JPS6024084A - Semiconductor laser element - Google Patents
Semiconductor laser elementInfo
- Publication number
- JPS6024084A JPS6024084A JP13210383A JP13210383A JPS6024084A JP S6024084 A JPS6024084 A JP S6024084A JP 13210383 A JP13210383 A JP 13210383A JP 13210383 A JP13210383 A JP 13210383A JP S6024084 A JPS6024084 A JP S6024084A
- Authority
- JP
- Japan
- Prior art keywords
- active layer
- gaas
- region
- layer
- semiconductor laser
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
- H01S5/24—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a grooved structure, e.g. V-grooved, crescent active layer in groove, VSIS laser
Landscapes
- Semiconductor Lasers (AREA)
Abstract
Description
【発明の詳細な説明】
く技術分野〉
本発明は半導体レーザ素子の構造に関し、特にディスク
装置等の信号光として有効な縦モードがマルチ化された
半導体レーザ素子に関するものである。DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to the structure of a semiconductor laser device, and more particularly to a semiconductor laser device having multiple longitudinal modes that are effective as signal light for disk devices and the like.
〈従来技術〉
民生用商品であるコンパクト型オーディオディスクプレ
ーヤの信号光線として半導体レーザが使用されて以来半
導体レーザ素子の需要は急激に増大している。半導体レ
ーザ素子は小型軽量であシ、ディヌク板の蓄積情報を読
み取る信号光源として適したものであるが、はぼ同様な
方式で信号を読み出しているビデオディスクには半導体
レーザを信号光線として適用することは困難である。そ
の最大の原因は半導体レーザ素子のノイズが大きいだめ
に例えばＨｅ−Ｎｅレーザを使用した場合に比較して画
質が大きく低下することにある。ビデオディスクの映像
信号を鮮明に再生するためには非常にＳ／Ｎ比の高い光
源を利用することが必要であり、従って小型の光源とし
ての特徴を有する半導体レーザ素子をビデオディスク等
の信号光源として有効に活用することを企図してそのＳ
／Ｎ比を改善する回置開発が積極的に堆し進められてい
る。<Prior Art> Ever since semiconductor lasers have been used as signal beams for compact audio disc players, which are consumer products, the demand for semiconductor laser elements has increased rapidly. Semiconductor laser elements are small and lightweight, making them suitable as signal light sources for reading the information stored on the Dinuk board, but semiconductor lasers are used as signal light sources for video discs that read signals using a similar method. That is difficult. The main reason for this is that the noise of the semiconductor laser element is large, so that the image quality is greatly degraded compared to when a He--Ne laser is used, for example. In order to clearly reproduce video signals from video discs, it is necessary to use a light source with a very high S/N ratio. Therefore, it is necessary to use a semiconductor laser element, which has the characteristics of a compact light source, as a signal light source for video discs, etc. The S
The development of replacement systems to improve the /N ratio is being actively pursued.
〈発明の目的〉
本発明は、半導体レーザ素子の素子構造特に結晶層厚に
技術的手段を駆使することにより、縦モードをマルチ化
し、低ノイズの動作特性を確立した新規有用な半導体レ
ーザ素子を提供することを目的とする。<Objective of the Invention> The present invention provides a new and useful semiconductor laser device that has multiple longitudinal modes and established low-noise operating characteristics by making full use of technical means for the device structure of the semiconductor laser device, especially the crystal layer thickness. The purpose is to provide.
〈実施例の説明〉
第１図は本発明の１実施例として用いられる基板にＶ字
型の溝を形成したＶ Ｓ Ｉ Ｓ （Ｖ−ｃｈａｎｎｅ
ｌｅｄＳｕｂｓｔｒａｔｅ Ｉｎｎｅｒ ５ｔｒｉｐｅ
）５半導体レーザ素子の基本構成を示す断面模式図であ
る。ｐ型ＧａＡｓ基板１上にｎ型ＧａＡｓ電流阻止層２
を堆積した後。<Explanation of Embodiments> FIG. 1 shows a V-channel (V-channel) in which a V-shaped groove is formed on a substrate used as an embodiment of the present invention.
ledSubstrate Inner 5tripe
) 5 is a schematic cross-sectional view showing the basic configuration of a semiconductor laser device. An n-type GaAs current blocking layer 2 is formed on a p-type GaAs substrate 1.
After depositing.
ヌトライプ状の７字溝をエツチング形成することによシ
ミ流阻止層２が除去された電流通路を開通し、この上に
ｐ ｑ、Ｇ ａ Ａ ｓクラッド層３、ｐ（又はｎ）ｆ
ｉｐＧａＡｓ活性層４、ｎ型ＧａＡ＃Ａｓクラッド層５
及びｎ型ＧａＡｓキャップ層６を順次エピタキシャル成
長させ、ｎ側電極７及びｎ側電極８を形成することによ
りダブルへテロ接合型の半導体レーザ素子が構成される
。ｎ側電極７及びｎ側電極８を介して電流を注入すると
７字溝の部分を電流通路として活性層４に電流が流れ、
レーザ発振が開始される。Ｖ字溝外ではｎ型クラッド層
３の厚さが薄いため、この部分で光の一部は基板１に吸
収され、屈折率差が付いて導波機構が形成される。また
、縦モードは通常の場合単一化される。縦モードが単一
化されると単独でのノイズは小さいが実装時に温度変化
に起因するモードポツプノイズや戻シ光に起因するノイ
ズが発生し、Ｓ／Ｎ比が低下する。尚、７字溝に対応す
る電流通路は１〜２μｍ非常に狭い幅の内部ストライプ
構造となっているため、利得導波作用もあシ、これはノ
イズを低減する効果を奏する。更に、内部ストライプ構
造は発振閾値電流が電極ストライプ構造に比較して低く
、遠視野像も均整のとれたものとなる。By etching and forming nutripe-shaped 7-shaped grooves, a current path is opened from which the stain flow prevention layer 2 has been removed, and on top of this, p q , Ga As cladding layers 3 , p (or n) f
ipGaAs active layer 4, n-type GaA#As cladding layer 5
A double heterojunction type semiconductor laser device is constructed by sequentially epitaxially growing an n-type GaAs cap layer 6 and forming an n-side electrode 7 and an n-side electrode 8. When a current is injected through the n-side electrode 7 and the n-side electrode 8, the current flows through the active layer 4 using the 7-shaped groove as a current path.
Laser oscillation starts. Since the thickness of the n-type cladding layer 3 is thin outside the V-shaped groove, part of the light is absorbed by the substrate 1 in this part, and a refractive index difference is created, forming a waveguide mechanism. Further, the longitudinal mode is normally unified. When longitudinal modes are unified, the noise alone is small, but mode pop noise caused by temperature changes and noise caused by reflected light occur during mounting, resulting in a decrease in the S/N ratio. Incidentally, since the current path corresponding to the 7-shaped groove has an internal stripe structure with a very narrow width of 1 to 2 μm, it also has a gain waveguide effect, which has the effect of reducing noise. Furthermore, the internal stripe structure has a lower oscillation threshold current than the electrode stripe structure, and the far-field pattern is well-balanced.
上記構造の半導体レーザ素子に於いて、ｎ型クラッド層
３のＶ字溝外での厚さをｄｉ 、活性層４の厚さをｄｌ
とし、ｄｌ及びｄｌを適宜変化させた場合の縦モードへ
の影響について説明する。ｄ１＋ｄ２を適当な範囲に設
定すれば縦モードをマルチ化することができ、ビデオデ
ィヌク装置の信号光線と１〜て充分に適用可能なＳ／Ｎ
比の高い出ノＪレーザ光が得られることが判明した。第
２図はｄｌ及びｄｌによって規定されるマルチモー、ド
領域Ｍとシング）ｖ（単一）モード領域Ｓ及びその境界
線を示す説明図である。ｎ型クラッド層３とｎ型クラッ
ド層５のＧ ａ ＡＩＡ ｓの混晶比は双方とも０．４
４であシ活性層の混晶比は０．１４とした。クラッド層
３，５と活性層４間の混晶比差はキャリアと光の閉じ込
め効果より０．２５〜０．４０程度に設定することが望
ましい。第２図より明らかな如くｄｌが０．２５ μ’
ｍ以上でｄｌが０．１μｍ以上の場合に縦モードがマル
チ化される。尚、ｄｌが０、’Ｊ２１ｉｍ以」−であれ
ばｄ】が０．２ｔｔｍ程度でもマルチ化され、またｄｉ
が０．３５μｍ以上であればｄｌが０．０８μｍ程度で
もマルチモード領域Ｍとなる。ｄｌとｄｌを変化させた
場合のノイズレベルを測定すると第３図の如くとなった
。図中Ｅａ領領域ビデオディスク用信号光源として充分
に適用１丁能なノイズの低い領域であり、Ｅｂ領領域ビ
デオディスク用としては不適肖なノイズの高い領域であ
る。また、その境界はＳ／Ｎ比が一７０ｄＢのレベルに
相当する。この図に於いてもｄｌとｄｌの条件は第２図
の結果と略々一致している。In the semiconductor laser device having the above structure, the thickness of the n-type cladding layer 3 outside the V-shaped groove is di, and the thickness of the active layer 4 is dl.
The influence on the longitudinal mode when dl and dl are changed appropriately will be explained. By setting d1 + d2 in an appropriate range, the vertical mode can be multiplied, and the S/N can be sufficiently applied to the signal beam of the video digital device.
It has been found that a high output J laser beam can be obtained. FIG. 2 is an explanatory diagram showing a multimode mode region M defined by dl and dl, a single)v (single) mode region S, and their boundaries. The mixed crystal ratio of G a AIA s in the n-type cladding layer 3 and the n-type cladding layer 5 is both 0.4.
The mixed crystal ratio of the active layer was set to 0.14. The difference in the mixed crystal ratio between the cladding layers 3 and 5 and the active layer 4 is desirably set to about 0.25 to 0.40 in view of carrier and light confinement effects. As is clear from Figure 2, dl is 0.25 μ'
The longitudinal mode is multiplied when dl is 0.1 μm or more. In addition, if dl is 0, 'J21im or later'-, it will be multiplied even if d] is about 0.2ttm, and di
If dl is 0.35 μm or more, the multimode region M occurs even if dl is about 0.08 μm. The noise level measured when changing dl and dl was as shown in Fig. 3. In the figure, the Ea area is a low-noise area that can be sufficiently applied as a signal light source for a video disc, and the Eb area is a high-noise area that is unsuitable for a video disc. Further, the boundary corresponds to a level where the S/N ratio is -70 dB. Also in this figure, the conditions for dl and dl are approximately the same as the results in FIG. 2.
尚、ノイズレベルはレーザ出力３ｍＷで測定した。Note that the noise level was measured at a laser output of 3 mW.
ｄｌを０．２５１１ｍ以上、ｄｌを０．１μｍ以上に設
定し、そのスベク）／し曲線をめると第４図の如くとな
る。出力は１ｍＷよ、ｉｌ）７ｍＷ迄変化させ、各出力
強度に於けるヌベクｌ−／し曲線を示している。When dl is set to 0.2511 m or more and dl is set to 0.1 μm or more, and the curve is plotted based on the curve, the result is as shown in FIG. The output was varied from 1 mW to il) 7 mW, and the Nubek l-/shi curves at each output intensity are shown.
ＶＳＩＳ構造の半導体レーザ素子はヌベクトル幅（１本
の縦モード幅）が１〜２λと広く可干渉性も悪いため、
戻シ光によるノイズが小さい。図より明らかな如くこの
半導体レーザ素子では縦モードが６ｍＷ以下の出力強度
に於いて顕著にマルチモード化されていることがわかる
。The VSIS structure semiconductor laser device has a wide nuvector width (width of one longitudinal mode) of 1 to 2λ and poor coherence.
Noise caused by returned light is small. As is clear from the figure, in this semiconductor laser device, the longitudinal mode is noticeably multi-mode at an output intensity of 6 mW or less.
一方、ｄｌ及びｄｌを大きく設定すると発振閾値電流が
高くなり、まだ素子の発熱のため寿命が短くなる。第５
図はｄ、、ｄｌの変化に対する発振閾値電流への影響を
示す特性図である。Ｅｃ領領域発振閾値電流が高く動作
寿命の短かい領域、Ｅｄは発振閾値電流が小さく動作寿
命の充分に長い領域である。境界線は発振閾値電流が９
０ｍＡの値に相当する。図よりｄｌが０．４５μｍより
小さくかつｄｌが０．２μｍよシ小さい条件下では発振
閾値電流も小さく動作寿命も長くなる。発振閾値電流が
９０ｍＡ以上になると実際の動作電流は］、ＯＯｍＡ以
上になり、寿命が大幅に低下する。On the other hand, when dl and dl are set large, the oscillation threshold current becomes high, and the life of the device is shortened due to heat generation of the element. Fifth
The figure is a characteristic diagram showing the influence of changes in d, dl on the oscillation threshold current. The Ec region is a region where the oscillation threshold current is high and the operating life is short, and the Ed region is a region where the oscillation threshold current is small and the operating life is sufficiently long. The boundary line is when the oscillation threshold current is 9
Corresponds to a value of 0mA. As can be seen from the figure, under conditions where dl is smaller than 0.45 μm and dl is smaller than 0.2 μm, the oscillation threshold current is small and the operating life is long. When the oscillation threshold current becomes 90 mA or more, the actual operating current becomes 00 mA or more, and the life span is significantly reduced.
捷だ先出力対電流特性にもキングが表われ易く横モード
が不安定になるため：実用上新たな問題点が生じる。従
って、ｄｌの上限値は０．４５μｍ。King tends to appear in the output vs. current characteristics at the cutting end, and the transverse mode becomes unstable: a new practical problem arises. Therefore, the upper limit of dl is 0.45 μm.
ｄ２の上限値は０２μηＬ程度に設定することが望まし
い。It is desirable to set the upper limit value of d2 to about 02μηL.
〈発明の効果〉
以上詳説した如く、本発明によれば縦モードがマルチ化
された半導体ンーザ素子が得られ、ビデオディスク装置
等の光源としても適用可能な低ノイズの出力特性を確立
することができる。<Effects of the Invention> As explained in detail above, according to the present invention, a semiconductor laser element with multiple longitudinal modes can be obtained, and low-noise output characteristics can be established that can be applied as a light source for video disk devices, etc. can.
第１図は本発明の１実施例として用いられるＶＳＩＳ型
半導体レーザ素子の断面模式図である。
第２図はｄｌ及びｄ２によって規定されるマルチモード
領域とシングルモード領域を示す説明図である。
第３図はｄｌとｄ２を変化させた場合のノイズレベルを
説明する説明図である。
第４図は出力強度とスペクトル曲線を示す特性図である
。
第５図はｄｌ及びｄ２の変化と発振閾値電流への影響を
示す特性図である。
１・・・基板 ２・・・電流阻止層 ３・・・ｐ型クラ
ッド層 ４ ・活性層 ５・・ｎ型クラッド層６・・・
キャップ層
代理人 弁理士 福 士 愛 彦（他２名）Ｑ ＯＪ
ｑ２ ０３ ０４ Ｑ５ ０１； ０７ ０１１−−一
−→−ｄｔＯｔｍノ
第５ 図FIG. 1 is a schematic cross-sectional view of a VSIS type semiconductor laser device used as an embodiment of the present invention. FIG. 2 is an explanatory diagram showing a multimode region and a single mode region defined by dl and d2. FIG. 3 is an explanatory diagram illustrating the noise level when changing dl and d2. FIG. 4 is a characteristic diagram showing output intensity and spectrum curve. FIG. 5 is a characteristic diagram showing changes in dl and d2 and their effects on the oscillation threshold current. 1... Substrate 2... Current blocking layer 3... P-type cladding layer 4 - Active layer 5... N-type cladding layer 6...
Cap layer agent Patent attorney Aihiko Fukushi (and 2 others) Q OJ
q2 03 04 Q5 01; 07 011--1-→-dtOtmFig.5
Claims (1)
たダブルへテロ接合型多層結晶層を有する半導体レーザ
素子に於いて、前記多層結晶層の活性層厚を０．１μｍ
以上、活性層に基板側で接合するクラッド層を０．２μ
ｍ以上にそれぞれ設定し７たことを特徴とする半導体レ
ーザ素子。1. In a semiconductor laser device having a double heterojunction multilayer crystal layer stacked on a substrate via a nutripe-like current path, the active layer thickness of the multilayer crystal layer is 0.1 μm.
Above, the cladding layer bonded to the active layer on the substrate side was 0.2μ
7. A semiconductor laser device characterized in that each of the semiconductor laser elements is set to 7 m or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13210383A JPS6024084A (en) | 1983-07-19 | 1983-07-19 | Semiconductor laser element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13210383A JPS6024084A (en) | 1983-07-19 | 1983-07-19 | Semiconductor laser element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6024084A true JPS6024084A (en) | 1985-02-06 |
| JPH0429235B2 JPH0429235B2 (en) | 1992-05-18 |
Family
ID=15073521
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13210383A Granted JPS6024084A (en) | 1983-07-19 | 1983-07-19 | Semiconductor laser element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6024084A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5432359A (en) * | 1992-12-21 | 1995-07-11 | Kabushiki Kaisha Toshiba | Light emitting device with AlAs mixed crystal ratios |
| GB2365218A (en) * | 2000-02-21 | 2002-02-13 | Sony Corp | Stripe laser |
-
1983
- 1983-07-19 JP JP13210383A patent/JPS6024084A/en active Granted
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5432359A (en) * | 1992-12-21 | 1995-07-11 | Kabushiki Kaisha Toshiba | Light emitting device with AlAs mixed crystal ratios |
| GB2365218A (en) * | 2000-02-21 | 2002-02-13 | Sony Corp | Stripe laser |
| US6628687B2 (en) | 2000-02-21 | 2003-09-30 | Sony Corporation | Semiconductor laser emitting apparatus |
| GB2365218B (en) * | 2000-02-21 | 2004-06-30 | Sony Corp | Semiconductor laser emitting apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0429235B2 (en) | 1992-05-18 |
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