguide direction is w, and the spacing period is a. The second-order aperture is as follows: Figure 4 As shown, the photonic crystals are spaced by 'a' along the waveguide direction and by 'b' perpendicular to the waveguide direction. A periodic grating structure with period 'a' is fabricated on the substrate material. According to the Bragg diffraction condition, Let λ be the wavelength of light, neff be the effective refractive index, i be a positive integer, and θ be the angle between the wavefront and the junction plane. When a = λ / neff, it is a second-order grating, and the scattered light, being perpendicular to the propagation direction of the incident light, also satisfies Bragg diffraction. Therefore, second-order and higher-order gratings can achieve surface emission.

[0050] Based on the aforementioned implementation, the grating structure penetrates the curved waveguide structure along its width direction, such as... Figure 3 As shown.

[0051] Based on the aforementioned implementation methods, the basic unit of the grating structure is a strip, a triangle, or a trapezoid, such as... Figure 3 As shown, these shaped grating structures can break the front-to-back symmetry along the curved waveguide direction to improve the emission coefficient and increase the surface emission efficiency; the basic unit of the aperture structure is a circle, an isosceles triangle, an equilateral triangle, or a double-aperture structure, etc. Figure 4As shown, a and b can be equal or unequal. For the shape of the hole, isosceles triangle, equilateral triangle, round hole + elliptical hole, round hole + rectangular hole, etc., are preferred. For a dual-hole structure of round hole + elliptical hole, or round hole + rectangular hole, the center of the round hole is preferably spaced 0.25a from the center of the elliptical / rectangular hole to reduce in-plane feedback, which is beneficial for single-mode lasing in large sizes.

[0052] Based on the aforementioned embodiments, the curved waveguide structure has at least two ends. For a closed curved waveguide structure, the grating or photonic crystal structure consists of a grating / photonic crystal with a period of a. Preferably, a 0.25a defect (i.e., no grating) is introduced into the periodic grating or photonic crystal structure to form a defect mode, such that the device outputs laser light at a single frequency.

[0053] Based on the aforementioned implementation method, the bent waveguide structure is a closed structure, such as... Figure 5 As shown, where Figure 5 The given structural diagram simplifies the width of the curved waveguide structure. Specifically, Figure 5 The lines in the diagram represent the curved waveguide structure. Under uniform electrical injection, the second-order grating / aperture structure creates uniform in-plane feedback, resulting in a uniform optical field distribution along the curved waveguide.

[0054] Based on the aforementioned embodiments, the curved waveguide structure includes a seed light generation structure ( Figure 6 The invention employs a master oscillator power amplifier (MO) and a bent waveguide optical amplification structure. Leveraging the advantages of the MOPA structure in single-mode laser output, a "seed light" generation segment can be introduced into the bent waveguide structure. This "seed light" is connected to the bent waveguide, which amplifies the mode of the "seed light." Simultaneously, the second-order grating / aperture structure generates vertical diffraction, achieving surface emission. The preferred structure of the "MO" is a first-order grating at both ends. Figure 6 (a) shows the “MO” structure, where the number of first-order gratings on the left end is greater than that on the right end, so that the “seed light” can enter the curved waveguide section from the right end, while avoiding light leakage from the left end. Figure 6 (b) shows the “MO” structure, where the first-order grating structures at both ends are identical. By controlling the number of first-order gratings, “seed light” can enter the left and right curved waveguides respectively. This structure is suitable for large-size devices, resulting in a large difference in threshold gain between the fundamental mode and higher-order modes.

[0055] Based on the aforementioned implementation method, the two ends of the seed light-generating structure are first-order gratings or first-order holes.

[0056] In one feasible implementation, the width D of the fixed curved waveguide structure is 5 μm, and the bending radius R1 is changed to obtain the electric field distribution along the width of the waveguide, as shown below. Figure 7As shown. When R1 is 5 μm, 10 μm, the electric field distribution oscillates more. When R1 is 50 μm, i.e. R1 / D=10, the electric field oscillates less. When R1 is 100 μm, 500 μm, the electric field distribution is more uniform. From the above, it can be seen that the electric field distribution of the curved waveguide deviates from the center position and leans to the outside. Figure 7

[0057] On the basis of the foregoing embodiment, the curved waveguide surface-emitting semiconductor laser further comprises an upper electrode 160 and a lower electrode 170, as shown. Figure 2 The upper electrode 160 is located on the side of the upper cladding layer 110 away from the upper waveguide layer 120, and the lower electrode 170 is located on the side of the lower cladding layer 150 away from the lower waveguide layer 140. In this embodiment, the upper electrode 160 is located at the center position of the curved waveguide structure, and the lower electrode 170 deviates from the center position of the curved waveguide structure and is arranged at the outer edge of the curved waveguide structure.

[0058] In addition, it should be noted that the position of the upper electrode in the curved waveguide surface-emitting semiconductor laser of the present application is not limited to the above embodiment.

[0059] Please refer to Figure 8 The curved waveguide surface-emitting semiconductor laser 200 of another embodiment of the present application comprises an upper cladding layer 210, an upper waveguide layer 220, an active layer 230, a lower waveguide layer 240 and a lower cladding layer 250 arranged in sequence, i.e. the epitaxial layer comprises the upper cladding layer 210, the upper waveguide layer 220, the active layer 230, the lower waveguide layer 240 and the lower cladding layer 250. The epitaxial layer structure forms a horizontal cavity, and most of the laser light field energy is confined in the upper waveguide layer 220, the active layer 230 and the lower waveguide layer 240. When carriers are injected into the active layer 230, the active layer 230 emits light.

[0060] At least one of the upper cladding layer 210, the upper waveguide layer 220, the active layer 230, the lower waveguide layer 240 and the lower cladding layer 250 is a curved waveguide structure with a spatially coiled expansion feature, and the curved waveguide structure has an extension path composed of circular arcs with different radii of curvature and / or circular arcs with different centers.

[0061] In this embodiment, the curved waveguide surface-emitting semiconductor laser 200 further comprises a second-order or higher-order periodic optical modulation layer, which is located in at least one of the upper cladding layer 210, the upper waveguide layer 220, the lower waveguide layer 240 and the lower cladding layer 250 in the curved waveguide structure, and the period of the optical modulation layer is designed to satisfy the Bragg diffraction condition to realize surface emission.

[0062] ​The curved waveguide surface emitting semiconductor laser 200 of the embodiment further comprises an upper electrode 260 and a lower electrode 270, wherein the upper electrode 260 is located on the side of the upper cladding layer 210 away from the upper waveguide layer 220, and the upper electrode 260 is offset from the central position of the curved waveguide structure and is arranged at the outer edge of the curved waveguide structure.

[0063] The embodiment considers that the curved waveguide structure causes the light field distribution to be offset from the central position, and thus the position of the upper electrode is preferably close to the outer edge of the curve and offset from the central position of the curved waveguide structure, so that the gain region of the electrical injection is matched with the light field distribution.

[0064] The curved waveguide surface emitting semiconductor laser of the technical scheme can maintain single-mode output while increasing the device area, and realizes high-power and high-brightness laser output. The beneficial effects are as follows:

[0065] (1) Mode control can be simplified. Since it is a curved waveguide structure, the physical model of the device is equivalent to a one-dimensional waveguide device, which avoids the problem that PCSEL needs to control the coupling in the x-y two directions to realize single-mode lasing. Therefore, only the in-plane feedback strength of the grating / photonic crystal needs to be controlled, which is more conducive to the fundamental mode surface emission of large-size devices.

[0066] (2) It is conducive to heat dissipation of large-size devices. Compared with PCSEL, the electrical injection region of the high-power device is lower, which is conducive to the lateral diffusion of heat and can better dissipate heat.

[0067] (3) Reduces the influence of non-uniformity of epitaxial wafer material on the device. Semiconductor lasers usually use MOCVD equipment for material epitaxial growth, and are affected by the airflow field and temperature field. The material components grown in different regions of the epitaxial wafer have certain deviations, resulting in different refractive indexes and different light emitting wavelengths, which limits the length of the long strip-shaped laser cavity. By arranging the curved waveguide structure, a laser with a longer length and a larger output power can be made in a relatively uniform region.

[0068] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered as within the scope of the present disclosure.

[0069] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A bend waveguide surface emitting semiconductor laser comprising, in order, an upper clad layer, an upper waveguide layer, an active layer, a lower waveguide layer, and a lower clad layer, the active layer emitting light when carriers are injected into the active layer, characterized in that, At least one of the upper cladding layer, the upper waveguide layer, the active layer, the lower waveguide layer and the lower cladding layer is a curved waveguide structure with a spatially coiled expansion feature, and the curved waveguide structure has an extension path composed of circular arcs with different radii of curvature and / or combinations of circular arcs with different centers; The curved waveguide surface-emitting semiconductor laser further comprises a second-order or higher-order periodic optical modulation layer, which is located in at least one of the upper cladding layer, the upper waveguide layer, the lower waveguide layer and the lower cladding layer in the curved waveguide structure, and the period of the optical modulation layer is designed to satisfy the Bragg diffraction condition to realize surface emission. The extension path of the curved waveguide structure is spiral-shaped.

2. The curved waveguide surface emitting semiconductor laser according to claim 1, characterized in that The curved waveguide structure comprises the upper cladding layer, the upper waveguide layer, the active layer, the lower waveguide layer and the lower cladding layer.

3. The curved waveguide surface emitting semiconductor laser according to claim 1, characterized in that The width of the curved waveguide structure is D, and the minimum radius of curvature of the curved waveguide structure is R, and R / D is greater than or equal to 10.

4. The curved waveguide surface-emitting semiconductor laser of claim 1, wherein, The optical modulation layer is a grating structure or a hole structure.

5. The curved waveguide surface emitting semiconductor laser according to claim 4, characterized in that The grating structure is a second-order grating, and the hole structure is a second-order hole.

6. The curved waveguide surface emitting semiconductor laser according to claim 4, characterized in that The grating structure extends through the curved waveguide structure in the width direction of the curved waveguide structure.

7. The curved waveguide surface emitting semiconductor laser according to any one of claims 4 to 6, characterized in that The basic unit of the grating structure is a long strip, a triangle or a trapezoid, and the basic unit of the hole structure is a circle, an isosceles triangle, an equilateral triangle or a double-hole structure.

8. The curved waveguide surface emitting semiconductor laser according to claim 1, characterized in that The curved waveguide structure has at least two end heads.

9. The curved waveguide surface emitting semiconductor laser according to claim 1, characterized in that The curved waveguide structure is a closed structure.

10. The curved waveguide surface emitting semiconductor laser according to claim 1, characterized in that The curved waveguide structure comprises a seed light generating structure and a curved waveguide optical amplification structure.

11. The curved waveguide surface emitting semiconductor laser according to claim 10, characterized in that The first-order grating or the first-order hole is located at both ends of the seed light generating structure.

12. The curved waveguide surface emitting semiconductor laser according to claim 1, characterized in that The curved waveguide surface-emitting semiconductor laser further comprises an upper electrode, which is located on the side of the upper cladding layer away from the upper waveguide layer, and is offset from the center position of the curved waveguide structure and arranged at the outer edge of the curved waveguide structure.

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