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WO2018008381A1 - Optical element, active layer structure, and display device - Google Patents

Optical element, active layer structure, and display device Download PDF

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Publication number
WO2018008381A1
WO2018008381A1 PCT/JP2017/022624 JP2017022624W WO2018008381A1 WO 2018008381 A1 WO2018008381 A1 WO 2018008381A1 JP 2017022624 W JP2017022624 W JP 2017022624W WO 2018008381 A1 WO2018008381 A1 WO 2018008381A1
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layer
optical element
quantum well
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義昭 渡部
河角　孝行
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Sony Corp
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/81—Bodies
    • H10H20/822—Materials of the light-emitting regions
    • H10H20/824—Materials of the light-emitting regions comprising only Group III-V materials, e.g. GaP
    • H10H20/825—Materials of the light-emitting regions comprising only Group III-V materials, e.g. GaP containing nitrogen, e.g. GaN
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
    • H01S5/3407—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers characterised by special barrier layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
    • H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
    • H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
    • H01S5/34333—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/81—Bodies
    • H10H20/811—Bodies having quantum effect structures or superlattices, e.g. tunnel junctions
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/81—Bodies
    • H10H20/811—Bodies having quantum effect structures or superlattices, e.g. tunnel junctions
    • H10H20/812—Bodies having quantum effect structures or superlattices, e.g. tunnel junctions within the light-emitting regions, e.g. having quantum confinement structures
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/81—Bodies
    • H10H20/813—Bodies having a plurality of light-emitting regions, e.g. multi-junction LEDs or light-emitting devices having photoluminescent regions within the bodies

Definitions

  • an optical element includes a first conductivity type layer, a second conductivity type layer, and an active layer.
  • the first conductivity type layer has a current confinement structure configured such that a current injection region is constricted.
  • the active layer is an active layer provided between the first conductivity type layer and the second conductivity type layer, and has one quantum well layer or a plurality of quantum well layers.
  • the thickness of the quantum well layer is 10 nm or less, and the total thickness of the plurality of quantum well layers is 10 nm or less.
  • the first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer
  • the second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer
  • the refractive index difference between the first cladding layer and the first guide layer is 0.01 or more and 0.10 or less
  • the difference in refractive index between the second cladding layer and the second guide layer may be not less than 0.01 and not more than 0.10.
  • the light emitted from the optical element can be output with high output and wide spectrum width as described above.
  • the thickness of the first guide layer is 50 nm or more and 200 nm or less
  • the thickness of the second guide layer may be 50 nm or more and 200 nm or less.
  • the emission color is red, taking into consideration the control of the emission pattern (spreading of emitted light) and the confinement of carriers, the refractive index difference between the first cladding layer and the first guide layer and the refraction of the second cladding layer and the second guide layer.
  • the rate difference is preferably 0.06 or more and 0.30 or less.
  • the difference in refractive index between the first cladding layer and the first guide layer and the second cladding layer and the second guide layer is preferably 0.02 or more and 0.06 or less.
  • an optical element As described above, according to the present technology, it is possible to provide an optical element, an active layer structure, and a display device that can emit light with high output and a wide spectrum width. Note that the effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.
  • the lower end of the p-type cladding layer 131 coincides with the lower end of the ridge portion 10, but this need not be the case, and the lower end of the ridge portion 10 includes a part of the p-type guide layer 132. Also good.
  • FIG. 3 is a schematic diagram showing the band structure of each layer.
  • the horizontal direction indicates energy (E in the figure), and indicates that the energy is higher toward the left side.
  • the vertical direction indicates the stacking direction of the layers constituting the optical element 100.
  • the lower energy band is a valence band (VB), and the higher energy band is a conduction band (CB).
  • conventional structure there is a structure including an active layer having a plurality of thin quantum wells (hereinafter, conventional structure 1).
  • conventional structure 1 in order to widen the spectrum width, the wavelength of each quantum well is changed variously to obtain a wide spectrum width.
  • injected carriers are dispersed in the plurality of quantum wells, the carrier distribution is likely to be non-uniform, and high gain is difficult to obtain.
  • FIG. 5 is a table showing the characteristics of the SLD having the conventional structure and the SLD according to the present embodiment.
  • the well width T is small and the carrier density is large, the quantum effect of the quantum well is increased, the use efficiency of injected carriers is promoted, and the output and temperature characteristics are improved. Moreover, the active layer loss is also reduced by reducing the volume of the active layer 20.
  • the well width T is reduced, that is, the optical loss of the active layer light absorption in the non-excitation region is reduced by the amount that the volume of the active layer 20 is reduced, and the heat source around the active layer is reduced. Further, it is effective in further improving the light emission efficiency or energy efficiency, lowering the temperature inside the device, and thus improving the reliability.
  • the light confinement ratio in the quantum well formed by the quantum well layer 20a is preferably 3% or less.
  • the light confinement rate in the quantum well means the ratio of the light density confined in the quantum well. Conventionally, the light confinement rate in the quantum well is generally 4% or more.
  • the material of the quantum well layer 20a is not particularly limited, but the emission color of the optical element 100 varies depending on the material of the quantum well layer 20a.
  • the quantum well layer 20a is made of AlInGaP, red light having an emission wavelength of 550 to 900 nm (practical range of 630 to 680 nm) is generated.
  • the quantum well layer 20a is made of AlInGaN, blue-violet to green light having an emission wavelength of 400 to 1000 nm (practical range of 400 to 550 nm) is generated.
  • the materials of the quantum well layer 20a include AlGaN (emission wavelength ultraviolet region to 400 nm), AlGaAs (emission wavelength 750 to 850 nm, infrared region), InGaAs (emission wavelength 800 to 980 nm, infrared region), InGaAsP (emission wavelength 1.2). To 1.6 ⁇ m, infrared region) and the like.
  • the light confinement ratio in the quantum well can be adjusted to 3% or less.
  • the thicknesses of the p-type guide layer 132 and the n-type guide layer 142 are each preferably 10 nm to 500 nm, and more preferably 50 nm to 200 nm.
  • the above 10 nm to 500 nm is a numerical range that can be taken in the device design of SLD, and 50 nm to 200 nm is a numerical range that considers not only light confinement but also light emission pattern control (spreading of emitted light) and carrier confinement. is there.
  • the refractive index difference between the p-type cladding layer 131 and the p-type guide layer 132 (hereinafter referred to as p-type refractive index difference) and the refractive index difference between the n-type cladding layer 141 and the n-type guide layer 142 (hereinafter referred to as n-type refractive index difference).
  • p-type refractive index difference refractive index difference between the n-type cladding layer 141 and the n-type guide layer 142
  • n-type refractive index difference Can also adjust the light confinement rate in the quantum well to 3% or less.
  • the p-type refractive index difference and the n-type refractive index difference are each preferably 0.03 to 0.50, and 0.06 More than 0.30 is more suitable.
  • 0.03 to 0.50 is a numerical range that can be taken in the device design of the SLD, and 0.06 to 0.30 is not only the confinement of light but also the control of the light emission pattern (spreading of the emitted light) This is a numerical range that also considers the confinement of carriers.
  • the range from 0.01 to 0.10 is a numerical range that can be taken in the device design of the SLD, and the range from 0.02 to 0.06 is not only the confinement of light but also the control of the light emission pattern (spreading of the emitted light) This is a numerical range that also considers the confinement of carriers.
  • the waveguide length when the waveguide length is increased, the light intensity is increased because the light is amplified through a longer path until the light is emitted.
  • the gain spectrum wavelength dependence
  • the emission spectrum width is narrowed. For this reason, low coherence property falls. That is, the output and coherence have a trade-off relationship.
  • the size of the SLD becomes large, which is not suitable for downsizing of the package, the influence of the entire waveguide loss is increased, and the light change efficiency is also lowered.
  • the injection electrode is divided or the material and structure of the active layer are divided into parts. Need to change. In the former case, it is necessary to drive the divided electrodes with separate drivers, which is expensive. In the latter case, it is difficult to manufacture, for example, since crystal regrowth is required, and the cost is high.
  • composition and film thickness of the active layer can be sufficiently detected by EDX (Energy Dispersive X-ray Spectrometry) analysis or WDX (Wavelength Dispersive X-ray Spectroscopy) analysis after TEM (Transmission Electron Microscope) analysis. Further, not only the film thickness but also the optical confinement ratio can be calculated by combining optical waveguide calculation.
  • FIG. 12 schematically shows a configuration of a display device that uses an SLD that is an optical element according to the embodiment as a light source.
  • the display device 200 is a raster scan projector.
  • a two-dimensional light modulation element such as a DMD (Digital Micro-mirror Device) manufactured using MEMS (Micro Electro Mechanical System) technology may be used.
  • DMD Digital Micro-mirror Device
  • MEMS Micro Electro Mechanical System
  • the one quantum well layer is an optical element made of AlInGaN.
  • An optical element The light emitted from the optical element can be scanned two-dimensionally, and based on image data, an image generation unit capable of controlling the luminance by the projected light,
  • the optical element is A first conductivity type layer having a current confinement structure configured to confine a current injection region; A second conductivity type layer; An active layer provided between the first conductivity type layer and the second conductivity type layer, the active layer having one quantum well layer or a plurality of quantum well layers,
  • a display device comprising: an active layer having a thickness of 10 nm or less and a total thickness of the plurality of quantum well layers being 10 nm or less.

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  • Condensed Matter Physics & Semiconductors (AREA)
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Abstract

[Problem] To provide an optical element with which light having a high output and a wide spectrum width can be emitted, and to provide an active layer structure and a display device. [Solution] An optical element of the present technology comprises a first conductivity-type layer, a second conductivity-type layer, and an active layer. The first conductivity-type layer has a current constriction structure that is configured so as to constrict an injection region of a current. The active layer is provided between the first conductivity-type layer and the second conductivity-type layer, and includes a single quantum well layer or multiple quantum well layers. The thickness of the single quantum well layer is 10 nm or less, and the total thickness of the multiple quantum well layers is 10 nm or less.

Description

光学素子、活性層構造及び表示装置Optical element, active layer structure, and display device

　本技術は、スーパールミネッセントダイオード（ＳＬＤ）の技術に関する。 This technology relates to the technology of super luminescent diode (SLD).

　スーパールミネッセントダイオード（ＳＬＤ）は、発光ダイオードに比較的近い広い発光スペクトル幅を持ちながら、同時に半導体レーザの発光状態のような狭い放射角と強い強度で光を出射する特徴を持つ発光素子である。このＳＬＤは、ファイバジャイロ等の干渉計分野に応用されている。近年では、その干渉性の低さから干渉ノイズの少ない画像投射用光源としてディスプレイへの応用も期待されている。 A super luminescent diode (SLD) is a light-emitting element that has a characteristic of emitting light with a narrow emission angle and strong intensity, such as the emission state of a semiconductor laser, while having a broad emission spectrum width relatively close to that of a light-emitting diode. is there. This SLD is applied to the field of interferometers such as fiber gyros. In recent years, application to displays is also expected as a light source for image projection with low interference noise due to its low coherence.

　例えば、特許文献１には、直線状のリッジ導波路とこれに続く曲線状の導波路を備えるＳＬＤが開示されている。リッジ導波路直下の活性層で発生した光は曲線状の導波路を進行し、ＳＬＤの端面に対して非垂直な方向に出射する。これにより、端面での反射光が導波路に戻ることが防止されている。 For example, Patent Document 1 discloses an SLD including a linear ridge waveguide followed by a curved waveguide. Light generated in the active layer immediately below the ridge waveguide travels through the curved waveguide and is emitted in a direction non-perpendicular to the end face of the SLD. This prevents the reflected light from the end face from returning to the waveguide.

　要するに、ＳＬＤは、通常のレーザダイオード（ＬＤ）のように、両端面に設けられたミラーで光を往復させて共振（レーザ発振）させる構造ではなく、光を導波路で一方通行させて光を増幅させる（誘導放出は行われる）構造を有する。最初の光の発生源はＳＬＤの後端面（光出射端面とは反対側の端面）付近の活性層で発生した自然放出光である。ＳＬＤはこのスペクトル幅が広い光をそのまま導波路で増幅して強度を高め、出射する構造となっている。 In short, the SLD does not have a structure in which light is reciprocated by a mirror provided on both end faces and resonates (laser oscillation) unlike a normal laser diode (LD), but light is made to pass through the waveguide in one direction. It has a structure to be amplified (stimulated emission is performed). The first light generation source is spontaneous emission light generated in the active layer near the rear end face of the SLD (end face opposite to the light exit end face). The SLD has a structure in which light having a wide spectral width is directly amplified by a waveguide to increase the intensity and output.

特開平2-310975号公報JP-A-2-310975

　上記のようなＳＬＤにおいては、ディスプレイ等への応用のために出射光の出力向上が求められている。しかしながら、出射光の出力とスペクトル幅はトレードオフの関係にあり、出射光を高出力化し、かつ広いスペクトル幅を実現することは容易ではない。 In the above-described SLD, output light output is required to be improved for application to a display or the like. However, the output of the emitted light and the spectral width are in a trade-off relationship, and it is not easy to increase the output of the emitted light and realize a wide spectral width.

　以上のような事情に鑑み、本技術の目的は、高出力かつスペクトル幅の広い光を出射することが可能な光学素子、活性層構造及び表示装置を提供することにある。 In view of the circumstances as described above, an object of the present technology is to provide an optical element, an active layer structure, and a display device that can emit light with high output and a wide spectrum width.

　上記目的を達成するため、本技術の一形態に係る光学素子は、第１導電型層と、第２導電型層と、活性層とを具備する。
　上記第１導電型層は、電流の注入領域が狭窄するように構成された電流狭窄構造を有する。
　上記活性層は、上記第１導電型層と上記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、上記１層の量子井戸層の厚みは１０ｎｍ以下であり、上記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である。 In order to achieve the above object, an optical element according to an embodiment of the present technology includes a first conductivity type layer, a second conductivity type layer, and an active layer.
The first conductivity type layer has a current confinement structure configured such that a current injection region is constricted.
The active layer is an active layer provided between the first conductivity type layer and the second conductivity type layer, and has one quantum well layer or a plurality of quantum well layers. The thickness of the quantum well layer is 10 nm or less, and the total thickness of the plurality of quantum well layers is 10 nm or less.

　この構成によれば、量子井戸層の厚みを小さくすることにより、量子井戸への光閉じ込め効果が小さくなり、自然放出光の利用効率が小さくなる。このため、発光を開始するために必要なキャリア密度が大きくなり、単位体積当たりの自然放出光の発光量は大きくなる。また、自然放出光が増幅される利得領域においても、キャリア密度が大きいため、利得やスペクトル幅も大きくなる。これにより、光学素子の出射光を高出力かつスペクトル幅の広い光とすることが可能となる。 According to this configuration, by reducing the thickness of the quantum well layer, the light confinement effect in the quantum well is reduced, and the utilization efficiency of spontaneous emission light is reduced. For this reason, the carrier density required to start light emission increases, and the amount of spontaneous emission light emitted per unit volume increases. Also in the gain region where the spontaneous emission light is amplified, the carrier density is high, so that the gain and the spectral width are also increased. As a result, the light emitted from the optical element can be made to have a high output and a wide spectrum width.

　上記１層の量子井戸層又は上記複数層の量子井戸層は、ＡｌＩｎＧａＰからなるものであってもよい。 The one quantum well layer or the plurality of quantum well layers may be made of AlInGaP.

　量子井戸層をＡｌＩｎＧａＰからなるものとすることにより、赤色の光が光学素子から出射される。 When the quantum well layer is made of AlInGaP, red light is emitted from the optical element.

　上記活性層は、上記１層の量子井戸層を有し、
　上記１層の量子井戸層はＡｌＩｎＧａＮからなるものであってもよい。 The active layer has the one quantum well layer,
The one quantum well layer may be made of AlInGaN.

　量子井戸層をＡｌＩｎＧａＮからなるものとすることにより、青紫色から緑色の光が光学素子から出射される。 When the quantum well layer is made of AlInGaN, blue-violet to green light is emitted from the optical element.

　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下であり、
　上記第２ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下であってもよい。 The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The thickness of the first guide layer is 10 nm or more and 500 nm or less,
The thickness of the second guide layer may be 10 nm or more and 500 nm or less.

　量子井戸への光閉じ込め率は、第１ガイド層及び第２ガイド層の厚さによって調整することができる。具体的にはこれらの層の厚さを１０ｎｍ以上５００ｎｍ以下とすることにより、量子井戸への光閉じ込め率を３％以下とすることができる。 The light confinement ratio in the quantum well can be adjusted by the thickness of the first guide layer and the second guide layer. Specifically, by setting the thickness of these layers to 10 nm or more and 500 nm or less, the optical confinement ratio in the quantum well can be 3% or less.

　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０３以上０．５０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０３以上０．５０以下であってもよい。 The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The difference in refractive index between the first cladding layer and the first guide layer is 0.03 or more and 0.50 or less,
The difference in refractive index between the second cladding layer and the second guide layer may be not less than 0.03 and not more than 0.50.

　量子井戸層がＡｌＩｎＧａＰからなり、発光色が赤色の場合、第１クラッド層と第１ガイド層の屈折率差及び第２クラッド層と第２ガイド層の屈折率差を０．０３以上０．５０以下とすることにより、量子井戸への光閉じ込め率を３％以下とすることができる。 When the quantum well layer is made of AlInGaP and the emission color is red, the refractive index difference between the first cladding layer and the first guide layer and the refractive index difference between the second cladding layer and the second guide layer are 0.03 or more and 0.50. By making it below, the light confinement rate in the quantum well can be made 3% or less.

　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０１以上０．１０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０１以上０．１０以下であってもよい。 The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The refractive index difference between the first cladding layer and the first guide layer is 0.01 or more and 0.10 or less,
The difference in refractive index between the second cladding layer and the second guide layer may be not less than 0.01 and not more than 0.10.

　量子井戸層がＡｌＩｎＧａＮからなり、発光色が青紫色から緑色の場合、第１クラッド層と第１ガイド層の屈折率差及び第２クラッド層と第２ガイド層の屈折率差を０．０１以上０．１０以下とすることにより、量子井戸への光閉じ込め率を３％以下とすることができる。 When the quantum well layer is made of AlInGaN and the emission color is from violet to green, the refractive index difference between the first cladding layer and the first guide layer and the refractive index difference between the second cladding layer and the second guide layer are 0.01 or more. By setting it to 0.10 or less, the light confinement ratio in the quantum well can be set to 3% or less.

　上記活性層は、量子井戸への光閉じ込め率が３％以下であってもよい。 The active layer may have a light confinement rate of 3% or less in the quantum well.

　量子井戸への光閉じ込め率を３％以下とすることにより、上記のように光学素子の出射光を高出力かつスペクトル幅の広い光とすることが可能となる。 By setting the light confinement ratio in the quantum well to 3% or less, the light emitted from the optical element can be output with high output and wide spectrum width as described above.

　上記目的を達成するため、本技術の一形態に係る光学素子は、第１導電型層と、第２導電型層と、活性層とを具備する。
　上記第１導電型層は、電流の注入領域が狭窄するように構成された電流狭窄構造を有する。
　上記活性層は、上記第１導電型層と上記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、量子井戸への光閉じ込め率が３％以下である。 In order to achieve the above object, an optical element according to an embodiment of the present technology includes a first conductivity type layer, a second conductivity type layer, and an active layer.
The first conductivity type layer has a current confinement structure configured such that a current injection region is constricted.
The active layer is an active layer provided between the first conductivity type layer and the second conductivity type layer, and has one quantum well layer or a plurality of quantum well layers. The light confinement rate is 3% or less.

　量子井戸への光閉じ込め率を３％以下とすることにより、上記のように光学素子の出射光を高出力かつスペクトル幅の広い光とすることが可能となる。 By setting the light confinement ratio in the quantum well to 3% or less, the light emitted from the optical element can be output with high output and wide spectrum width as described above.

　上記１層の量子井戸層又は上記複数層の量子井戸層は、ＡｌＩｎＧａＰからなるものであってもよい。 The one quantum well layer or the plurality of quantum well layers may be made of AlInGaP.

　上記活性層は、上記１層の量子井戸層を有し、
　上記１層の量子井戸層はＡｌＩｎＧａＮからなるものであってもよい。 The active layer has the one quantum well layer,
The one quantum well layer may be made of AlInGaN.

　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下であり、
　上記第２ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下であってもよい。 The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The thickness of the first guide layer is 10 nm or more and 500 nm or less,
The thickness of the second guide layer may be 10 nm or more and 500 nm or less.

　上記第１ガイド層の厚さは５０ｎｍ以上２００ｎｍ以下であり、
　上記第２ガイド層の厚さは５０ｎｍ以上２００ｎｍ以下であってもよい。 The thickness of the first guide layer is 50 nm or more and 200 nm or less,
The thickness of the second guide layer may be 50 nm or more and 200 nm or less.

　発光パターンの制御(出射光の広がり）やキャリアの閉じ込めを考慮すると、第１ガイド層及び第２ガイド層の厚さは５０ｎｍ以上２００ｎｍ以下がより好適である。 Considering the control of the light emission pattern (spreading of the emitted light) and the confinement of carriers, the thickness of the first guide layer and the second guide layer is more preferably 50 nm or more and 200 nm or less.

　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０３以上０．５０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０３以上０．５０以下であってもよい。 The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The difference in refractive index between the first cladding layer and the first guide layer is 0.03 or more and 0.50 or less,
The difference in refractive index between the second cladding layer and the second guide layer may be not less than 0.03 and not more than 0.50.

　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０６以上０．３０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０６以上０．３０以下であってもよい。 The refractive index difference between the first cladding layer and the first guide layer is 0.06 or more and 0.30 or less,
The difference in refractive index between the second cladding layer and the second guide layer may be not less than 0.06 and not more than 0.30.

　発光色が赤色の場合、発光パターンの制御(出射光の広がり）やキャリアの閉じ込めを考慮すると、第１クラッド層と第１ガイド層の屈折率差及び第２クラッド層と第２ガイド層の屈折率差は０．０６以上０．３０以下が好適である。 When the emission color is red, taking into consideration the control of the emission pattern (spreading of emitted light) and the confinement of carriers, the refractive index difference between the first cladding layer and the first guide layer and the refraction of the second cladding layer and the second guide layer. The rate difference is preferably 0.06 or more and 0.30 or less.

　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０１以上０．１０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０１以上０．１０以下であってもよい。 The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The refractive index difference between the first cladding layer and the first guide layer is 0.01 or more and 0.10 or less,
The difference in refractive index between the second cladding layer and the second guide layer may be not less than 0.01 and not more than 0.10.

　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０２以上０．０６以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０２以上０．０６以下であってもよい。 The refractive index difference between the first cladding layer and the first guide layer is 0.02 or more and 0.06 or less,
The refractive index difference between the second cladding layer and the second guide layer may be not less than 0.02 and not more than 0.06.

　発光色が青紫色から緑色の場合発光パターンの制御(出射光の広がり）やキャリアの閉じ込めを考慮すると、第１クラッド層と第１ガイド層の屈折率差及び第２クラッド層と第２ガイド層の屈折率差は０．０２以上０．０６以下が好適である。 When the emission color is blue violet to green, considering the control of the emission pattern (spreading of the emitted light) and the confinement of carriers, the difference in refractive index between the first cladding layer and the first guide layer and the second cladding layer and the second guide layer The refractive index difference is preferably 0.02 or more and 0.06 or less.

　上記光学素子は、スーパールミネッセンスダイオードであってもよい。 The optical element may be a super luminescence diode.

　上記光学素子は、光増幅器であってもよい。 The optical element may be an optical amplifier.

　上記目的を達成するため、本技術の一形態に係る活性層構造は、電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、第２導電型層と、上記第１導電型層と上記第２導電型層の間に設けられた活性層とを具備する光学素子の活性層構造である。
　上記活性層は、１層の量子井戸層又は複数層の量子井戸層を有し、上記１層の量子井戸層の厚みは１０ｎｍ以下であり、上記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である。 In order to achieve the above object, an active layer structure according to an embodiment of the present technology includes a first conductivity type layer having a current confinement structure configured to confine a current injection region, a second conductivity type layer, It is an active layer structure of an optical element comprising an active layer provided between the first conductivity type layer and the second conductivity type layer.
The active layer has one quantum well layer or a plurality of quantum well layers, the thickness of the one quantum well layer is 10 nm or less, and the total thickness of the plurality of quantum well layers is 10 nm. It is as follows.

　上記目的を達成するため、本技術の一形態に係る表示装置は、光学素子と、画像生成部とを具備する。
　上記画像生成部は、上記光学素子から出射された光を２次元状にスキャン可能であり、画像データに基づき、投射される上記光による輝度を制御可能である。
　上記光学素子は、第１導電型層と、第２導電型層と、活性層とを具備する。
　上記第１導電型層は、電流の注入領域が狭窄するように構成された電流狭窄構造を有する。
　上記活性層は、上記第１導電型層と上記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、上記１層の量子井戸層の厚みは１０ｎｍ以下であり、上記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である。 In order to achieve the above object, a display device according to an embodiment of the present technology includes an optical element and an image generation unit.
The image generation unit can scan the light emitted from the optical element in a two-dimensional manner, and can control the luminance of the projected light based on the image data.
The optical element includes a first conductivity type layer, a second conductivity type layer, and an active layer.
The first conductivity type layer has a current confinement structure configured such that a current injection region is constricted.
The active layer is an active layer provided between the first conductivity type layer and the second conductivity type layer, and has one quantum well layer or a plurality of quantum well layers. The thickness of the quantum well layer is 10 nm or less, and the total thickness of the plurality of quantum well layers is 10 nm or less.

　以上、本技術によれば、高出力かつスペクトル幅の広い光を出射することが可能な光学素子、活性層構造及び表示装置を提供することができる。なお、ここに記載された効果は必ずしも限定されるものではなく、本開示中に記載されたいずれかの効果であってもよい。 As described above, according to the present technology, it is possible to provide an optical element, an active layer structure, and a display device that can emit light with high output and a wide spectrum width. Note that the effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

本技術の一実施形態に係る光学素子を示す斜視図及び平面図である。It is the perspective view and top view which show the optical element which concerns on one Embodiment of this technique. 図１に示す光学素子の断面図である。It is sectional drawing of the optical element shown in FIG. 図１に示す光学素子のバンド構造を示す模式図である。It is a schematic diagram which shows the band structure of the optical element shown in FIG. 量子井戸の井戸幅とスペクトル幅の関係を示すグラフである。It is a graph which shows the relationship between the well width and spectrum width of a quantum well. 従来構造の光学素子と本技術の実施形態に係る光学素子の特性を示す表である。It is a table | surface which shows the characteristic of the optical element of embodiment of this technique, and the optical element of conventional structure. キャリア密度による波長と利得の関係を示すグラフである。It is a graph which shows the relationship between the wavelength by a carrier density, and a gain. 量子井戸の井戸幅による電流と出力の関係を示すグラフである。It is a graph which shows the relationship between the electric current by the well width of a quantum well, and an output. 量子井戸の井戸幅による波長と強度の関係を示すグラフである。It is a graph which shows the relationship between the wavelength by the well width of a quantum well, and intensity | strength. 量子井戸への光閉じ込め率とスペクトル幅の関係を示すグラフである。It is a graph which shows the relationship between the optical confinement rate to a quantum well, and a spectrum width. 複数層の量子井戸層を有する光学素子のバンド構造を示す模式図である。It is a schematic diagram which shows the band structure of the optical element which has multiple quantum well layers. 図１０に示す光学素子の活性層の層構造を示す断面図である。It is sectional drawing which shows the layer structure of the active layer of the optical element shown in FIG. 本技術の一実施形態に係る表示装置を示す模式図である。It is a mimetic diagram showing a display concerning one embodiment of this art.

　（光学素子の構造）
　図１Ａは、本技術の一実施形態に係る光学素子１００を示す模式的な斜視図であり、図１Ｂはその平面図である。図２は、図１ＢにおけるＣ－Ｃ断面図である。この光学素子は、例えばｐ型またはｎ型の導電層にリッジ部１０を有するリッジ型のスーパールミネッセントダイオード（ＳＬＤ）である。 (Optical element structure)
FIG. 1A is a schematic perspective view showing an optical element 100 according to an embodiment of the present technology, and FIG. 1B is a plan view thereof. 2 is a cross-sectional view taken along the line CC in FIG. 1B. This optical element is, for example, a ridge type superluminescent diode (SLD) having a ridge portion 10 in a p-type or n-type conductive layer.

　光学素子１００は、図２において上から、ｐ型電極層（または図示しないｐ型電極層に接するコンタクト層）１１、半導体層のうちｐ型である第１導電型層１３、活性層２０、半導体層のうちｎ型である第２導電型層１４、ｎ型半導体の基板１５、ｎ型電極層（または図示しないｎ型電極層に接するコンタクト層）１２を備える。 The optical element 100 includes a p-type electrode layer (or a contact layer in contact with a p-type electrode layer not shown) 11 from the top in FIG. 2, a p-type first conductivity type layer 13 among the semiconductor layers, an active layer 20, and a semiconductor. Among the layers, an n-type second conductivity type layer 14, an n-type semiconductor substrate 15, and an n-type electrode layer (or a contact layer in contact with an n-type electrode layer not shown) 12 are provided.

　第１導電型層１３は、ｐ型電極層１１側から順に形成されたｐ型クラッド層１３１及びｐ型ガイド層１３２を有する。第２導電型層１４は、基板１５側から順に形成されたｎ型クラッド層１４１及びｎ型ガイド層１４２を有する。例えば、ｐ型電極層１１及びｐ型クラッド層１３１によりリッジ部１０が構成される。基板１５と第２導電型層１４との間には、ｎ型のバッファ層が設けられていてもよい。図１Ｂに示すように、光学素子１００は光出射端面３３と、光出射端面３３に対して反対側の端面である後端面３５を備える。 The first conductivity type layer 13 includes a p-type cladding layer 131 and a p-type guide layer 132 formed in this order from the p-type electrode layer 11 side. The second conductivity type layer 14 includes an n-type cladding layer 141 and an n-type guide layer 142 formed in this order from the substrate 15 side. For example, the ridge portion 10 is configured by the p-type electrode layer 11 and the p-type cladding layer 131. An n-type buffer layer may be provided between the substrate 15 and the second conductivity type layer 14. As shown in FIG. 1B, the optical element 100 includes a light exit end face 33 and a rear end face 35 that is an end face opposite to the light exit end face 33.

　図１Ｂに示すようにリッジ部１０は、直線状部分１０ａと曲線状部分１０ｂを有する。直線状部分１０ａは後端面３５に対して垂直方向に沿って直線状に延伸されており、曲線状部分１０ｂは直線状部分１０ａに連続して曲線状に延伸されている。なお、リッジ部１０は、必ずしも直線状部分１０ａと曲線状部分１０ｂを有するものでなくてもよく、後端面３５から光出射端面３３にかけて直線状に構成されていてもよい。 As shown in FIG. 1B, the ridge portion 10 has a linear portion 10a and a curved portion 10b. The linear portion 10a is linearly extended along a direction perpendicular to the rear end surface 35, and the curved portion 10b is extended in a curved shape continuously to the linear portion 10a. The ridge portion 10 does not necessarily have the linear portion 10a and the curved portion 10b, and may be configured linearly from the rear end surface 35 to the light emitting end surface 33.

　第１導電型層１３は、図２に示すように電流狭窄構造３２を有する。具体的には、リッジ部１０の構造により、ｐ型電極層１１からの活性層２０までの電流の注入領域が狭窄するように構成された電流狭窄構造３２が形成される。これにより、活性層２０におけるリッジ部１０付近に、リッジ部１０の長手方向に沿った光導波路が形成される。 The first conductivity type layer 13 has a current confinement structure 32 as shown in FIG. Specifically, the current confinement structure 32 configured to confine the current injection region from the p-type electrode layer 11 to the active layer 20 is formed by the structure of the ridge portion 10. Thereby, an optical waveguide along the longitudinal direction of the ridge portion 10 is formed near the ridge portion 10 in the active layer 20.

　ｐ型ガイド層１３２上やリッジ部１０の周囲には、図示しない絶縁層が形成される。 An insulating layer (not shown) is formed on the p-type guide layer 132 and around the ridge portion 10.

　なお、ｐ型クラッド層１３１の下端は、リッジ部１０の下端と一致しているが、そうでなくてもよいし、当該リッジ部１０の下端がｐ型ガイド層１３２の一部を含んでいてもよい。 Note that the lower end of the p-type cladding layer 131 coincides with the lower end of the ridge portion 10, but this need not be the case, and the lower end of the ridge portion 10 includes a part of the p-type guide layer 132. Also good.

　図１Ｂに示すように、光出射端面３３には低反射ミラー膜１８が設けられ、その反対側の後端面３５には高反射ミラー膜１９が設けられている。 As shown in FIG. 1B, a low reflection mirror film 18 is provided on the light emitting end face 33, and a high reflection mirror film 19 is provided on the rear end face 35 on the opposite side.

　ｐ型電極層１１とｎ型電極層１２の間に電流を印加すると、後端面３５近傍の活性層２０で自然放出光が生じる。自然放出光は、光導波路を光出射端面３３に向かって進行しながら誘導放出により増幅される。自然放出光のうち後端面３５側に向かう光は、高反射ミラー膜１９によって反射され、光出射端面３３に向かって進行しながら増幅される。増幅された光は低反射ミラー膜１８を介して光出射端面３３から出射される。図１Ａ及び図１Ｂに光学素子１００の出射光Ｌを示す。 When a current is applied between the p-type electrode layer 11 and the n-type electrode layer 12, spontaneous emission light is generated in the active layer 20 near the rear end face 35. Spontaneous emission light is amplified by stimulated emission while traveling through the optical waveguide toward the light exit end face 33. Of the spontaneously emitted light, the light traveling toward the rear end face 35 is reflected by the highly reflective mirror film 19 and amplified while traveling toward the light exit end face 33. The amplified light is emitted from the light emitting end face 33 through the low reflection mirror film 18. 1A and 1B show the emitted light L of the optical element 100. FIG.

　リッジ部１０が直線状部分１０ａと曲線状部分１０ｂを有することにより、活性層２０から出射される光は光出射端面３３に対して垂直方向から傾斜した方向に出射される。これにより、低反射ミラー膜１８でわずかに生じる反射光が活性層２０に戻ることが防止されている。低反射ミラー膜１８での反射光が活性層２０に戻るとレーザ発振が生じるためである。 When the ridge portion 10 includes the linear portion 10a and the curved portion 10b, the light emitted from the active layer 20 is emitted in a direction inclined from the vertical direction with respect to the light emitting end surface 33. Thereby, the reflected light slightly generated in the low reflection mirror film 18 is prevented from returning to the active layer 20. This is because laser oscillation occurs when the reflected light from the low reflection mirror film 18 returns to the active layer 20.

　なお、上記のようにリッジ部１０は直線状部分のみから構成されていてもよい。また、高反射ミラー膜１９に変えて低反射ミラー膜を設けてもよい。この場合、光学素子１００の出射光は光学素子１００の両端から出射される。 Note that, as described above, the ridge portion 10 may be composed of only a linear portion. Further, a low reflection mirror film may be provided instead of the high reflection mirror film 19. In this case, the light emitted from the optical element 100 is emitted from both ends of the optical element 100.

　光学素子１００はＳＬＤとして利用することができるが、他の光源で発生した光を増幅するための増幅器としても利用することができる。この場合には高反射ミラー膜１９に変えて無反射膜が設けられる。他の光源で発生した光は当該無反射膜を介して光導波路に入射し、光導波路を進行しながら増幅される。 The optical element 100 can be used as an SLD, but can also be used as an amplifier for amplifying light generated by another light source. In this case, an antireflection film is provided in place of the high reflection mirror film 19. Light generated by another light source enters the optical waveguide through the antireflective film and is amplified while traveling through the optical waveguide.

　（活性層の構造）
　光学素子１００の活性層構造について説明する。図３は、各層のバンド構造を示す模式図である。横方向はエネルギー（図中、Ｅ）を示し、左側へ向かうほどエネルギーが高いことを示す。縦方向は光学素子１００を構成する各層の積層方向を示す。エネルギーが低い側のバンドは価電子帯（ＶＢ：valence band）であり、エネルギーが高い側のバンドは伝導帯（ＣＢ：conduction band）である。 (Active layer structure)
The active layer structure of the optical element 100 will be described. FIG. 3 is a schematic diagram showing the band structure of each layer. The horizontal direction indicates energy (E in the figure), and indicates that the energy is higher toward the left side. The vertical direction indicates the stacking direction of the layers constituting the optical element 100. The lower energy band is a valence band (VB), and the higher energy band is a conduction band (CB).

　活性層２０は、単層の量子井戸層２０ａを有する。量子井戸層２０ａは図３に示すように、周囲の層（ｐ型ガイド層１３２及びｎ型ガイド層１４２）よりバンドギャップが小さい層である。ｐ型電極層１１とｎ型電極層１２の間に電流が印加されると、伝導帯（ＣＢ）に存在する電子が量子井戸層２０ａのバンドギャップを介して価電子帯（ＶＢ）の正孔と再結合し、発光を生じる。この量子井戸層２０ａのバンドギャップは、発光再結合準位エネルギーギャップと呼ばれる。 The active layer 20 has a single quantum well layer 20a. As shown in FIG. 3, the quantum well layer 20a is a layer having a smaller band gap than the surrounding layers (p-type guide layer 132 and n-type guide layer 142). When a current is applied between the p-type electrode layer 11 and the n-type electrode layer 12, electrons existing in the conduction band (CB) are transferred to holes in the valence band (VB) through the band gap of the quantum well layer 20a. Recombine with each other to produce light emission. The band gap of the quantum well layer 20a is called a light emission recombination level energy gap.

　（量子井戸層の厚みについて）
　量子井戸層２０ａの厚みＴは、量子井戸層２０ａが形成する量子井戸の幅であり、以下、単位に井戸幅Ｔとする。井戸幅Ｔは、１０ｎｍ以下が好適である。 (About the thickness of the quantum well layer)
The thickness T of the quantum well layer 20a is the width of the quantum well formed by the quantum well layer 20a. The well width T is preferably 10 nm or less.

　図４は、井戸幅ＴとＳＬＤスペクトル幅（左軸）の関係及び井戸幅ＴとＰＬスペクトル幅（右軸）の関係を示すグラフである。ＳＬＤスペクトル幅は、光学素子１００から出射される光（ＳＬＤ）のスペクトル幅であり、ＰＬスペクトル幅は、量子井戸層２０ａで生じる自然放出光（ＰＬ：Photoluminescence）のスペクトル幅である。 FIG. 4 is a graph showing the relationship between the well width T and the SLD spectrum width (left axis) and the relationship between the well width T and the PL spectrum width (right axis). The SLD spectral width is the spectral width of light (SLD) emitted from the optical element 100, and the PL spectral width is the spectral width of spontaneous emission light (PL: Photoluminescence) generated in the quantum well layer 20a.

　同図に示すように、井戸幅Ｔを小さくするとＰＬスペクトル幅は小さくなる。これは、井戸幅Ｔが小さくなると発光に寄与する量子井戸内の遷移準位が少なくなるためである。このため、従来では単層で薄い量子井戸層をＳＬＤに用いる理由はなかった。 As shown in the figure, when the well width T is reduced, the PL spectrum width is reduced. This is because the transition level in the quantum well contributing to light emission decreases as the well width T decreases. For this reason, there has been no reason to use a single-layer thin quantum well layer for SLD in the past.

　例えば、従来のＳＬＤの構造としては、複数の薄い量子井戸を有する活性層を備えた構造（以下、従来構造１）がある。この構造では、スペクトル幅の拡大のため、各量子井戸の波長を様々に変え、広いスペクトル幅を得る構造となっている。一方、複数の量子井戸を備えた構造では、注入キャリアが複数の量子井戸に分散され、キャリア分布が不均一となり易く、高利得が得にくい。 For example, as a conventional SLD structure, there is a structure including an active layer having a plurality of thin quantum wells (hereinafter, conventional structure 1). In this structure, in order to widen the spectrum width, the wavelength of each quantum well is changed variously to obtain a wide spectrum width. On the other hand, in a structure including a plurality of quantum wells, injected carriers are dispersed in the plurality of quantum wells, the carrier distribution is likely to be non-uniform, and high gain is difficult to obtain.

　このため、単層で厚い量子井戸を有する活性層を備えたＳＬＤ（以下、従来構造２）が開発されている。この構造では、単層の量子井戸にキャリアが集中し、その中に含まれる多くのエネルギー準位で様々な波長の発光が生じる。しかしながらこの構造でも出力は不十分であり、特にディスプレイ用途には不適である。 For this reason, an SLD (hereinafter, conventional structure 2) having an active layer having a single layer and a thick quantum well has been developed. In this structure, carriers are concentrated in a single-layer quantum well, and light of various wavelengths is emitted at many energy levels contained therein. However, even with this structure, the output is insufficient, and is not particularly suitable for display applications.

　これに対し、本実施形態に係る活性層２０は上記のように、単層で薄い量子井戸層２０ａを有する。井戸幅Ｔが小さくなると、ＰＬスペクトル幅が小さくなることから、ＳＬＤスペクトル幅も小さくなる（図中、破線）と予測された。 On the other hand, the active layer 20 according to the present embodiment has a single quantum well layer 20a as described above. When the well width T is reduced, the PL spectrum width is reduced, so that the SLD spectrum width is also expected to be reduced (broken line in the figure).

　しかしながら、実際には、井戸幅Ｔを小さくすると図中囲みＡに示すようにＳＬＤスペクトル幅が向上することが判明した。図５は、上記従来構造のＳＬＤと本実施形態に係るＳＬＤの特性を表す表である。 However, in practice, it has been found that when the well width T is reduced, the SLD spectral width is improved as shown in box A in the figure. FIG. 5 is a table showing the characteristics of the SLD having the conventional structure and the SLD according to the present embodiment.

　同図の「本実施形態」に示すように、井戸幅Ｔを小さくすると、量子井戸での光閉じ込め効果が小さくなり、自然放出光（ＳＬＤ発光の源となる光）の光導波路への結合割合が小さくなるため、自然放出光の利用効率が小さくなる。 As shown in the “present embodiment” in the figure, when the well width T is reduced, the optical confinement effect in the quantum well is reduced, and the coupling ratio of spontaneously emitted light (light that is the source of SLD light emission) to the optical waveguide is reduced. Therefore, the utilization efficiency of spontaneously emitted light is reduced.

　このため、ＳＬＤ発光を開始するためには従来構造に対して数倍高いキャリア密度が必要となる。この結果、ＳＬＤ発光の開始時にはキャリア密度が大きいため、単位体積当たりの自然放出光の発光量は大きくなる。また、自然放出光が増幅される利得領域（自然放出光が増幅される領域）においても、キャリア密度が大きいため、利得やスペクトル幅も大きくなる。 Therefore, in order to start SLD light emission, a carrier density several times higher than that of the conventional structure is required. As a result, since the carrier density is high at the start of SLD light emission, the amount of spontaneous emission light emitted per unit volume increases. Also in the gain region where spontaneous emission light is amplified (region where spontaneous emission light is amplified), the carrier density is high, so the gain and spectral width are also large.

　図６はキャリア密度によるスペクトル幅と利得の関係を示すグラフである。同図に示すように、ＳＬＤ発光開始時のキャリア密度が大きいと、スペクトル幅と利得の両者が向上する。 FIG. 6 is a graph showing the relationship between the spectrum width and the gain depending on the carrier density. As shown in the figure, when the carrier density at the start of SLD light emission is large, both the spectrum width and the gain are improved.

　さらに、井戸幅Ｔが小さく、キャリア密度が大きいために量子井戸の量子効果が大きくなり、注入キャリアの利用効率が促進され、出力改善や温度特性の改善も達成される。また、活性層２０の体積減少により活性層ロスも低減する。 Furthermore, since the well width T is small and the carrier density is large, the quantum effect of the quantum well is increased, the use efficiency of injected carriers is promoted, and the output and temperature characteristics are improved. Moreover, the active layer loss is also reduced by reducing the volume of the active layer 20.

　結果として、井戸幅Ｔが小さいと困難とされていた広いスペクトル幅を実現し、高出力及び高効率も同時に達成することが可能となる。 As a result, it is possible to achieve a wide spectrum width which has been considered difficult when the well width T is small, and to achieve high output and high efficiency at the same time.

　図７は、光学素子１００に供給される電流と光学素子１００の出射光の出力の関係を示すグラフであり、井戸幅Ｔが６ｎｍの場合と１５ｎｍの場合についての計算結果である。同図に示すように、井戸幅Ｔが６ｎｍの場合、１５ｎｍの場合に比べて出射光の出力が３０％以上向上している。 FIG. 7 is a graph showing the relationship between the current supplied to the optical element 100 and the output of the emitted light from the optical element 100, and shows the calculation results when the well width T is 6 nm and 15 nm. As shown in the figure, when the well width T is 6 nm, the output of the emitted light is improved by 30% or more compared to the case of 15 nm.

　また、グラフの最大電流付近では１５ｎｍの場合に出力飽和がみられるのに対し、６ｎｍの場合には出力飽和がみられない。このため、より高い電流では両者の差はさらに開くと予想される。また、この計算では、自己発熱効果も考慮されており、高電流域での動作での出力が特に改善されている結果から、高温での動作も６ｎｍの場合が優位である。 In the vicinity of the maximum current in the graph, output saturation is observed at 15 nm, whereas output saturation is not observed at 6 nm. For this reason, the difference between the two is expected to increase further at higher currents. Further, in this calculation, the self-heating effect is also taken into consideration, and from the result that the output in the operation in the high current region is particularly improved, the operation at the high temperature is advantageous in the case of 6 nm.

　また、図８は、光学素子１００の出射光の波長と強度の関係を示すグラフであり、井戸幅Ｔが６ｎｍの場合と１５ｎｍの場合についての計算結果である。同図に示すように、井戸幅Ｔが６ｎｍの場合、１５ｎｍの場合に対してスペクトル幅やスペクトル形状が同等である。 FIG. 8 is a graph showing the relationship between the wavelength and intensity of the emitted light from the optical element 100, and shows the calculation results when the well width T is 6 nm and 15 nm. As shown in the figure, when the well width T is 6 nm, the spectral width and the spectral shape are the same as in the case of 15 nm.

　この他にも井戸幅Ｔが６ｎｍの場合、１５ｎｍの場合と比べて温度特性が改善されており、ビーム形状も１５ｎｍの場合と同等となる。このように、井戸幅Ｔを１０ｎｍ以下とすることにより、ＳＬＤ光の立ち上がり電流低減、ＳＬＤ光のスペクトル幅維持、発光効率の改善及び温度特性改善等を達成することが可能である。 In addition, when the well width T is 6 nm, the temperature characteristics are improved compared to the case of 15 nm, and the beam shape is equivalent to that of 15 nm. As described above, by setting the well width T to 10 nm or less, it is possible to reduce the rising current of the SLD light, maintain the spectral width of the SLD light, improve the light emission efficiency, and improve the temperature characteristics.

　なお、井戸幅Ｔについては１０ｎｍ以下が好適であるが、特性改善のためにはさらなる薄膜化によるキャリアの有効活用促進が有効であり、光学素子１００製造時のエピタキシャル成長のプロセス上、結晶性を損なわないレベルで極薄化されることが望ましい。特に井戸幅Ｔが７ｎｍ以下の場合に効果が大きく、好適である。 The well width T is preferably 10 nm or less. However, in order to improve the characteristics, it is effective to promote the effective use of carriers by further thinning the film, and the crystallinity is impaired in the process of epitaxial growth when the optical element 100 is manufactured. It is desirable to make it extremely thin at no level. In particular, when the well width T is 7 nm or less, the effect is large and suitable.

　また、井戸幅Ｔが小さくなり、即ち活性層２０の体積が低下した分だけ、非励起領域の活性層光吸収の光損失も低減し、活性層周辺の発熱源が小さくなることがわかっており、さらなる発光効率、またはエネルギー効率の改善の促進、素子内温度の低下、ひいては信頼性の改善にも効果がある。 In addition, it is known that the well width T is reduced, that is, the optical loss of the active layer light absorption in the non-excitation region is reduced by the amount that the volume of the active layer 20 is reduced, and the heat source around the active layer is reduced. Further, it is effective in further improving the light emission efficiency or energy efficiency, lowering the temperature inside the device, and thus improving the reliability.

　（量子井戸への光閉じ込め率について）
　量子井戸層２０ａが形成する量子井戸への光閉じ込め率は３％以下が好適である。量子井戸への光閉じ込め率は、量子井戸に閉じ込められる光密度の割合を意味し、従来では量子井戸への光閉じ込め率は４％以上が一般的である。 (About optical confinement ratio in quantum well)
The light confinement ratio in the quantum well formed by the quantum well layer 20a is preferably 3% or less. The light confinement rate in the quantum well means the ratio of the light density confined in the quantum well. Conventionally, the light confinement rate in the quantum well is generally 4% or more.

　上記のように井戸幅Ｔを小さくすると量子井戸への光閉じ込め率は小さくなり、量子井戸層２０ａで生じる自然放出光のスペクトル幅は小さくなる。図９は、量子井戸への光閉じ込め率とＳＬＤスペクトル幅（左軸）の関係及び同閉じ込め率とＰＬスペクトル幅（右軸）の関係を示すグラフである。 As described above, when the well width T is reduced, the light confinement rate in the quantum well is reduced, and the spectrum width of the spontaneous emission light generated in the quantum well layer 20a is reduced. FIG. 9 is a graph showing the relationship between the optical confinement rate in the quantum well and the SLD spectrum width (left axis), and the relationship between the confinement rate and the PL spectrum width (right axis).

　同図に示すように、量子井戸への光閉じ込め率が小さくなるとＰＬスペクトル幅が小さくなることから、ＳＬＤスペクトル幅も小さくなる（図中、破線）と予測された。しかしながら、実際には、量子井戸への光閉じ込め率を小さくすると、図中囲みＢに示すようにＳＬＤスペクトル幅が向上することが判明した。 As shown in the figure, when the light confinement ratio in the quantum well is reduced, the PL spectrum width is reduced, so that the SLD spectrum width is also expected to be reduced (broken line in the figure). However, in practice, it has been found that when the light confinement ratio in the quantum well is reduced, the SLD spectrum width is improved as shown by a box B in the figure.

　これは、図５に示すように、量子井戸への光閉じ込め率が小さく、自然放出光の利用効率が小さくなると、ＳＬＤ発光の開始時に高いキャリア密度が必要となり、上述のように量子井戸の量子効果が大きくなること及び活性層ロスが低減することによる。このように量子井戸への光閉じ込め率を３％以下とすることにより、広いスペクトル幅を実現し、高出力及び高効率も同時に達成することが可能である。 As shown in FIG. 5, when the light confinement rate in the quantum well is small and the utilization efficiency of spontaneous emission becomes small, a high carrier density is required at the start of SLD light emission. This is because the effect is increased and the active layer loss is reduced. Thus, by setting the light confinement ratio in the quantum well to 3% or less, it is possible to realize a wide spectrum width and simultaneously achieve high output and high efficiency.

　（量子井戸層の条件について）
　上記のように、量子井戸層２０ａの厚み（井戸幅Ｔ）は１０ｎｍ以下が好適であり、量子井戸層２０ａが形成する量子井戸への光閉じ込め率は３％以下が好適である。本実施形態に係る光学素子１００は、量子井戸層２０ａの厚みが１０ｎｍ以下という条件と、量子井戸への光閉じ込め率が３％以下という条件のうち、少なくともいずれか一方を満たすものであればよい。 (Concerning conditions for quantum well layers)
As described above, the thickness (well width T) of the quantum well layer 20a is preferably 10 nm or less, and the optical confinement ratio in the quantum well formed by the quantum well layer 20a is preferably 3% or less. The optical element 100 according to the present embodiment only needs to satisfy at least one of the condition that the thickness of the quantum well layer 20a is 10 nm or less and the condition that the light confinement ratio in the quantum well is 3% or less. .

　（量子井戸層の材料について）
　量子井戸層２０ａの材料は特に限定されないが、光学素子１００の発光色は量子井戸層２０ａの材料によって異なる。例えば、量子井戸層２０ａがＡｌＩｎＧａＰからなる場合、発光波長550～900nm（実用域630～680nm）の赤色光が生成される。また、量子井戸層２０ａがＡｌＩｎＧａＮからなる場合、発光波長400～1000nm（実用域400～550nm）の青紫色から緑色の光が生成される。 (About material of quantum well layer)
The material of the quantum well layer 20a is not particularly limited, but the emission color of the optical element 100 varies depending on the material of the quantum well layer 20a. For example, when the quantum well layer 20a is made of AlInGaP, red light having an emission wavelength of 550 to 900 nm (practical range of 630 to 680 nm) is generated. When the quantum well layer 20a is made of AlInGaN, blue-violet to green light having an emission wavelength of 400 to 1000 nm (practical range of 400 to 550 nm) is generated.

　この他にも量子井戸層２０ａの材料としてＡｌＧａＮ（発光波長紫外域～400nm）、ＡｌＧａＡｓ（発光波長750～850nm、赤外域）、ＩｎＧａＡｓ（発光波長800～980nm、赤外域）、ＩｎＧａＡｓＰ（発光波長1.2～1.6μｍ、赤外域）等が挙げられる。 In addition, the materials of the quantum well layer 20a include AlGaN (emission wavelength ultraviolet region to 400 nm), AlGaAs (emission wavelength 750 to 850 nm, infrared region), InGaAs (emission wavelength 800 to 980 nm, infrared region), InGaAsP (emission wavelength 1.2). To 1.6 μm, infrared region) and the like.

　（ガイド層及びクラッド層ついて）
　ｐ型ガイド層１３２及びｎ型ガイド層１４２の厚みによって、量子井戸への光閉じ込め率を３％以下に調整することができる。ｐ型ガイド層１３２及びｎ型ガイド層１４２の厚みはそれぞれ１０ｎｍ以上５００ｎｍ以下が好適であり、５０ｎｍ以上２００ｎｍ以下がより好適である。 (Guide layer and cladding layer)
Depending on the thickness of the p-type guide layer 132 and the n-type guide layer 142, the light confinement ratio in the quantum well can be adjusted to 3% or less. The thicknesses of the p-type guide layer 132 and the n-type guide layer 142 are each preferably 10 nm to 500 nm, and more preferably 50 nm to 200 nm.

　上記１０ｎｍ以上５００ｎｍ以下はＳＬＤのデバイス設計で採り得る数値範囲であり、５０ｎｍ以上２００ｎｍは、光の閉じ込めだけでなく、発光パターンの制御(出射光の広がり）やキャリアの閉じ込めも考慮した数値範囲である。 The above 10 nm to 500 nm is a numerical range that can be taken in the device design of SLD, and 50 nm to 200 nm is a numerical range that considers not only light confinement but also light emission pattern control (spreading of emitted light) and carrier confinement. is there.

　また、ｐ型クラッド層１３１とｐ型ガイド層１３２の屈折率差（以下、ｐ型屈折率差）及びｎ型クラッド層１４１とｎ型ガイド層１４２の屈折率差（以下、ｎ型屈折率差）によって量子井戸への光閉じ込め率を３％以下に調整することもできる。 Further, the refractive index difference between the p-type cladding layer 131 and the p-type guide layer 132 (hereinafter referred to as p-type refractive index difference) and the refractive index difference between the n-type cladding layer 141 and the n-type guide layer 142 (hereinafter referred to as n-type refractive index difference). ) Can also adjust the light confinement rate in the quantum well to 3% or less.

　具体的には、量子井戸層２０ａがＡｌＩｎＧａＰからなり、発光色が赤色の場合、ｐ型屈折率差及びｎ型屈折率差はそれぞれ０．０３以上０．５０以下が好適であり、０．０６以上０．３０以下がより好適である。 Specifically, when the quantum well layer 20a is made of AlInGaP and the emission color is red, the p-type refractive index difference and the n-type refractive index difference are each preferably 0.03 to 0.50, and 0.06 More than 0.30 is more suitable.

　上記０．０３以上０．５０以下はＳＬＤのデバイス設計で採り得る数値範囲であり、０．０６以上０．３０以下は、光の閉じ込めだけでなく、発光パターンの制御(出射光の広がり）やキャリアの閉じ込めも考慮した数値範囲である。 The above 0.03 to 0.50 is a numerical range that can be taken in the device design of the SLD, and 0.06 to 0.30 is not only the confinement of light but also the control of the light emission pattern (spreading of the emitted light) This is a numerical range that also considers the confinement of carriers.

　また、量子井戸層２０ａがＡｌＩｎＧａＮからなり、発光色が青紫色から緑色の場合、ｐ型屈折率差及びｎ型屈折率差はそれぞれ０．０１以上０．１０以下が好適であり、０．０２以上０．０６以下がより好適である。 When the quantum well layer 20a is made of AlInGaN and the emission color is from violet to green, the p-type refractive index difference and the n-type refractive index difference are each preferably 0.01 or more and 0.10 or less, and 0.02 More preferred is 0.06 or less.

　上記０．０１以上０．１０以下はＳＬＤのデバイス設計で採り得る数値範囲であり、０．０２以上０．０６以下は、光の閉じ込めだけでなく、発光パターンの制御(出射光の広がり）やキャリアの閉じ込めも考慮した数値範囲である。 The range from 0.01 to 0.10 is a numerical range that can be taken in the device design of the SLD, and the range from 0.02 to 0.06 is not only the confinement of light but also the control of the light emission pattern (spreading of the emitted light) This is a numerical range that also considers the confinement of carriers.

　ｐ型クラッド層１３１、ｐ型ガイド層１３２、ｎ型クラッド層１４１及びｎ型ガイド層１４２の材料は特に限定されない。例えば、ｐ型クラッド層１３１はＭｇがドープされたＡｌ０．５Ｉｎ０．５Ｐ、ｐ型ガイド層１３２はＧａｘＩｎ１－ｘＰ、ｎ型クラッド層１４１はＧａｘＩｎ１－ｘＰ、ｎ型ガイド層１４２はＳｉがドープされたＡｌ０．５Ｉｎ０．５Ｐからなるものとすることができる。 The materials of the p-type cladding layer 131, the p-type guide layer 132, the n-type cladding layer 141, and the n-type guide layer 142 are not particularly limited. For example, the p-type cladding layer 131 is Al 0.5 In 0.5 P doped with Mg, the p-type guide layer 132 is Ga x In 1-x P, and the n-type cladding layer 141 is Ga x In 1-x P. The n-type guide layer 142 may be made of Al 0.5 In 0.5 P doped with Si.

　（従来構造との比較による光学素子の効果について）
　ＳＬＤの出力向上のためには、電流を多く注入する、導波路長を長くする、あるいはリッジ導波路の幅を大きくする等が考えられる。 (Effects of optical elements compared with conventional structures)
In order to improve the output of the SLD, it is conceivable to inject a large amount of current, increase the waveguide length, or increase the width of the ridge waveguide.

　しかしながら、電流を多く注入する場合、その上限値は出力の熱飽和によって制限されるため、高出力化のためには、実装あるいはパッケージへの放熱負担が大きくなる。これは高コスト化の原因となる他、わずかな端面反射でレーザ発振が生じやすくなるため、熱飽和による制限よりも大幅に低い電流で使用する必要がある。 However, when a large amount of current is injected, the upper limit value is limited by the thermal saturation of the output. Therefore, in order to increase the output, the heat radiation burden on the mounting or package becomes large. In addition to increasing the cost, laser oscillation is likely to occur due to slight end surface reflection. Therefore, it is necessary to use a current much lower than the limit due to thermal saturation.

　また、導波路長を長くする場合、光が出射されるまでの間により長い経路で増幅されるため、光強度が大きくなる。一方で誘導放出による光の増幅をより多く受けることによって利得スペクトラム（波長依存性）の影響を強く受け、発光スペクトル幅が狭くなる。このため、低コヒーレンス性が低下する。即ち、出力とコヒーレンスはトレードオフの関係を有する。さらに、導波路長を長い場合、ＳＬＤのサイズが大きくなり、パッケージの小型化に不向きとなる上、全体の導波ロスの影響が増え、光変化効率も低下する。 Also, when the waveguide length is increased, the light intensity is increased because the light is amplified through a longer path until the light is emitted. On the other hand, by receiving more light amplification by stimulated emission, it is strongly influenced by the gain spectrum (wavelength dependence), and the emission spectrum width is narrowed. For this reason, low coherence property falls. That is, the output and coherence have a trade-off relationship. Further, when the waveguide length is long, the size of the SLD becomes large, which is not suitable for downsizing of the package, the influence of the entire waveguide loss is increased, and the light change efficiency is also lowered.

　また、リッジ導波路の幅を大きくする場合、電流密度の集中を緩和して発光する面積を増やすことにより、出力を高めることができる。しかしながら、出射されるビームの幅が広くなり、特別に光学系が必要となる等、光源として利用しにくくなる。さらに、リッジ導波路の幅を大きくすることで導波し得るモードが多くなるため、出力の不安定性の原因となる。 Also, when the width of the ridge waveguide is increased, the output can be increased by reducing the concentration of current density and increasing the light emitting area. However, it becomes difficult to use as a light source because the width of the emitted beam becomes wider and a special optical system is required. Furthermore, increasing the width of the ridge waveguide increases the number of modes that can be guided, which causes output instability.

　この他にも、増幅を受ける前の自然放出光の段階でスペクトル幅を大きくする方法もあるが、そのためには、注入電極を分割して設置するか、活性層の材料や構造を部分毎に変更する必要がある。前者の場合には別々のドライバで分割電極を駆動する必要があり、高コストである。後者の場合には結晶の再成長が必要になる等、製造が困難であり、やはり高コストとなる。 There are other methods to increase the spectral width at the stage of spontaneous emission before amplification, but for this purpose, the injection electrode is divided or the material and structure of the active layer are divided into parts. Need to change. In the former case, it is necessary to drive the divided electrodes with separate drivers, which is expensive. In the latter case, it is difficult to manufacture, for example, since crystal regrowth is required, and the cost is high.

　また、上記いずれの方法でも消費される電流が増加するため、光源としての効率は低下する。 In addition, since the current consumed by any of the above methods increases, the efficiency as a light source decreases.

　これに対し、本実施形態に係る光学素子１００では、量子井戸層２０ａの厚みを１０ｎｍ以下とし、または量子井戸への光閉じ込め率を３％以下とすることにより、高出力かつスペクトル幅の広い光を出射することが可能となっている。 On the other hand, in the optical element 100 according to the present embodiment, light having a high output and a wide spectral width can be obtained by setting the thickness of the quantum well layer 20a to 10 nm or less or setting the optical confinement ratio to the quantum well to 3% or less. Can be emitted.

　上記のように、従来構造では、スペクトル幅拡大と出力改善の間にトレードオフの関係があり、両特性の妥協点を考える素子設計が用いられていたが、本技術では、その制限を受けずに設計することが可能であり、より高い性能を両立できる。 As described above, in the conventional structure, there is a trade-off relationship between the spectral width expansion and the output improvement, and the element design that considers a compromise between both characteristics has been used. However, this technology is not subject to this limitation. It is possible to design at the same time, and both higher performance can be achieved.

　また、後端面近傍での自然放出光の導波路結合が素子特性に直接影響する独特の動作原理を利用したＳＬＤに好適な構造であり、特別な活性層製成膜方法を必要とせず、既存の成膜方法を用いて作製することができる。 In addition, the structure is suitable for SLD using a unique operation principle in which the waveguide coupling of spontaneous emission light near the rear end face directly affects the device characteristics, and does not require a special active layer deposition method. The film formation method can be used.

　さらに、量子井戸素の薄膜化による量子効果の増大によって光利得が改善されることでＳＬＤ出力を大幅に高め、かつ高温での特性劣化も抑制できる。また、追加される工程は、エピタキシャル成長での一部工程の変更のみであり、製造プロセス全体への影響は僅少である。 Furthermore, the optical gain is improved by increasing the quantum effect due to the thinning of the quantum well element, so that the SLD output can be greatly increased and the deterioration of characteristics at high temperatures can be suppressed. Further, the added process is only a partial process change in the epitaxial growth, and the influence on the entire manufacturing process is small.

　活性層の組成及び膜厚に関しては、ＴＥＭ（Transmission Electron Microscope）解析後でのＥＤＸ（Energy dispersive X-ray spectrometry）解析又はＷＤＸ（Wavelength Dispersive X-ray spectroscopy）解析で十分検出可能である。また、膜厚のみならず、光導波計算を組み合わせて光閉じ込め率算出も可能である。 The composition and film thickness of the active layer can be sufficiently detected by EDX (Energy Dispersive X-ray Spectrometry) analysis or WDX (Wavelength Dispersive X-ray Spectroscopy) analysis after TEM (Transmission Electron Microscope) analysis. Further, not only the film thickness but also the optical confinement ratio can be calculated by combining optical waveguide calculation.

　さらに、用途に合わせて出力を共振器長により調整し、必要となるスペクトル幅と出力に調整することができる。また、薄い量子井戸層を用いることで、スペクトラムが単峰化しやすく、OCT（Optical Coherence Tomography）等の干渉を利用する用途でも、外乱の少ない測定結果を得る事ができる。 Furthermore, it is possible to adjust the output to the required spectral width and output by adjusting the output according to the resonator length according to the application. In addition, by using a thin quantum well layer, it is easy to make the spectrum unimodal, and even in applications using interference such as OCT (Optical Coherence Tomography), measurement results with little disturbance can be obtained.

　また、増幅器として利用する場合であっても、同様の効果が期待でき、同等の構造とすることによって増幅波長域の広帯域化、効率アップ等の機能向上を図ることができる。  In addition, even when used as an amplifier, the same effect can be expected. By using the same structure, it is possible to improve functions such as widening the amplification wavelength band and increasing efficiency.

　（量子井戸層の層数について）
　上記実施形態においては活性層２０は単層の量子井戸層２０ａを有するものとしたが、複数層の量子井戸層２０ａを有するものであってもよい。図１０は、複数層の量子井戸層２０ａを有する活性層２０におけるバンド構造を示す模式図である。 (Regarding the number of quantum well layers)
In the above embodiment, the active layer 20 has the single quantum well layer 20a. However, the active layer 20 may have a plurality of quantum well layers 20a. FIG. 10 is a schematic diagram showing a band structure in the active layer 20 having a plurality of quantum well layers 20a.

　同図に示すように、活性層２０は複数層の量子井戸層２０ａを有し、各量子井戸層２０ａの間には障壁層２０ｂが設けられている。なお、活性層２０が有する量子井戸層２０ａの数は３層に限られず、２層又は４層以上であってもよいが、ここでは３層の量子井戸層２０ａを例にとって説明する。 As shown in the figure, the active layer 20 has a plurality of quantum well layers 20a, and a barrier layer 20b is provided between the quantum well layers 20a. Note that the number of the quantum well layers 20a included in the active layer 20 is not limited to three, and may be two or four or more. Here, a description will be given by taking the three quantum well layers 20a as an example.

　それぞれの量子井戸層２０ａの厚みを厚みＴ１、厚みＴ２及び厚みＴ３とすると、量子井戸層２０ａの厚みの合計、即ち厚みＴ１、厚みＴ２及び厚みＴ３の合計は１０ｎｍ以下が好適である。量子井戸層２０ａの数が２層又は４層以上の場合も同様に、量子井戸層２０ａの厚みの合計は１０ｎｍ以下が好適である。 When the thickness of each quantum well layer 20a is defined as thickness T1, thickness T2, and thickness T3, the total thickness of the quantum well layers 20a, that is, the total thickness T1, thickness T2, and thickness T3 is preferably 10 nm or less. Similarly, when the number of quantum well layers 20a is two or four or more, the total thickness of the quantum well layers 20a is preferably 10 nm or less.

　これにより、活性層２０が単層の量子井戸層２０ａを有する場合と同様の原理によって光学素子１００は高出力かつスペクトル幅の広い光を出射することが可能となる。それぞれの量子井戸層２０ａの厚みは同一であってもよく、互いに異なってもよい。また、それぞれの量子井戸層２０ａのバンドギャップは同一であってもよく、互いに異なってもよい。 Thereby, the optical element 100 can emit light having a high output and a wide spectral width according to the same principle as that in the case where the active layer 20 has the single quantum well layer 20a. The thicknesses of the respective quantum well layers 20a may be the same or different from each other. Further, the band gaps of the respective quantum well layers 20a may be the same or different from each other.

　また、量子井戸層２０ａが形成する量子井戸への光閉じ込め率は３％以下が好適である。量子井戸への光閉じ込め率を３％以下とすることにより、広いスペクトル幅を実現し、高出力及び高効率も同時に達成することが可能である。 Further, the light confinement rate in the quantum well formed by the quantum well layer 20a is preferably 3% or less. By setting the optical confinement ratio in the quantum well to 3% or less, it is possible to realize a wide spectral width and simultaneously achieve high output and high efficiency.

　活性層２０が複数層の量子井戸層２０ａを有する場合であっても、量子井戸層２０ａの厚みの合計が１０ｎｍ以下という条件と、量子井戸への光閉じ込め率が３％以下という条件のうち、少なくともいずれか一方を満たすものであればよい。 Even when the active layer 20 has a plurality of quantum well layers 20a, among the conditions that the total thickness of the quantum well layers 20a is 10 nm or less and the light confinement ratio in the quantum wells is 3% or less, What is necessary is just to satisfy | fill at least any one.

　図１１は、複数層の量子井戸層２０ａを備える活性層２０の具体的構成を示す模式図である。なお、同図では活性層２０、ｐ型ガイド層１３２及びｎ型ガイド層１４２以外の構成については図示を省略する。同図に示すように、活性層２０は、量子井戸層２０ａと障壁層２０ｂが交互に積層されて構成されている。 FIG. 11 is a schematic diagram showing a specific configuration of the active layer 20 including a plurality of quantum well layers 20a. In the figure, the illustration of components other than the active layer 20, the p-type guide layer 132, and the n-type guide layer 142 is omitted. As shown in the figure, the active layer 20 is configured by alternately stacking quantum well layers 20a and barrier layers 20b.

　量子井戸層２０ａは、上述のようにＡｌＩｎＧａＡｌＰ（赤色）又はＡｌＩｎＧａＮ（青紫色から緑色）等の材料からなる。また、量子井戸層２０ａの間で材料が異なってもよい。障壁層２０ｂは、例えばＡｌＧａＳｓ等からなるものとすることができる。 The quantum well layer 20a is made of a material such as AlInGaAlP (red) or AlInGaN (blue purple to green) as described above. Further, the materials may be different between the quantum well layers 20a. The barrier layer 20b can be made of, for example, AlGaSs.

　なお、活性層２０以外の構成は活性層２０が単層の量子井戸層２０ａを有する構造と同一とすることができる。即ち、ｐ型ガイド層１３２及びｎ型ガイド層１４２の厚みやｐ型クラッド層１３１とｐ型ガイド層１３２の屈折率差及びｎ型ガイド層１４２とｎ型クラッド層１４１の屈折率差を上記範囲とすることにより、量子井戸への光閉じ込め率を３％以下とすることができる。 The configuration other than the active layer 20 can be the same as the structure in which the active layer 20 includes a single quantum well layer 20a. That is, the thicknesses of the p-type guide layer 132 and the n-type guide layer 142, the refractive index difference between the p-type cladding layer 131 and the p-type guide layer 132, and the refractive index difference between the n-type guide layer 142 and the n-type cladding layer 141 are within the above ranges. By doing so, the light confinement rate in the quantum well can be made 3% or less.

　（表示装置）
　図１２は、上記実施形態に係る光学素子であるＳＬＤを光源として用いる表示装置の構成を模式的に示す。この表示装置２００は、ラスタスキャン方式のプロジェクタである。 (Display device)
FIG. 12 schematically shows a configuration of a display device that uses an SLD that is an optical element according to the embodiment as a light source. The display device 200 is a raster scan projector.

　表示装置２００は、画像生成部７０を備える。画像生成部７０は、光源としての光学素子から出射された光を２次元状にスキャン可能、例えばラスタスキャン可能であり、画像データに基づき、スクリーンや壁面等の照射面１０５に投射される光による輝度を制御可能に構成される。 The display device 200 includes an image generation unit 70. The image generation unit 70 can scan light emitted from an optical element as a light source in a two-dimensional manner, for example, raster scan, and is based on light projected on an irradiation surface 105 such as a screen or a wall surface based on image data. The brightness can be controlled.

　画像生成部７０は、例えば水平スキャナ１０３及び垂直スキャナ１０４を主に含む。赤色発光の光学素子１００Ｒ、緑色発光の光学素子１００Ｇ及び青色発光の光学素子１００Ｂからのビームのそれぞれは、ダイクロイックプリズム１０２Ｒ，１０２Ｇ，１０２Ｂによって１本のビームに纏められる。このビームが、水平スキャナ１０３及び垂直スキャナ１０４によってスキャンされ、照射面１０５に投影されることで画像が表示される。 The image generation unit 70 mainly includes a horizontal scanner 103 and a vertical scanner 104, for example. Each of the beams from the red light emitting optical element 100R, the green light emitting optical element 100G, and the blue light emitting optical element 100B is combined into one beam by the dichroic prisms 102R, 102G, and 102B. This beam is scanned by the horizontal scanner 103 and the vertical scanner 104 and projected onto the irradiation surface 105 to display an image.

　なお、ＲＧＢの各色発光の光源のうち、少なくとも１つが本実施形態に係る光学素子１００の構成を有するＳＬＤであればよく、他の素子は通常のＬＤであってもよい。 It should be noted that at least one of the light sources for emitting light of RGB colors may be an SLD having the configuration of the optical element 100 according to the present embodiment, and the other elements may be ordinary LDs.

　水平スキャナ１０３及び垂直スキャナ１０４は、例えば、ポリゴンミラーとガルバノスキャナとの組合せにより構成される。この場合、輝度の制御手段としては、例えば光学素子へ注入する電流を制御する回路が用いられる。 The horizontal scanner 103 and the vertical scanner 104 are configured by a combination of a polygon mirror and a galvano scanner, for example. In this case, as the luminance control means, for example, a circuit for controlling the current injected into the optical element is used.

　あるいは、水平スキャナ及び垂直スキャナとして、例えば、ＭＥＭＳ（Micro Electro Mechanical System）技術を用いて製造されるＤＭＤ（Digital Micro-mirror Device）等の、２次元光変調素子が用いられてもよい。 Alternatively, as the horizontal scanner and the vertical scanner, for example, a two-dimensional light modulation element such as a DMD (Digital Micro-mirror Device) manufactured using MEMS (Micro Electro Mechanical System) technology may be used.

　あるいは、画像生成部７０は、ＧＬＶ（Grating Light Valve）素子等の１次元光変調素子と、上述の１次元スキャンミラーとの組み合わせにより構成されていてもよい。 Alternatively, the image generation unit 70 may be configured by a combination of a one-dimensional light modulation element such as a GLV (Grating Light Valve) element and the above-described one-dimensional scan mirror.

　あるいは、画像生成部７０は、音響光学効果スキャナや電気光学効果スキャナといった屈折率変調型スキャナにより構成されていてもよい。 Alternatively, the image generation unit 70 may be configured by a refractive index modulation type scanner such as an acousto-optic effect scanner or an electro-optic effect scanner.

　（他の実施形態）
　本技術は、以上説明した実施形態に限定されず、他の種々の実施形態を実現することができる。 (Other embodiments)
The present technology is not limited to the embodiments described above, and other various embodiments can be realized.

　電流の注入領域が狭窄するように構成された電流狭窄構造３２は、リッジ部１０を構成する構造に限られない。例えば電流狭窄構造は、埋め込み型又は埋め込みリッジ型の構造であってもよい。 The current confinement structure 32 configured to constrict the current injection region is not limited to the structure constituting the ridge portion 10. For example, the current confinement structure may be a buried type or a buried ridge type structure.

　上記実施形態では、基板１５としてｎ型基板が用いられたが、ｐ型基板が用いられ、電流狭窄構造を構成する半導体層がｎ型であってもよい。この場合、「第１導電型」がｎ型、「第２導電型」がｐ型となる。 In the above embodiment, an n-type substrate is used as the substrate 15. However, a p-type substrate may be used, and the semiconductor layer constituting the current confinement structure may be n-type. In this case, the “first conductivity type” is n-type, and the “second conductivity type” is p-type.

　上記実施形態に係る光学素子は、活性層２０を中心として基板１５の反対側に電流狭窄構造３２が配置される構成を有していた。しかし、活性層２０を中心として基板（ｎ型でもｐ型でもよい）と同じ側に電流狭窄構造が配置されていてもよい。ただし、上記実施形態の光学素子は、そのように基板と同じ側に電流狭窄構造が配置される構成を有する光学素子に比べ、構造上、放熱性が高いとうメリットがある。 The optical element according to the above embodiment has a configuration in which the current confinement structure 32 is disposed on the opposite side of the substrate 15 with the active layer 20 as the center. However, a current confinement structure may be disposed on the same side as the substrate (which may be n-type or p-type) with the active layer 20 as the center. However, the optical element of the above embodiment has a merit that the heat dissipation is high in structure as compared with the optical element having the configuration in which the current confinement structure is arranged on the same side as the substrate.

　以上説明した他の実施形態の特徴部分のうち、少なくとも２つの特徴部分を組み合わせることも可能である。 Among the feature portions of the other embodiments described above, it is possible to combine at least two feature portions.

　なお、本技術は以下のような構成もとることができる。
　（１）
　電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、
　第２導電型層と、
　上記第１導電型層と上記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、上記１層の量子井戸層の厚みは１０ｎｍ以下であり、上記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である活性層と
　を具備する光学素子。 In addition, this technique can also take the following structures.
(1)
A first conductivity type layer having a current confinement structure configured to confine a current injection region;
A second conductivity type layer;
An active layer provided between the first conductivity type layer and the second conductivity type layer, the active layer having one quantum well layer or a plurality of quantum well layers, An optical element comprising: an active layer having a thickness of 10 nm or less and a total thickness of the plurality of quantum well layers being 10 nm or less.

　（２）
　上記（１）に記載の光学素子であって、
　上記１層の量子井戸層又は上記複数層の量子井戸層は、ＡｌＩｎＧａＰからなる
　光学素子。 (2)
The optical element according to (1) above,
The one quantum well layer or the plurality of quantum well layers is made of AlInGaP.

　（３）
　上記（１）に記載の光学素子であって、
　上記活性層は、上記１層の量子井戸層を有し、
　上記１層の量子井戸層はＡｌＩｎＧａＮからなる
　光学素子。 (3)
The optical element according to (1) above,
The active layer has the one quantum well layer,
The one quantum well layer is an optical element made of AlInGaN.

　（４）
　上記（１）から（３）のうちいずれか一つに記載の光学素子であって、
　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下であり、
　上記第２ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下である
　光学素子。 (4)
The optical element according to any one of (1) to (3) above,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The thickness of the first guide layer is 10 nm or more and 500 nm or less,
The thickness of the said 2nd guide layer is 10 nm or more and 500 nm or less.

　（５）
　上記（１）から（４）のうちいずれか一つに記載の光学素子であって、
　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０３以上０．５０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０３以上０．５０以下である
　光学素子。 (5)
The optical element according to any one of (1) to (4) above,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The difference in refractive index between the first cladding layer and the first guide layer is 0.03 or more and 0.50 or less,
An optical element, wherein a difference in refractive index between the second cladding layer and the second guide layer is 0.03 or more and 0.50 or less.

　（６）
　上記（１）から（４）のうちいずれか一つに記載の光学素子であって、
　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０１以上０．１０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０１以上０．１０以下である
　光学素子。 (6)
The optical element according to any one of (1) to (4) above,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The refractive index difference between the first cladding layer and the first guide layer is 0.01 or more and 0.10 or less,
The optical element has a refractive index difference between the second cladding layer and the second guide layer of 0.01 or more and 0.10 or less.

　（７）
　上記（１）から（６）のうちいずれか一つに記載の光学素子であって、
　上記活性層は、量子井戸への光閉じ込め率が３％以下である
　光学素子。 (7)
The optical element according to any one of (1) to (6) above,
The optical element has an optical confinement ratio of 3% or less in the quantum well.

　（８）
　電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、
　第２導電型層と、
　上記第１導電型層と上記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、量子井戸への光閉じ込め率が３％以下である活性層と
　を具備する光学素子。 (8)
A first conductivity type layer having a current confinement structure configured to confine a current injection region;
A second conductivity type layer;
An active layer provided between the first conductivity type layer and the second conductivity type layer, having one quantum well layer or a plurality of quantum well layers, and having an optical confinement ratio in the quantum well An optical element comprising: an active layer that is 3% or less.

　（９）
　上記（８）に記載の光学素子であって、
　上記１層の量子井戸層又は上記複数層の量子井戸層は、ＡｌＩｎＧａＰからなる
　光学素子。 (9)
The optical element according to (8) above,
The one quantum well layer or the plurality of quantum well layers is made of AlInGaP.

　（１０）
　上記（８）に記載の光学素子であって、
　上記活性層は、上記１層の量子井戸層を有し、
　上記１層の量子井戸層はＡｌＩｎＧａＮからなる
　光学素子。 (10)
The optical element according to (8) above,
The active layer has the one quantum well layer,
The one quantum well layer is an optical element made of AlInGaN.

　（１１）
　上記（８）から（９）のうちいずれか一つに記載の光学素子であって、
　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下であり、
　上記第２ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下である
　光学素子。 (11)
The optical element according to any one of (8) to (9) above,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The thickness of the first guide layer is 10 nm or more and 500 nm or less,
The thickness of the said 2nd guide layer is 10 nm or more and 500 nm or less.

　（１２）
　上記（１１）に記載の光学素子であって、
　上記第１ガイド層の厚さは５０ｎｍ以上２００ｎｍ以下であり、
　上記第２ガイド層の厚さは５０ｎｍ以上２００ｎｍ以下である (12)
The optical element according to (11) above,
The thickness of the first guide layer is 50 nm or more and 200 nm or less,
The thickness of the second guide layer is 50 nm or more and 200 nm or less.

　（１３）
　上記（８）から（１２）のうちいずれか一つに記載の光学素子であって、
　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０３以上０．５０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０３以上０．５０以下である
　光学素子。 (13)
The optical element according to any one of (8) to (12) above,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The difference in refractive index between the first cladding layer and the first guide layer is 0.03 or more and 0.50 or less,
An optical element, wherein a difference in refractive index between the second cladding layer and the second guide layer is 0.03 or more and 0.50 or less.

　（１４）
　上記（１３）に記載の光学素子であって、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０６以上０．３０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０６以上０．３０以下である
　光学素子。 (14)
The optical element according to (13) above,
The refractive index difference between the first cladding layer and the first guide layer is 0.06 or more and 0.30 or less,
The optical element has a refractive index difference between the second cladding layer and the second guide layer of 0.06 or more and 0.30 or less.

　（１５）
　上記（８）から（１２）のうちいずれか一つに記載の光学素子であって、
　上記第１導電型層は、第１クラッド層と、上記第１クラッド層と上記活性層の間に設けられた第１ガイド層とを有し、
　上記第２導電型層は、第２クラッド層と、上記第２クラッド層と上記活性層の間に設けられた第２ガイド層とを有し、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０１以上０．１０以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０１以上０．１０以下である
　光学素子。 (15)
The optical element according to any one of (8) to (12) above,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The refractive index difference between the first cladding layer and the first guide layer is 0.01 or more and 0.10 or less,
The optical element has a refractive index difference between the second cladding layer and the second guide layer of 0.01 or more and 0.10 or less.

　（１６）
　上記（１５）に記載の光学素子であって、
　上記第１クラッド層と上記第１ガイド層の屈折率差は０．０２以上０．０６以下であり、
　上記第２クラッド層と上記第２ガイド層の屈折率差は０．０２以上０．０６以下である
　光学素子。 (16)
The optical element according to (15) above,
The refractive index difference between the first cladding layer and the first guide layer is 0.02 or more and 0.06 or less,
The optical element has a refractive index difference between the second cladding layer and the second guide layer of 0.02 or more and 0.06 or less.

　（１７）
　上記（１）から（１６）のうちいずれか一つに記載の光学素子であって、
　スーパールミネッセンスダイオードである
　光学素子。 (17)
The optical element according to any one of (1) to (16) above,
An optical element that is a super luminescence diode.

　（１８）
　上記（１）から（１６）のうちいずれか一つに記載の光学素子であって、
　光増幅器である
　光学素子。 (18)
The optical element according to any one of (1) to (16) above,
An optical element that is an optical amplifier.

　（１９）
　電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、第２導電型層と、上記第１導電型層と上記第２導電型層の間に設けられた活性層とを具備する光学素子の活性層構造であって、
　上記活性層は、１層の量子井戸層又は複数層の量子井戸層を有し、上記１層の量子井戸層の厚みは１０ｎｍ以下であり、上記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である
　活性層構造。 (19)
Provided between a first conductivity type layer having a current confinement structure configured to confine a current injection region, a second conductivity type layer, and between the first conductivity type layer and the second conductivity type layer An active layer structure of an optical element comprising an active layer,
The active layer has one quantum well layer or a plurality of quantum well layers, the thickness of the one quantum well layer is 10 nm or less, and the total thickness of the plurality of quantum well layers is 10 nm. The active layer structure is:

　（２０）
　光学素子と、
　上記光学素子から出射された光を２次元状にスキャン可能であり、画像データに基づき、投射される上記光による輝度を制御可能な画像生成部とを具備し、
　上記光学素子は、
　電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、
　第２導電型層と、
　上記第１導電型層と上記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、上記１層の量子井戸層の厚みは１０ｎｍ以下であり、上記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である活性層と
　を具備する表示装置。 (20)
An optical element;
The light emitted from the optical element can be scanned two-dimensionally, and based on image data, an image generation unit capable of controlling the luminance by the projected light,
The optical element is
A first conductivity type layer having a current confinement structure configured to confine a current injection region;
A second conductivity type layer;
An active layer provided between the first conductivity type layer and the second conductivity type layer, the active layer having one quantum well layer or a plurality of quantum well layers, A display device comprising: an active layer having a thickness of 10 nm or less and a total thickness of the plurality of quantum well layers being 10 nm or less.

　１１…ｐ型電極層
　１２…ｎ型電極層
　１３…第１導電型層
　１３１…ｐ型クラッド層
　１３２…ｐ型ガイド層
　１４…第２導電型層
　１４１…ｎ型クラッド層
　１４２…ｎ型ガイド層
　２０…活性層
　２０ａ…量子井戸層
　２０ｂ…障壁層
　３２…電流狭窄構造 DESCRIPTION OF SYMBOLS 11 ... p-type electrode layer 12 ... n-type electrode layer 13 ... 1st conductivity type layer 131 ... p-type clad layer 132 ... p-type guide layer 14 ... 2nd conductivity type layer 141 ... n-type clad layer 142 ... n-type guide layer 20 ... Active layer 20a ... Quantum well layer 20b ... Barrier layer 32 ... Current confinement structure

Claims (20)

　電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、
　第２導電型層と、
　前記第１導電型層と前記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、前記１層の量子井戸層の厚みは１０ｎｍ以下であり、前記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である活性層と
　を具備する光学素子。 A first conductivity type layer having a current confinement structure configured to confine a current injection region;
A second conductivity type layer;
An active layer provided between the first conductivity type layer and the second conductivity type layer, the active layer having one quantum well layer or a plurality of quantum well layers, An optical element comprising: an active layer having a thickness of 10 nm or less and a total thickness of the plurality of quantum well layers being 10 nm or less. 　請求項１に記載の光学素子であって、
　前記１層の量子井戸層又は前記複数層の量子井戸層は、ＡｌＩｎＧａＰからなる
　光学素子。 The optical element according to claim 1,
The one quantum well layer or the plurality of quantum well layers is made of AlInGaP. 　請求項１に記載の光学素子であって、
　前記活性層は、前記１層の量子井戸層を有し、
　前記１層の量子井戸層はＡｌＩｎＧａＮからなる
　光学素子。 The optical element according to claim 1,
The active layer has the one quantum well layer,
The one quantum well layer is an optical element made of AlInGaN. 　請求項１に記載の光学素子であって、
　前記第１導電型層は、第１クラッド層と、前記第１クラッド層と前記活性層の間に設けられた第１ガイド層とを有し、
　前記第２導電型層は、第２クラッド層と、前記第２クラッド層と前記活性層の間に設けられた第２ガイド層とを有し、
　前記第１ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下であり、
　前記第２ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下である
　光学素子。 The optical element according to claim 1,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The thickness of the first guide layer is 10 nm or more and 500 nm or less,
The thickness of the second guide layer is 10 nm or more and 500 nm or less. 　請求項２に記載の光学素子であって、
　前記第１導電型層は、第１クラッド層と、前記第１クラッド層と前記活性層の間に設けられた第１ガイド層とを有し、
　前記第２導電型層は、第２クラッド層と、前記第２クラッド層と前記活性層の間に設けられた第２ガイド層とを有し、
　前記第１クラッド層と前記第１ガイド層の屈折率差は０．０３以上０．５０以下であり、
　前記第２クラッド層と前記第２ガイド層の屈折率差は０．０３以上０．５０以下である
　光学素子。 The optical element according to claim 2,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The refractive index difference between the first cladding layer and the first guide layer is 0.03 or more and 0.50 or less,
An optical element, wherein a difference in refractive index between the second cladding layer and the second guide layer is 0.03 or more and 0.50 or less. 　請求項３に記載の光学素子であって、
　前記第１導電型層は、第１クラッド層と、前記第１クラッド層と前記活性層の間に設けられた第１ガイド層とを有し、
　前記第２導電型層は、第２クラッド層と、前記第２クラッド層と前記活性層の間に設けられた第２ガイド層とを有し、
　前記第１クラッド層と前記第１ガイド層の屈折率差は０．０１以上０．１０以下であり、
　前記第２クラッド層と前記第２ガイド層の屈折率差は０．０１以上０．１０以下である
　光学素子。 The optical element according to claim 3,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The refractive index difference between the first cladding layer and the first guide layer is 0.01 or more and 0.10 or less,
The optical element has a refractive index difference between the second cladding layer and the second guide layer of 0.01 or more and 0.10 or less. 　請求項１に記載の光学素子であって、
　前記活性層は、量子井戸への光閉じ込め率が３％以下である
　光学素子。 The optical element according to claim 1,
The optical element has an optical confinement ratio of 3% or less in the quantum well. 　電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、
　第２導電型層と、
　前記第１導電型層と前記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、量子井戸への光閉じ込め率が３％以下である活性層と
　を具備する光学素子。 A first conductivity type layer having a current confinement structure configured to confine a current injection region;
A second conductivity type layer;
An active layer provided between the first conductivity type layer and the second conductivity type layer, having one quantum well layer or a plurality of quantum well layers, and having an optical confinement ratio in the quantum well An optical element comprising: an active layer that is 3% or less. 　請求項８に記載の光学素子であって、
　前記１層の量子井戸層又は前記複数層の量子井戸層は、ＡｌＩｎＧａＰからなる
　光学素子。 The optical element according to claim 8,
The one quantum well layer or the plurality of quantum well layers is made of AlInGaP. 　請求項８に記載の光学素子であって、
　前記活性層は、前記１層の量子井戸層を有し、
　前記１層の量子井戸層はＡｌＩｎＧａＮからなる
　光学素子。 The optical element according to claim 8,
The active layer has the one quantum well layer,
The one quantum well layer is an optical element made of AlInGaN. 　請求項８に記載の光学素子であって、
　前記第１導電型層は、第１クラッド層と、前記第１クラッド層と前記活性層の間に設けられた第１ガイド層とを有し、
　前記第２導電型層は、第２クラッド層と、前記第２クラッド層と前記活性層の間に設けられた第２ガイド層とを有し、
　前記第１ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下であり、
　前記第２ガイド層の厚さは１０ｎｍ以上５００ｎｍ以下である
　光学素子。 The optical element according to claim 8,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The thickness of the first guide layer is 10 nm or more and 500 nm or less,
The thickness of the second guide layer is 10 nm or more and 500 nm or less. 　請求項１１に記載の光学素子であって、
　前記第１ガイド層の厚さは５０ｎｍ以上２００ｎｍ以下であり、
　前記第２ガイド層の厚さは５０ｎｍ以上２００ｎｍ以下である
　光学素子。 The optical element according to claim 11,
The first guide layer has a thickness of 50 nm to 200 nm,
The optical element having a thickness of the second guide layer of 50 nm or more and 200 nm or less. 　請求項９に記載の光学素子であって、
　前記第１導電型層は、第１クラッド層と、前記第１クラッド層と前記活性層の間に設けられた第１ガイド層とを有し、
　前記第２導電型層は、第２クラッド層と、前記第２クラッド層と前記活性層の間に設けられた第２ガイド層とを有し、
　前記第１クラッド層と前記第１ガイド層の屈折率差は０．０３以上０．５０以下であり、
　前記第２クラッド層と前記第２ガイド層の屈折率差は０．０３以上０．５０以下である
　光学素子。 The optical element according to claim 9,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The refractive index difference between the first cladding layer and the first guide layer is 0.03 or more and 0.50 or less,
An optical element, wherein a difference in refractive index between the second cladding layer and the second guide layer is 0.03 or more and 0.50 or less. 　請求項１３に記載の光学素子であって、
　前記第１クラッド層と前記第１ガイド層の屈折率差は０．０６以上０．３０以下であり、
　前記第２クラッド層と前記第２ガイド層の屈折率差は０．０６以上０．３０以下である
　光学素子。 The optical element according to claim 13,
The refractive index difference between the first cladding layer and the first guide layer is 0.06 or more and 0.30 or less,
The optical element has a refractive index difference between the second cladding layer and the second guide layer of 0.06 or more and 0.30 or less. 　請求項１０に記載の光学素子であって、
　前記第１導電型層は、第１クラッド層と、前記第１クラッド層と前記活性層の間に設けられた第１ガイド層とを有し、
　前記第２導電型層は、第２クラッド層と、前記第２クラッド層と前記活性層の間に設けられた第２ガイド層とを有し、
　前記第１クラッド層と前記第１ガイド層の屈折率差は０．０１以上０．１０以下であり、
　前記第２クラッド層と前記第２ガイド層の屈折率差は０．０１以上０．１０以下である
　光学素子。 The optical element according to claim 10,
The first conductivity type layer includes a first cladding layer, and a first guide layer provided between the first cladding layer and the active layer,
The second conductivity type layer includes a second cladding layer, and a second guide layer provided between the second cladding layer and the active layer,
The refractive index difference between the first cladding layer and the first guide layer is 0.01 or more and 0.10 or less,
The optical element has a refractive index difference between the second cladding layer and the second guide layer of 0.01 or more and 0.10 or less. 　請求項１５に記載の光学素子であって、
　前記第１クラッド層と前記第１ガイド層の屈折率差は０．０２以上０．０６以下であり、
　前記第２クラッド層と前記第２ガイド層の屈折率差は０．０２以上０．０６以下である
　光学素子。 The optical element according to claim 15,
The refractive index difference between the first cladding layer and the first guide layer is 0.02 or more and 0.06 or less,
The optical element has a refractive index difference between the second cladding layer and the second guide layer of 0.02 to 0.06. 　請求項１又は８に記載の光学素子であって、
　スーパールミネッセンスダイオードである
　光学素子。 The optical element according to claim 1 or 8,
An optical element that is a super luminescence diode. 　請求項１又は８に記載の光学素子であって、
　光増幅器である
　光学素子。 The optical element according to claim 1 or 8,
An optical element that is an optical amplifier. 　電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、第２導電型層と、前記第１導電型層と前記第２導電型層の間に設けられた活性層とを具備する光学素子の活性層構造であって、
　前記活性層は、１層の量子井戸層又は複数層の量子井戸層を有し、前記１層の量子井戸層の厚みは１０ｎｍ以下であり、前記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である
　活性層構造。 Provided between a first conductivity type layer having a current confinement structure configured to confine a current injection region, a second conductivity type layer, and between the first conductivity type layer and the second conductivity type layer An active layer structure of an optical element comprising an active layer,
The active layer has one quantum well layer or a plurality of quantum well layers, the thickness of the one quantum well layer is 10 nm or less, and the total thickness of the plurality of quantum well layers is 10 nm. The active layer structure is: 　光学素子と、
　前記光学素子から出射された光を２次元状にスキャン可能であり、画像データに基づき、投射される前記光による輝度を制御可能な画像生成部とを具備し、
　前記光学素子は、
　電流の注入領域が狭窄するように構成された電流狭窄構造を有する第１導電型層と、
　第２導電型層と、
　前記第１導電型層と前記第２導電型層の間に設けられた活性層であって、１層の量子井戸層又は複数層の量子井戸層を有し、前記１層の量子井戸層の厚みは１０ｎｍ以下であり、前記複数層の量子井戸層の厚みの合計は１０ｎｍ以下である活性層と
　を具備する表示装置。 An optical element;
The light emitted from the optical element can be scanned two-dimensionally, and based on image data, an image generation unit capable of controlling the luminance by the projected light,
The optical element is
A first conductivity type layer having a current confinement structure configured to confine a current injection region;
A second conductivity type layer;
An active layer provided between the first conductivity type layer and the second conductivity type layer, the active layer having one quantum well layer or a plurality of quantum well layers, A display device comprising: an active layer having a thickness of 10 nm or less and a total thickness of the plurality of quantum well layers being 10 nm or less.
PCT/JP2017/022624 2016-07-04 2017-06-20 Optical element, active layer structure, and display device Ceased WO2018008381A1 (en)

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