JP3791193B2 - Surface emitting laser element and surface emitting laser element array - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface emitting laser element and a surface emitting laser element array, and more particularly to a surface emitting laser element and a surface emitting laser element array capable of controlling polarization.
[0002]
[Prior art]
In the surface emitting laser element, since the emitted light beam is emitted perpendicular to the active layer, the polarization tends to be irregular. In particular, in order to make the light spot of the light beam emitted from the surface emitting laser element circular, the cross-sectional structure of the optical waveguide of the surface emitting laser element is made to have a highly symmetrical shape such as a circle or a square. Indicates no control at all. For example, a VCSEL (vertical cavity surface emitting laser) device 100 shown in FIG. 14 is a proton injection type VCSEL device that forms an 8 × 8 VCSEL array in which 8 elements are arranged in the row direction and the column direction, respectively. The waveguide structure is 15 μm, the exit window diameter is about 6.7 μm, and the cross section is symmetrical with respect to the center of the exit window. In FIG. 14, reference numeral 102 denotes an upper electrode wiring connected to the upper electrode (p-type electrode), 104 denotes a bonding wire, and 106 denotes a conductor terminal. The electrodes formed on the waveguide are also square, and in such a highly symmetric configuration, the polarization state of the light beam emitted from the VCSEL element corresponding to each pixel varies as shown in FIGS. Indicates the direction. 15 and 16 show the measurement results of the polarization state of each VCSEL element for two 8 × 8 VCSEL arrays. For example, in FIG. 15, the angle of the polarization plane of the VCSEL element corresponding to the pixel P1 is indicated by θ ₁ .
[0003]
Moreover, switching may be caused by the injected current. For this reason, several methods for controlling the polarization have been proposed. For example, Japanese Patent Laid-Open No. 4-242989 proposes a method in which an electrode for injecting a current into an active layer has an anisotropic shape. Japanese Patent Laid-Open No. 5-110198 proposes a method of forming a quantum well structure on a (110) substrate, and Japanese Patent Laid-Open No. 6-302911 proposes to use an optical waveguide having a rectangular or cross structure. .
[0004]
Furthermore, IEEE Photonic technoloy letters, vol.5 pp133-135 (1993) proposed a method of applying uniaxial stress in the (001) plane of a semiconductor substrate by Mukaihara et al., And by Numai et al. (001) A method using an off-substrate is also known (The Institute of Electronics, Information and Communication Engineers IEICE Technical Report OQE-93-104, p43-48 (1993)). Here, the off substrate refers to a substrate cut out in a direction inclined from a crystal axis serving as a reference of the semiconductor substrate material, and the off direction refers to the inclined direction.
[0005]
[Problems to be solved by the invention]
As a method of controlling the polarization of the light emitted from the surface emitting laser element, if the polarization is controlled by making the optical waveguide anisotropic, the cross-sectional shape of the light beam of the surface emitting laser element may be elliptical. There's a problem.
[0006]
In addition, by making the electrode for injecting current into the active layer anisotropic, the charge injected from the electrode diffuses afterwards, in an attempt to control the polarization by making the current density distribution anisotropic. There is a problem that a desired current density distribution cannot be maintained in the optical waveguide.
[0007]
Furthermore, the polarization control by the off-substrate is that the off-direction stress is generated inside the waveguide by using the off-substrate, and this causes the polarization to be aligned, but the paper (The Institute of Electronics, Information and Communication Engineers IEICE Technical Report OQE-) 93-104, p43-48 (1993)), it is not fully controlled in all elements, switching in two polarization states occurs, or the polarization directions are 90 degrees different from each other. Some elements have the same polarization.
[0008]
Polarized light is easily affected by various factors such as the state of the optical waveguide, the amount of current injected from the electrode, the current density distribution, and the substrate temperature, so the electrode that injects current into the active layer is simply made anisotropic. Alternatively, even if an off-substrate is used, even if there is a point where polarization is controlled, the polarization characteristics are likely to be unstable due to changes in the amount of injected current and substrate temperature. For example, when the polarization characteristics of three VCSEL elements 110 formed on the off-substrate 10 as shown in FIG. 17 were measured, the polarization was not controlled. The off-substrate 10 shown in FIG. 17 is a substrate that includes the [001] direction and is inclined by −2 ° (∠CAC ′ = 2 °) with respect to the (100) plane as shown in FIG. FIG. 19 shows the result of measuring the polarization characteristics of the VCSEL element 110 in which the wiring 114 connected to the upper electrode 112 is disposed on the off-substrate 10 so as to be long in the [00-1] direction.
[0009]
As shown in FIGS. 19A, 19B, and 19C, there is an element having relatively good polarization characteristics, but the polarization characteristics are different for each element. The polarization could not be controlled. Thus, the polarization cannot be reliably controlled only by using the off-substrate.
[0010]
The VCSEL element 110 shown in FIG. 17 has a rectangular upper electrode (p-type electrode) 112 that is long in the [01-1] direction. The polarization characteristics of the VCSEL element 110 are the longitudinal direction of the upper electrode 112 (or the longitudinal direction). There was no dependence on the orthogonal direction.
[0011]
The present invention has been made in view of such circumstances, and a surface emitting laser element capable of reliably obtaining a stable and constant polarization state regardless of the substrate temperature, the amount of current injected into the active layer, and the like. An object of the present invention is to provide a surface emitting laser element array.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is formed such that an active layer and a mirror layer positioned above and below the active layer are stacked on a semiconductor substrate, and the vertical direction of the active layer is formed. In the surface emitting laser element that emits light, the active layer and the mirror layer are formed on an inclined surface of the semiconductor substrate inclined at a predetermined angle with respect to a surface including a crystal axis serving as a reference of the semiconductor substrate. An electrode for injecting a current into the active layer through the mirror layer formed on the top of the layer and a wiring for guiding a current to the electrode are formed on the inclined surface, The wiring directly connected to the electrode has a long shape and is formed so that the longitudinal direction thereof substantially coincides with the inclined direction of the inclined surface.
[0013]
According to a second aspect of the present invention, in the surface emitting laser element according to the first aspect, the plane including the crystal axis serving as a reference of the semiconductor substrate material is a (100) plane.
[0014]
According to a third aspect of the invention, the surface-emission laser device according to claim 2, wherein the inclined surface is in the range of contain and (100) plane vs. to + 5 ° from -5 ° to the [001] direction is formed so as to be inclined, the wiring that is directly connected to said electrode, characterized in that it is formed in an elongated shape in the direction obtained by projecting the [010] direction on the inclined surface.
[0015]
According to a fourth aspect of the present invention, in the surface light emitting device according to any one of the first to third aspects, a laser element region including the active layer and mirror layers formed above and below the active layer has an air post structure. An electrode for injecting current into the active layer is formed on the upper surface of the air post, and wiring directly connected to the electrode is formed on the side surface of the air post via an insulating film.
[0016]
According to a fifth aspect of the present invention, an active layer and a mirror layer positioned above and below the active layer are stacked on a semiconductor substrate, and at least the active layer is formed by epitaxial growth, and by proton implantation. In a gain waveguide type surface emitting laser element that emits light in a direction perpendicular to a current confined active layer, it includes the [001] direction and is tilted in a range of −5 ° to + 5 ° with respect to the (100) plane A laser element region formed on the inclined surface of the semiconductor substrate and including the active layer and a mirror layer formed above and below the active layer is formed in an air post structure, and current is supplied to the active layer on the upper surface of the air post. An electrode for injection is formed, and a wiring for guiding current to the electrode via the insulating film on the side surface intersecting the [010] direction of the air post has the [010] direction on the inclined surface. It is characterized in being formed so as to be directly connected to the electrode with elongated in the direction projected on.
[0017]
A sixth aspect of the present invention is characterized in that a plurality of the surface emitting laser elements according to any one of the first to fifth aspects are arranged two-dimensionally and a matrix wiring is applied to each of the surface emitting elements. .
[0018]
According to the first to fifth aspects of the present invention, the shape near the electrode of the wiring directly connected to the off-direction of the semiconductor substrate and the electrode for injecting current into the active layer is formed in a long shape, and the length thereof The direction in which the off-direction of the semiconductor substrate matches the direction in which the stress is generated in the optical waveguide due to the use of the off-substrate, and the portion where the current density of the current injected into the optical waveguide is large. Therefore, the polarization is controlled, and stable polarization characteristics can be maintained even if the amount of current injected into the active layer and the substrate temperature change.
[0019]
According to the invention described in claims 4 and 5, the laser element region is formed in an air post structure, and the wiring directly connected to the electrode for injecting current into the active layer is provided in the off direction of the semiconductor substrate through the insulating film. The direction in which the stress is generated in the optical waveguide due to the use of the off-substrate and the direction in which the stress is applied to the air post due to the wiring being attached to the air post are formed. As a result, the polarization is controlled more firmly, and stable polarization characteristics can be maintained even if the amount of current injected into the active layer and the substrate temperature change.
[0020]
Further, according to the invention described in claim 6, since the plurality of surface emitting laser elements obtained by the invention described in claims 1 to 5 are two-dimensionally arranged, the active layer of the surface emitting laser element is obtained. A surface-emitting laser element array suitable as a light source for an image forming apparatus such as a printer or a copier, or an image display apparatus having stable polarization characteristics with respect to fluctuations in the injection current to the substrate and the substrate temperature can be obtained.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
First embodiment of the present invention A configuration of a surface emitting laser element according to a first embodiment of the present invention will be described. First, FIG. 1 shows the configuration of a surface emitting laser element array to which the present invention is applied. In this figure, an n-GaAs substrate 10 as a semiconductor substrate is -2 ° (２) in the [010] direction with respect to the (100) plane (plane passing through points A, B, C, D) as shown in FIG. CAC ′ = 2 °) is a (100) -plane off-substrate cut out so as to be inclined, and on the inclined surface S _I (surface passing through points A, B ′, C ′, D ′) of the n-GaAs substrate 10. It is to inject current into the active layer of the laser element 01-1] projection direction obtained by projecting the direction the inclined surface S _I (hereinafter, projection direction for convenience, be. to be displayed in the direction of the front projection) extends A plurality of surface-emitting laser elements (VCSEL) 12 in which long upper wirings (p-type electrode wirings) 16 directly connected to the p-type electrode 14 are formed. The upper wiring 16 is formed so that the longitudinal direction substantially coincides with the [010] direction. 3 to 5 show the structure of the surface emitting laser element array. 3 is a plan view showing a planar structure of a single surface emitting laser element in the surface emitting laser array, FIG. 4 is a sectional view taken along line XX ′ in FIG. 3, and FIG. 5 is taken along line YY ′ in FIG. It is sectional drawing. In these figures, an n ⁺ -GaAs buffer layer 20 and n-Al _0.3 Ga _0.7 As / Al _0.9 Ga _0.1 As are formed on the inclined surface of the n-GaAs substrate 10 by using a metal organic chemical vapor deposition (MOCVD) method. A lower distributed Bragg reflecting film (DBR) mirror 22 made of and an upper distributed Bragg reflecting film (DBR) mirror 26 made of p-Al _0.3 Ga _0.7 As / Al _0.9 Ga _0.1 As are laminated. Between the upper DBR mirror 26 and the lower DBR mirror 22, Al _0.6 Ga _0.4 As spacer layers 28 and 28, and an active layer 24 (Al _0.12 Ga _{0.88 at} the center of the Al _0.6 Ga _0.4 As spacer layers 28 and 28). A triple quantum well structure is formed by three quantum well layers of 90 mm thick formed of As and four layers of barrier layers of 50 mm thick formed of Al _0.3 Ga _0.7 As. ing.
In order to confine the current, protons are injected into the upper DBR mirror 26 leaving a region having a diameter of 10 μm to form a proton injection region 30. Next, etching is performed from the surface until reaching the n ⁺ -GaAs buffer layer 20 to form an air post (mesa) long in the [01-1] direction of 20 × 35 μm. After the side surface of the air post is insulated with the polyimide 34, a metal to be the p-type electrode 14 is deposited. An n-type electrode 32 was formed on the entire back surface of the n-GaAs substrate 10 by vapor deposition. The p-type electrode 14 formed on the upper portion is provided with an emission window 11 having a diameter of about 6 μm in order to extract emitted light. As shown in FIG. 3, the p-type electrode 14 is directly connected to an elongated p-type electrode wiring 16 elongated in the [010] direction, and the p-type electrode wiring 16 is connected to an electrode pad 18 (not shown in FIG. (See FIG. 1).
[0023]
In this way, the surface emitting laser element 12 in which the longitudinal direction of the p-type electrode wiring 16 coincides with the [010] direction is formed on the inclined surface of the off substrate 10 inclined with respect to the [010] direction. When a plurality of surface-emitting laser elements 12 having such a structure are manufactured, all the surface-emitting laser elements 12 are in the off direction of the n-GaAs substrate 10 and in the longitudinal direction of the p-type electrode wiring 16 [010] ] Laser light linearly polarized in the direction was emitted.
[0024]
FIG. 6 shows the relationship between the injection current I injected into the active layer 24 from the p-type electrode 14 and the laser output P in the surface emitting laser element 12. As shown in FIG. 6, even when the injection current I to the active layer 24 is increased, the laser output characteristics are stable, and the polarization is completely controlled in the [010] direction.
[0025]
Further, even when the substrate temperature was changed from 10 to 60 ° C., the polarization direction was constant, and the switching of the polarization direction and the oscillation of light polarized in directions other than the [010] direction did not occur. Of course, no light was generated that oscillated with the long axis direction [01-1] of the p-type electrode 14.
[0026]
According to the surface-emitting laser device according to the first embodiment of the present invention, the shape in the vicinity of the electrode of the wiring directly connected to the off-direction of the semiconductor substrate and the electrode for injecting current into the active layer is elongated. Since the length direction and the off direction of the semiconductor substrate coincide with each other, the direction in which stress is generated in the optical waveguide by using the off substrate and the current density of the current injected into the optical waveguide Therefore, the polarization can be controlled, and stable polarization characteristics can be maintained even if the amount of current injected into the active layer or the substrate temperature changes.
[0027]
Further, according to the first embodiment of the present invention, the laser element region is formed in the air post structure, and the wiring directly connected to the electrode for injecting current into the active layer is in the off direction of the semiconductor substrate via the insulating film. The direction in which the stress is generated in the optical waveguide due to the use of the off-substrate and the direction in which the stress is applied to the air post due to the attachment of the wiring to the air post As a result, the polarization is controlled more firmly, and stable polarization characteristics can be maintained even when the amount of current injected into the active layer and the substrate temperature change.
[0028]
In the present embodiment, the surface emitting laser element having the air post structure has been described. However, the present invention is not limited to this. For example, the same effect can be obtained even when applied to a surface emitting laser element having a flat structure.
[0029]
Second embodiment of the present invention Next, the configuration of a surface emitting laser element array according to a second embodiment of the present invention will be described. FIG. 7 shows a planar structure of a surface emitting laser element array according to the second embodiment of the present invention. In FIG. 8, a GaAs substrate 10 ′ as a semiconductor substrate includes a [001] direction (arrow B′D ′ direction) and passes through a (100) plane (points A, B, C, D) as shown in FIG. (100) plane semi-insulating GaAs off-substrate cut so as to be inclined by −2 ° (∠CAC ′ = 2 °) with respect to the surface), and the inclined surface S _I ( On the surface passing through the points A, B ′, C ′, and D ′), the long upper wiring 16 extending in the [010] direction directly to the p-type electrode 14 ′ for injecting current into the active layer of the laser element. The surface emitting laser elements (VCSEL) 12 ′ thus configured are formed so as to be arranged in 3 × 3 in 3 rows and 3 columns. 32 'is an n-type electrode wiring.
9 to 11 show the structure of the surface emitting laser element array. 9 is a plan view showing a planar structure of a single surface emitting laser element in the surface emitting laser array, FIG. 10 is a sectional view taken along line XX ′ in FIG. 9, and FIG. 11 is taken along line YY ′ in FIG. It is sectional drawing. In these figures, an n ⁺ -GaAs buffer layer 20 ′ and n-Al _0.3 Ga _0.7 As / Al _0.9 Ga are formed on the inclined surface of the semi-insulating substrate 10 ′ by using a metal organic chemical vapor deposition (MOCVD) method. _A lower distributed Bragg reflecting film (DBR) mirror 22 ′ made of _0.1 As and an upper distributed Bragg reflecting film (DBR) mirror 26 ′ made of p-Al _0.3 Ga _0.7 As / Al _0.9 Ga _0.1 As are laminated. Between the upper DBR mirror 26 ′ and the lower DBR mirror 22 ′, Al _0.6 Ga _0.4 As spacer layers 28 ′ and 28 ′ and an active layer at the center of the Al _0.6 Ga _0.4 As spacer layers 28 ′ and 28 ′. A triple quantum well structure is formed by 3 layers of 90Å thick quantum well layers made of 24 '(Al _0.12 Ga _0.88 As) and 4 layers of 50Å thick barrier layers made of Al _0.3 Ga _0.7 As. Was provided.
For current confinement, protons are implanted leaving a 10 μm diameter region in the upper DBR mirror 26 ′ to form a proton implantation region. Next, etching is performed from the surface until reaching the n ⁺ -GaAs buffer layer 20 ′, thereby forming a long air post (mesa) of [01-1] of 20 × 35 μm. An n-type electrode wiring 32 ′ is provided in the vicinity of the air post using a vapor deposition method, and further, the side surface of the air post is insulated with polyimide 34 ′, and then a metal to be the p-type electrode 14 ′ is vapor-deposited. As apparent from FIG. 9, the n-type electrode wiring 32 ′ is formed along the long axis [01-1] of the air post. The p-type electrode 14 ′ formed on the upper part of the air post is provided with an exit window 11 ′ having a diameter of about 6 μm in order to extract the emitted light. As shown in FIG. 9, the p-type electrode 14 ′ is formed so as to be connected to an electrode pad (not shown) by a p-type electrode wiring 16 ′ that is long in the [010] direction.
[0030]
In this way, the surface emitting laser element in which the longitudinal direction of the p-type electrode wiring 16 ′ coincides with the [010] direction is formed on the off-substrate 10 ′ inclined with respect to the [010] direction. When the surface emitting laser element array arranged in 3 rows and 3 columns as shown in FIG. 7 having such a structure is manufactured, all the surface emitting laser elements are in the off direction of the semi-insulating substrate 10 ′, and Laser light linearly polarized in the [010] direction, which is the longitudinal direction of the p-type electrode wiring 16 ', was emitted. FIGS. 12A and 12B show the relationship between the injection current I injected into the active layer 24 ′ from the p-type electrode 14 ′ and the laser output P for the two surface emitting laser elements 12 ′.
[0031]
As shown in FIG. 12, the laser output characteristics are stable even when the injection current I is increased in both the surface emitting laser elements 12 ′, and the polarization is completely controlled in the [010] direction.
[0032]
Further, even when the substrate temperature was changed from 10 to 60 ° C., the polarization direction was constant, and the switching of the polarization direction and the oscillation of light polarized in directions other than the [010] direction did not occur. Furthermore, no light oscillated in accordance with the longitudinal direction [01-1] of the p-type electrode 14 ′ was generated.
[0033]
In the embodiment of the present invention, the off direction and the p-type electrode wiring direction of the semiconductor substrate are the [010] direction. However, the present invention is not limited to this. There is no problem even if it is aligned with the [011] and [01-1] directions. In the present invention, it is important to match the off direction of the semiconductor substrate with the longitudinal direction of the p-type wiring for injecting current into the active layer of the surface emitting laser element.
[0034]
In the first and second embodiments of the present invention, in the gain waveguide surface emitting laser element, the active layer is inclined by −2 ° in a plane including the [001] direction with respect to the (100) plane. Although the off-substrate formed on the surface has been described, the present invention is not limited to this, and the active layer is inclined in a range of −5 ° to + 5 ° in a plane including the [001] direction with respect to the (100) plane. The same effect was obtained when it was formed on the semiconductor substrate surface.
[0035]
The surface-emitting laser element and the surface-emitting laser array according to the present invention are also effective for structures other than those shown in the first and second embodiments. For example, the cross-sectional shape of the air post may be a symmetrical shape such as a circle or a square, and the longitudinal direction of the air post may be aligned with the off direction. An example of this is shown in FIG. In FIG. 13, as in the first and second embodiments, the surface light emitting elements 50 and 51 having a circular cross section and the surface light emitting element 52 having a rectangular cross section on the semiconductor substrate 10 whose off direction is [010]. , 54 are formed. The upper electrodes (p-type electrodes) 50A, 51A, 52A, 54A of the surface light emitting elements 50, 51, 52, 54 are wirings 60, 61, 62 formed in the same [010] direction as the off direction of the semiconductor substrate 10, respectively. 63, and these wirings 60, 61, 62, 63 are connected to the electrode pad 70, respectively. A current is supplied from each electrode pad 70 to each p-type electrode 50A, 51A, 52A, 54A, and a current is injected into the active layer of each surface emitting laser element.
[0036]
According to the second embodiment of the present invention, since the plurality of surface emitting laser elements obtained by the present invention are arranged two-dimensionally, the injection current into the active layer of the surface emitting laser element and the A surface emitting laser element array suitable for light sources such as an image forming apparatus such as a printer or a copier, or an image display apparatus having stable polarization characteristics with respect to fluctuations in the substrate temperature or the like can be obtained.
[0037]
【The invention's effect】
According to the first to fifth aspects of the present invention, the shape near the electrode of the wiring directly connected to the off-direction of the semiconductor substrate and the electrode for injecting current into the active layer is formed in a long shape, and the length thereof The direction in which the off-direction of the semiconductor substrate matches the direction in which the stress is generated in the optical waveguide due to the use of the off-substrate, and the portion where the current density of the current injected into the optical waveguide is large. Therefore, the polarization is controlled, and stable polarization characteristics can be maintained even if the amount of current injected into the active layer and the substrate temperature change.
[0038]
According to the invention described in claims 4 and 5, the laser element region is formed in an air post structure, and the wiring directly connected to the electrode for injecting current into the active layer is provided in the off direction of the semiconductor substrate through the insulating film. The direction in which the stress is generated in the optical waveguide due to the use of the off-substrate and the direction in which the stress is applied to the air post due to the wiring being attached to the air post are formed. As a result, the polarization is controlled more firmly, and stable polarization characteristics can be maintained even if the amount of current injected into the active layer and the substrate temperature change.
[0039]
Further, according to the invention described in claim 6, since the plurality of surface emitting laser elements obtained by the invention described in claims 1 to 6 are arranged two-dimensionally, the active layer of the surface emitting laser element A surface-emitting laser element array suitable as a light source for an image forming apparatus such as a printer or a copier, or an image display apparatus having stable polarization characteristics with respect to fluctuations in the injection current to the substrate and the substrate temperature can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of a surface emitting laser element according to a first embodiment of the present invention.
FIG. 2 is an explanatory view showing an inclination direction of the off-substrate shown in FIG.
FIG. 3 is a plan view showing a planar structure of the surface emitting laser element according to the first embodiment of the invention.
4 is a cross-sectional view taken along line XX ′ in FIG.
5 is a cross-sectional view taken along line YY ′ in FIG.
FIG. 6 is a characteristic diagram showing a measurement example of the relationship between the laser output and the injection current into the active layer of the surface emitting laser element according to the first embodiment of the invention.
FIG. 7 is a plan view showing a planar structure of a surface emitting laser element array according to a second embodiment of the present invention.
8 is an explanatory diagram showing an inclination direction of the off-substrate shown in FIG.
9 is a plan view showing a planar structure of a single surface emitting laser element in the surface emitting laser array shown in FIG.
10 is a cross-sectional view taken along line XX ′ in FIG.
11 is a cross-sectional view taken along line YY ′ in FIG. 9;
FIG. 12 is a characteristic diagram showing a measurement example of the relationship between the laser output P and the injection current I injected into the active layer for two surface emitting laser elements.
FIG. 13 is a plan view showing a planar structure of a modification of the surface emitting laser element according to the present invention.
FIG. 14 is a plan view showing a specific planar configuration of a conventional surface emitting laser element array.
FIG. 15 is an explanatory view showing a measurement result of a polarization state of each surface emitting laser element of a conventional surface emitting laser element array.
FIG. 16 is an explanatory view showing a measurement result of a polarization state of each surface emitting laser element of a conventional surface emitting laser element array.
FIG. 17 is a plan view showing a planar structure of a surface emitting laser element array formed on a conventional off-substrate.
18 is an explanatory diagram showing an inclination direction of the off-substrate shown in FIG.
FIG. 19 is a characteristic diagram showing a measurement result of polarization characteristics of each surface emitting laser element of the surface emitting laser element array shown in FIG. 17;
[Explanation of symbols]
10 n-GaAS substrate 11 exit window 12 surface emitting laser element 14 p-type electrode 16 upper wiring (p-type electrode wiring)
18 p-type electrode pad 20 n ⁺ GaAs buffer layer 22 Lower distributed Bragg reflector (DBR) mirror 24 Active layer 26 Upper distributed Bragg reflector (DBR) mirror 28 Spacer layer 30 Proton injection region 32 N-type wiring 34 Insulating film

Claims (6)

In a surface-emitting laser device that is formed so that an active layer and mirror layers positioned above and below the active layer are stacked on a semiconductor substrate and emits light in a direction perpendicular to the active layer,
The active layer and the mirror layer are formed on an inclined surface of the semiconductor substrate inclined at a predetermined angle with respect to a surface including a crystal axis serving as a reference of the semiconductor substrate, and the mirror layer formed on the active layer An electrode for injecting a current through the active layer and a wiring for guiding the current to the electrode are formed on the inclined surface,
A surface-emitting laser element characterized in that a wire directly connected to the electrode among the wires is elongated and formed such that the longitudinal direction thereof substantially coincides with the inclined direction of the inclined surface.   2. The surface emitting laser element according to claim 1, wherein a plane including a crystal axis serving as a reference of the semiconductor substrate material is a (100) plane. The inclined surface includes the [001] direction and is formed to be inclined in a range of −5 ° to + 5 ° with respect to the (100) plane, and the wiring directly connected to the electrode extends in the [010] direction. surface-emitting laser element according to claim 2, characterized in that it is formed in an elongated shape in the direction projected on the inclined surface.   A laser element region including the active layer and a mirror layer formed above and below the active layer is formed in an air post structure, and an electrode for injecting current into the active layer is formed on the upper surface of the air post. 4. The surface emitting laser element according to claim 1, wherein the directly connected wiring is formed on the side surface of the air post via an insulating film. An active layer and a mirror layer positioned above and below the active layer are stacked on a semiconductor substrate, and at least the active layer is formed by epitaxial growth, and a vertical direction of the active layer in which current is confined by proton implantation In a gain waveguide surface emitting laser element that emits light to
Formed on the inclined surface of the semiconductor substrate including the [001] direction and inclined in a range of −5 ° to + 5 ° with respect to the (100) plane, and formed on the active layer and the upper and lower portions of the active layer. A laser element region including a mirror layer is formed in an air post structure, an electrode for injecting current into the active layer is formed on an upper surface of the air post, and an insulating film is provided on a side surface crossing the [010] direction of the air post. Te, wiring for directing current to the electrode is characterized in that it is formed so as to be connected [010] in the direction of the direction projected onto the inclined surface directly to the electrodes in the elongate faces Light emitting laser element.   6. A surface-emitting laser element array, wherein a plurality of surface-emitting laser elements according to claim 1 are arranged two-dimensionally, and matrix wiring is applied to each surface-emitting element.

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