Semiconductor light emitter

Abstract

To provide a semiconductor light emitter capable of shaping light in a lateral direction of a luminous flux emitted diagonally from a semiconductor laminated structure.SOLUTION: A semiconductor light emitter includes: a substrate; a semiconductor laminated structure including a light emitting part emitting light in an emission region in a longitudinal direction and a lateral direction orthogonal to the longitudinal direction, diagonally with respect to the substrate; and a shaping optics shaping a luminous flux emitted from the light emitting part. A lens closest to the light emitting part in the shaping optics is a cylindrical lens having positive power in the lateral direction. The front main plane of the cylindrical lens is parallel to the light emitting part, and the generatrix direction of the cylindrical lens is parallel to the longitudinal direction. When D represents a distance from the light emitting part to the light incident surface of the cylindrical lens, HA represents a distance from the light incident surface of the cylindrical lens to the front main plane, and f represents the focal length of the cylindrical lens, the following conditional expression (1) is satisfied. D<f-HA...(1)SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a semiconductor light emitter. [Background technology]

[0002] Patent Document 1 discloses a semiconductor laminated structure using a distributed Bragg reflector waveguide, the semiconductor laminated structure having a light source unit that emits laser light, and an optical amplification unit that is formed on a substrate and has an active region that extends from the light source unit in a predetermined direction along the substrate surface of the substrate, amplifies the propagating light that propagates in a predetermined direction from the light source unit, and emits the amplified propagating light as output light in a direction oblique to the substrate surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-136655 A Summary of the Invention [Problem to be solved by the invention]

[0004] The light emitted from the light emitting portion of the semiconductor laminated structure as described above has plane wave characteristics in the longitudinal direction (the same as the extension direction) and spherical wave characteristics in the lateral direction. Therefore, the light beam emitted from the light emitting portion of the semiconductor laminated structure becomes almost parallel light in the longitudinal direction, whereas in the lateral direction it becomes diffuse light compared to the light from the longitudinal direction. Therefore, unless the lateral direction of the light beam emitted from the semiconductor laminated structure is also first shaped into parallel light, the light beam emitted from the semiconductor laminated structure may not be effectively used. In addition, the light characteristics of the light emitted in an oblique direction and the light emitted in a perpendicular direction are different.

[0005] An object of the present invention is to provide a semiconductor light emitter capable of shaping light in the shorter direction of a light beam emitted obliquely from a semiconductor laminate structure. [Means for solving the problem]

[0006] A semiconductor light emitter of a first aspect of the present invention comprises a substrate, a semiconductor laminate structure having a light emitting portion that emits light in a direction oblique to the substrate, at an emission region in a longitudinal direction and a lateral direction perpendicular to the longitudinal direction, and a shaping optical system that shapes a light flux emitted from the light emitting portion, wherein the lens in the shaping optical system closest to the light emitting portion is a cylindrical lens having positive power in the lateral direction, a front principal plane of the cylindrical lens is parallel to the light emitting portion, and a generatrix direction of the cylindrical lens is parallel to the longitudinal direction, and wherein the semiconductor light emitter satisfies the following conditional formula (1): D is the distance from the light emitting portion to the light incident surface of the cylindrical lens, HA is the distance from the light incident surface of the cylindrical lens to the front principal plane, and f is the focal length of the cylindrical lens. D <f-HA …(1)

[0007] A semiconductor light emitter according to a second aspect of the present invention is the semiconductor light emitter according to the first aspect, wherein the semiconductor laminate structure includes an optical amplifier section that amplifies light by propagating it in the longitudinal direction.

[0008] A semiconductor light emitter of a third aspect of the present invention is a semiconductor light emitter of the first or second aspect, which satisfies the following conditional formula (2): f <L / (2×tan(θw / 2)) …(2)

[0009] A semiconductor light emitter according to a fourth aspect of the present invention is the semiconductor light emitter according to the third aspect, which satisfies the following conditional formula (3). 0.4L<2×f×tan(θw / 2) <L …(3)

[0010] A semiconductor light emitter of a fifth aspect of the present invention is a semiconductor light emitter of any one of the first to fourth aspects, wherein one end of the cylindrical lens in the longitudinal direction is offset relative to one end of the light emitting portion in the longitudinal direction.

[0011] A semiconductor light emitter of a sixth aspect of the present invention is a semiconductor light emitter of any one of the first to fifth aspects, comprising a plurality of semiconductor laminate structures, the plurality of semiconductor laminate structures being arranged so that the longitudinal directions of the respective light emitting portions are parallel to each other, and the shaping optical system has an optical axis that is the center of the plurality of semiconductor laminate structures and a positive lens that forms an image of the light beams emitted from the plurality of semiconductor laminate structures.

[0012] A semiconductor light emitter of a seventh aspect of the present invention is a semiconductor light emitter of any one of the first to fifth aspects, which comprises a plurality of semiconductor laminate structures, and the shaping optical system comprises a plurality of cylindrical lenses corresponding to each of the plurality of semiconductor laminate structures and a positive lens that forms an image of the light beam emitted from the plurality of cylindrical lenses, and the plurality of semiconductor laminate structures are arranged so that the imaging positions of the light beams emitted from the semiconductor laminate structures coincide.

[0013] A semiconductor light emitter of an eighth aspect of the present invention is a semiconductor light emitter of any one of the first to seventh aspects, wherein the shaping optical system includes a cylindrical lens and a positive lens that forms an image of the light beam emitted from the cylindrical lens, and an aperture is provided between the cylindrical lens and the positive lens.

[0014] A semiconductor light emitter of a ninth aspect of the present invention is a semiconductor light emitter of any one of the first to eighth aspects, wherein at least one lens in the shaping optical system has a size that transmits only the main diffracted light in the light beam emitted from the semiconductor laminate structure.

[0015] A semiconductor light emitter according to a tenth aspect of the present invention is the semiconductor light emitter according to any one of the first to ninth aspects, wherein the shaping optical system includes a wavelength filter. Effect of the Invention

[0016] According to the semiconductor light emitter of the first aspect of the present invention, it is possible to shape light in the short direction of a light flux emitted obliquely from a semiconductor laminate structure.

[0017] According to the semiconductor light emitter of the second aspect of the present invention, it is possible to emit amplified light.

[0018] According to the semiconductor light emitter of the third aspect of the present invention, it is possible to improve the transmittance at the cylindrical lens of the light emitted from the semiconductor laminate structure, as compared with a configuration that does not satisfy conditional formula (2).

[0019] According to the semiconductor light emitter of the fourth aspect of the present invention, it is possible to make the aspect ratio of the beam diameter of the light emitted from the semiconductor laminate structure after passing through the cylindrical lens uniform, compared to a configuration that does not satisfy conditional formula (3).

[0020] According to the semiconductor light emitter of the fifth aspect of the present invention, it is possible to suppress stray light in the shaping optical system.

[0021] According to the semiconductor light emitter of the sixth aspect of the present invention, it is possible to improve the light output, as compared with the case where only one semiconductor laminate structure is provided.

[0022] According to the semiconductor light emitter of the seventh aspect of the present invention, it is possible to improve the light output, as compared with the case where only one semiconductor laminate structure is provided.

[0023] According to the semiconductor light emitter of the eighth aspect of the present invention, it is possible to suppress stray light in the shaping optical system.

[0024] According to the semiconductor light emitter of the ninth aspect of the present invention, it is possible to suppress stray light in the shaping optical system.

[0025] According to the light output device of the tenth aspect of the present invention, it is possible to suppress stray light within the shaping optical system. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic configuration diagram of a semiconductor light emitter according to a first embodiment. [Diagram 2] 1 is a plan view of a semiconductor laminated structure according to a first embodiment. [Diagram 3] 3 is a cross-sectional view taken along line AA' shown in FIG. 2. [Figure 4] 1 is a front view of a semiconductor light emitter according to a first embodiment. [Diagram 5] 2 is a side view showing the positional relationship between a semiconductor laminated structure and a shaping optical system in the first embodiment. FIG. [Figure 6] 2 is a top view showing the positional relationship between a semiconductor laminated structure and a shaping optical system in the first embodiment. FIG. [Figure 7] 7A and 7B are diagrams showing the positional relationship between a semiconductor laminate structure and a cylindrical lens when light is emitted vertically from the semiconductor laminate structure, where FIG. 7(a) shows the state of both in the longitudinal direction, and FIG. 7(b) shows the state of both in the short direction. [Figure 8] 8A and 8B are diagrams showing the positional relationship between an actual semiconductor laminate structure and a cylindrical lens, where FIG. 8A shows the state of both in the longitudinal direction, and FIG. 8B shows the state of both in the short direction. [Figure 9] 9A and 9B are diagrams showing the light amount distribution of light emitted from a semiconductor laminated structure, in which FIG. 9A shows the state in the longitudinal direction, and FIG. 9B shows the states of both in the lateral direction. [Figure 10] 13 is a graph showing the light amount distribution when the focal length f is changed to change the ratio α of the LD in the longitudinal direction to the element length L. [Figure 11] 11 is a graph showing the relationship between the aspect ratio of the beam diameter and the transmittance when an image is formed using a spherical lens with a focal length of 30 mm, for the light quantity distribution characteristic shown in FIG. 10. [Figure 12] 11 is a graph showing the relationship between the ratio α of the effective light flux width (half width) in the short side direction to the element length in the long side direction and the energy density for the light amount distribution characteristic shown in FIG. [Figure 13]FIG. 4 is a side view showing a modified example of the shaping optical system in the first embodiment. [Figure 14] FIG. 4 is a plan view of another type of semiconductor laminated structure according to the first embodiment. [Figure 15] 15 is a cross-sectional view taken along line AA' shown in FIG. 14. [Figure 16] FIG. 11 is a plan view of a semiconductor laminated structure according to still another embodiment of the first embodiment. [Figure 17] 17 is a cross-sectional view taken along line AA' shown in FIG. 16. [Figure 18] FIG. 11 is a plan view of a semiconductor laminated structure according to still another embodiment of the first embodiment. [Figure 19] 19 is a cross-sectional view taken along line AA' shown in FIG. 18. [Figure 20] 13 is a schematic configuration diagram showing a semiconductor laminate structure and a shaping optical system of a semiconductor light emitter according to a second embodiment. FIG. [Figure 21] 13 is a schematic configuration diagram showing a semiconductor laminate structure and a shaping optical system of a semiconductor light emitter according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0028] [First embodiment] A semiconductor light emitter 10 according to the present embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of the semiconductor light emitter 10.

[0029] As shown in FIG. 1, a semiconductor light emitter 10 includes a substrate 11, a semiconductor laminate structure 20 having a light emitting portion that emits light obliquely relative to the substrate 11 in an emission region in a longitudinal direction LD and a short direction SD perpendicular to the longitudinal direction LD, and a shaping optical system 12 that shapes the light beam emitted from the light emitting portion.

[0030] The semiconductor laminated structure 20 may be any element as long as it is a semiconductor laminated structure having a light emitting portion that emits light in an oblique direction with respect to the substrate 11 at an emission region in a longitudinal direction LD and a short direction SD perpendicular to the longitudinal direction LD. In the present embodiment, the semiconductor laminated structure 20 is, as an example, a surface emission type semiconductor laminated structure using a DBR (Distributed Bragg Reflector) waveguide.

[0031] Fig. 2 is a plan view of the semiconductor laminated structure 20, and Fig. 3 is a cross-sectional view taken along line A-A' shown in Fig. 2. As shown in Fig. 2 and Fig. 3, the semiconductor laminated structure 20 includes a light emitting section 50 and an optical amplifier 52 that extends from the light emitting section 50 in the longitudinal direction LD and amplifies light by propagating it in the longitudinal direction LD.

[0032] The light emitting unit 50 is a part that generates the seed light Ls, and is configured as a VCSEL (Vertical Cavity Surface Emitting Laser) in this embodiment. As shown in FIG. 3, the seed light Ls generated from the light emitting unit 50 propagates toward the optical amplifying unit 52.

[0033] The optical amplifier 52 has a function of amplifying and emitting seed light Ls, which is light generated in the light emitter 50. The optical amplifier 52 according to the present embodiment is a surface emission type optical amplifier that uses a GaAs-based distributed Bragg reflector waveguide (hereinafter, "DBR waveguide"), as an example.

[0034] The semiconductor laminated structure 20 is composed of a lower DBR 32, an active region 34, a non-conductive region 60, an upper DBR 36, an insulating portion 54, a first P electrode 41, and a second P electrode 42 formed on the base layer 30, as well as an N electrode 40 formed on the back surface of the base layer 30.

[0035] In this embodiment, base layer 30 is an n-type GaAs substrate, and N-electrode 40 is provided on the back surface of base layer 30. Meanwhile, lower DBR 32 in this embodiment is n-type, and upper DBR 36 as a whole is p-type.

[0036] The lower DBR 32 is paired with an upper DBR 36 described below to form a light source that generates light in the light emitting section 50, and a resonator that amplifies and emits the light in the optical amplification section 52.

[0037] The lower DBR 32 is a multilayer reflector configured by alternately stacking two semiconductor layers having different refractive indices and a thickness of 0.25λ / n, where λ is the oscillation wavelength of the semiconductor laminated structure 20 and n is the refractive index of the medium (semiconductor layer). As a specific example, the lower DBR 32 is configured by alternately stacking an n-type low refractive index layer made of Al0.90Ga0.1As and an n-type high refractive index layer made of Al0.2Ga0.8As.

[0038] The active region 34 according to this embodiment may include, for example, a lower spacer layer, a quantum well active region, and an upper spacer layer (not shown). The quantum well active region according to this embodiment may include, for example, four barrier layers made of Al0.3Ga0.7As and three quantum well layers made of GaAs provided therebetween. The lower spacer layer and the upper spacer layer are disposed between the quantum well active region and the lower DBR 32 and between the quantum well active region and the upper DBR 36, respectively, to adjust the length of the resonator and also to function as a cladding layer for confining carriers.

[0039] The non-conductive region 60 and the conductive region 58 provided on the active region 34 are p-type oxide confinement layers, i.e., current confinement layers. That is, the non-conductive region 60 corresponds to an oxidized region, and the conductive region 58 corresponds to a non-oxidized region. The interface between the conductive region 58 and the non-conductive region 60 forms an oxidation front 56.

[0040] In this embodiment, one layer of the multilayer film constituting the lower DBR 32 is oxidized to form a non-conductive region 60 (oxidized region), and the region other than this one non-conductive region 60 serves as an unoxidized conductive region 58 (non-oxidized region). The current flowing from the first P electrode 41 and the second P electrode 42 to the N electrode 40 is restricted by the conductive region 58.

[0041] In this embodiment, an example is given of a form in which the non-conductive region 60 (oxidized region) is formed in one layer of the lower DBR 32, but the present invention is not limited to this and may be formed in multiple layers of the lower DBR 32, or may be formed in the upper DBR 36.

[0042] The upper DBR 36 includes a p-DBR 66, a phase control layer 64, and an i-DBR 68. The p-DBR 66 is p-type, while the i-DBR 68 does not contain impurities. The phase control layer 64 is formed between the p-DBR 66 and the i-DBR 68, and is a layer that adjusts the relationship between the wavelength of the seed light Ls and the vertical resonance wavelength in the optical amplification section 52. In this embodiment, the phase control layer 64 is formed using, for example, a silicon oxide film (SiO2), a silicon nitride film (SiON), or GaAs.

[0043] The insulating section 54 is a layer that electrically insulates the light emitting section 50 from the optical amplifying section 52, and in this embodiment, is formed by ion implantation, for example.

[0044] The first P electrode 41 is a P electrode of the light emitting section 50 , and the second P electrode 42 is a P electrode of the optical amplifying section 52 .

[0045] When driving the semiconductor laminated structure 20, the positive polarity of the driving power supply is applied to the first P electrode 41 and the second P electrode 42, the negative polarity is applied to the N electrode 40, and a driving current is passed from the first P electrode 41 and the second P electrode 42 to the N electrode 40. However, the polarities of the base layer 30, the lower DBR 32, and the upper DBR 36 are not limited to this, and these polarities may be reversed, that is, the base layer 30 may be a p-type GaAs substrate, the lower DBR 32 may be p-type, and the upper DBR 36 may be n-type.

[0046] Here, the semiconductor laminated structure 20 according to this embodiment will be described in more detail. As shown in Fig. 3, when a current is injected into the active region 34 by the first P electrode 41 and the N electrode 40 provided on both sides of the DBR in the light emitting section 50, seed light Ls is generated, and the seed light Ls generated in the light emitting section 50 propagates in a propagation direction from the left side to the right side of the page. At this time, the propagating light propagates mainly through the lower DBR 32, the active region 34, the conductive region 58, and the upper DBR 36 with a predetermined distribution. Therefore, the "DBR waveguide" is configured to include these parts.

[0047] The semiconductor laminated structure 20 using the DBR waveguide is composed of a pair of DBRs provided on a base layer 30, which is a semiconductor substrate, and an active region and a resonator spacer layer between the pair of DBRs. The region sandwiched between the DBRs functions as an optical waveguide, and light input into this DBR waveguide propagates slowly while being multiple-reflected in oblique directions.

[0048] At this time, when a current is injected into the active region 34 by the second P electrode 42 and the N electrode 40 provided on both sides of the DBR in the optical amplifier 52, light with a wavelength shorter than the vertical resonance wavelength is amplified, and an amplified beam is output in a direction intersecting the plane of the base layer 30 and tilted forward in the propagation direction of the DBR waveguide of the propagating light (diagonal forward direction). In FIG. 3, this output light is shown as "output light Lf". In other words, the region of the optical amplifier 52 where the second P electrode 42 and the N electrode 40 are provided functions as both an optical waveguide and an optical amplifier. In addition, the light emission region on the surface of the optical amplifier 52 functions as the light emission section 52a in this embodiment.

[0049] Fig. 4 is a front view of the semiconductor light emitter 10. As shown in Fig. 4, the shaping optical system 12 includes, as an example, a cylindrical lens 71 having a positive power in the short direction SD, and a positive lens 72 that collects the light emitted from the cylindrical lens 71. The cylindrical lens 71 is disposed at a position in the shaping optical system 12 closest to the light amplification section 52.

[0050] The cylindrical lens 71 is held by a mechanical arm 13 fixed to the substrate 11. The mechanical arm 13 includes an arm portion 13a that holds the cylindrical lens 71, and a support 13b that is fixed to the substrate 11 and holds the arm portion 13a. The arm portion 13a is configured to be movable in the left-right direction relative to the support 13b when the semiconductor light emitter 10 is viewed from the front (as shown in FIG. 4). The cylindrical lens 71 is configured to be rotatable within a horizontal plane relative to the arm portion 13a. The positive lens 72 is held by a support 14 that is fixed to the substrate 11.

[0051] FIG. 5 is a side view showing the positional relationship between the semiconductor laminated structure 20 and the shaping optical system 12, and FIG. 6 is a top view showing the positional relationship between the semiconductor laminated structure 20 and the shaping optical system 12.

[0052] As shown in FIGS. 5 and 6, the front principal plane FP of the cylindrical lens 71 is parallel to the optical amplification section 52, and the direction of the generatrix GL of the cylindrical lens 71 is parallel to the longitudinal direction LD.

[0053] Moreover, one end of the cylindrical lens 71 in the longitudinal direction LD is offset with respect to one end of the light emitting portion 52 in the longitudinal direction. The light emitted from the semiconductor laminated structure 20 is emitted in an oblique direction at an emission angle θ with respect to the light emitting surface of the semiconductor laminated structure 20. Here, the offset direction of the cylindrical lens 71 may be the front side of the light emitting direction in the longitudinal direction LD, or the rear side of the light emitting direction in the longitudinal direction LD. In this way, by offsetting the cylindrical lens 71 with respect to the light emitting portion 52, the light transmission area can be limited, and therefore stray light in the shaping optical system 12 can be suppressed.

[0054] Here, an example will be described in which the direction in which the cylindrical lens 71 is offset with respect to the light emitting portion 52 is the forward light emitting direction in the longitudinal direction LD, as in this embodiment.

[0055] When the emission angle θ is smaller than 90° and the light is emitted in an upper right direction in FIG. 5, the cylindrical lens 71 is offset to the right. On the other hand, when the emission angle θ is larger than 90° and the light is emitted in an upper left direction in FIG. 5, the cylindrical lens 71 may be offset to the left. In this way, by offsetting the cylindrical lens 71 in the emission direction of the light, it is possible to make most of the main diffracted light in the light flux emitted from the semiconductor laminated structure 20 enter the cylindrical lens 71. In addition, it is possible to make it difficult for light other than the main diffracted light in the light flux emitted from the semiconductor laminated structure 20 to enter, so that stray light in the shaping optical system 12 can be suppressed.

[0056] Moreover, at least one lens in the shaping optical system 12 has a size that transmits only the main diffracted light in the light beam emitted from the semiconductor laminated structure 20. In this embodiment, as an example, the positive lens 72 is cut into a rectangle around the optical axis so that the size of the positive lens 72 transmits only the main diffracted light in the light beam emitted from the semiconductor laminated structure 20. In this way, by limiting the light transmission area, stray light in the shaping optical system 12 can be suppressed.

[0057] The shaping optical system 12 also includes a wavelength filter 73 that transmits light having a wavelength of the main diffracted light and blocks light having a wavelength of the sub diffracted light among the light emitted from the optical amplifier 52. The wavelength filter 73 may be inserted anywhere in the shaping optical system 12 as a parallel flat plate filter, or may be coated on any lens surface in the shaping optical system 12. In this embodiment, as an example, the wavelength filter 73 is coated on the light incident surface of the cylindrical lens 71. In this way, by blocking the light having the wavelength of the sub diffracted light, stray light in the shaping optical system 12 can be suppressed.

[0058] Here, the positional relationship between the semiconductor laminated structure 20 and the cylindrical lens 71 in the shaping optical system 12 will be described in detail.

[0059] The light emitted from the light emitting portion of the semiconductor laminated structure 20 has plane wave characteristics in the longitudinal direction LD and spherical wave characteristics in the transverse direction SD. Therefore, the light beam emitted from the light emitting portion of the semiconductor laminated structure 20 becomes almost parallel light in the longitudinal direction LD, whereas it becomes diffuse light in the transverse direction SD compared to the light from the longitudinal direction LD. Therefore, in order to effectively utilize the light beam emitted from the semiconductor laminated structure 20, the light beam emitted from the semiconductor laminated structure 20 is once shaped into parallel light by a cylindrical lens 71.

[0060] Fig. 7 is a diagram showing the positional relationship between the semiconductor laminated structure 20 and the cylindrical lens 71 when light is emitted vertically from the semiconductor laminated structure 20, Fig. 7(a) is a diagram showing the state of both in the longitudinal direction LD, and Fig. 7(b) is a diagram showing the state of both in the transverse direction SD. Fig. 8 is a diagram showing the positional relationship between the actual semiconductor laminated structure 20 and the cylindrical lens 71, Fig. 8(a) is a diagram showing the state of both in the longitudinal direction LD, and Fig. 8(b) is a diagram showing the state of both in the transverse direction SD.

[0061] As shown in Figure 7, if the distance from the light output portion of the semiconductor laminated structure 20 to the light incident surface of the cylindrical lens 71 is D, the distance from the light incident surface of the cylindrical lens 71 to the front principal plane FP is HA, and the focal length of the cylindrical lens 71 is f, when light is output vertically from the semiconductor laminated structure 20, the distance D from the light output portion of the semiconductor laminated structure 20 to the light incident surface of the cylindrical lens 71 is as shown in the following formula. D=f-HA

[0062] However, as shown in FIG. 8, in reality, light is emitted from the semiconductor laminated structure 20 in an oblique direction at an emission angle θ relative to the substrate 11, so that the radius of curvature of the convex surface of the cylindrical lens 71 is effectively small, and the positive power of the cylindrical lens 71 in the short direction SD becomes stronger compared to the case where light is incident perpendicularly on the cylindrical lens 71 as shown in FIG.

[0063] Therefore, if the distance D from the light output portion of the semiconductor laminated structure 20 to the light input surface of the cylindrical lens 71 is f-HA, the light beam output from the semiconductor laminated structure 20 cannot actually be shaped into parallel light.

[0064] In order to solve such problems, in the semiconductor light emitter 10 of the present embodiment, the distance D from the light emission portion of the semiconductor laminate structure 20 to the light incident surface of the cylindrical lens 71 is configured to satisfy the following conditional formula (1). D <f-HA …(1)

[0065] In other words, taking into consideration that when light is incident on the cylindrical lens 71 at an angle, the positive power of the cylindrical lens 71 becomes stronger in effect, by making the distance D from the light exit portion of the semiconductor laminated structure 20 to the light entrance surface of the cylindrical lens 71 smaller than f-HA, it is possible to make the light beam emitted from the semiconductor laminated structure 20 closer to a parallel beam by the cylindrical lens 71, even when light is incident on the cylindrical lens 71 at an angle.

[0066] When the unit of each of the distance D from the light output portion of the semiconductor laminated structure 20 to the light incident surface of the cylindrical lens 71, the distance HA from the light incident surface of the cylindrical lens 71 to the front principal plane FP, and the focal length f of the cylindrical lens 71 is mm, the semiconductor laminated structure 20 may be configured to satisfy the following conditional formula (1A): By configuring the semiconductor light emitter 10 so as not to be equal to or smaller than the lower limit of the conditional formula (1A), the distance between the semiconductor laminated structure 20 and the cylindrical lens 71 can be set to 0.3 mm or more, which facilitates the manufacture of the semiconductor laminated structure 20, and in particular the bonding of the semiconductor laminated structure 20 to the substrate 11. 0.3mm <D<f-HA …(1A)

[0067] 9A and 9B are diagrams showing the light quantity distribution of light emitted from the semiconductor laminated structure 20, where Fig. 9A shows the state in the longitudinal direction LD and Fig. 9B shows the state in the short direction SD of both. Note that in Fig. 9A showing the state in the longitudinal direction LD, for convenience, light is shown as being emitted vertically from the semiconductor laminated structure 20, but in reality, light is emitted obliquely from the semiconductor laminated structure 20. However, since the light emitted from the semiconductor laminated structure 20 has characteristics close to parallel light in the longitudinal direction LD, there is no significant difference in the shape of the graph of the light quantity distribution.

[0068] As shown in FIG. 9(b), in semiconductor light emitter 10 of the present embodiment, when the focal length of cylindrical lens 71 is f, the length of the light emitting portion in the longitudinal direction LD is L, and the full angle at half maximum of the light beam emitted from the light emitting portion in the transverse direction SD is θw, the following conditional formula (2) is satisfied. f <L / (2×tan(θw / 2)) …(2)

[0069] The effective beam width (half width) in the short-side direction SD of the light emitted from the semiconductor laminated structure 20 is expressed as 2×f×tan(θw / 2). In this case, when the focal length f of the cylindrical lens 71 is rewritten on the left side of the conditional expression in the case where the effective beam width (half width) in the short-side direction SD of the light emitted from the semiconductor laminated structure 20 is made smaller than the length L of the longitudinal direction LD of the light emitting part, the expression takes the form of conditional expression (2). By satisfying conditional expression (2), it is possible to improve the transmittance of the cylindrical lens of the light emitted from the semiconductor laminated structure, as compared with a configuration that does not satisfy conditional expression (2).

[0070] Furthermore, in semiconductor light emitter 10 of the present embodiment, when the focal length of cylindrical lens 71 is f, the length of the light emitting portion in the longitudinal direction LD is L, and the full angle at half maximum of the light beam emitted from the light emitting portion in the transverse direction SD is θw, the following conditional formula (3) is satisfied. 0.4L<2×f×tan(θw / 2) <L …(3)

[0071] The effective beam width (half width: 2×f×tan(θw / 2)) in the short direction SD of the light emitted from the semiconductor laminated structure 20 changes by moving the cylindrical lens 71, as shown by the cylindrical lens 71 and the cylindrical lens 71' in Fig. 9(b), for example. By keeping the effective beam width (half width: 2×f×tan(θw / 2)) in the short direction SD of the light emitted from the semiconductor laminated structure 20 within the range of conditional formula (3) with respect to the length L of the longitudinal direction LD of the light emitting part, it is possible to make the aspect ratio of the beam diameter of the light emitted from the semiconductor laminated structure 20 after passing through the cylindrical lens 71 uniform, compared to a configuration that does not satisfy conditional formula (3).

[0072] Condition (2) can also be defined from another perspective.

[0073] Regarding the effective beam width (half width) in the short direction SD of the light emitted from the semiconductor laminate structure 20, when L=2 mm and θw=10°, the light amount distribution when the focal length f is changed to change the ratio α of the element length L of the longitudinal direction LD is shown in the graph in FIG. 10.

[0074] Furthermore, when these light intensity distributions are imaged using a spherical lens with a focal length of 30 mm, the relationship between the aspect ratio of the beam diameter and the transmittance is as shown in the graph in Figure 11. Here, if, from the processing conditions, the aspect ratio is set to a value exceeding 0.95 and the transmittance to 75% or more, the ratio α of the effective beam width (half width) in the short direction SD to the element length L of the long direction LD is expressed by the following conditional formula. 1<α<2.5

[0075] When this is applied to conditional expression (2), the following conditional expression (2A) is obtained. L / (2.5×2×tan(θw / 2)) <f<L / (2×tan(θw / 2)) …(2A)

[0076] Moreover, the relationship between the ratio α of the effective light flux width (half width) in the short direction SD to the element length L in the long direction LD and the energy density is as shown in the graph in FIG.

[0077] Here, in order to maintain a high energy density from the processing conditions, the ratio α of the effective light beam width (half width) in the short direction SD to the element length L in the long direction LD is expressed by the following conditional formula. α<2.5

[0078] When this is applied to conditional expression (2), the following conditional expression (2B) is obtained. L / (2.5×2×tan(θw / 2)) <f …(2B)

[0079] In addition, the ideal distance DS between the semiconductor laminate structure 20 and the cylindrical lens 71 when a light ray is emitted in the θ direction can be expressed as follows, assuming that the distance from the light incident surface of the cylindrical lens 71 in the θ direction to the front principal plane FP is HAs, the focal length of the cylindrical lens 71 in the θ direction is fs, the thickness of the cylindrical lens 71 is t, the refractive index of the cylindrical lens 71 is n, and the radius of curvature of the light exit surface of the cylindrical lens 71 is r. HAs = -t / (n × sinθ) fs=-r×cosθ / (n-1) Ds / sinθ=fs-HAs Ds=-r×sinθ×cosθ / (n-1)-t / n=D+r / (n-1)×(1-sin(2θ / θ))

[0080] 13, as a modification of the semiconductor light emitter 10 according to the present embodiment, the shaping optical system 12 may include a cylindrical lens 71 and a positive lens 72 that forms an image of the light beam emitted from the cylindrical lens 71, and an aperture 74 may be provided between the cylindrical lens 71 and the positive lens 72. Even in such an embodiment, only the main diffracted light in the light beam emitted from the semiconductor laminate structure 20 can be transmitted, and stray light in the shaping optical system 12 can be suppressed.

[0081] In addition, in this embodiment, the semiconductor laminate structure 20 emits light that has been propagated longitudinally and amplified in the optical amplification section 52 from the light emitting section 52a, but the light emitted from the light emitting section 52a does not have to be amplified light.

[0082] In addition, in this embodiment, an example has been shown in which the semiconductor laminate structure 20 amplifies the seed light Ls generated from the light emitting section 50 by the optical amplification section 52, but it is also possible to amplify the light emitted by the semiconductor layer of the optical amplification section itself by applying a current directly to the optical amplification section without the seed light Ls.

[0083] In addition, in this embodiment, the semiconductor stacked structure 20 does not have to have the seed light generating unit integrated on the same chip as in Figure 3, but may be configured to introduce seed light from the outside, as in the semiconductor stacked structure 120 shown in Figures 14 and 15.

[0084] Fig. 14 is a plan view of the semiconductor laminated structure 120, and Fig. 15 is a cross-sectional view taken along the line A-A' shown in Fig. 14. The semiconductor laminated structure 120 includes an optical coupling section 150 and an optical amplifying section 152 that extends from the optical coupling section 150 and amplifies light propagating in the extending direction.

[0085] The optical coupling unit 150 propagates input light from an external light source (not shown) through the optical fiber 170, and couples an output end of the optical fiber 170 to the optical coupling unit 150 functioning as a light source unit of the semiconductor optical amplifier 120 to introduce the input light to the optical amplification unit 52. As the external light source, for example, a vertical cavity surface emitting laser (VCSEL) is used. From the viewpoint of light coupling efficiency, the optical fiber 170 may be a lensed fiber.

[0086] The optical amplifier 152 has a function of amplifying and emitting the seed light Ls introduced in the optical coupling unit 150. A light emitting region on the surface of the optical amplifier 152 functions as a light emitting unit 152a.

[0087] The semiconductor laminated structure 120 includes a lower DBR 132, an active region 134, a non-conductive region 160, an upper DBR 136, and a P-electrode 141 formed on a base layer 130, and an N-electrode 140 formed on the back surface of the base layer 130. Unlike the semiconductor laminated structure 20 shown in FIG. 3, the upper DBR 136 does not include a phase control layer or an i-DBR.

[0088] The non-conductive region 160 and the conductive region 158 provided on the active region 134 are p-type oxide confinement layers, i.e., current confinement layers. That is, the non-conductive region 160 corresponds to an oxidized region, and the conductive region 158 corresponds to a non-oxidized region. The interface between the conductive region 158 and the non-conductive region 160 forms an oxidation front 156.

[0089] Like the semiconductor laminated structure 20, the semiconductor laminated structure 120 amplifies light having a wavelength shorter than the vertical resonance wavelength. The wavelength and optical output of the seed light are variable, which is advantageous for searching for an optimal amplifier structure, seed light conditions, etc. Furthermore, the semiconductor laminated structure 120 has a simpler structure than the semiconductor laminated structure 20, and therefore can be fabricated by the same process as a general VCSEL process.

[0090] In addition, in this embodiment, the semiconductor stack 20 may be applied to a configuration that utilizes a diffraction grating, such as the semiconductor stack 220 shown in Figures 16 and 17, or the semiconductor stack 320 shown in Figures 18 and 19.

[0091] Fig. 16 is a plan view of the semiconductor laminated structure 220, and Fig. 17 is a cross-sectional view taken along line A-A' shown in Fig. 16. The semiconductor laminated structure 220 includes an optical amplifier 252 that amplifies light propagating in the elongated direction.

[0092] The optical amplifier 252 has a function of amplifying and emitting seed light Ls generated therein, similar to a typical VCSEL. A light emission region on the surface of the optical amplifier 252 functions as a light emission portion 252a.

[0093] The semiconductor laminated structure 220 is composed of a lower DBR 232, an active region 234, a non-conductive region 260, an upper DBR 236, a P electrode 241, and a diffraction grating 270 formed on a base layer 230, and an N electrode 240 formed on the back surface of the base layer 230.

[0094] The non-conductive region 260 and the conductive region 258 provided on the active region 234 are p-type oxide confinement layers, i.e., current confinement layers. That is, the non-conductive region 260 corresponds to the oxidized region, and the conductive region 258 corresponds to the non-oxidized region. The interface between the conductive region 258 and the non-conductive region 260 forms an oxidation front 256.

[0095] The semiconductor stacked structure 220 amplifies light having a wavelength shorter than the vertical resonance wavelength, similarly to the semiconductor stacked structure 20. Furthermore, the semiconductor stacked structure 220 outputs light in a slow light mode determined by the configuration of the diffraction grating 270 formed in the light emitting portion 252a. The semiconductor stacked structure 220 does not require a seed light, and emits light in the same manner as a general VCSEL, and the wavelength to be amplified is determined by the configuration of the diffraction grating 270.

[0096] Fig. 18 is a plan view of the semiconductor laminated structure 320, and Fig. 19 is a cross-sectional view taken along line A-A' shown in Fig. 18. The semiconductor laminated structure 320 includes a light emitting section 350 and an optical amplifier 352 extending from the light emitting section 350 and amplifying light propagating in the extending direction.

[0097] The light emitting section 350 is a section that generates the seed light Ls, and is configured as a VCSEL equipped with a diffraction grating 370. The seed light Ls generated from the light emitting section 350 propagates toward the optical amplifier section 352, as shown in FIG.

[0098] The optical amplifier 252 has a function of amplifying and emitting seed light Ls, which is light generated in the light emitter 350. A light emission region on the surface of the optical amplifier 352 functions as a light emission section 352a.

[0099] The semiconductor laminated structure 320 includes a lower DBR 332, an active region 334, a non-conductive region 360, an upper DBR 336, a first P electrode 341, a second P electrode 342, an ion implantation portion 354, and a diffraction grating 370 formed on a base layer 330, and an N electrode 340 formed on the back surface of the base layer 330.

[0100] The non-conductive region 360 and the conductive region 358 provided on the active region 334 are p-type oxide confinement layers, i.e., current confinement layers. That is, the non-conductive region 360 corresponds to an oxidized region, and the conductive region 358 corresponds to a non-oxidized region. The interface between the conductive region 358 and the non-conductive region 360 forms an oxidation front 356.

[0101] The semiconductor laminated structure 320 amplifies light having a wavelength shorter than the vertical resonance wavelength, similarly to the semiconductor laminated structure 20. Moreover, in the semiconductor laminated structure 320, light having a wavelength determined by the configuration of the diffraction grating 370 formed in the light emitting section 350 is output.

[0102] In addition, by offsetting the cylindrical lens 71 so that it does not overlap with the end of the semiconductor laminate structure where the seed light section, the optical coupling section, or the P electrode is formed, it becomes easier to wire the electrode and introduce light into the optical coupling section even when the cylindrical lens 71 and the light emission surface are brought close to each other.

[0103] [Second embodiment] Next, a semiconductor light emitter 10A according to this embodiment will be described with reference to Fig. 20. Fig. 20 is a schematic diagram showing a semiconductor laminate structure 20 and a shaping optical system 12A of the semiconductor light emitter 10A. Note that the same components as those in the semiconductor light emitter 10 of the first embodiment are given the same reference numerals, and descriptions of the same components will be omitted.

[0104] As shown in Figure 20, the semiconductor light emitter 10A has a plurality of semiconductor laminate structures 20, and the shaping optical system 12A has a plurality of cylindrical lenses 71 corresponding to each of the plurality of semiconductor laminate structures 20, and a positive lens 72 that forms an image of the light beam emitted from the plurality of cylindrical lenses 71, and the plurality of semiconductor laminate structures 20 are arranged so that the imaging positions P of the light beams emitted from the semiconductor laminate structures 20 coincide.

[0105] With this configuration, the optical output of multiple semiconductor stacked structures 20 can be concentrated at one point, making it possible to improve the optical output compared to a case in which only one semiconductor stacked structure 20 is provided.

[0106] [Third embodiment] Next, a semiconductor light emitter 10B according to this embodiment will be described with reference to Fig. 21. Fig. 21 is a schematic diagram showing a semiconductor stacked structure 20 and a shaping optical system 12B of the semiconductor light emitter 10B. Note that the same components as those in the semiconductor light emitter 10 of the first embodiment are given the same reference numerals, and descriptions of the same components will be omitted.

[0107] As shown in FIG. 21, the semiconductor light emitter 10B includes a plurality of semiconductor laminate structures 20 and a shaping optical system 12B. The plurality of semiconductor laminate structures 20 are arranged such that the longitudinal directions of the light emitting portions of the respective semiconductor laminate structures 20 are parallel to each other. The shaping optical system 12B includes a plurality of cylindrical lenses 71 corresponding to the plurality of semiconductor laminate structures 20, and one positive lens 75, the optical axis of which is the center of the plurality of semiconductor laminate structures 20 and which images the light flux emitted from the plurality of semiconductor laminate structures 20 and passed through the cylindrical lens 71 at an imaging position P. In the example shown in FIG. 21, the optical axis of the semiconductor laminate structure 20 in the middle stage among the three semiconductor laminate structures 20 arranged in the upper stage, middle stage, and lower stage is configured to be the optical axis of the entire semiconductor light emitter 10B.

[0108] Even with this configuration, the optical output of the multiple semiconductor laminated structures 20 can be concentrated to one point, so that the optical output can be improved compared to the case where only one semiconductor laminated structure 20 is provided.

[0109] Various typical embodiments of the present invention have been described above, but the present invention is not limited to these embodiments and can be modified as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0110] 10, 10A, 10B Semiconductor light emitter 11 Substrate 12,12A,12B Shaping optical system 13 Mechanical Arm 13a Arm section 13b Post 14 Posts 20 Semiconductor laminated structure 71 Cylindrical Lens 72 Positive Lens 73 Wavelength Filter 74 Aperture 75 Positive Lens

Claims

1. A substrate; a semiconductor laminated structure including a light emitting portion that emits light in an oblique direction with respect to the substrate, from an emission region in a longitudinal direction and a lateral direction perpendicular to the longitudinal direction; a shaping optical system that shapes the light beam emitted from the light emitting unit, a lens in the shaping optical system that is closest to the light output portion is a cylindrical lens having a positive power in the short side direction, a front principal plane of the cylindrical lens is parallel to the light output portion, and a generatrix direction of the cylindrical lens is parallel to the longitudinal direction; The distance from the light exit portion to the light entrance surface of the cylindrical lens is D. The distance from the light incidence surface of the cylindrical lens to the front principal plane is HA, If the focal length of the cylindrical lens is f, The following condition (1) is satisfied: D<f-HA...(1) Semiconductor light emitter.

2. The semiconductor laminated structure is An optical amplifier that amplifies light by propagating it in the longitudinal direction.

2. The semiconductor light emitter of claim 1.

3. The length of the light emitting portion in the longitudinal direction is L, When the full angle at half maximum of the light beam emitted from the light emitting portion in the short side direction is θw, The following condition (2) is satisfied: f<L / (2×tan(θw / 2))…(2) 3. A semiconductor light emitter according to claim 1 or 2.

4. The following condition (3) is satisfied: 0.4L<2×f×tan(θw / 2)<L…(3) 4. The semiconductor light emitter of claim 3.

5. An end portion on one side in the longitudinal direction of the cylindrical lens is offset with respect to an end portion on the one side in the longitudinal direction of the light emitting portion.

5. A semiconductor light emitter according to claim 1.

6. A plurality of the semiconductor laminated structures are provided, The semiconductor laminated structures are arranged such that the longitudinal directions of the light emitting portions are parallel to each other, The shaping optical system has an optical axis that is the center of the plurality of semiconductor laminated structures, and includes a positive lens that forms an image of the light beams emitted from the plurality of semiconductor laminated structures.

6. A semiconductor light emitter according to claim 1.

7. A plurality of the semiconductor laminated structures are provided, the shaping optical system includes a plurality of the cylindrical lenses corresponding to the plurality of semiconductor laminated structures, respectively, and a positive lens that forms an image of the light beams emitted from the plurality of cylindrical lenses; A plurality of the semiconductor laminate structures are arranged so that the image positions of the light beams emitted from the semiconductor laminate structures coincide with each other.

6. A semiconductor light emitter according to claim 1.

8. the shaping optical system includes the cylindrical lens and a positive lens that forms an image of the light beam emitted from the cylindrical lens, An aperture is provided between the cylindrical lens and the positive lens.

8. A semiconductor light emitter according to claim 1.

9. At least one lens in the shaping optical system has a size that transmits only the main diffracted light in the light beam emitted from the semiconductor laminated structure.

9. A semiconductor light emitter according to claim 1.

10. The shaping optical system includes a wavelength filter.

10. A semiconductor light emitter according to claim 1.

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