JP5835561B2 - Light emitting device, super luminescent diode, and projector - Google Patents

Description

  The present invention relates to a light emitting device, a super luminescent diode, and a projector.

  A super luminescent diode (hereinafter also referred to as “SLD”) is incoherent like a normal light emitting diode and has a broad spectrum shape, but has a single optical output characteristic similar to that of a semiconductor laser. This is a semiconductor light emitting device capable of obtaining an output up to about several hundreds mW.

  The SLD is used as a light source for a projector, for example. In order to realize a small and high brightness projector, it is necessary to use a light source having a large light output and a small etendue. For this purpose, it is desirable that light emitted from a plurality of gain regions travel in the same direction. In Patent Document 1, a gain region having a linear shape and a gain region having a shape bent by passing through a reflecting surface are combined to emit light from light emitting portions (light emitting points) of two gain regions. The light to be transmitted is traveling in the same direction.

JP 2010-3833 A

  In order to reduce the loss of the optical system and reduce the number of parts, there has been proposed a projector of a type in which an SLD is disposed directly under a light valve and condensing and uniform illumination are simultaneously performed using a lens array. In such a type of projector, it is necessary to arrange the emitting portion in accordance with the interval between the lens arrays.

  In the technique described in Patent Document 1, it is difficult to arrange the intervals between a plurality of emitting portions in accordance with various lens arrays having different pitches, and the technique cannot be applied to the projector of the above-described method.

  One of the objects according to some aspects of the present invention is to provide a light emitting device that can be applied to a projector in which the interval between a plurality of emitting portions can be increased and the light emitting device is disposed immediately below a light valve. There is. Another object of some embodiments of the present invention is to provide a projector having the light-emitting device.

The light emitting device according to the present invention is
A first layer that generates light by injecting current;
A second layer and a third layer sandwiching the first layer and suppressing leakage of the light;
Including
In the first layer,
A first optical waveguide having a band-like shape extending from a first emitting portion provided on the first side surface of the first layer to a first reflecting portion provided on the second side surface of the first layer;
A second optical waveguide having a strip shape extending from the first reflecting portion to a second reflecting portion provided on a third side surface of the first layer;
A third optical waveguide having a strip shape extending from the second reflecting portion to the second emitting portion provided on the first side surface;
Formed,
The extending direction of the second optical waveguide is parallel to the first side surface,
The first light emitted from the first emission part and the second light emitted from the second emission part are emitted in the same direction,
The third layer is
A first oxidation region formed including at least a part of a fourth side continuous with the second side;
A second oxidation region formed including at least a part of a fifth side surface continuous with the third side surface;
Have
The first oxidation region overlaps with the first reflective portion when viewed from the stacking direction of the first layer, the second layer, and the third layer,
The second oxidation region overlaps with the second reflecting portion when viewed from the stacking direction.

  According to such a light emitting device, the second optical waveguide is provided from the second side surface to the third side surface in parallel to the first side surface on which the first emission part and the second emission part are formed. . Therefore, for example, compared with the case where the second optical waveguide is not parallel to the first side surface, the distance between the first emission portion and the second emission portion is increased while suppressing an increase in the total length of the optical waveguide. be able to. In other words, the distance between the first emission part and the second emission part can be increased while reducing the element length in the direction perpendicular to the side surface on which the first emission part and the second emission part are formed.

  Furthermore, according to such a light emitting device, the third layer includes the first oxide region formed including at least a part of the fourth side surface, and the second layer formed including at least a part of the fifth side surface. And an oxidation region. The first oxidation region overlaps with the first reflection portion, and the second oxidation region overlaps with the second reflection portion. Thereby, it can suppress that an electric current is inject | poured into a 1st reflection part and a 2nd reflection part, and can suppress the non-light-emission recombination in a 1st reflection part and a 2nd reflection part. As a result, it is possible to suppress COD destruction in the first reflecting part and the second reflecting part.

In the light emitting device according to the present invention,
The surfaces of the first reflecting part and the second reflecting part may be covered with a dielectric layer.

  According to such a light emitting device, a part of the dangling bonds appearing on the surfaces of the first reflecting portion and the second reflecting portion can be terminated. Thereby, the breakdown voltage against COD can be improved.

In the light emitting device according to the present invention,
A resin layer may be formed on the opposite side of the first reflective portion and the second reflective portion via the dielectric layer.

  According to such a light emitting device, it is possible to bury the notch portion formed when forming the first reflection portion and the second reflection portion in a short time.

In the light emitting device according to the present invention,
The surfaces of the first reflecting part and the second reflecting part may be exposed.

  According to such a light emitting device, the distance between the first emission part and the second emission part can be increased while downsizing.

In the light emitting device according to the present invention,
The third layer is
A third oxide region disposed across the first optical waveguide and the second optical waveguide with respect to the first oxide region when viewed from the stacking direction;
A fourth oxide region disposed across the second optical waveguide and the third optical waveguide with respect to the second oxide region when viewed from the stacking direction;
You may have.

  According to such a light emitting device, light loss can be reduced.

In the light emitting device according to the present invention,
The perpendicular length of the fourth side surface of the first oxidation region is 20 μm or more,
The length in the perpendicular direction of the fifth side surface of the second oxidation region may be 20 μm or more.

  According to such a light emitting device, it is possible to suppress the diffused current from reaching the first reflecting portion and the second reflecting portion. Thereby, the COD destruction of the first reflection part and the second reflection part can be further suppressed.

In the light emitting device according to the present invention,
Seen from the stacking direction,
The first optical waveguide and the second optical waveguide are connected to the first reflecting portion by being inclined at a first angle with respect to a normal of the second side surface,
The second optical waveguide and the third optical waveguide are connected to the second reflecting part by being inclined at a second angle with respect to the perpendicular of the third side surface,
The first angle and the second angle may be greater than a critical angle.

  According to such a light emitting device, the first reflecting portion and the second reflecting portion can totally reflect light generated in the first optical waveguide, the second optical waveguide, and the third optical waveguide. Therefore, it is possible to suppress light loss in the first reflecting portion and the second reflecting portion, and it is possible to reflect light efficiently.

In the light emitting device according to the present invention,
The length in the extending direction of the second optical waveguide is:
The length in the extending direction of the first optical waveguide and the length in the extending direction of the third optical waveguide may be larger.

  According to such a light emitting device, the interval between the first emission part and the second emission part can be reliably increased.

In the light emitting device according to the present invention,
The second side surface and the third side surface may be etched surfaces formed by etching.

  According to such a light emitting device, COD breakdown can be suppressed by the first oxidized region and the second oxidized region even on the etched surface where dangling bonds are easily formed.

The projector according to the present invention is
A light emitting device according to the present invention;
A lens array for condensing the light emitted from the light emitting device;
A light modulation device that modulates light collected by the lens array according to image information;
A projection device for projecting an image formed by the light modulation device;
including.

  According to such a projector, the alignment of the lens array is easy, and the liquid crystal light valve (light modulation device) can be irradiated with good uniformity.

Superluminescent diode according to the present invention,
A first layer that generates light by injecting current;
A second layer and a third layer sandwiching the first layer and suppressing leakage of the light;
Including
In the first layer,
A first optical waveguide having a band-like shape extending from a first emitting portion provided on the first side surface of the first layer to a first reflecting portion provided on the second side surface of the first layer;
A second optical waveguide having a strip shape extending from the first reflecting portion to a second reflecting portion provided on a third side surface of the first layer;
A third optical waveguide having a strip shape extending from the second reflecting portion to the second emitting portion provided on the first side surface;
Formed,
The extending direction of the second optical waveguide is parallel to the first side surface,
The first light emitted from the first emission part and the second light emitted from the second emission part are emitted in the same direction,
The third layer is
A first oxidation region formed including at least a part of a fourth side continuous with the second side;
A second oxidation region formed including at least a part of a fifth side surface continuous with the third side surface;
Have
The first oxidation region overlaps with the first reflective portion when viewed from the stacking direction of the first layer, the second layer, and the third layer,
The second oxidation region overlaps with the second reflecting portion when viewed from the stacking direction.

  According to such a super luminescent diode, the interval between the first emission part and the second emission part can be increased while reducing the size.

The projector according to the present invention is
A superluminescent diode according to the present invention;
A lens array that collects the light emitted from the superluminescent diode;
A light modulation device that modulates light collected by the lens array according to image information;
A projection device for projecting an image formed by the light modulation device;
including.

  According to such a projector, the alignment of the lens array is easy, and the liquid crystal light valve (light modulation device) can be irradiated with good uniformity.

The top view which shows typically the light-emitting device which concerns on this embodiment. FIG. 3 is a cross-sectional view schematically showing the light emitting device according to the embodiment. FIG. 3 is a cross-sectional view schematically showing the light emitting device according to the embodiment. FIG. 3 is a cross-sectional view schematically showing the light emitting device according to the embodiment. The top view which shows typically the light-emitting device which concerns on a reference example. Sectional drawing which shows typically the light-emitting device which concerns on a reference example. The graph which shows the relationship between the width | variety of an electrode and current density of the light-emitting device which concerns on a reference example. Sectional drawing which shows typically the manufacturing process of the light-emitting device which concerns on this embodiment. Sectional drawing which shows typically the manufacturing process of the light-emitting device which concerns on this embodiment. Sectional drawing which shows typically the manufacturing process of the light-emitting device which concerns on this embodiment. Sectional drawing which shows typically the manufacturing process of the light-emitting device which concerns on this embodiment. Sectional drawing which shows typically the light-emitting device which concerns on the 1st modification of this embodiment. Sectional drawing which shows typically the light-emitting device which concerns on the 2nd modification of this embodiment. The top view which shows typically the light-emitting device which concerns on the 3rd modification of this embodiment. Sectional drawing which shows typically the light-emitting device which concerns on the 3rd modification of this embodiment. Sectional drawing which shows typically the light-emitting device which concerns on the 3rd modification of this embodiment. The top view which shows typically the light-emitting device which concerns on the 4th modification of this embodiment. 1 is a diagram schematically showing a projector according to an embodiment. 1 is a diagram schematically showing a projector according to an embodiment. FIG. 2 is a diagram schematically showing a light source of a projector according to the present embodiment. FIG. 2 is a cross-sectional view schematically showing a light source of the projector according to the embodiment. FIG. 2 is a cross-sectional view schematically showing a light source of the projector according to the embodiment. FIG. 2 is a cross-sectional view schematically showing a light source of the projector according to the embodiment.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

1. First, the light emitting device according to the present embodiment will be described with reference to the drawings. FIG. 1 is a plan view schematically showing the light emitting device 100 according to the present embodiment. 2 is a cross-sectional view taken along the line II-II of FIG. 1 schematically showing the light emitting device 100 according to the present embodiment. 3 is a cross-sectional view taken along line III-III in FIG. 1 schematically showing the light emitting device 100 according to the present embodiment. 4 is a cross-sectional view taken along the line IV-IV in FIG. 1 schematically showing the light emitting device 100 according to the present embodiment. In FIG. 1, the second electrode 114 is not shown for convenience.

  Hereinafter, a case where the light emitting device 100 is an InGaAlP-based (red) SLD will be described. Unlike a semiconductor laser, an SLD can prevent laser oscillation by suppressing the formation of a resonator due to end face reflection. Therefore, speckle noise can be reduced.

  As illustrated in FIGS. 1 to 4, the light emitting device 100 can include a stacked body 120, a first electrode 112, and a second electrode 114.

  The stacked body 120 includes a substrate 102, a second layer 104 (hereinafter also referred to as “first cladding layer 104”), a first layer 106 (hereinafter also referred to as “active layer 106”), and a third layer 108 (hereinafter referred to as “first cladding layer 104”). A second cladding layer 108 ”), a fourth layer 110 (hereinafter also referred to as“ contact layer 110 ”), and an insulating layer 116.

  As the substrate 102, for example, a first conductivity type (for example, n-type) GaAs substrate or the like can be used. The board | substrate 102 may have the level | step difference surface 103, as shown in FIGS. The step surface 103 can be formed by etching for exposing reflective portions 190 and 192 described later (for exposing the side surfaces 132 and 133).

  The first cladding layer 104 is formed on the substrate 102 (on the upper surface of the substrate 102 excluding the stepped surface 103). As the first cladding layer 104, for example, an n-type InGaAlP layer can be used. Although not shown, a buffer layer may be formed between the substrate 102 and the first cladding layer 104. As the buffer layer, for example, an n-type GaAs layer, an AlGaAs layer, an InGaP layer, or the like can be used. The buffer layer can improve the crystallinity of the layer formed thereabove.

  The active layer 106 is formed on the first cladding layer 104. The active layer 106 is sandwiched between the first cladding layer 104 and the second cladding layer 108. The active layer 106 has, for example, a multiple quantum well (MQW) structure in which three quantum well structures each composed of an InGaP well layer and an InGaAlP barrier layer are stacked.

  The planar shape of the active layer 106 viewed from the stacking direction of the stacked body 120 is the same as the planar shape of the cladding layers 104 and 108 and the contact layer 110, for example. The active layer 106 has a first side surface 131, a second side surface 132, and a third side surface 133. In the example shown in FIG. 1, the active layer 106 further has side surfaces 134, 135, and 136, and the planar shape of the active layer 106 is a hexagon. The side surfaces 131 to 136 are surfaces of the active layer 106 that are not in contact with the first cladding layer 104 or the second cladding layer 108 and that form the outer shape of the stacked body 120. The side surfaces 131 to 136 are side walls of the active layer 106 as viewed from the stacking direction of the stacked body 120 (hereinafter also referred to simply as “in plan view” when viewed from the stacking direction of the active layer 106 and the cladding layers 104 and 108). In other words, it can be said that it is provided on the side surface of the laminate 120. The side surfaces 131 to 136 are flat surfaces.

  In the example shown in FIG. 1, the side surfaces 134 and 135 are orthogonal to the side surface 131. The side surface 136 faces the side surface 131. The side surface 132 is connected to the side surfaces 134 and 136 and is inclined with respect to the side surface 131. The side surface 133 is connected to the side surfaces 135 and 136 and is inclined with respect to the side surface 131. For example, the side surfaces 131, 134, 135, and 136 are cleaved surfaces formed by cleavage, and the side surfaces 132 and 133 are etched surfaces formed by etching.

  Part of the active layer 106 constitutes a first optical waveguide 160, a second optical waveguide 162, and a third optical waveguide 164. The portions of the optical waveguides 160, 162, and 164 where current is injected can generate light. The generated light can be guided through the optical waveguides 160, 162 and 164. The light guided in the optical waveguides 160, 162, and 164 can receive a gain in the portion where the current of the optical waveguides 160, 162, and 164 is injected. That is, in the light emitting device 100, it can be said that a part of the active layer 106 constitutes the first gain region 160, the second gain region 162, and the third gain region 164.

  The first optical waveguide 160 extends from the first side surface 131 to the second side surface 132 in plan view. The first optical waveguide 160 has a predetermined width in a plan view, and has a strip-like and linear longitudinal shape along the extending direction of the first optical waveguide 160. The first optical waveguide 160 has a first end surface 181 provided at a connection portion with the first side surface 131 and a second end surface 182 provided at a connection portion with the second side surface 132.

  The extending direction of the first optical waveguide 160 is, for example, a linear extending direction passing through the center of the first end surface 181 and the center of the second end surface 182 in plan view. Moreover, the extension direction of the boundary line of the 1st optical waveguide 160 (and the part except the 1st optical waveguide 160) may be sufficient. The first optical waveguide 160 may be parallel to the perpendicular P1 of the first side surface 131 (α = 0 °).

  The first optical waveguide 160 is connected to the first side surface 131 at an angle α with respect to the perpendicular P1 of the first side surface 131 in plan view. In other words, it can be said that the extending direction of the first optical waveguide 160 has an angle α with respect to the perpendicular P1. The angle α is an acute angle that is smaller than the critical angle.

  The first optical waveguide 160 is connected to the second side surface 132 at an angle β with respect to the perpendicular P2 of the second side surface 132 in plan view. In other words, it can be said that the extending direction of the first optical waveguide 160 has an angle β with respect to the perpendicular P2.

  The second optical waveguide 162 extends from the second side surface 132 to the third side surface 133 in plan view. The second optical waveguide 162 has a predetermined width in a plan view, and has a strip-like and linear longitudinal shape along the extending direction of the second optical waveguide 162. The second optical waveguide 162 has a third end surface 183 provided at a connection portion with the second side surface 132 and a fourth end surface 184 provided at a connection portion with the third side surface 133. In the plan view, the extending direction of the second optical waveguide 162 is parallel to the first side surface 131.

  The extending direction of the second optical waveguide 162 is, for example, a linear extending direction passing through the center of the third end surface 183 and the center of the fourth end surface 184 in plan view. Moreover, the extension direction of the boundary line of the 2nd optical waveguide 162 (and the part except the 2nd optical waveguide 162) may be sufficient. Further, “the extending direction of the second optical waveguide 162 is parallel to the first side surface 131” means that the inclination angle of the second optical waveguide 162 with respect to the first side surface 131 is ± in plan view in consideration of manufacturing variation and the like. It means that it is within 1 °.

  The third end surface 183 of the second optical waveguide 162 overlaps the second end surface 182 of the first optical waveguide 160 on the second side surface 132. In the illustrated example, the second end surface 182 and the third end surface 183 completely overlap each other on the overlapping surface 190.

  The second optical waveguide 162 is connected to the second side surface 132 at an angle β with respect to the normal P2 of the second side surface 132 in plan view. In other words, it can be said that the extending direction of the second optical waveguide 162 has an angle β with respect to the perpendicular P2. That is, the angle of the first optical waveguide 160 with respect to the perpendicular P2 and the angle of the second optical waveguide 162 with respect to the perpendicular P2 are the same within the range of manufacturing variations. The angle β is, for example, an acute angle and is not less than the critical angle. Thereby, the second side surface 132 can totally reflect the light generated in the optical waveguides 160, 162, 164.

  Note that “the angle of the first optical waveguide 160 with respect to the perpendicular P2 is the same as the angle of the second optical waveguide 162 with respect to the perpendicular P2” takes into account manufacturing variations such as etching, and the difference between the angles is, for example, about ± 2 °. It means that it is within.

  The second optical waveguide 162 is connected to the third side surface 133 at an angle γ with respect to the perpendicular P3 of the third side surface 133 in plan view. In other words, it can be said that the extending direction of the second optical waveguide 162 has an angle γ with respect to the perpendicular P3.

  The length of the second optical waveguide 162 in the extending direction is larger than the length of the first optical waveguide 160 in the extending direction and the length of the third optical waveguide 164 in the extending direction. The length of the second optical waveguide 162 in the extending direction may be equal to or greater than the sum of the length of the first optical waveguide 160 in the extending direction and the length of the third optical waveguide 164 in the extending direction. The “length in the extending direction of the second optical waveguide 162” can be said to be the distance between the center of the third end surface 183 and the center of the fourth end surface 184. Similarly, in the other optical waveguides, the length in the extending direction can be said to be the distance between the centers of the two end faces.

  The third optical waveguide 164 extends from the third side surface 133 to the first side surface 131 in plan view. The third optical waveguide 164 has, for example, a predetermined width in a plan view, and a belt-like and linear longitudinal shape along the extending direction of the third optical waveguide 164. The third optical waveguide 164 includes a fifth end surface 185 provided at a connection portion with the third side surface 133 and a sixth end surface 186 provided at a connection portion with the first side surface 131.

  The extending direction of the third optical waveguide 164 is, for example, a linear extending direction passing through the center of the fifth end surface 185 and the center of the sixth end surface 186 in plan view. Moreover, the extension direction of the boundary line of the 3rd optical waveguide 164 (and the part except the 3rd optical waveguide 164) may be sufficient.

  The fifth end surface 185 of the third optical waveguide 164 overlaps the fourth end surface 184 of the second optical waveguide 162 on the third side surface 133. In the illustrated example, the fourth end surface 184 and the fifth end surface 185 completely overlap each other on the overlapping surface 192.

  The first optical waveguide 160 and the third optical waveguide 164 are separated from each other. In the example shown in FIG. 1, the first end surface 181 of the first optical waveguide 160 and the sixth end surface 186 of the third optical waveguide 164 are separated by a distance D.

  The third optical waveguide 164 is connected to the third side surface 133 at an angle γ with respect to the perpendicular P3 of the third side surface 133 in plan view. In other words, it can be said that the extending direction of the third optical waveguide 164 has an angle γ with respect to the perpendicular P3. That is, the angle of the second optical waveguide 162 with respect to the perpendicular P3 and the angle of the third optical waveguide 164 with respect to the perpendicular P3 are the same within the range of manufacturing variations. The angle γ is, for example, an acute angle and is not less than the critical angle. Thereby, the third side surface 133 can totally reflect the light generated in the optical waveguides 160, 162, 164.

  Note that “the angle of the second optical waveguide 162 with respect to the perpendicular P3 is the same as the angle of the third optical waveguide 164 with respect to the perpendicular P3” takes into account manufacturing variations such as etching, and the difference between the angles is, for example, about ± 2 °. It means that it is within.

  The third optical waveguide 164 is connected to the first side surface 131 at an angle α with respect to the perpendicular line P1 in plan view. In other words, it can be said that the longitudinal direction of the third optical waveguide 164 has an angle α with respect to the perpendicular P1. That is, the first optical waveguide 160 and the third optical waveguide 164 are connected to the first side surface 131 in the same direction in plan view, and are parallel to each other. More specifically, the extending direction of the first optical waveguide 160 and the extending direction of the third optical waveguide 164 are parallel to each other. Thereby, the light 20 emitted from the first end surface 181 and the light 22 emitted from the sixth end surface 186 can travel in the same direction. The third optical waveguide 164 may be parallel (α = 0 °) to the perpendicular line P1 of the first side surface 131.

  As described above, by setting the angles β and γ to be greater than or equal to the critical angle and making the angle α smaller than the critical angle, the reflectivity of the first side surface 131 is greater than the reflectivity of the second side surface 132 and the reflectivity of the third side surface 133. Can be lowered. Accordingly, the first end surface 181 provided on the first side surface 131 can serve as a first emission part (first emission part 181) that emits light generated in the optical waveguides 160, 162, and 164. The sixth end surface 186 provided on the first side surface 131 can serve as a second emission portion (second emission portion 186) that emits light generated in the optical waveguides 160, 162, and 164. The overlapping surface 190 of the end surfaces 182 and 183 provided on the second side surface 132 can serve as a first reflecting portion (first reflecting portion 190) that reflects light generated in the optical waveguides 160, 162, and 164. An overlapping surface 192 of the end surfaces 184 and 185 provided on the third side surface 133 can serve as a second reflecting portion (second reflecting portion 192) that reflects light generated in the optical waveguides 160, 162, and 164.

  That is, the first optical waveguide 160 extends from the first emitting portion 181 to the first reflecting portion 190. The second optical waveguide 162 extends from the first reflecting part 190 to the second reflecting part 192. The third optical waveguide 164 extends from the second reflecting part 192 to the second emitting part 186.

  In the illustrated example, the surfaces of the emitting portions 181 and 186 and the reflecting portions 190 and 192 are exposed. For example, the first side surface 131 (the emitting portions 181 and 186) is covered with an antireflection film, and the first The second side surface 132 and the third side surface 133 (reflecting portions 190 and 192) may be covered with a reflective film. As a result, light generated in the optical waveguides 160, 162, and 164 is generated in the optical waveguides 160, 162, and 164 even under conditions such as an incident angle and a refractive index that do not totally reflect in the reflecting portions 190 and 192. The reflectance of the first side surface 131 in the light wavelength band can be made lower than the reflectance of the second side surface 132 and the reflectance of the third side surface 133. Further, by covering the first side surface 131 with an antireflection film, it is possible to reduce the direct multiple reflection between the first end surface 181 and the sixth end surface 186 of the light generated in the optical waveguides 160, 162, 164. it can. As a result, since a direct resonator cannot be formed, laser oscillation of light generated in the optical waveguides 160, 162, and 164 can be suppressed.

As the reflection film and the antireflection film, for example, a SiO ₂ layer, a Ta ₂ O ₅ layer, an Al ₂ O ₃ layer, a TiN layer, a TiO ₂ layer, a SiON layer, a SiN layer, or a multilayer film thereof can be used. . Alternatively, the side surfaces 132 and 133 may be DBR (Distributed Bragg Reflector) formed by etching to obtain a high reflectance.

  Further, the angle α can be an angle greater than 0 °. Thereby, the light generated in the optical waveguides 160, 162, and 164 between the first end surface 181 and the sixth end surface 186 can be prevented from being directly subjected to multiple reflection. As a result, since a direct resonator cannot be formed, laser oscillation of light generated in the optical waveguides 160, 162, and 164 can be suppressed or prevented.

  The second cladding layer 108 is formed on the active layer 106. As shown in FIGS. 1 to 3, the second cladding layer 108 includes a fourth side surface 142 that is continuous with the second side surface 132 of the active layer 106, and a fifth side surface 143 that is continuous with the third side surface 133 of the active layer 106. Have.

As the second cladding layer 108, for example, a second conductivity type (for example, p-type) InGaAlP layer or the like can be used. The second cladding layer 108 is a stacked layer composed of a plurality of layers in which the value of x is changed in an In _y (Ga _x Al _1-x ) _1-y P layer (0 ≦ x ≦ 1, 0 <y <1). It may be a body. In the illustrated example, the second cladding layer 108 has an Al high composition layer 108a having a higher Al composition (a smaller value of x) than other layers. More specifically, the Al high composition layer 108a is an In _0.49 Al _0.51 P layer, and the other layers constituting the second cladding layer 108 are In _0.49 (Ga _0.05 Al _0.95 ). It can be a _0.51 P layer. The distance between the Al high composition layer 108 a and the active layer 106 is, for example, 300 nm or less, and the Al high composition layer 108 a may be in contact with the active layer 106.

  The Al high composition layer 108a includes at least a part of the fourth side surface 142 (in other words, in contact with at least a part of the fourth side surface 142), and the first oxidized region 170 and the fifth side surface 143. And a second oxidized region 172 formed including at least a part (in other words, in contact with at least a part of the fifth side surface 143). The first oxidized region 170 and the second oxidized region 172 are oxidized portions of the Al high composition layer 108a. For example, the first oxidized region 170 is formed entirely along the fourth side surface 142 in plan view. For example, the second oxidized region 172 is formed along the fifth side surface 143 in a plan view.

  The first oxidation region 170 overlaps part of the first optical waveguide 160 and the second optical waveguide 162 and the first reflection unit 190 in plan view. The second oxidation region 172 overlaps a part of the second optical waveguide 162 and the third optical waveguide 164 and the second reflecting portion 192 in plan view. That is, the optical waveguides 160, 162, 164 can have overlapping regions 160 a, 162 a, 164 a that overlap with the oxidized regions 170, 172, respectively, due to the oxidized regions 170, 172.

  In the overlapping regions 160a, 162a, and 164a, the oxidized regions 170 and 172 are formed thereabove, so that the current from the electrodes 112 and 114 is not positively injected. Thereby, the electric current which flows into the reflection parts 190 and 192 can be suppressed, and COD (Catastrophic Optical Damage) destruction in the reflection parts 190 and 192 can be suppressed.

  Note that “the current is not actively injected” includes that the currents from the electrodes 112 and 114 are injected into the overlapping regions 160a, 162a, and 164a by diffusing. That is, even if the oxidized regions 170 and 172 are formed above the overlapping regions 160a, 162a, and 164a, the current injected by the electrodes 112 and 114 is diffused and injected into the overlapping regions 160a, 162a, and 164a. Sometimes.

  For example, the length L1 of the first oxidized region 170 in the perpendicular P2 direction of the second side surface 132 (the length of the fourth side surface 142 in the perpendicular direction) L1 is 20 μm or more, and the third side surface of the second oxidized region 172 A length L2 of 133 in the perpendicular P3 direction (a length of the fifth side surface 143 in the perpendicular direction) L2 is 20 μm or more. If the lengths L1 and L2 are 20 μm or more, even if the current diffuses in the overlapping regions 160a, 162a, and 164a, the diffused current can be prevented from reaching the reflecting portions 190 and 192. That is, it can be said that the current diffusion distance is less than 20 μm (for details, refer to the experimental example described later). Thereby, the COD destruction in the reflection parts 190 and 192 can be suppressed.

  Although not shown, the second cladding layer 108 may not have an oxidized region, and the first cladding layer 104 may have an oxidized region. That is, the first cladding layer 104 may have a side surface continuous with each of the side surfaces 132 and 133, and may have an oxidized region so as to include at least a part of the side surface. Further, both the first cladding layer 104 and the second cladding layer 108 may have an oxidized region. Furthermore, the active layer 106 may have an oxidized region so as to include at least a part of the side surfaces 132 and 133.

  Although not shown, the thickness of the oxidized region may be equal to the thickness of the second cladding layer 108. For example, the entire second cladding layer 108 may be an Al high composition layer.

  Although not shown, the second cladding layer 108 may have a side surface continuous with the side surface 131 and may have an oxidized region so as to include at least a part of the side surface. The oxidation region can overlap with the first optical waveguide 160 and the second optical waveguide 164 and the emitting portions 181 and 186 in plan view. Thereby, the COD destruction in the emission parts 181 and 186 can be suppressed.

  For example, the p-type second cladding layer 108, the active layer 106 not doped with impurities, and the n-type first cladding layer 104 constitute a pin diode. Each of the first cladding layer 104 and the second cladding layer 108 is a layer having a larger forbidden band width and a smaller refractive index than the active layer 106. The active layer 106 has a function of generating light when current is injected and guiding the light while amplifying the light. The first cladding layer 104 and the second cladding layer 108 have a function of confining injected carriers (electrons and holes) and light (a function of suppressing light leakage) with the active layer 106 interposed therebetween.

  In the light emitting device 100, when a forward bias voltage of a pin diode is applied between the first electrode 112 and the second electrode 114 (current is injected), electrons are injected into the optical waveguides 160, 162, and 164 into which current is injected. And hole recombination occur. This recombination causes light emission. With this generated light as a starting point, stimulated emission occurs in a chain, and the light intensity is amplified in the optical waveguides 160, 162, 164.

  For example, as shown in FIG. 1, the light 10 generated in the first optical waveguide 160 and directed toward the second side surface 132 is amplified in the first optical waveguide 160 and then reflected by the first reflection unit 190. The second optical waveguide 162 travels toward the third side surface 133. Then, the light is further reflected by the second reflecting portion 192, travels through the third optical waveguide 164, and is emitted as the outgoing light 22 from the sixth end face 186. At this time, the light intensity is also amplified in the optical waveguides 162 and 164. Similarly, light generated in the third optical waveguide 164 and directed toward the third side surface 133 is amplified in the third optical waveguide 164, then reflected by the second reflecting portion 192, and directed toward the second side surface 132. It proceeds through the second optical waveguide 162. Then, the light is further reflected by the first reflecting portion 190, travels through the first optical waveguide 160, and is emitted from the first end face 181 as the emitted light 20. At this time, the light intensity is also amplified in the optical waveguides 160 and 162.

  Note that some of the light generated in the first optical waveguide 160 is directly emitted from the first end face 181 as the emitted light 20. Similarly, some of the light generated in the third optical waveguide 164 is emitted directly from the sixth end face 186 as the emitted light 22. Similarly, the intensity of these lights is amplified in the respective optical waveguides 160 and 164.

  The contact layer 110 is formed on the second cladding layer 108. The contact layer 110 is formed between the second cladding layer 108 and the second electrode 114. The contact layer 110 can be in ohmic contact with the second electrode 114. It can be said that the upper surface 115 of the contact layer 110 is a contact surface 115 between the contact layer 110 and the second electrode 114. As the contact layer 110, for example, a p-type GaAs layer can be used.

  The contact layer 110 and a part of the second cladding layer 108 can form a columnar portion 111 as shown in FIG. The planar shape viewed from the stacking direction of the stacked body 120 of the columnar section 111 is the same as the planar shape viewed from the stacking direction of the stacked body 120 of the optical waveguides 160, 162, and 164. That is, it can be said that the planar shape of the upper surface 115 of the contact layer 110 is the same as the planar shape of the optical waveguides 160, 162, 164. For example, the current path between the electrodes 112 and 114 is determined by the planar shape of the columnar section 111, and as a result, the planar shapes of the optical waveguides 160, 162, and 164 are determined. Although not shown, the side surface of the columnar portion 111 can be inclined.

The insulating layer 116 is formed on the second cladding layer 108 and on the side of the columnar portion 111 (around the columnar portion 111 in plan view). The insulating layer 116 can be in contact with the side surface of the columnar portion 111. For example, the upper surface of the insulating layer 116 is continuous with the upper surface 115 of the contact layer 110. As the insulating layer 116, for example, a SiN layer, a SiO ₂ layer, a SiON layer, an Al ₂ O ₃ layer, a polyimide layer, or the like can be used. When the above material is used for the insulating layer 116, the current between the electrodes 112 and 114 can flow through the columnar portion 111 sandwiched between the insulating layers 116, avoiding the insulating layer 116.

  The insulating layer 116 can have a refractive index smaller than that of the active layer 106. In this case, the effective refractive index of the vertical cross section of the portion where the insulating layer 116 is formed is smaller than the effective refractive index of the vertical cross section of the portion where the insulating layer 116 is not formed, that is, the portion where the columnar portion 111 is formed. Thereby, light can be efficiently confined in the optical waveguides 160, 162, and 164 in the planar direction. Although not illustrated, the insulating layer 116 may be an air layer without using the above material. In this case, the air layer can function as the insulating layer 116.

  The first electrode 112 is formed on the entire lower surface of the substrate 102. The first electrode 112 can be in contact with a layer that is in ohmic contact with the first electrode 112 (the substrate 102 in the illustrated example). The first electrode 112 is electrically connected to the first cladding layer 104 via the substrate 102. The first electrode 112 is one electrode for driving the light emitting device 100. As the first electrode 112, for example, a layer in which a Cr layer, an AuGe layer, a Ni layer, and an Au layer are stacked in this order from the substrate 102 side can be used.

  A second contact layer (not shown) is provided between the first cladding layer 104 and the substrate 102, and the second contact layer is placed on the opposite side of the substrate 102 by dry etching or the like from the opposite side of the substrate 102. It is also possible to expose the first electrode 112 on the second contact layer. Thereby, a single-sided electrode structure can be obtained. This form is particularly effective when the substrate 102 is insulative.

  The second electrode 114 is formed in contact with the upper surface 115 of the contact layer 110. Further, the second electrode 114 may be formed on the insulating layer 116 as shown in FIG. The second electrode 114 is electrically connected to the second cladding layer 108 via the contact layer 110. The second electrode 114 is the other electrode for driving the light emitting device 100. As the second electrode 114, for example, a layer in which a Cr layer, an AuZn layer, and an Au layer are stacked in this order from the contact layer 110 side can be used. Although not shown, the second electrode 114 may not be formed above the oxidized regions 170 and 172.

  As described above, the case of the InGaAlP system has been described as an example of the light emitting device 100 according to the present embodiment. However, the light emitting device 100 can use any material system capable of forming an optical waveguide. As the semiconductor material, for example, semiconductor materials such as AlGaN, GaN, InGaN, GaAs, AlGaAs, InGaAs, InGaAsP, InP, GaP, AlGaP, and ZnCdSe can be used.

  Further, in the above, the light emitting device 100 according to the present embodiment includes a region between the region where the insulating layer 116 is formed and the region where the insulating layer 116 is not formed, that is, the region where the columnar portion 111 is formed. It has been described as a so-called refractive index waveguide type in which light is confined by providing a refractive index difference. Although not shown, the light emitting device according to the present embodiment does not provide a difference in refractive index by forming the columnar portion 111, and the gain regions 160, 162, and 164 serve as waveguide regions as they are, so-called gain waveguide. It may be a mold.

  The light emitting device 100 according to the present embodiment can be applied to a light source such as a projector, a display, a lighting device, and a measuring device.

  The light emitting device 100 according to the present embodiment has, for example, the following characteristics.

  According to the light emitting device 100, the second optical waveguide 162 is provided in parallel to the first side surface 131 on which the emission portions 181 and 186 are formed from the second side surface 132 to the third side surface 133. Therefore, for example, as compared with a case where the second optical waveguide is not parallel to the first side surface, it is possible to increase the interval between the emission portions while suppressing an increase in the total length of the optical waveguide. That is, it is possible to increase the interval between the plurality of emission portions (the interval between the emission portions 181 and 186) while reducing the element length in the direction perpendicular to the side surface on which the emission portions are formed. Thereby, in the light-emitting device 100, it is not necessary to flow an enormous current, and power consumption can be suppressed. Furthermore, the production cost can be suppressed without wasting resources. More specifically, in the light emitting device 100, the interval D between the emitting portions 181 and 186 is set to 0.262 mm or more and less than 3 mm, the angle α is set to 5 ° or less (including 0 °), and the optical waveguides 160, 162, and 164 The total length can be 1.5 mm or more and 3 mm or less.

  For example, when the total length of the optical waveguide is increased, in general, higher output can be achieved, but a large amount of current must be passed in order to obtain an inversion distribution. If not used, high efficiency cannot be achieved. That is, if the light output is less than the predetermined value, the efficiency is deteriorated. Furthermore, as the total length of the optical waveguide increases, the area of the entire device increases, causing problems such as waste of resources and improvement of manufacturing costs. Such a problem can be avoided in the light emitting device 100 according to the present embodiment.

  Further, in the light emitting device 100, the second cladding layer 108 includes the first oxidation region 170 formed including at least a part of the fourth side surface 142 and the first oxidation region 170 including at least a part of the fifth side surface 143. 2 oxidation region 172. The first oxidation region 170 overlaps part of the optical waveguides 160 and 162 and the first reflection part 190, and the second oxidation region 172 includes part of the optical waveguides 162 and 164 and the second reflection part 192. overlapping. Thereby, it can suppress that an electric current is inject | poured into the reflection parts 190 and 192, and can suppress the non-light-emission recombination in the reflection parts 190 and 192. FIG. As a result, it is possible to suppress the COD destruction in the reflecting portions 190 and 192.

  Here, in general, so-called dangling bonds are formed on the side surface of the active layer serving as a reflection portion or the like, in which atoms constituting the crystal cannot supply electrons and bond with each other. When a current is passed through such a portion, a surface recombination current flows, and the non-radiative recombination current due to the surface recombination inhibits luminescence recombination and generates heat. When heat is generated, the band gap is reduced and the reabsorption of light in the quantum well is increased. Increasing light reabsorption increases the heat generated by non-radiative recombination. In this way, heat generation and light reabsorption are repeated, and eventually the side surface is destroyed, resulting in COD destruction. In the light emitting device 100 according to the present embodiment, as described above, the oxidation regions 170 and 172 can prevent the current from being injected into the reflection portions 190 and 192, and the non-light emission re-emission in the reflection portions 190 and 192 can be suppressed. Binding can be suppressed. As a result, it is possible to suppress the COD destruction in the reflecting portions 190 and 192.

  According to the light emitting device 100, the length L1 of the first oxidation region 170 in the direction perpendicular to the fourth side surface 142 is 20 μm or more, and the length L2 of the second oxidation region 172 in the direction perpendicular to the fifth side surface 143. Is 20 μm or more. When the lengths L1 and L2 are 20 μm or more, even if the current diffuses in the overlapping regions 160a, 162a, and 164a, the diffused current can be prevented from reaching the reflecting portions 190 and 192 (for details). (See experimental examples below). Thereby, the COD destruction of the reflection parts 190 and 192 can be further suppressed.

  According to the light emitting device 100, the first optical waveguide 160 and the second optical waveguide 162 are connected to the first reflecting unit 190 at an angle β with respect to the perpendicular P2 of the second side surface 132, and the second optical waveguide 162 and The third optical waveguide 164 can be connected to the second reflecting portion 192 at an angle γ with respect to the perpendicular P3 of the third side surface 133. The angles β and γ are greater than the critical angle. Therefore, the reflection units 190 and 192 can totally reflect the light generated in the optical waveguides 160, 162, and 164. Therefore, in the light emitting device 100, it is possible to suppress light loss in the reflection units 190 and 192, and to reflect light efficiently. Furthermore, since the process of covering the reflecting portions 190 and 192 with a reflecting film is not required, the manufacturing cost and the materials and resources necessary for manufacturing can be reduced.

  According to the light emitting device 100, the length of the second optical waveguide 162 can be made larger than the length of the first optical waveguide 160 and the length of the third optical waveguide 164. Thereby, the space | interval D of the output parts 181 and 186 can be enlarged reliably.

  According to the light emitting device 100, the second side surface 132 and the third side surface 133 can be etched surfaces formed by etching. In general, dangling bonds are more easily formed on the etched surface than the cleaved surface formed by cleavage. In the light emitting device 100, even the reflective portions 190 and 192 provided on the etched surface can suppress COD destruction by the oxidized regions 170 and 172.

2. Experimental Example Next, an experiment for investigating the current diffusion distance will be described. In addition, this invention is not limited at all by the following experiment.

  FIG. 5 is a plan view schematically showing a light emitting device 1000 according to a reference example used in the experiment. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5 schematically showing a light emitting device 1000 according to a reference example used in the experiment.

  In the light emitting device 1000, as shown in FIGS. 5 and 6, the substrate 1102, the first cladding layer 1104, the active layer 1106, the second cladding layer 1108, the contact layer 1110, the first electrode 1112, 2 electrodes 1114.

  In the light emitting device 1000, a GaAs substrate is used as the substrate 1102. As the first cladding layer 1104, an InGaAlP layer was used. As the active layer 1106, an InGaP well layer and an InGaAlP barrier layer were used. As the second cladding layer 1108, an InGaAlP layer was used. As the contact layer 1110, a GaAs layer was used. The first electrode 1112 was formed on the entire lower surface of the substrate 1102 by using a layer in the order of the Cr layer, the AuGe layer, the Ni layer, and the Au layer from the substrate 1102 side. As the second electrode 1114, a layer in which a Cr layer, an AuZn layer, and an Au layer are stacked in this order from the contact layer 110 side was used.

  In this experiment, the semiconductor laser having the above configuration is used as the light emitting element 1000, and the width W (length in the short direction) of the second electrode 1114 is changed to 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, and 60 μm to emit light. The threshold current density of the device 1000 was measured.

  FIG. 7 is a graph showing a value (Jth) obtained by dividing the threshold current density by the width W with respect to the width W. In FIG. 7, for each width W, the length L (length in the longitudinal direction) of the second electrode 1114 is changed to 300 μm, 400 μm, 500 μm, 700 μm, and 900 μm, and values in which the threshold current density is saturated are plotted. It is. That is, in FIG. 7, it can be said that the value which can disregard the loss in the end surface of an optical waveguide is plotted.

  As shown in FIG. 7, Jth increased when W was less than 40 μm. That is, if W is less than 40 μm, the width of the second electrode 1114 and the width of the optical waveguide are not equal (the width of the optical waveguide is larger), and it can be said that the current is diffused. On the other hand, when W is 40 μm or more, Jth becomes almost constant. Therefore, it was found that the current diffused in the width W direction of the second electrode 1114 within a range of less than 20 μm on one side. Therefore, as described above, it has been found that if the lengths L1 and L2 are set to 20 μm or more, the current diffused in the overlapping regions 160a, 162a, and 164a can be prevented from reaching the reflecting portions 190 and 192.

3. Method for Manufacturing Light-Emitting Device Next, a method for manufacturing a light-emitting device according to the present embodiment will be described with reference to the drawings. 8-11 is sectional drawing which shows typically the manufacturing process of the light-emitting device 100 which concerns on this embodiment, Comprising: It respond | corresponds to FIG.

  As shown in FIG. 8, the first cladding layer 104, the active layer 106, the second cladding layer 108, and the contact layer 110 are epitaxially grown in this order on the substrate 102. As a method for epitaxial growth, for example, MOCVD (Metal Organic Chemical Vapor Deposition) method, MBE (Molecular Beam Epitaxy) method or the like can be used.

  As shown in FIG. 9, the second side surface 132 and the fourth side surface 142 where the first reflecting portion 190 is provided are exposed by, for example, etching. By the etching process, the third side surface 133 and the fifth side surface 143 (see FIG. 3) where the second reflecting portion 192 is provided can also be exposed. In the illustrated example, the stepped surface 103 is formed on the substrate 102 by stopping the etching when a part of the substrate 102 is etched, but the surface of the substrate 102 or in the middle of the first cladding layer 104 is formed. Etching may be stopped.

  As shown in FIG. 10, the Al high composition layer 108a is oxidized to form a first oxidized region 170. More specifically, the 1st oxidation area | region 170 can be formed from a side surface by the steam oxidation heated to about 450 degreeC in water vapor | steam. The vicinity of the outer edge of the Al high composition layer 108a is oxidized by steam oxidation. The second oxidation region 172 (see FIG. 3) can also be formed by the steam oxidation.

  As shown in FIG. 11, the second electrode 114 is formed on the contact layer 110. Next, the first electrode 112 is formed under the lower surface of the substrate 102. The first electrode 112 and the second electrode 114 are formed by, for example, a vacuum evaporation method. Note that the order of forming the first electrode 112 and the second electrode 114 is not particularly limited.

  As shown in FIGS. 2 and 3, the first side surface 131 on which the emitting portions 181 and 186 are provided is exposed, for example, by cleavage.

  The light emitting device 100 according to this embodiment can be manufactured through the above steps.

  For example, before the step of forming the electrodes 112 and 114, as shown in FIG. 4, the contact layer 110 and the second cladding layer 108 are etched to form the columnar portion 111, and the columnar portion 111 is further formed. A step of forming the insulating layer 116 by, for example, a CVD (Chemical Vapor Deposition) method, a coating method, or the like can be included. The order of the step of forming the columnar portion 111 and the step of forming the insulating layer 116 is not particularly limited as long as it is before the step of forming the electrodes 112 and 114.

  According to the manufacturing method of the light-emitting device 100, the light-emitting device 100 which can enlarge the space | interval D of the emission parts 181 and 186 can be obtained, aiming at size reduction.

4). 4. Modification of light emitting device 4.1. Next, a light-emitting device according to a first modification of the present embodiment will be described with reference to the drawings. FIG. 12 is a cross-sectional view schematically showing a light emitting device 200 according to a first modification of the present embodiment, and corresponds to FIG.

  Hereinafter, in the light emitting device 200 according to the first modification of the present embodiment, members having the same functions as those of the constituent members of the light emitting device 100 according to the present embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. To do.

  In the example of the light emitting device 100, as shown in FIGS. 2 and 3, the surfaces of the reflecting portions 190 and 192 are exposed. On the other hand, in the light emitting device 200, as shown in FIG. 12, the surfaces of the reflecting portions 190 and 192 are covered with a dielectric layer 202.

  In the illustrated example, the dielectric layer 202 is formed on the step surface 103 of the substrate 102 and on the side of the first cladding layer 104, the active layer 106, the second cladding layer 108, and the contact layer 110. . The upper surface of the dielectric layer 202 is continuous with the upper surface 115 of the contact layer 110, for example. The dielectric layer 202 is provided so as to fill the notch portion 122 of the stacked body 120 formed by, for example, an etching process for exposing the reflection portions 190 and 192 (side surfaces 132 and 133).

More specifically, examples of the dielectric layer 202 include a SiN layer, a SiON layer, a SiO ₂ layer, and a Ta ₂ O ₅ layer. The dielectric layer 202 is formed by, for example, a CVD method.

  According to the light emitting device 200, since the reflective portions 190 and 192 are covered with the dielectric layer 202, part of the dangling bonds of the reflective portions 190 and 192 can be terminated. Thereby, the breakdown voltage against COD can be improved.

  Furthermore, according to the light emitting device 200, by embedding the notch portion 122 with the dielectric layer 202, mounting by junction down (mounting for connecting the second electrode 114 side to the mounting substrate) can be easily performed. It is possible to prevent a conductive bonding member such as a material from contacting the reflecting portions 190 and 192 and short-circuiting the pn junction.

4.2. Next, a light-emitting device according to a second modification of the present embodiment will be described with reference to the drawings. FIG. 13 is a cross-sectional view schematically showing a light emitting device 300 according to a second modification of the present embodiment, and corresponds to FIG.

  Hereinafter, in the light emitting device 300 according to the second modified example of the present embodiment, members having the same functions as the constituent members of the light emitting device 200 according to the first modified example of the present embodiment are denoted by the same reference numerals, and Detailed description is omitted.

  In the example of the light emitting device 200, as shown in FIG. 12, the cutout portion 122 of the stacked body 120 is embedded with the dielectric layer 202. On the other hand, in the light emitting device 300, the notch 122 is embedded with the dielectric layer 202 and the resin layer 302.

  In the illustrated example, a resin layer 302 is formed on the side of the dielectric layer 202 (in other words, on the side opposite to the reflective portions 190 and 192 via the dielectric layer 202). Are formed between the first cladding layer 104, the active layer 106, the second cladding layer 108, and the contact layer 110. For example, the upper surface of the resin layer 302 is continuous with the upper surface of the dielectric layer 202 and the upper surface 115 of the contact layer 110.

  An example of the resin layer 302 is a polyimide layer. The resin layer 302 is formed by, for example, a coating method.

  According to the light emitting device 300, for example, as in the light emitting device 200, the notch 122 can be easily embedded as compared with the case where the notch 122 is filled with a single dielectric layer 202. That is, for example, since the resin layer 302 formed by the coating method has a film forming rate higher than that of the dielectric layer 202 formed by the CVD method, the notch 122 can be embedded in a short time. Therefore, in the light emitting device 300, the cutout portion 122 can be embedded in the resin layer 302 in a short time while the dielectric layer 202 terminates a part of the dangling bonds of the reflection portions 190 and 192.

4.3. Next, a light-emitting device according to a third modification of the present embodiment will be described with reference to the drawings. FIG. 14 is a plan view schematically showing a light emitting device 400 according to a third modification of the present embodiment. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14 schematically showing a light emitting device 400 according to a third modification of the present embodiment. FIG. 16 is a cross-sectional view taken along line XVI-XVI of FIG. 14 schematically showing a light emitting device 400 according to a third modification of the present embodiment. In FIG. 14, the second electrode 114 is not shown for convenience.

  Hereinafter, in the light emitting device 400 according to the third modification example of the present embodiment, members having the same functions as the constituent members of the light emitting device 100 according to the present embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. To do. The same applies to the light emitting device 500 according to the fourth modification of the present embodiment described below.

  In the light emitting device 100, as shown in FIGS. 1 to 3, the second cladding layer 108 has a first oxidized region 170 and a second oxidized region 172. In the light emitting device 400, as shown in FIGS. 14 to 16, the second cladding layer 108 further has a third oxidation region 174 and a fourth oxidation region 176.

  The third oxidation region 174 is disposed opposite to the first oxidation region 170. In other words, the third oxidation region 174 is disposed with the first optical waveguide 160 and the second optical waveguide 162 interposed therebetween with respect to the first oxidation region 170 in plan view. In other words, the first optical waveguide 160 and the second optical waveguide 162 are disposed between the first oxidized region 170 and the third oxidized region 174 in plan view.

  In the illustrated example, the first opening 124 is formed in the stacked body 120, and the third oxide region 174 is formed including the side surface 144 of the second cladding layer 108 that forms the inner surface of the first opening 124. That is, the third oxidation region 174 is formed around the first opening 124 in plan view. In the example shown in FIG. 15, the bottom surface of the first opening 124 is located between the upper surface and the lower surface of the substrate 102.

  The fourth oxidation region 176 is disposed opposite to the second oxidation region 172. In other words, the fourth oxidation region 176 is arranged with the second optical waveguide 162 and the third optical waveguide 164 sandwiched with respect to the second oxidation region 172 in plan view. In other words, the second optical waveguide 162 and the third optical waveguide 164 are disposed between the second oxidized region 172 and the fourth oxidized region 176 in plan view.

  In the illustrated example, the second opening 126 is formed in the stacked body 120, and the fourth oxidation region 176 is formed including the side surface 146 of the second cladding layer 108 that forms the inner surface of the second opening 126. That is, the fourth oxidation region 176 is formed around the second opening 126 in plan view. In the example illustrated in FIG. 16, the bottom surface of the second opening 126 is located between the upper surface and the lower surface of the substrate 102.

  According to the light emitting device 400, the oxidation regions 170, 172, 174, and 176 are formed on both sides of the optical waveguides 160, 162, and 164 in a plan view. Therefore, optical loss can be reduced. For example, when the oxidized region is formed only on one side of the optical waveguide, the refractive index distribution is asymmetric in plan view, and the electric field distribution of light in this region is also asymmetric. The electric field distribution is substantially symmetric in the portions where the oxidized regions of the optical waveguides 160, 162, and 164 are not formed (non-oxidized regions). Therefore, when light enters and exits between the oxidized region and the non-oxidized region, the optical coupling loss may increase.

4.4. Next, a light-emitting device according to a fourth modification of the present embodiment will be described with reference to the drawings. FIG. 17 is a plan view schematically showing a light emitting device 500 according to a fourth modification of the present embodiment. In FIG. 17, the second electrode 114 is not shown for convenience.

  In the example of the light emitting device 100, as shown in FIG. 1, the first optical waveguide 160, the second optical waveguide 162, and the third optical waveguide 164 are provided one by one. On the other hand, in the light emitting device 500, as shown in FIG. 17, a plurality of first optical waveguides 160, second optical waveguides 162, and third optical waveguides 164 are provided.

  That is, the first optical waveguide 160, the second optical waveguide 162, and the third optical waveguide 164 can constitute an optical waveguide group 550. In the light emitting device 500, a plurality of optical waveguide groups 550 are provided. In the illustrated example, three optical waveguide groups 550 are provided, but the number thereof is not particularly limited.

  The plurality of optical waveguide groups 550 are arranged along a direction orthogonal to the direction in which the perpendicular P1 of the first side surface 131 extends. More specifically, in the adjacent optical waveguide groups 550, the distance between the sixth end surface 186 of one optical waveguide group 550 and the first end surface 181 of the other optical waveguide group 550 is D (outgoing). Are arranged so as to be spaced apart. Thereby, the light 20 and 22 can be easily incident on a lens array described later.

  According to the light emitting device 500, higher output can be achieved as compared with the example of the light emitting device 100.

5. Next, the projector according to the present embodiment will be described with reference to the drawings. FIG. 18 is a diagram schematically showing a projector 800 according to the present embodiment. FIG. 19 is a diagram schematically showing a part of the projector 800 according to the present embodiment. Note that in FIG. 18, for convenience, the housing that configures the projector 800 is omitted, and the light source 700 is simplified. In FIG. 19, for convenience, the light source 700, the lens array 802, and the liquid crystal light valve 804 are illustrated, and the light source 700 is illustrated in a simplified manner.

  As shown in FIG. 18, the projector 800 includes a red light source 700R that emits red light, green light, and blue light, a green light source 700G, and a blue light source 700B. The light sources 700R, 700G, and 700B include the light emitting device according to the present invention. In the following example, light sources 700R, 700G, and 700B having the light emitting device 500 as the light emitting device according to the present invention will be described.

  FIG. 20 is a diagram schematically showing a light source 700 of the projector 800 according to the present embodiment. FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 20 schematically showing the light source 700 of the projector 800 according to the present embodiment.

  As shown in FIGS. 20 and 21, the light source 700 can include a light emitting device 500, a base 710, and a submount 720.

  The two light emitting devices 500 and the submount 720 can form the structure 730. A plurality of structures 730 are provided, and are arranged in a direction (Y-axis direction) orthogonal to the arrangement direction (X-axis direction) of the end surfaces 181 and 186 serving as the emission portions of the light-emitting device 500, as shown in FIG. . The structures 730 can be arranged so that the interval between the emission parts in the X-axis direction is the same as the interval between the emission parts in the Y-axis direction. Thereby, the light emitted from the light emitting device 500 can be easily incident on the lens array 802.

  The two light emitting devices 500 constituting the structure 730 are arranged with the submount 720 interposed therebetween. In the example shown in FIGS. 20 and 21, the two light emitting devices 500 are arranged so that the second electrodes 114 face each other with the submount 720 interposed therebetween. For example, wiring is formed on the surface of the submount 720 that is in contact with the second electrode 114. Thereby, a voltage can be individually supplied to each of the plurality of second electrodes 114. Examples of the material of the submount 720 include aluminum nitride and aluminum oxide.

  The base 710 supports the structure body 730. In the example illustrated in FIG. 21, the base 710 is connected to the first electrodes 112 of the plurality of light emitting devices 500. Accordingly, the base 710 can function as a common electrode for the plurality of first electrodes 112. Examples of the material of the base 710 include copper and aluminum. Although not shown, the base 710 may be connected to a heat sink via a Peltier element.

  Note that the structure of the structure 730 is not limited to the example illustrated in FIGS. For example, as illustrated in FIG. 22, the two light emitting devices 500 constituting the structure 730 include a first electrode 112 of one light emitting device 500 and a second electrode of the other light emitting device 500 via a submount 720. 114 may be arranged so as to be opposed to each other. Further, as shown in FIG. 23, the first electrodes 112 of the two light emitting devices 500 may be arranged to be a common electrode.

  As shown in FIG. 18, the projector 800 further includes lens arrays 802R, 802G, and 802B, transmissive liquid crystal light valves (light modulation devices) 804R, 804G, and 804B, and a projection lens (projection device) 808. Including.

  Light emitted from the light sources 700R, 700G, and 700B is incident on the lens arrays 802R, 802G, and 802B. As shown in FIG. 19, the lens array 802 can have a flat surface 801 on the light source 700 side on which the light 20 and 22 emitted from the emission units 181 and 186 are incident. A plurality of flat surfaces 801 are provided corresponding to the plurality of light emitting portions 181 and 186, and are arranged at equal intervals. Further, the normal line of the flat surface 801 is inclined with respect to the optical axes of the light 20 and 22. Accordingly, the flat surfaces 801 can make the optical axes of the lights 20 and 22 orthogonal to the irradiation surface 805 of the liquid crystal light valve 804. In particular, when the angle α formed by the first side 131, the first optical waveguide 160, and the third optical waveguide 164 is not 0 ° (see FIG. 1), the light 20 and 22 are transmitted from the light emitting portions 181 and 186, respectively. Since the light is emitted with an inclination with respect to the perpendicular P1 of the one side 131, it is desirable to provide a flat surface 801.

  The lens array 802 can have a convex curved surface 803 on the liquid crystal light valve 804 side. A plurality of convex curved surfaces 803 are provided corresponding to the plurality of flat surfaces 801, and are arranged at equal intervals. The light 20 and 22 whose optical axis is converted on the flat surface 801 can be superposed (partially superposed) by being condensed by the convex curved surface 803 or by reducing the diffusion angle. Thereby, the liquid crystal light valve 804 can be irradiated with good uniformity.

  As described above, the lens array 802 can focus the lights 20 and 22 by controlling the optical axes of the lights 20 and 22 emitted from the light source 700.

  As shown in FIG. 18, the light condensed by the lens arrays 802R, 802G, and 802B is incident on the liquid crystal light valves 804R, 804G, and 804B. Each of the liquid crystal light valves 804R, 804G, and 804B modulates incident light according to image information. The projection lens 808 enlarges and projects an image formed by the liquid crystal light valves 804R, 804G, and 804B onto a screen (display surface) 810.

  Further, the projector 800 can include a cross dichroic prism (color light combining means) 806 that combines the light emitted from the liquid crystal light valves 804R, 804G, and 804B and guides the light to the projection lens 808.

  The three color lights modulated by the liquid crystal light valves 804R, 804G, and 804B are incident on the cross dichroic prism 806. This prism is formed by bonding four right-angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged in a cross shape on the inner surface thereof. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected onto the screen 810 by the projection lens 808 which is a projection optical system, and an enlarged image is displayed.

  The projector 800 includes the light emitting device 500 that can increase the interval between the plurality of emitting portions. Therefore, in the projector 800, the alignment of the lens array 802 is easy, and the liquid crystal light valve 804 can be irradiated with good uniformity.

  In the above example, a transmissive liquid crystal light valve is used as the light modulation device. However, a light valve other than liquid crystal may be used, or a reflective light valve may be used. Examples of such a light valve include a reflective liquid crystal light valve and a digital micromirror device. Further, the configuration of the projection optical system is appropriately changed depending on the type of light valve used.

  Further, the light source 700 and the lens array 802 can be modularized in an aligned state. Furthermore, the light source 700, the lens array 802, and the light valve 804 may be modularized in an aligned state.

  Further, the light source 700 scans light on the screen with the light from the light source 700 to display an image of a desired size on the display surface. It can also be applied to a light source device of a projector.

  The above-described embodiments and modifications are merely examples, and the present invention is not limited to these. For example, it is possible to appropriately combine each embodiment and each modification.

  Although the embodiments of the present invention have been described in detail as described above, those skilled in the art will readily understand that many modifications are possible without substantially departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention.

10 light, 20 light, 22 light, 100 light emitting device, 102 substrate, 103 step surface,
104 first cladding layer, 106 active layer, 108 second cladding layer,
108a Al high composition layer, 110 contact layer, 111 columnar portion, 112 first electrode,
114 second electrode, 115 contact surface, 116 insulating layer, 120 laminate,
122 notch, 124 first opening, 126 second opening, 131 first side,
132 second side, 133 third side, 134 side, 135 side, 136 side,
142 4th side, 143 5th side, 144 side, 146 side,
160 first optical waveguide, 160a overlapping region, 162 second optical waveguide,
162a overlap region, 164 third optical waveguide, 164a overlap region,
170 first oxidation region, 172 second oxidation region, 174 third oxidation region,
176 4th oxidation area | region, 181 1st end surface, 182 2nd end surface, 183 3rd end surface,
184 4th end surface, 185 5th end surface, 186 6th end surface, 190 Overlapping surface,
192 overlapping surface, 200 light emitting device, 202 dielectric layer, 300 light emitting device,
302 resin layer, 400 light emitting device, 500 light emitting device, 550 optical waveguide group,
700 light source, 710 base, 720 submount, 730 structure,
800 projector, 801 flat surface, 802 lens array, 803 convex curved surface,
804 liquid crystal light valve, 805 irradiation surface, 806 cross dichroic prism,
808 projection lens, 810 screen, 1000 light emitting device, 1102 substrate,
1104 First cladding layer, 1106 active layer, 1108 second cladding layer,
1110 contact layer, 1112 first electrode, 1114 second electrode

Claims (12)

A first layer that generates light by injecting current;
A second layer and a third layer sandwiching the first layer and suppressing leakage of the light;
Including
In the first layer,
A first optical waveguide having a band-like shape extending from a first emitting portion provided on the first side surface of the first layer to a first reflecting portion provided on the second side surface of the first layer;
A second optical waveguide having a strip shape extending from the first reflecting portion to a second reflecting portion provided on a third side surface of the first layer;
A third optical waveguide having a strip shape extending from the second reflecting portion to the second emitting portion provided on the first side surface;
Formed,
The extending direction of the second optical waveguide is parallel to the first side surface,
The first light emitted from the first emission part and the second light emitted from the second emission part are emitted in the same direction,
The first reflecting portion is a part of the second side surface itself,
The second reflecting portion is a part of the third side surface itself,
The third layer is
A first oxidation region formed including at least a part of a fourth side continuous with the second side;
A second oxidation region formed including at least a part of a fifth side surface continuous with the third side surface;
Have
The first optical waveguide has a first overlapping region that overlaps the first oxidation region when viewed from the stacking direction of the first layer, the second layer, and the third layer;
The second optical waveguide has a second overlapping region that overlaps the first oxidized region and a third overlapping region that overlaps the second oxidized region when viewed from the stacking direction,
The third optical waveguide has a fourth overlapping region that overlaps the second oxidation region when viewed from the stacking direction,
The first overlapping region and the second overlapping region are formed including the first reflecting portion,
The third overlapping region and the fourth overlapping region are formed so as to include the second reflecting portion .   2. The light emitting device according to claim 1, wherein surfaces of the first reflecting portion and the second reflecting portion are covered with a dielectric layer.   The light-emitting device according to claim 2, wherein a resin layer is formed on the opposite side of the first reflective portion and the second reflective portion via the dielectric layer.   The light emitting device according to claim 1, wherein surfaces of the first reflecting portion and the second reflecting portion are exposed. The third layer is
A third oxide region disposed across the first optical waveguide and the second optical waveguide with respect to the first oxide region when viewed from the stacking direction;
A fourth oxide region disposed across the second optical waveguide and the third optical waveguide with respect to the second oxide region when viewed from the stacking direction;
The light-emitting device according to claim 1, wherein the light-emitting device comprises: The perpendicular length of the fourth side surface of the first oxidation region is 20 μm or more,
6. The light-emitting device according to claim 1, wherein a length of the second oxidation region in a perpendicular direction of the fifth side surface is 20 μm or more. Seen from the stacking direction,
The first optical waveguide and the second optical waveguide are connected to the first reflecting portion by being inclined at a first angle with respect to a normal of the second side surface,
The second optical waveguide and the third optical waveguide are connected to the second reflecting part by being inclined at a second angle with respect to the perpendicular of the third side surface,
The light emitting device according to claim 1, wherein the first angle and the second angle are equal to or greater than a critical angle. The length in the extending direction of the second optical waveguide is:
8. The light emitting device according to claim 1, wherein the light emitting device has a length in an extending direction of the first optical waveguide and a length in an extending direction of the third optical waveguide.   The light emitting device according to claim 1, wherein the second side surface and the third side surface are etched surfaces formed by etching. A light emitting device according to any one of claims 1 to 9,
A lens array for condensing the light emitted from the light emitting device;
A light modulation device that modulates light collected by the lens array according to image information;
A projection device for projecting an image formed by the light modulation device;
Including a projector. A first layer that generates light by injecting current;
A second layer and a third layer sandwiching the first layer and suppressing leakage of the light;
Including
In the first layer,
A first optical waveguide having a band-like shape extending from a first emitting portion provided on the first side surface of the first layer to a first reflecting portion provided on the second side surface of the first layer;
A second optical waveguide having a strip shape extending from the first reflecting portion to a second reflecting portion provided on a third side surface of the first layer;
A third optical waveguide having a strip shape extending from the second reflecting portion to the second emitting portion provided on the first side surface;
Formed,
The extending direction of the second optical waveguide is parallel to the first side surface,
The first light emitted from the first emission part and the second light emitted from the second emission part are emitted in the same direction,
The first reflecting portion is a part of the second side surface itself,
The second reflecting portion is a part of the third side surface itself,
The third layer is
A first oxidation region formed including at least a part of a fourth side continuous with the second side;
A second oxidation region formed including at least a part of a fifth side surface continuous with the third side surface;
Have
The first optical waveguide has a first overlapping region that overlaps the first oxidation region when viewed from the stacking direction of the first layer, the second layer, and the third layer;
The second optical waveguide has a second overlapping region that overlaps the first oxidized region and a third overlapping region that overlaps the second oxidized region when viewed from the stacking direction,
The third optical waveguide has a fourth overlapping region that overlaps the second oxidation region when viewed from the stacking direction,
The first overlapping region and the second overlapping region are formed including the first reflecting portion,
The superluminescent diode, wherein the third overlapping region and the fourth overlapping region are formed including the second reflecting portion . A superluminescent diode according to claim 11,
A lens array that collects the light emitted from the superluminescent diode;
A light modulation device that modulates light collected by the lens array according to image information;
A projection device for projecting an image formed by the light modulation device;
Including a projector.

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