Surface-emitting semiconductor laser and optical transmission device

Abstract

To expand the modulation bandwidth of light compared to a configuration in which the opening of a metal layer and the aperture of a current confinement layer have the same shape and their centers coincide when viewed from the stacking direction in a configuration in which a metal layer is disposed between a second semiconductor multilayer reflector having a current confinement layer and a dielectric multilayer reflector.SOLUTION: A surface-emitting semiconductor laser includes a substrate, a first semiconductor multilayer reflector stacked on the substrate, an active layer stacked on the first semiconductor multilayer reflector, a second semiconductor multilayer reflector including a current confinement layer and stacked on the active layer, a dielectric multilayer reflector stacked on the second semiconductor multilayer reflector, and a metal layer disposed between the second semiconductor multilayer reflector and the dielectric multilayer reflector, the metal layer having an opening inside which an aperture representing a portion of the current confinement layer that is not oxidized and confined is disposed when viewed from the stacking direction, and the center of the opening being shifted from the center of the aperture.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a surface-emitting semiconductor laser and an optical transmission device. [Background technology]

[0002] Patent Document 1 discloses a surface-emitting laser characterized by comprising a VCSEL (Vertical Cavity Surface-Emitting Laser) structure having an aperture formed by a current confinement structure, an aperture in an upper DBR (Distributed Bragg Reflector) of the VCSEL structure, and an optically discontinuous member formed in a spaced apart region.

[0003] Patent Document 2 discloses a surface-emitting semiconductor laser comprising a semiconductor layer having an active layer and a current confinement layer, and a transverse mode adjustment section formed on the semiconductor layer, wherein the current confinement layer has a current injection region and a current confinement region, the transverse mode adjustment section has a high-reflection region and a low-reflection region, the high-reflection region is formed in a region including a first opposing region with the center point of the current injection region and has a cross shape, and the low-reflection region is formed in a region opposing the current injection region where the high-reflection region is not formed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-2299 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-135854 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure aims to expand the modulation bandwidth of light in a configuration in which a metal layer is disposed between a second semiconductor multilayer reflector having a current confinement layer and a dielectric multilayer reflector, compared to a configuration in which the opening of the metal layer and the aperture of the current confinement layer have the same shape and their centers coincide when viewed from the stacking direction. [Means for solving the problem]

[0006] A surface-emitting semiconductor laser according to a first aspect of the present disclosure comprises a substrate, a first semiconductor multilayer reflector stacked on the substrate, an active layer stacked on the first semiconductor multilayer reflector, a second semiconductor multilayer reflector including a current confinement layer and stacked on the active layer, a dielectric multilayer reflector stacked on the second semiconductor multilayer reflector, and a metal layer disposed between the second semiconductor multilayer reflector and the dielectric multilayer reflector, the metal layer having an opening inside which an aperture representing an oxidized non-confined portion of the current confinement layer is disposed when viewed from the stacking direction, the center of the opening being offset from the center of the aperture.

[0007] A surface-emitting semiconductor laser according to a second aspect of the present disclosure is the surface-emitting semiconductor laser according to the first aspect, and has a portion in which the distance between the edge of the opening and the edge of the aperture changes continuously along the outer periphery of the aperture when viewed from the stacking direction.

[0008] A surface-emitting semiconductor laser according to a third aspect of the present disclosure is the surface-emitting semiconductor laser according to the second aspect, wherein an edge of at least one of the opening and the aperture is curved in an arc when viewed from the stacking direction.

[0009] A surface-emitting semiconductor laser according to a fourth aspect of the present disclosure is the surface-emitting semiconductor laser according to the second aspect, wherein the distance between the edge of the opening and the edge of the aperture changes continuously around the entire circumference of the aperture when viewed from the stacking direction.

[0010] A surface-emitting semiconductor laser according to a fifth aspect of the present disclosure is the surface-emitting semiconductor laser according to the fourth aspect, wherein the aperture has a circular or elliptical shape, and the opening has a circular or elliptical shape.

[0011] A surface-emitting semiconductor laser according to a sixth aspect of the present disclosure is the surface-emitting semiconductor laser according to the fifth aspect, wherein the opening has the same shape as the aperture when viewed from the stacking direction.

[0012] A surface-emitting semiconductor laser according to a seventh aspect of the present disclosure is the surface-emitting semiconductor laser according to the first aspect, wherein a recess is formed in the uppermost layer of the second semiconductor multilayer film reflector, and when viewed from the stacking direction, the recess is positioned inside the aperture and the center of the recess is shifted from the center of the aperture.

[0013] A surface-emitting semiconductor laser according to an eighth aspect of the present disclosure is the surface-emitting semiconductor laser according to the seventh aspect, wherein the aperture has a circular or elliptical shape, and the recess has a circular or elliptical shape.

[0014] A surface-emitting semiconductor laser according to a ninth aspect of the present disclosure is the surface-emitting semiconductor laser according to the eighth aspect, wherein the shape of the recess and the shape of the aperture are the same when viewed from the stacking direction.

[0015] A surface-emitting semiconductor laser according to a tenth aspect of the present disclosure comprises a substrate, a first semiconductor multilayer reflector stacked on the substrate, an active layer stacked on the first semiconductor multilayer reflector, a second semiconductor multilayer reflector including a current confinement layer and stacked on the active layer, a dielectric multilayer reflector stacked on the second semiconductor multilayer reflector, and a metal layer disposed between the second semiconductor multilayer reflector and the dielectric multilayer reflector, the metal layer having an opening inside which an aperture representing an oxidized non-confined portion of the current confinement layer is disposed when viewed from the stacking direction, and in which a plurality of external resonators having different resonance frequencies are formed between the edge of the opening and the edge of the aperture.

[0016] An optical transmission device according to an eleventh aspect of the present disclosure includes the surface-emitting semiconductor laser according to the first or tenth aspect, and an optical transmission section that transmits light output from the surface-emitting semiconductor laser. [Effects of the Invention]

[0017] According to the first aspect, in a configuration in which a metal layer is disposed between a second semiconductor multilayer reflector having a current confinement layer and a dielectric multilayer reflector, the modulation bandwidth of light can be expanded compared to a configuration in which the opening of the metal layer and the aperture of the current confinement layer have the same shape and their centers coincide when viewed from the stacking direction.

[0018] According to the second aspect, the modulation band of light can be expanded continuously, compared to a configuration in which the distance between the edge of the opening and the edge of the aperture changes intermittently along the periphery of the aperture.

[0019] According to the third aspect, the modulation band of light can be continuously expanded compared to when the edges of the opening and the aperture are linear.

[0020] According to the fourth aspect, since there are no portions that change intermittently, the modulation band of light can be continuously expanded.

[0021] According to the fifth aspect, the modulation band of light can be continuously expanded compared to when the aperture and the opening are each polygonal.

[0022] According to the sixth aspect, the modulation band of light can be continuously expanded compared to when the aperture and the opening have different shapes.

[0023] According to the seventh aspect, the modulation band of light can be expanded compared to a configuration in which the center of the recess and the center of the aperture coincide when viewed from the stacking direction.

[0024] According to the eighth aspect, the modulation band of light can be continuously expanded compared to when the aperture and the recess are each polygonal in shape.

[0025] According to the ninth aspect, the modulation band of light can be continuously expanded compared to when the aperture and the recess have different shapes.

[0026] According to the tenth aspect, in a configuration in which a metal layer is disposed between a second semiconductor multilayer reflector having a current confinement layer and a dielectric multilayer reflector, the modulation bandwidth of light can be expanded compared to a configuration in which a single external resonator is formed between the edge of the opening in the metal layer and the edge of the aperture in the current confinement layer.

[0027] According to the eleventh aspect, in a configuration in which a metal layer is disposed between a second semiconductor multilayer reflector having a current confinement layer and a dielectric multilayer reflector, stable optical transmission is possible even when the usage environment changes, compared to a case in which a surface-emitting semiconductor laser is used in which the aperture of the metal layer and the aperture of the current confinement layer have the same shape and their centers coincide when viewed from the stacking direction. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a cross-sectional view showing a surface-emitting semiconductor laser according to a first embodiment of the present disclosure. [Figure 2] 2 is an enlarged cross-sectional view of the active layer and its surroundings of the surface-emitting type semiconductor laser shown in FIG. [Figure 3] FIG. 10 is a plan view of the openings and apertures in the metal layer as viewed from the stacking direction. [Figure 4] FIG. 2 is a plan view of the openings, apertures, and recesses of the metal layer as viewed from the stacking direction. [Figure 5] FIG. 2 is a diagram schematically illustrating the surface-emitting semiconductor laser shown in FIG. [Figure 6] 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to a second embodiment of the present disclosure, viewed from the stacking direction. FIG. [Figure 7] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 8]FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 9] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 10] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 11] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 12] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 13] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 14] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 15] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 16] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 17] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 18] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 19] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 20]FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 21] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 22] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. [Figure 23] FIG. 10 is a plan view of an opening and an aperture in a metal layer of a surface-emitting type semiconductor laser according to another embodiment of the present disclosure, viewed from the stacking direction. DETAILED DESCRIPTION OF THE INVENTION

[0029] An embodiment for implementing the technology of the present disclosure will be described in detail below with reference to the drawings. Note that components and processes that perform the same operations, actions, and functions are given the same reference numerals throughout the drawings, and duplicated descriptions may be omitted as appropriate. Each drawing is merely a schematic illustration to allow a sufficient understanding of the technology of the present disclosure. Therefore, the technology of the present disclosure is not limited to only the illustrated examples. Furthermore, in this embodiment, descriptions of configurations that are not directly related to the technology of the present disclosure or well-known configurations may be omitted.

[0030] [First embodiment] FIG. 1 is a cross-sectional view showing a surface-emitting semiconductor laser 20 according to a first embodiment of the present disclosure.

[0031] As shown in FIG. 1, the surface-emitting semiconductor laser 20 according to this embodiment is, for example, a VCSEL (Vertical Cavity Surface Emitting Laser).

[0032] As shown in FIG. 1, the surface-emitting semiconductor laser 20 according to this embodiment includes a substrate 22, a contact layer 24, a first semiconductor multilayer reflector 26, an active layer 28, a second semiconductor multilayer reflector 30, a contact metal 34, and a dielectric multilayer reflector 44.

[0033] In this embodiment, the first semiconductor multilayer reflector 26 is n-type and the second semiconductor multilayer reflector 30 is p-type, but the present disclosure is not limited to this configuration.

[0034] In the surface-emitting semiconductor laser 20 according to this embodiment, components including the contact layer 24, the first semiconductor multilayer reflector 26, the active layer 28, the second semiconductor multilayer reflector 30, and the dielectric multilayer reflector 44 form a mesa structure 36. The mesa structure 36 constitutes the laser portion of the surface-emitting semiconductor laser 20.

[0035] The substrate 22 is, for example, a semi-insulating GaAs (gallium arsenide) substrate. A semi-insulating GaAs substrate is a GaAs substrate that is not doped with impurities. A semi-insulating GaAs substrate has a very high resistivity, and the sheet resistance of the substrate is, for example, several MΩ.

[0036] The material of the substrate 22 may be other than GaAs, and may be, for example, GaN (gallium nitride) or InP (indium phosphide).

[0037] The contact layer 24 is stacked on the substrate 22. As an example, the contact layer 24 is formed of an n-type GaAs layer doped with Si.

[0038] The contact layer 24 is connected to the n-type first semiconductor multilayer film reflector 26. An n-side electrode pad 42B is formed on the contact layer 24. Therefore, the contact layer 24 has the function of applying a negative potential to the laser portion formed by the mesa structure 36.

[0039] The contact layer 24 may also serve as a buffer layer provided to improve the crystallinity of the substrate surface after, for example, thermal cleaning.

[0040] An n-type first semiconductor multilayer reflector 26 is stacked on the contact layer 24. This first semiconductor multilayer reflector 26 constitutes a lower DBR (Distributed Bragg Reflector).

[0041] The first semiconductor multilayer film reflector 26 is a multilayer film reflector configured by alternately stacking two semiconductor films having different refractive indices. Specifically, the first semiconductor multilayer film reflector 26 is made of Al 0.90 GaAs n-type low refractive index film and Al 0.15 It is composed of alternately stacked n-type Al 0.90 The refractive index of GaAs is 0.15 The refractive index is lower than that of GaAs.

[0042] The active layer 28 is laminated on the first semiconductor multilayer film reflector 26. The active layer 28 functions as a resonator. Details of the active layer 28 will be described later.

[0043] The p-type second semiconductor multilayer reflector 30 is stacked on the active layer 28. In other words, the second semiconductor multilayer reflector 30 is stacked on the first semiconductor multilayer reflector 26 via the active layer 28. This second semiconductor multilayer reflector 30 constitutes an upper DBR.

[0044] The second semiconductor multilayer film reflector 30 is a multilayer film reflector configured by alternately stacking two semiconductor films having different refractive indices. Specifically, the second semiconductor multilayer film reflector 30 is made of Al 0.90 A p-type low refractive index film made of GaAs and Al 0.15 It is composed of p-type Al, GaAs, and p-type Al. 0.90 The refractive index of GaAs is p-type Al 0.15 The refractive index is lower than that of GaAs.

[0045] The second semiconductor multilayer reflector 30 also includes a selective oxidation layer 32. The selective oxidation layer 32 is an example of a current confinement layer. The selective oxidation layer 32 is disposed above the active layer 28. The selective oxidation layer 32 includes an aperture 32A representing a portion that is not confined by oxidation, and an oxidation confinement region 32B which is a region that is confined by oxidation. In addition to selective oxidation for current confinement, current confinement may also be achieved by, for example, temporarily forming a pattern corresponding to an opening when stacking a layer structure to selectively allow current to pass through the opening, or by introducing ions to make it difficult for current to pass through the ion-introduced portion.

[0046] The amount of aluminum per unit amount of the aluminum-containing material forming the selective oxidation layer 32 may be greater than the amount of aluminum per unit amount of the aluminum-containing material forming the second semiconductor multilayer film reflector 30. The selective oxidation layer 32 may be made of, for example, AlAs (aluminum arsenide), Al 0.98 It is made of GaAs etc.

[0047] An interlayer insulating film 38 serving as an inorganic insulating film is deposited around the semiconductor layer including the mesa structure 36. The interlayer insulating film 38 extends from the side surface of the mesa structure 36 to the surface of the substrate 22. The interlayer insulating film 38 is also disposed below the electrode pad 42A.

[0048] The interlayer insulating film 38 is formed of, for example, a silicon nitride film (SiN film). Note that the material of the interlayer insulating film 38 is not limited to a silicon nitride film, and may be, for example, a silicon oxide film (SiO film) or a silicon oxynitride film (SiON film).

[0049] Wiring 40 is provided on the interlayer insulating film 38. One end of this wiring 40 is connected to the contact metal 34, which will be described later. Meanwhile, the other end of the wiring 40 extends from the contact metal 34 on the interlayer insulating film 38, passing through the side surface of the mesa structure 36, to the surface of the substrate 22. A p-side electrode pad 42A is formed by a portion of the interlayer insulating film 38 located on the surface of the substrate 22.

[0050] The contact metal 34 is an example of a metal layer, and is provided on the second semiconductor multilayer reflector 30. In other words, the contact metal 34 is disposed between the second semiconductor multilayer reflector 30 and the dielectric multilayer reflector 44.

[0051] The contact metal 34 is connected to the wiring 40. The contact metal 34 may be, for example, a Ti / Au laminated film.

[0052] 3, the contact metal 34 has an opening 34A inside which the aperture 32A is disposed when viewed from the stacking direction. The stacking direction here refers to the stacking direction of the layers (which may also be referred to as the reflectors) that make up the surface-emitting type semiconductor laser 20, and is the direction indicated by arrow Z in FIGS. 1 and 2. Hereinafter, when simply referring to the "stacking direction," this refers to the direction indicated by arrow Z.

[0053] As shown in FIG. 3, when viewed from the stacking direction, the center 34C of the opening 34A of the contact metal 34 is shifted from the center 32C of the aperture 32A.

[0054] Furthermore, when viewed from the stacking direction, the distance L between the edge 34E of the opening 34A of the contact metal 34 and the edge 32E of the aperture 32A may have a portion where it continuously changes along the outer periphery of the aperture 32A. In other words, the shape of the opening 34A, the shape of the aperture 32A, and the positions of the centers 34C of the opening 34A and 32C of the aperture 32A may each be set so as to have the continuously changing portion. Note that the edge 34E of the aperture 32A here refers to the boundary between the portion of the selective oxidation layer 32 that is not oxidized and the region that is oxidized and confined. Additionally, "along the outer periphery of the aperture 32A" refers to following the above-mentioned boundary.

[0055] Alternatively, aperture 32A may have a circular or elliptical shape, and opening 34A may have a circular or elliptical shape. When viewed from the stacking direction, opening 34A and aperture 32A may have the same shape. In this embodiment, aperture 32A and opening 34A are each circular, for example.

[0056] Furthermore, a dielectric multilayer film reflector 44 is laminated on the contact metal 34. This dielectric multilayer film reflector 44 may be included in the upper DBR.

[0057] The dielectric multilayer reflector 44 is stacked on the second semiconductor multilayer reflector 30. Specifically, the dielectric multilayer reflector 44 is stacked on the contact metal 34 stacked on the second semiconductor multilayer reflector 30.

[0058] The dielectric multilayer reflector 44 is a multilayer reflector formed by alternately stacking two dielectric films with different refractive indices. Specifically, the dielectric multilayer reflector 44 is formed by alternately stacking a high refractive index film made of Ta2O5 (tantalum pentoxide) and a low refractive index film made of silicon oxide (SiO2).

[0059] In this embodiment, as an example, a recess 50 is formed in the uppermost layer of the second semiconductor multilayer film reflector 30 (see FIG. 2). As shown in FIG. 4, this recess 50 is disposed inside the aperture 32A when viewed from the stacking direction. Furthermore, the center 50C of the recess 50 is shifted from the center 32C of the aperture 32A. Note that the present disclosure is not limited to this configuration, and the center 50C of the recess 50 may coincide with the center 32C of the aperture 32A or the center 34C of the opening 34A.

[0060] Furthermore, when viewed from the stacking direction, the distance SL between the edge 50E of the recess 50 and the edge 32E of the aperture 32A may have a portion where it changes continuously along the outer periphery of the aperture 32A. In other words, the shape of the recess 50, the shape of the aperture 32A, and the positions of the center 50C of the recess 50 and the center 32C of the aperture 32A may each be set so as to have the above-mentioned continuously changing portion.

[0061] Furthermore, when viewed from the stacking direction, the shape of the recess 50 and the shape of the aperture 32A may be the same as or different from each other. Furthermore, the shape of the recess 50 may be the same as or different from the shape of the opening 34A. In the present embodiment, as an example, the shape of the recess 50 is circular, similar to the shape of the aperture 32A and the opening 34A.

[0062] Next, the effects of this embodiment will be described.

[0063] In the surface-emitting semiconductor laser 20 of this embodiment, when viewed from the stacking direction, the aperture 32A is disposed inside the opening 34A of the contact metal 34, and the center 34C of the opening 34A is shifted from the center 32C of the aperture 32A. As a result, as shown in FIG. 3 , multiple portions (regions) are formed in which the distance L between the edge 34E of the opening 34A and the edge 32E of the aperture 32A varies. Note that the distances L1, L2, and L3 in FIG. 3 are all different. The distance L between the edge 34E of the opening 34A and the edge 32E of the aperture 32A corresponds to the cavity length. That is, multiple portions with different distances L are formed between the edge 34E of the opening 34A and the edge 32E of the aperture 32A, resulting in multiple cavity lengths. A pseudo external cavity is then formed for each cavity length. 5 is a schematic diagram of the surface-emitting semiconductor laser 20. In FIG. c1 , L c2 In other words, the surface-emitting semiconductor laser 20 has a cavity length L c1 , L c25, a main resonator 200 is provided between the first external resonator 202 and the second external resonator 204. Here, the first external resonator 202 and the second external resonator 204 are coupled to the main resonator 200 in the lateral direction (direction perpendicular to the stacking direction). In addition, in FIG. 5, the coupling coefficient between the main resonator 200 and the first external resonator 202 is η1, the coupling coefficient between the main resonator 200 and the second external resonator 204 is η2, the resonant wavelength of the main resonator 200 is λ1, and the resonant wavelength of the first external resonator 202 is λ h1 , the resonant wavelength of the second external resonator 204 is λ h2 is shown as

[0064] As shown in FIG. 3, in the surface-emitting semiconductor laser 20 of this embodiment, the aperture 32A is disposed inside the opening 34A when viewed from the stacking direction, and the center 34C of the opening 34A is offset from the center 32C of the aperture 32A, thereby achieving multiple cavity lengths. That is, multiple external cavities with different resonant frequencies are formed between the edge 34E of the opening 34A and the edge 32E of the aperture 32A. By forming multiple external cavities in this manner, a coupled resonance effect can be achieved in any of the multiple external cavities even when the operating environment (temperature, drive current, etc.) changes. This allows the surface-emitting semiconductor laser 20 of this embodiment to expand the optical modulation bandwidth compared to a configuration in which the opening 34A and the aperture 32A have the same shape and their centers 34C and 32C are aligned when viewed from the stacking direction.

[0065] When the surface-emitting semiconductor laser 20 of this embodiment has a portion where, as viewed from the stacking direction, the distance L between the edge 34E of the opening 34A and the edge 32E of the aperture 32A changes continuously along the outer periphery of the aperture 32A, the modulation band of light can be continuously expanded compared to when the distance L between the edge 34E of the opening 34A and the edge 32E of the aperture 32A changes intermittently along the outer periphery of the aperture 32A. Specifically, when the surface-emitting semiconductor laser 20 has a portion where the distance L changes continuously as shown in FIG. 3, it becomes possible to form a large number of continuous external resonators, and it becomes possible to continuously expand the modulation band of light.

[0066] In the surface-emitting semiconductor laser 20 of this embodiment, when viewed from the stacking direction, the distance L between the edge 34E of the opening 34A and the edge 32E of the aperture 32A changes continuously around the entire circumference of the aperture 32A, and since there are no parts that change intermittently, the modulation band of the light can be continuously expanded.

[0067] In the surface-emitting semiconductor laser 20 of this embodiment, when the shape of the aperture 32A is circular or elliptical and the shape of the opening 34A is also circular or elliptical, the modulation band of light can be continuously expanded compared to when the shapes of the aperture 32A and the opening 34A are each polygonal.

[0068] In the surface-emitting semiconductor laser 20 of this embodiment, when viewed from the stacking direction, if the shape of the opening 34A and the shape of the aperture 32A are the same, the modulation band of light can be continuously expanded compared to when the shapes of the aperture 32A and the opening 34A are different.

[0069] In the surface-emitting semiconductor laser 20 of this embodiment, when a recess 50 is provided in the second semiconductor multilayer reflector 30 as viewed in the stacking direction, the equivalent refractive index between the recess 50 and the area surrounding the recess 50 is changed, thereby increasing the amount of light seeping into the external cavity. This increases the coupling coefficient of the external cavity. Furthermore, in the surface-emitting semiconductor laser 20, when the recess 50 is disposed inside the aperture 32A and the center 50C of the recess 50 is shifted from the center 32C of the aperture 32A, the optical modulation bandwidth can be expanded, similar to the relationship between the aperture 32A and the opening 34A, compared to when the center 50C of the recess 50 and the center 32C of the aperture 32A are aligned as viewed in the stacking direction.

[0070] In the surface-emitting semiconductor laser 20 of this embodiment, when the shape of the aperture 32A is circular or elliptical and the shape of the recess 50 is also circular or elliptical, the modulation band of light can be continuously expanded compared to when the shapes of the aperture 32A and the recess 50 are both polygonal.

[0071] In the surface-emitting semiconductor laser 20 of this embodiment, when viewed from the stacking direction, if the shape of the recess 50 and the shape of the aperture 32A are the same, the modulation band of light can be continuously expanded compared to when the shapes of the aperture 32A and the recess 50 are different.

[0072] [Second embodiment] Next, a surface-emitting semiconductor laser 60 according to a second embodiment of the present disclosure will be described. Note that a description of the same configuration as in the first embodiment will be omitted.

[0073] As shown in Fig. 6, in the surface-emitting semiconductor laser 60 of this embodiment, the shape of the opening 34A and the shape of the aperture 62A are different. Specifically, the opening 34A is circular, and the aperture 62A is elliptical. In the surface-emitting semiconductor laser 60 of this embodiment, when viewed from the stacking direction, the aperture 62A is disposed inside the opening 34A, and the center 34C of the opening 34A and the center of the aperture 62A coincide with each other. Note that in Fig. 6, only the center 34C is indicated by a reference numeral, and the reference numeral for the center of the aperture 62A is omitted.

[0074] Next, the effects of this embodiment will be described, with the same effects as those obtained in the first embodiment being omitted where appropriate.

[0075] In the surface-emitting semiconductor laser 20 of this embodiment, the distance L between the edge 34E of the opening 34A and the edge 62E of the aperture 62A varies along the outer periphery of the aperture 62A. That is, in the surface-emitting semiconductor laser 20, multiple external resonators with different resonance frequencies are formed between the edge 34E of the opening 34A and the edge 62E of the aperture 62A. This allows for a wider modulation bandwidth of light than in a configuration in which a single external resonator is formed between the edge 34E of the opening 34A and the edge 32E of the aperture 32A.

[0076] [Other embodiments] In the surface-emitting semiconductor laser 20 of the first embodiment, when viewed from the stacking direction, the shape of the aperture 32A and the shape of the opening 34A are the same circle, and the center 34C of the opening 34A is shifted from the center 32C of the aperture 32A, but the present disclosure is not limited to this configuration. For example, the surface-emitting semiconductor lasers 70, 74, 78, 84, 86, 90, 94, 98, 102, and 106 shown in Figures 7 to 16 may also be used. Below, the surface-emitting semiconductor lasers 70, 74, 78, 84, 86, 90, 94, 98, 102, and 106 will be described respectively.

[0077] As shown in FIG. 7 , in the surface-emitting semiconductor laser 70, the aperture 72A has an elliptical shape and the opening 34A has a circular shape when viewed from the stacking direction, so the aperture 72A and the opening 34A have different shapes. Furthermore, the center 34C of the opening 34A is offset from the center 72C of the aperture 72A. Furthermore, the surface-emitting semiconductor laser 70 has a portion where the distance L between the edge 34E of the opening 34A and the edge 72E of the aperture 72A changes continuously along the periphery of the aperture 72A when viewed from the stacking direction. Note that in FIG. 7 , the distance L2 refers to the minimum distance between the edge 34E of the opening 34A and the edge 72E of the aperture 72A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 70, the same effects as those of the first embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 20 of the first embodiment.

[0078] As shown in FIG. 8, in the surface-emitting semiconductor laser 74, the aperture 76A has a rectangular shape and the opening 34A has a circular shape when viewed from the stacking direction, so the aperture 76A and the opening 34A have different shapes. Furthermore, the center 34C of the opening 34A is offset from the center 76C of the aperture 76A. Furthermore, the surface-emitting semiconductor laser 74 has a portion where the distance L between the edge 34E of the opening 34A and the edge 76E of the aperture 76A changes continuously along the periphery of the aperture 76A when viewed from the stacking direction. Note that in FIG. 8, the distance L2 refers to the minimum distance between the edge 34E of the opening 34A and the edge 72E of the aperture 72A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 74, the same effects as those of the first embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 20 of the first embodiment.

[0079] As shown in FIG. 9, in the surface-emitting semiconductor laser 78, when viewed from the stacking direction, the aperture 80A has a semicircular shape, and the opening 82A also has a semicircular shape, so that the aperture 80A and the opening 82A have the same shape. Furthermore, the center 82C of the opening 82A is offset from the center 80C of the aperture 80A. Furthermore, the surface-emitting semiconductor laser 78 has a portion where the distance L between the edge 82E of the opening 82A and the edge 80E of the aperture 80A changes continuously along the outer periphery of the aperture 80A when viewed from the stacking direction. Note that in FIG. 9, the distance L2 refers to the minimum distance between the edge 82E of the opening 82A and the edge 80E of the aperture 80A. Furthermore, the distance L1 is longer than the distance L2. Furthermore, in the surface-emitting semiconductor laser 78, the arc-shaped portion of the aperture 80A and the arc-shaped portion of the opening 82A face in the same direction. In the surface-emitting semiconductor laser 78, the same effects as those of the first embodiment can be obtained in parts having the same configuration as the surface-emitting semiconductor laser 20 of the first embodiment. Note that the surface-emitting semiconductor laser 78 may be configured such that the center 80C of the aperture 80A and the center 82C of the opening 82A coincide with each other, as in the surface-emitting semiconductor laser 60 of the second embodiment.

[0080] 10, the surface-emitting semiconductor laser 84 has the aperture 80A and opening 82A of the surface-emitting semiconductor laser 78, with the arc-shaped portion of the aperture 80A and the arc-shaped portion of the opening 82A arranged in opposite directions. The rest of the configuration of the surface-emitting semiconductor laser 84 is the same as that of the surface-emitting semiconductor laser 78. In the surface-emitting semiconductor laser 84, the same functions and effects as those of the first embodiment can be obtained in the parts having the same configuration as the surface-emitting semiconductor laser 20 of the first embodiment. Note that the surface-emitting semiconductor laser 84 may be configured such that the center 80C of the aperture 80A and the center 82C of the opening 82A coincide with each other, as in the surface-emitting semiconductor laser 60 of the second embodiment.

[0081] As shown in FIG. 11 , in the surface-emitting semiconductor laser 86, when viewed from the stacking direction, the aperture 88A has a rectangular shape and the opening 82A has a semicircular shape, so that the aperture 88A and the opening 82A have different shapes. Furthermore, the center 82C of the opening 82A is offset from the center 88C of the aperture 88A. Furthermore, the surface-emitting semiconductor laser 86 has a portion where the distance L between the edge 82E of the opening 82A and the edge 88E of the aperture 88A changes continuously along the outer periphery of the aperture 88A when viewed from the stacking direction. Note that in FIG. 11 , the distance L2 refers to the minimum distance between the edge 82E of the opening 82A and the edge 88E of the aperture 88A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 86, the same effects as those of the first embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 20 of the first embodiment. The surface-emitting semiconductor laser 86 may be configured such that the center 88C of the aperture 88A and the center 82C of the opening 82A coincide with each other, as in the surface-emitting semiconductor laser 60 of the second embodiment.

[0082] As shown in FIG. 12 , in the surface-emitting semiconductor laser 90, the aperture 32A has a circular shape and the opening 92A has a rectangular shape when viewed from the stacking direction, so the aperture 32A and the opening 92A have different shapes. Furthermore, the center 92C of the opening 92A is offset from the center 32C of the aperture 32A. Furthermore, the surface-emitting semiconductor laser 90 has a portion where the distance L between the edge 92E of the opening 92A and the edge 32E of the aperture 32A changes continuously along the periphery of the aperture 32A when viewed from the stacking direction. Note that in FIG. 12 , distance L2 refers to the minimum distance between the edge 92E of the opening 92A and the edge 32E of the aperture 32A. Furthermore, distance L1 is longer than distance L2. In the surface-emitting semiconductor laser 90, the same effects as those of the first embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 20 of the first embodiment.

[0083] As shown in FIG. 13 , in the surface-emitting semiconductor laser 94, the aperture 96A has an elliptical shape and the opening 92A has a rectangular shape when viewed from the stacking direction, so the aperture 96A and the opening 92A have different shapes. Furthermore, the center 92C of the opening 92A is offset from the center 96C of the aperture 96A. Furthermore, the surface-emitting semiconductor laser 94 has a portion where the distance L between the edge 92E of the opening 92A and the edge 96E of the aperture 96A changes continuously along the periphery of the aperture 96A when viewed from the stacking direction. Note that in FIG. 13 , the distance L2 refers to the minimum distance between the edge 92E of the opening 92A and the edge 96E of the aperture 96A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 94, the same effects as those of the first embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 20 of the first embodiment.

[0084] As shown in FIG. 14 , in the surface-emitting semiconductor laser 98, when viewed from the stacking direction, the aperture 32A has a circular shape and the opening 100A has a polygonal shape (e.g., a pentagonal shape), so the aperture 32A and the opening 100A have different shapes. Furthermore, the center 100C of the opening 100A is offset from the center 32C of the aperture 32A. Furthermore, the surface-emitting semiconductor laser 98 has a portion where the distance L between the edge 100E of the opening 100A and the edge 32E of the aperture 32A changes continuously along the periphery of the aperture 32A when viewed from the stacking direction. Note that in FIG. 14 , the distance L2 refers to the minimum distance between the edge 100E of the opening 100A and the edge 32E of the aperture 32A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 98, the same effects as those of the first embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 20 of the first embodiment.

[0085] As shown in FIG. 15, in the surface-emitting semiconductor laser 102, when viewed from the stacking direction, the shape of the aperture 104A is semicircular and the shape of the opening 100A is polygonal (e.g., pentagonal), so the shapes of the aperture 104A and the opening 100A are different. Furthermore, the center 100C of the opening 100A is offset from the center 104C of the aperture 104A. Furthermore, when viewed from the stacking direction, the surface-emitting semiconductor laser 102 has a portion where the distance L between the edge 100E of the opening 100A and the edge 104E of the aperture 104A continuously changes along the outer periphery of the aperture 104A. Note that in FIG. 15, the distance L2 refers to the minimum distance between the edge 100E of the opening 100A and the edge 104E of the aperture 104A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 102, the same effects as those of the first embodiment can be obtained in parts having the same configuration as the surface-emitting semiconductor laser 20 of the first embodiment. Note that the surface-emitting semiconductor laser 102 may be configured such that the center 104C of the aperture 104A coincides with the center 100C of the opening 100A, as in the surface-emitting semiconductor laser 60 of the second embodiment.

[0086] As shown in FIG. 16, in surface-emitting semiconductor laser 106, aperture 108A has a circular shape and opening 110A has a polygonal shape (e.g., a star shape) when viewed from the stacking direction, so aperture 108A and opening 110A have different shapes. Furthermore, center 110C of opening 110A is offset from center 108C of aperture 108A. Furthermore, surface-emitting semiconductor laser 106 has a portion where distance L between edge 110E of opening 110A and edge 108E of aperture 108A changes continuously along the outer periphery of aperture 108A when viewed from the stacking direction. Note that distance L2 in FIG. 16 refers to the minimum distance between edge 110E of opening 110A and edge 108E of aperture 108A. Distance L1 is longer than distance L2. In the surface-emitting semiconductor laser 106, the same effects as those of the first embodiment can be obtained in parts having the same configuration as the surface-emitting semiconductor laser 20 of the first embodiment. Note that the surface-emitting semiconductor laser 106 may be configured such that the center 108C of the aperture 108A and the center 110C of the opening 110A coincide with each other, as in the surface-emitting semiconductor laser 60 of the second embodiment.

[0087] In the surface-emitting semiconductor laser 60 of the second embodiment, the aperture 62A has an elliptical shape and the opening 34A has a circular shape when viewed in the stacking direction, but the present disclosure is not limited to this configuration. For example, the surface-emitting semiconductor lasers 112, 116, 120, 124, 128, 132, and 136 shown in Figures 17 to 23 may be used. The surface-emitting semiconductor lasers 112, 116, 120, 124, 128, 132, and 136 will be described below.

[0088] As shown in FIG. 17 , in the surface-emitting semiconductor laser 112, the aperture 32A has a circular shape and the opening 114A has an elliptical shape when viewed from the stacking direction, so that the aperture 32A and the opening 114A have different shapes. Furthermore, the center 32C of the aperture 32A coincides with the center 114C of the opening 114A. Furthermore, the surface-emitting semiconductor laser 112 has a portion where the distance L between the edge 114E of the opening 114A and the edge 32E of the aperture 32A changes continuously along the periphery of the aperture 32A when viewed from the stacking direction. Note that in FIG. 17 , the distance L2 refers to the minimum distance between the edge 114E of the opening 114A and the edge 32E of the aperture 32A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 112, the same effects as those of the second embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 60 of the second embodiment.

[0089] As shown in FIG. 18 , in the surface-emitting semiconductor laser 116, the aperture 32A has a circular shape and the opening 118A has a rectangular shape when viewed from the stacking direction, so that the aperture 32A and the opening 118A have different shapes. Furthermore, the center 32C of the aperture 32A coincides with the center 118C of the opening 118A. Furthermore, the surface-emitting semiconductor laser 116 has a portion where the distance L between the edge 118E of the opening 118A and the edge 32E of the aperture 32A changes continuously along the periphery of the aperture 32A when viewed from the stacking direction. Note that in FIG. 18 , the distance L2 refers to the minimum distance between the edge 118E of the opening 118A and the edge 32E of the aperture 32A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 116, the same effects as those of the second embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 60 of the second embodiment. The shape of the aperture 122A may be elliptical, as in the surface-emitting semiconductor laser 120 shown in Fig. 19. In this surface-emitting semiconductor laser 120, the same effects as those of the second embodiment can be obtained in parts having the same configuration as the surface-emitting semiconductor laser 60 of the second embodiment. In Fig. 19, reference numeral 122E indicates the edge of the aperture 122A. 20, the shape of the aperture 126A may be rectangular. In this surface-emitting semiconductor laser 124, the same effects as those of the second embodiment can be obtained in parts having the same configuration as the surface-emitting semiconductor laser 60 of the second embodiment. Note that the reference numeral 126E in FIG. 20 indicates the edge of the aperture 126A. 21, the shape of the aperture 130A may be rectangular. In this surface-emitting semiconductor laser 128, the same effects as those of the second embodiment can be obtained in parts having the same configuration as the surface-emitting semiconductor laser 60 of the second embodiment. Note that the reference numeral 130E in FIG. 21 indicates the edge of the aperture 130A.

[0090] As shown in FIG. 22, in the surface-emitting semiconductor laser 132, when viewed from the stacking direction, the aperture 32A has a circular shape, and the opening 134A has a polygonal shape (e.g., a pentagon), so the aperture 32A and the opening 134A have different shapes. Furthermore, the center 32C of the aperture 32A coincides with the center 134C of the opening 134A. Furthermore, the surface-emitting semiconductor laser 132 has a portion where the distance L between the edge 134E of the opening 134A and the edge 32E of the aperture 32A changes continuously along the periphery of the aperture 32A when viewed from the stacking direction. Note that in FIG. 22, the distance L2 refers to the minimum distance between the edge 134E of the opening 134A and the edge 32E of the aperture 32A. Furthermore, the distance L1 is longer than the distance L2. In the surface-emitting semiconductor laser 132, the same effects as those of the second embodiment can be obtained in a portion having a configuration similar to that of the surface-emitting semiconductor laser 60 of the second embodiment. 23, the shape of the aperture 138A may be elliptical. In this surface-emitting semiconductor laser 136, the same effects as those of the second embodiment can be obtained in parts having the same configuration as the surface-emitting semiconductor laser 60 of the second embodiment. Note that the reference numeral 138E in FIG. 23 indicates the edge of the aperture 138A.

[0091] Among the above-described embodiments included in the technology of the present disclosure, the examples shown in Figures 3, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 are all examples in which, when viewed from the stacking direction, the distance L between the edge of the opening and the edge of the aperture has a portion where it changes continuously along the outer periphery of the aperture. Also, the examples shown in Figures 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, and 23 are all examples in which, when viewed from the stacking direction, the distance L between the edge of the opening and the edge of the aperture has a portion where it changes continuously and a portion where it changes intermittently along the outer periphery of the aperture. In addition, the examples shown in FIGS. 3, 6, 7 and 17 are all examples in which the distance between the edge of the opening and the edge of the aperture changes continuously over the entire circumference of the aperture when viewed in the stacking direction.

[0092] In the above embodiment, the recess 50 is provided in the second semiconductor multilayer film reflector 30, but the recess 50 does not have to be provided.

[0093] The above describes an embodiment of the surface-emitting semiconductor laser 20. Alternatively, the embodiment may be an optical transmission device including the surface-emitting semiconductor laser 20. This optical transmission device includes an optical transmission section (not shown) that transmits light output from the surface-emitting semiconductor laser 20. This type of optical transmission device enables stable optical transmission even when the operating environment changes, compared to a case where a surface-emitting semiconductor laser having the opening 34A and the aperture 32A of the same shape and the centers 32C of the opening 34A and the aperture 32A aligned when viewed from the stacking direction is used. This allows for increased optical transmission speed.

[0094] In the above embodiment, a GaAs-based surface-emitting semiconductor laser using a semi-insulating GaAs substrate has been described as an example. However, the present invention is not limited to this. A GaN (gallium nitride) substrate or an InP (indium phosphide) substrate may also be used. If the substrate material is changed, the material and narrowing method must be appropriately selected to suit the substrate material. For example, in the case of a GaN substrate, a pair of AlGaN (aluminum gallium nitride) and GaN may be used for the lower DBR (described later), a pair of InGaN (indium gallium nitride) quantum well layer and GaN barrier layer may be used for the active layer, and a dielectric DBR may be used for the upper DBR. In the case of an InP substrate, a pair of InGaAsP with different compositions may be used for the lower DBR, an InGaAsP quantum well layer and barrier layer with different compositions may be used for the active layer, and a dielectric DBR may be used for the upper DBR. Furthermore, when using a GaN substrate and an InP substrate, materials that can be selectively oxidized cannot be used, and oxidation confinement is not possible. Therefore, it is advisable to use current confinement using, for example, a buried tunnel junction.

[0095] In the above embodiment, an n-type contact layer is formed on the substrate, but the present invention is not limited to this and a p-type contact layer may be formed on the substrate. In this case, the n-type and p-type may be reversed in the above description.

[0096] Furthermore, the present disclosure is not limited to the above, and it goes without saying that various modifications can be made without departing from the spirit of the present disclosure.

[0097] The following additional notes are provided regarding the above-described embodiments. (((1))) A substrate; a first semiconductor multilayer film reflector laminated on the substrate; an active layer laminated on the first semiconductor multilayer film reflector; a second semiconductor multilayer reflector including a current confinement layer and stacked on the active layer; a dielectric multilayer reflector stacked on the second semiconductor multilayer reflector; a metal layer disposed between the second semiconductor multilayer film reflector and the dielectric multilayer film reflector, the metal layer having an opening inside which an aperture representing a portion of the current confinement layer that is not oxidized and confined is disposed when viewed from the stacking direction, the center of the opening being shifted from the center of the aperture; A surface-emitting semiconductor laser comprising:

[0098] (((2))) When viewed from the stacking direction, the distance between the edge of the opening and the edge of the aperture has a portion that changes continuously along the outer periphery of the aperture. The surface-emitting semiconductor laser according to (((1))).

[0099] (((3))) When viewed from the stacking direction, at least one edge of the opening and the aperture is curved in an arc. The surface-emitting semiconductor laser according to (((2))).

[0100] (((4))) When viewed from the stacking direction, the distance between the edge of the opening and the edge of the aperture changes continuously over the entire circumference of the aperture. The surface-emitting semiconductor laser according to (((2))).

[0101] (((5))) The aperture is circular or elliptical in shape; The opening is circular or elliptical in shape. The surface-emitting semiconductor laser according to (((4))).

[0102] (((6))) When viewed from the stacking direction, the shape of the opening and the shape of the aperture are the same. The surface-emitting semiconductor laser according to (((5))).

[0103] (((7))) a recess is formed in the top layer of the second semiconductor multilayer film reflector, When viewed from the stacking direction, the recess is disposed inside the aperture, and the center of the recess is shifted from the center of the aperture. The surface-emitting semiconductor laser according to (((1))).

[0104] (((8))) The aperture is circular or elliptical in shape; The recess has a circular or elliptical shape. The surface-emitting semiconductor laser according to (((7))). (((9))) When viewed from the stacking direction, the shape of the recess and the shape of the aperture are the same. The surface-emitting semiconductor laser according to (((8))).

[0105] (((10))) A substrate; a first semiconductor multilayer film reflector laminated on the substrate; an active layer laminated on the first semiconductor multilayer film reflector; a second semiconductor multilayer reflector including a current confinement layer and stacked on the active layer; a dielectric multilayer reflector stacked on the second semiconductor multilayer reflector; a metal layer disposed between the second semiconductor multilayer film reflector and the dielectric multilayer film reflector, the metal layer having an opening inside which an aperture representing a portion of the current confinement layer that is not confined by oxidation is disposed when viewed from the stacking direction, and a plurality of external resonators having different resonance frequencies are formed between the edge of the opening and the edge of the aperture; A surface-emitting semiconductor laser comprising:

[0106] (((11))) a surface-emitting semiconductor laser according to (((1))) or (((10))); an optical transmission section that transmits light output from the surface-emitting semiconductor laser; An optical transmission device comprising:

[0107] According to (((1))), in a configuration in which a metal layer is disposed between a second semiconductor multilayer reflector having a current confinement layer and a dielectric multilayer reflector, the modulation bandwidth of light can be expanded compared to a configuration in which the opening of the metal layer and the aperture of the current confinement layer have the same shape and their centers coincide when viewed from the stacking direction.

[0108] According to (((2))), the modulation band of light can be expanded continuously compared to a configuration in which the distance between the edge of the opening and the edge of the aperture changes intermittently along the outer periphery of the aperture.

[0109] According to (((3))), the modulation band of light can be continuously expanded compared to when the edges of the opening and the aperture are linear.

[0110] According to (((4))), there are no intermittent changing portions, so the modulation band of light can be expanded continuously.

[0111] According to (((5))), the modulation band of light can be continuously expanded compared to when the aperture and opening are each polygonal.

[0112] According to (((6))), the modulation band of light can be continuously expanded compared to when the aperture and the opening have different shapes.

[0113] According to (((7))), the modulation band of light can be expanded compared to a configuration in which the center of the recess and the center of the aperture coincide when viewed from the stacking direction.

[0114] According to (((8))), the modulation band of light can be continuously expanded compared to when the aperture and the recess are each polygonal.

[0115] According to (((9))), the modulation band of light can be continuously expanded compared to when the aperture and the recess have different shapes.

[0116] According to (((10))), in a configuration in which a metal layer is disposed between a second semiconductor multilayer reflector having a current confinement layer and a dielectric multilayer reflector, the modulation bandwidth of light can be expanded compared to a configuration in which a single external resonator is formed between the edge of the opening in the metal layer and the edge of the aperture in the current confinement layer. According to (((11))), in a configuration in which a metal layer is disposed between a second semiconductor multilayer reflector having a current confinement layer and a dielectric multilayer reflector, stable optical transmission becomes possible even when the usage environment changes, compared to a case in which a surface-emitting semiconductor laser is used in which the aperture of the metal layer and the aperture of the current confinement layer have the same shape and their centers coincide when viewed from the stacking direction. [Explanation of symbols]

[0117] 20 Surface-emitting semiconductor laser 22 PCB 26 First Semiconductor Multilayer Reflector 28 Active layer 30 Second semiconductor multilayer mirror 32 Selective oxidation layer 32A aperture 32B Oxidized constriction region 32C center 32E Edge 34 Contact metal (an example of a metal layer) 34A aperture 34C center 34E Edge 44 Dielectric multilayer mirror 50 recess 50C center 50E Edge 200 Main Resonator 202 First external resonator 104 Second external resonator L distance Z stacking direction

Claims

1. A substrate; a first semiconductor multilayer film reflector laminated on the substrate; an active layer laminated on the first semiconductor multilayer film reflector; a second semiconductor multilayer reflector including a current confinement layer and stacked on the active layer; a dielectric multilayer reflector stacked on the second semiconductor multilayer reflector; a metal layer disposed between the second semiconductor multilayer film reflector and the dielectric multilayer film reflector, the metal layer having an opening inside which an aperture representing a portion of the current confinement layer that is not oxidized and confined is disposed when viewed from the stacking direction, the center of the opening being shifted from the center of the aperture; A surface-emitting semiconductor laser comprising:

2. When viewed from the stacking direction, the distance between the edge of the opening and the edge of the aperture has a portion that changes continuously along the outer periphery of the aperture.

2. The surface-emitting semiconductor laser according to claim 1.

3. When viewed from the stacking direction, at least one edge of the opening and the aperture is curved in an arc.

3. The surface-emitting semiconductor laser according to claim 2.

4. When viewed from the stacking direction, the distance between the edge of the opening and the edge of the aperture changes continuously over the entire circumference of the aperture.

3. The surface-emitting semiconductor laser according to claim 2.

5. The aperture is circular or elliptical in shape; The opening is circular or elliptical in shape.

5. The surface-emitting semiconductor laser according to claim 4.

6. When viewed from the stacking direction, the shape of the opening and the shape of the aperture are the same.

6. The surface-emitting semiconductor laser according to claim 5.

7. a recess is formed in the top layer of the second semiconductor multilayer film reflector, When viewed from the stacking direction, the recess is disposed inside the aperture, and the center of the recess is shifted from the center of the aperture.

2. The surface-emitting semiconductor laser according to claim 1.

8. The aperture is circular or elliptical in shape; The recess has a circular or elliptical shape.

8. The surface-emitting semiconductor laser according to claim 7.

9. When viewed from the stacking direction, the shape of the recess and the shape of the aperture are the same.

9. The surface-emitting semiconductor laser according to claim 8.

10. A substrate; a first semiconductor multilayer film reflector laminated on the substrate; an active layer laminated on the first semiconductor multilayer film reflector; a second semiconductor multilayer reflector including a current confinement layer and stacked on the active layer; a dielectric multilayer reflector stacked on the second semiconductor multilayer reflector; a metal layer disposed between the second semiconductor multilayer film reflector and the dielectric multilayer film reflector, the metal layer having an opening inside which an aperture representing a portion of the current confinement layer that is not confined by oxidation is disposed when viewed from the stacking direction, and a plurality of external resonators having different resonance frequencies are formed between the edge of the opening and the edge of the aperture; A surface-emitting semiconductor laser comprising:

11. a surface-emitting semiconductor laser according to claim 1 or 10; an optical transmission section that transmits light output from the surface-emitting semiconductor laser; An optical transmission device comprising:

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