Single-mode semiconductor microcavity laser

Abstract

The invention provides a single-mode semiconductor microcavity laser. The laser comprises an N-type substrate; the echo wall microcavity is located on the N-type substrate, and the area of the echo wall microcavity is smaller than that of the N-type substrate; and the waveguide is arranged on the N-type substrate and is connected with the preset output end of the echo wall microcavity. According to the single-mode semiconductor microcavity laser, the mode field distribution of light can be regulated and controlled in the microcavity, stable and controllable single-mode lasing is finally obtained, the requirement of a coherent light communication system for a light source is met, and therefore large-capacity and long-distance data transmission is achieved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical communication and semiconductor lasers, and in particular to a single-mode semiconductor microcavity laser. Background Art

[0002] As a modern communication technology, optical communication has the advantages of faster transmission speed, larger bandwidth and better anti-interference performance. It has gradually replaced traditional electrical communication technology and has been widely used. As the light source of the optical communication system, semiconductor laser is one of the most important components. Single-mode laser is an ideal light source for coherent optical communication due to its good coherence and strong anti-interference ability. It can effectively meet the needs of modern communication for large-capacity and long-distance data transmission. At present, there are three main ways to achieve single-mode lasers: the first is to achieve single-mode lasing by reducing the size of the resonant cavity. Because the free spectral range (FSR) is inversely proportional to the length of the laser resonant cavity, reducing the size of the resonant cavity makes only one high-Q value mode exist in the gain spectrum range, thereby achieving single-mode lasing. However, this method is still difficult to prevent adjacent mode lasing for lasers with high gain bandwidth. The second is to introduce a periodic grating structure in the resonant cavity for mode selection, thereby achieving single-mode lasing, but this laser has a complex structure and has high requirements for the process preparation process. The third method is to utilize the vernier effect of the coupled cavity structure to couple two cavities of different structures or sizes together for mode selection to achieve single-mode lasing. However, this structure will increase the size of the laser cavity. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the above problems, the present disclosure provides a single-mode semiconductor microcavity laser to at least partially solve the technical problems of current single-mode lasers such as poor stability, complex structure, high preparation requirements and large laser cavity size.

[0005] (II) Technical solution

[0006] The present disclosure provides a single-mode semiconductor microcavity laser, comprising: an N-type substrate; a whispering gallery microcavity located on the N-type substrate, wherein the area of ​​the whispering gallery microcavity is smaller than that of the N-type substrate; and a waveguide disposed on the N-type substrate and connected to a preset output end of the whispering gallery microcavity.

[0007] According to an embodiment of the present disclosure, the whispering gallery microcavity includes: an N-type confinement layer disposed on the upper surface of the N-type substrate; an active layer disposed on the upper surface of the N-type confinement layer; and a P-type confinement layer disposed on the upper surface of the active layer.

[0008] According to an embodiment of the present disclosure, the whispering gallery microcavity is formed by the intersection of two arc-edged quadrilateral parts obtained by deforming a square.

[0009] According to an embodiment of the present disclosure, the waveguide includes: a first end face and a second end face; wherein the first end face is connected to a preset output end of the whispering gallery microcavity, and the second end face is a cleavage face, located at the other end where the waveguide is connected to the whispering gallery microcavity.

[0010] According to an embodiment of the present disclosure, the waveguide is a strip waveguide.

[0011] According to an embodiment of the present disclosure, the original square side lengths and arc-side deformation amounts of the two arc-side quadrilaterals are not equal, and the centers are a certain distance apart.

[0012] According to an embodiment of the present disclosure, it also includes: an N-side electrode, which is arranged on the lower surface of the N-type substrate and has the same shape and size as the N-type substrate; and a P-side electrode, which is arranged on the upper surface of the whispering gallery microcavity and has the same shape and size as the whispering gallery microcavity.

[0013] According to an embodiment of the present disclosure, the height of the whispering gallery microcavity is the same as the height of the waveguide.

[0014] According to an embodiment of the present disclosure, the sidewall of the whispering gallery microcavity is wrapped with a filling material, and the refractive index of the filling material is smaller than the refractive index of the whispering gallery microcavity.

[0015] According to an embodiment of the present disclosure, the deformation amounts of the two arc sides of the two arc-side quadrilaterals are and They are:

[0016]

[0017]

[0018] Among them, a1, a2, r1 and r2 represent the side length and arc radius of the original square of the two arc-sided quadrilaterals respectively.

[0019] (III) Beneficial effects

[0020] The single-mode semiconductor microcavity laser provided by the present invention can achieve the regulation of the mode field distribution of light in the microcavity by optimizing the shape structure of the whispering gallery microcavity, and finally obtain stable and controllable single-mode lasing, which meets the requirements of the coherent optical communication system for the light source, thereby realizing large-capacity and long-distance data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] For a more complete understanding of the present disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, in which:

[0022] Figure 1A schematic diagram of a three-dimensional structure of a single-mode semiconductor microcavity laser according to an embodiment of the present disclosure is shown;

[0023] Figure 2 A schematic diagram of a planar structure of a single-mode semiconductor microcavity laser according to an embodiment of the present disclosure is shown;

[0024] Figure 3 A diagram schematically shows a corresponding relationship between the quality factor (Q value) and the characteristic wavelength of a whispering gallery microcavity mode of a single-mode semiconductor microcavity laser according to an embodiment of the present disclosure;

[0025] Figure 4 Schematically showing the mode field distribution diagram of the fundamental mode and the first-order mode of a whispering gallery microcavity according to an embodiment of the present disclosure;

[0026] Figure 5 Schematically showing the quality factors of the fundamental mode and the first-order mode of the single-mode semiconductor microcavity laser according to the embodiment of the present disclosure and the corresponding diagram of the mode spacing of the fundamental mode and the first-order mode and the arc edge deformation;

[0027] Figure 6 The optical spectrum diagram of a single-mode semiconductor microcavity laser according to an embodiment of the present disclosure is schematically shown when the injection current is continuously changed from 0 to 100 mA at intervals of 1 mA;

[0028] Figure 7 Schematically shows a detailed spectrum diagram of a single-mode semiconductor microcavity laser according to an embodiment of the present disclosure when the injection current is 30mA, 50mA and 70mA;

[0029] Figure 8 The diagram schematically shows the change of the side mode suppression ratio when the injection current of a single-mode semiconductor microcavity laser according to an embodiment of the present disclosure changes continuously from 0 to 100 mA at intervals of 1 mA.

[0030] Description of reference numerals:

[0031] 1-N surface electrode;

[0032] 2-P surface electrode;

[0033] 3-N-type substrate;

[0034] 4- Whispering gallery microcavity;

[0035] 403-N type restriction layer;

[0036] 402-active layer;

[0037] 401-P type restriction layer;

[0038] 5- Waveguide;

[0039] 6- second end surface;

[0040] 7-the first arc-side quadrilateral;

[0041] 8- The second arc-sided quadrilateral. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0043] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0044] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0045] The inventor has found through research that in related technologies, with the development of the current 5G technology, the amount of data has shown an explosive growth trend, and traditional electrical communication technology can no longer meet the needs of daily life and production. Optical communication, as an alternative technology, has been proven to be the direction of future communication technology development. Optical communication uses photons as the carrier of information transmission, requiring the laser to be able to stably lasing for a long time to provide photons. However, due to its high gain bandwidth characteristics and the lack of mode selection ability of the resonant cavity itself, the laser tends to multi-mode lasing. In order to achieve single-mode lasing, special artificial design is required to perform mode control and suppress other modes. Therefore, in order to solve the above problems, the embodiments of the present disclosure provide a single-mode semiconductor microcavity laser with good stability, simple preparation and small size.

[0046] Figure 1 The three-dimensional structure diagram of a single-mode semiconductor microcavity laser according to an embodiment of the present disclosure is schematically shown.

[0047] like Figure 1 As shown, the single-mode semiconductor microcavity laser includes: an N-side electrode 1, a P-side electrode 2, an N-type substrate 3, a whispering gallery microcavity 4 and a waveguide 5.

[0048] In the embodiment of the present disclosure, the N-side electrode 1 is disposed on the lower surface of the N-type substrate 3, i.e., the bottom of the semiconductor microcavity laser, and its shape and size are the same as the N-type substrate 3. The N-side electrode 1 is connected to an external circuit for carrier injection.

[0049] The P-surface electrode 2 is disposed on the upper surface of the whispering gallery microcavity 4, i.e., the top of the single-mode semiconductor microcavity laser, and its shape and size are the same as those of the whispering gallery microcavity 4. The P-surface electrode 2 is connected to an external circuit to achieve uniform electrical injection into the laser, i.e., inject current into the whispering gallery microcavity 4.

[0050] The N-type substrate 3 is located on the upper surface of the N-side electrode 1 and is used to ensure the thermal stability and structural stability of the device.

[0051] Optionally, the material of the N-type substrate 3 may be silicon, gallium arsenide, indium phosphide or other compound semiconductor materials.

[0052] Whispering gallery microcavity 4 is an active medium, located between N-side electrode 1 and P-side electrode 2, that is, located on an N-type substrate. The area of ​​whispering gallery microcavity 4 is smaller than that of N-type substrate 3, and is used to achieve total internal reflection of light to form a stable light field mode distribution.

[0053] Specifically, the whispering gallery microcavity 4 is formed by the intersection of two arc-edged quadrilaterals obtained by deforming a square, that is, the top view of the whispering gallery microcavity 4 appears as at least two partially overlapping arc-edged quadrilaterals of unequal sizes connected by straight sides.

[0054] The projection of the whispering gallery microcavity 4 on the N-type substrate is a deformed arc-edged quadrilateral. The side lengths and arc-edged deformation amounts of the two arc-edged quadrilaterals are different, and the centers are a certain distance apart, which is used to limit the light field in the vertical direction and produce a stable light field mode distribution, so that photons form a stable lasing mode through total internal reflection in the whispering gallery microcavity 4.

[0055] Figure 2 The planar structure diagram of a single-mode semiconductor microcavity laser according to an embodiment of the present disclosure is schematically shown.

[0056] like Figure 2 As shown, the whispering gallery microcavity 4 includes two partially overlapping first arc-edge quadrilaterals 7 and second arc-edge quadrilaterals 8 connected by straight edges. The arc-edge deformation of the arc-edge quadrilateral is defined as the vertical distance between the midpoint of the arc edge and the straight edge, expressed as and express.

[0057]

[0058]

[0059] Among them, a1 and r1 represent the side length and arc radius of the original square of the first arc-sided quadrilateral 7, and a2 and r2 represent the side length and arc radius of the original square of the second arc-sided quadrilateral 8.

[0060] Specifically, in some exemplary embodiments, the side lengths a1 and a2 of the original square are used to describe the sizes of the first arc-edge quadrilateral 7 and the second arc-edge quadrilateral 8, respectively. The corresponding areas of the whispering gallery microcavity 4 determine the optical path of the total internal reflection of light therein, thereby determining the size of the longitudinal mode interval of the light field. and They are used to describe the deformation degree of the original square corresponding to the first arc-edge quadrilateral 7 and the second arc-edge quadrilateral 8, which can affect the motion trajectory of the light in the echo gallery microcavity 4, thereby affecting the formation of the mode. The distance xl between the centers of the first arc-edge quadrilateral 7 and the second arc-edge quadrilateral 8 is used to describe the distance between the two arc-edge quadrilaterals, and then the overlap degree of the two arc-edge quadrilaterals can be determined. The three vertex angles of the larger arc-edge quadrilateral of the two arc-edge quadrilaterals are marked with a radius of r. c The fillet radius is r c Used to describe the degree of deformation of the vertex angle of the first arc-edge quadrilateral 7, the fillet radius r c It can also affect the movement trajectory of light in the whispering gallery microcavity 4, thereby affecting the pattern formation of the light field.

[0061] It can be understood that the semiconductor microcavity laser provided in the embodiments of the present disclosure can achieve wavelength-stable and tunable single-mode lasing within a large current range by optimizing the structure and parameters, meeting the basic requirements of coherent optical communication, thereby increasing data transmission capacity and transmission distance.

[0062] Figure 3 The diagram schematically shows the corresponding relationship between the quality factor (Q value) of the whispering gallery microcavity mode and the characteristic wavelength of the semiconductor microcavity laser provided by the embodiment of the present disclosure.

[0063] For example, the first arc-edge quadrilateral 7 and the second arc-edge quadrilateral 8 partially overlap, and the upper and lower vertices are connected by a straight line. The original square side lengths of the first arc-edge quadrilateral 7 and the second arc-edge quadrilateral 8 are respectively a1=25 μm and a2=20 μm, and the deformation values ​​of the first arc-edge quadrilateral 7 and the second arc-edge quadrilateral 8 are respectively =2.75 μm and =2.10 μm, and the center distance of the two arc-sided quadrilaterals is xl=9 μm. At the same time, the three vertex angles of the first arc-sided quadrilateral 7 are respectively c =11 μm fillet. Figure 3As shown, there are three groups of longitudinal modes in the wavelength range of 1540-1560 nm, and the longitudinal mode interval is about 7.8nm. Each group of longitudinal modes has a high Q value mode with a Q value of more than 10000, which is defined as the fundamental mode, and in addition, there is a high Q value mode with a Q value of more than 7000, which is defined as the first-order mode. Consider the second set of longitudinal modes near 1550nm, where the fundamental mode wavelength is about 1549.58nm, the Q value is about 10328.51, the first-order mode wavelength is about 1549.40nm, the Q value is about 8168.53, and the wavelength interval between the two modes is about 0.18nm.

[0064] Continue to refer to Figure 1 The whispering gallery microcavity 4 includes an N-type confinement layer 403 , an active layer 402 and a P-type confinement layer 401 .

[0065] The N-type confinement layer 403 is an N-type confinement layer, which is disposed on the upper surface of the N-type substrate 3 and is used to reduce the radiation loss of light in the vertical direction.

[0066] The active layer 402 is disposed on the upper surface of the N-type confinement layer 403 and is used to generate light by stimulated radiation, that is, to generate light under the action of injected current and form a specific light field mode distribution.

[0067] The P-type confinement layer 401 is a P-type confinement layer, which is disposed on the upper surface of the active layer 402 and is used to match the N-type confinement layer 403 to increase the confinement capability of the light field in the vertical direction.

[0068] It can be understood that the whispering gallery microcavity 4 limits the light field by superimposing the first deformed arc-edge quadrilateral 7 and the second deformed arc-edge quadrilateral 8. At the same time, the existence of two arc-edge quadrilaterals of different sizes makes the distribution of light in the whispering gallery microcavity 4 relatively dispersed, which can effectively reduce the microcavity's ability to limit the light field and increase the output power of the laser.

[0069] It should be noted that the whispering gallery microcavity 4 can be set to be left-right asymmetric to suppress the high-order modes in the whispering gallery microcavity 4 and adjust the quality factor of the light field mode. When the arc edge deformation is large, the quality factor of the corresponding microcavity mode is large. By adjusting the arc edge deformation, the quality factor of the fundamental mode can be achieved to exceed 10 4 .

[0070] In the embodiment of the present disclosure, the single-mode semiconductor microcavity laser further includes: a waveguide 5, which is disposed on the N-type substrate 3 and connected to a preset output end of the whispering gallery microcavity 4, that is, connected to a corner of the whispering gallery microcavity 4, for realizing directional output of the laser in the microcavity. The waveguide 5 has the same height as the whispering gallery microcavity 4 in the vertical direction and is located on the same epitaxial wafer.

[0071] For example, Figure 2As shown, the waveguide 5 radially extends from the intersection of two arc-shaped sides of the second deformed arc-shaped quadrilateral 8 to guide the light in the whispering gallery microcavity 4 to be emitted in a directional manner to improve the coupling efficiency between the emitted light and the optical fiber.

[0072] Optionally, the waveguide 5 is a strip waveguide.

[0073] Further, the waveguide 5 includes a first end face and a second end face 6 .

[0074] The first end surface is connected to the preset output end of the whispering gallery microcavity 4, that is, located at the top corner of the whispering gallery microcavity 4, and directly connected to a top corner of the arc-edge quadrilateral with a smaller size of the whispering gallery microcavity 4.

[0075] The second end face 6 is a cleavage face, which is arranged at the other end of the waveguide 5 connected to the whispering gallery microcavity 4, that is, the end extending outward. The second end face 6 serves as the light outlet (light outlet end face) of the laser, and is used to realize the directional emission of the laser so as to be butt-coupled with the optical fiber.

[0076] Figure 4 The mode field distribution diagram of the fundamental mode and the first-order mode of a whispering gallery microcavity provided by an embodiment of the present disclosure is schematically shown.

[0077] For example, the whispering gallery microcavity 4 is composed of two deformed arc-edge quadrilaterals 7 and 8 of different sizes overlapping each other, with the upper and lower vertex angles connected by a straight line, each retaining two arc edges, and the three vertex angles of the arc-edge quadrilateral 7 are replaced by smooth arcs. Figure 4 As shown, the fundamental mode and the first-order mode are selected as the fundamental mode and the first-order mode near 1550nm. Due to the asymmetric distribution of the left and right shapes of the whispering gallery microcavity 4, compared with the symmetrically distributed arc-edge deformed square microcavity, the distribution of the mode in the microcavity is uneven, and the reflection point of the light in the microcavity is not at the midpoint of the arc edge. At the same time, it can be seen that the mode field intensity of the fundamental mode and the first-order mode at the vertex of the deformed arc-edge quadrilateral 8 is very weak, and the direct-connected waveguide has little effect on the mode field here.

[0078] Figure 5 The diagram schematically shows the quality factors of the fundamental mode and the first-order mode of a semiconductor microcavity laser provided by an embodiment of the present disclosure, as well as the corresponding relationship between the mode spacing of the fundamental mode and the first-order mode and the arc edge deformation.

[0079] For example, the whispering gallery microcavity 4 is composed of two deformed arc-edge quadrilaterals 7 and 8 of different sizes overlapping each other, with the upper and lower vertex angles connected by a straight line, each retaining two arc edges, and the three vertex angles of the arc-edge quadrilateral 7 are replaced by smooth arcs. Figure 5 As shown, the arc deformation of the fixed deformed arc quadrilateral 8 =2.10 μm, changing the arc edge deformation of the deformed arc edge quadrilateral 7 , the corresponding diagram of the change of the quality factor of the fundamental mode and the first-order mode in the whispering gallery microcavity 4. As the arc edge deformation of the arc edge quadrilateral 7 As the arc edge deformation increases, the Q values ​​of the fundamental mode and the first-order mode gradually increase, and the Q value difference between the fundamental mode and the first-order mode will also gradually increase. When the wavelength is 2.75 μm, the wavelengths of the fundamental mode and the first-order mode are about 1549.58 nm and 1549.40 nm, respectively, the Q values ​​are about 10328.51 and 8168.53, respectively, and the mode spacing is about 22.73 GHz. Therefore, based on the microcavity with this geometric structure, by changing the arc edge deformation , which can achieve a larger Q value difference between the fundamental mode and the first-order mode, thereby realizing single-mode lasing to meet the basic requirements of coherent optical communication for light sources.

[0080] Figure 6 The optical spectrum diagram of a semiconductor microcavity laser provided by an embodiment of the present disclosure when the injection current changes continuously from 0 to 100 mA at intervals of 1 mA is schematically shown.

[0081] Exemplarily, the arc-side deformation amount of the first deformed arc-side quadrilateral 7 is set to =2.75μm, e.g. Figure 6 As shown in the figure, with the increase of injection current, the semiconductor microcavity laser starts single-mode lasing at 13mA current, and this state is maintained until 100mA. However, due to the temperature rise of the laser caused by the increase of injection current, the wavelength of the lasing mode gradually increases from 1531nm to 1537nm, and a wavelength tunable range of 6nm can be achieved.

[0082] Figure 7 The detailed spectrum diagram of a semiconductor microcavity laser provided by an embodiment of the present disclosure when the injection current is 30 mA, 50 mA and 70 mA is schematically shown.

[0083] For example, Figure 7 As shown in the figure, when the injection current increases from 30mA to 70mA, the semiconductor microcavity laser always maintains single-mode lasing without mode hopping. In addition, the side mode suppression ratio can be stably controlled above 30dB, meeting the basic conditions for single-mode lasing of the laser.

[0084] Figure 8 A schematic diagram showing the change in side mode suppression ratio of a semiconductor microcavity laser provided by an embodiment of the present disclosure as the injection current increases from 0 to 100 mA is shown.

[0085] In some embodiments of the present disclosure, Figure 8As shown, the injected current is lasered when the threshold current is 13mA. As the current increases, it can be seen that the side mode suppression ratio gradually increases at the beginning, and basically stabilizes at more than 40dB after the current reaches 60mA.

[0086] On the basis of the above embodiments, in this embodiment, the sidewalls of the whispering gallery microcavity are wrapped with a filling material, and the refractive index of the filling material is smaller than the refractive index of the whispering gallery microcavity.

[0087] In some exemplary embodiments, the filling material is benzocyclobutene, that is, the whispering gallery microcavity 4 is surrounded by benzocyclobutene, and the refractive index of benzocyclobutene is smaller than that of the whispering gallery microcavity 4. By forming a high refractive index difference with the cavity, the total internal reflection condition of light is met, so that the light is continuously totally reflected internally in the whispering gallery microcavity 4, forming a specific and stable lasing light field mode.

[0088] Exemplarily, the refractive index of the whispering gallery microcavity is set to 3.2, and the cavity is wrapped by benzocyclobutene with a refractive index of 1.54, forming a high refractive index difference with the cavity, thereby satisfying the total reflection restriction condition of the light in the cavity.

[0089] In some exemplary embodiments, a perfect matching layer is disposed outside the whispering gallery microcavity during simulation.

[0090] Specifically, the outermost layer of the whispering gallery microcavity is a perfectly matched layer (PML), which is used to prevent light from reflecting at the boundary and affecting the mode in the cavity, and to terminate the calculation at the boundary of the model.

[0091] The single-mode semiconductor microcavity laser provided in the embodiment of the present disclosure can adjust the wavelength interval and Q value of the semiconductor microcavity laser lasing mode by adjusting the arc edge deformation of the whispering gallery microcavity 4, thereby achieving tunable single-mode lasing with a side mode suppression ratio greater than 30 dB in a large current range.

[0092] The semiconductor microcavity laser provided in the embodiment of the present disclosure is a deep etched structure, does not require a complex epitaxial growth process, can simultaneously achieve single-mode lasing in a large current range, and the lasing intensity is controllable. Compared with the existing semiconductor single-mode lasers, the semiconductor microcavity laser in the embodiment of the present disclosure has the advantages of flexible structural design, controllable mode, small device size, simple process, high yield rate and low cost.

[0093] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0094] Although the present disclosure has been shown and described with reference to specific exemplary embodiments of the present disclosure, it should be understood by those skilled in the art that various changes in form and details may be made to the present disclosure without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents. Therefore, the scope of the present disclosure should not be limited to the above-mentioned embodiments, but should be determined not only by the appended claims, but also by the equivalents of the appended claims.

Claims

1. A single-mode semiconductor microcavity laser, characterized in that: include: N-type substrate; A whispering gallery microcavity is located on an N-type substrate, and an area of ​​the whispering gallery microcavity is smaller than an area of ​​the N-type substrate; The waveguide is arranged on the N-type substrate and connected to a preset output end of the whispering gallery microcavity.

2. The single-mode semiconductor microcavity laser according to claim 1, characterized in that: The whispering gallery microcavity comprises: An N-type restriction layer, disposed on the upper surface of the N-type substrate; An active layer, disposed on the upper surface of the N-type confinement layer; The P-type confinement layer is arranged on the upper surface of the active layer.

3. The single-mode semiconductor microcavity laser according to claim 1, characterized in that: The whispering gallery microcavity is formed by the intersection of two arc-edged quadrilateral parts obtained by deforming a square.

4. The single-mode semiconductor microcavity laser according to claim 1, characterized in that: The waveguide comprises: A first end face and a second end face; wherein, The first end surface is connected to a preset output end of the whispering gallery microcavity, and the second end surface is a cleavage surface located at the other end where the waveguide is connected to the whispering gallery microcavity.

5. The single-mode semiconductor microcavity laser according to claim 1, characterized in that: The waveguide is a strip waveguide.

6. The single-mode semiconductor microcavity laser according to claim 3, characterized in that: The original square side lengths and arc side deformation amounts of the two arc-side quadrilaterals are not equal, and the centers are at a certain distance from each other.

7. The single-mode semiconductor microcavity laser according to claim 1, characterized in that: Also includes: An N-side electrode, disposed on the lower surface of the N-type substrate, having the same shape and size as the N-type substrate; The P-surface electrode is disposed on the upper surface of the whispering gallery microcavity and has the same shape and size as the whispering gallery microcavity.

8. The single-mode semiconductor microcavity laser according to claim 1, characterized in that: The height of the whispering gallery microcavity is the same as the height of the waveguide.

9. The single-mode semiconductor microcavity laser according to claim 1, characterized in that: The side wall of the whispering gallery microcavity is wrapped with a filling material, and the refractive index of the filling material is smaller than the refractive index of the whispering gallery microcavity.

10. The single-mode semiconductor microcavity laser according to claim 3 or 6, characterized in that: The deformation of the two arc sides of the two arc-side quadrilaterals and They are: Among them, a1, a2, r1 and r2 represent the side length and arc radius of the original square of the two arc-sided quadrilaterals respectively.

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