JPS6318876B2 - - Google Patents
Info
- Publication number
- JPS6318876B2 JPS6318876B2 JP8704980A JP8704980A JPS6318876B2 JP S6318876 B2 JPS6318876 B2 JP S6318876B2 JP 8704980 A JP8704980 A JP 8704980A JP 8704980 A JP8704980 A JP 8704980A JP S6318876 B2 JPS6318876 B2 JP S6318876B2
- Authority
- JP
- Japan
- Prior art keywords
- region
- cladding region
- active region
- cladding
- laser device
- 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.)
- Expired
Links
- 238000005253 cladding Methods 0.000 claims description 46
- 239000004065 semiconductor Substances 0.000 claims description 16
- 239000000758 substrate Substances 0.000 claims description 9
- 239000013078 crystal Substances 0.000 claims description 6
- 230000010355 oscillation Effects 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 229910015363 Au—Sn Inorganic materials 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
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
- H01S5/22—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 ridge or stripe structure
- H01S5/227—Buried mesa structure ; Striped active layer
Description
【発明の詳細な説明】
本発明は光フアイバ通信用に適した半導体レー
ザ素子に関し、特に埋め込み形ダブルヘテロ接合
レーザ素子の改良に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor laser device suitable for optical fiber communication, and more particularly to improvements in a buried double heterojunction laser device.
GaAlAs系あるいはInGaAsP系等の−族化
合物半導体混晶を組成とし、ダブルヘテロ接合構
造をもつダイオードは、電流注入型の半導体レー
ザとして、その高効率、低消費電力及び小形・軽
量の特徴により、広く光フアイバ通信装置内で使
用されている。中でもレーザ作用領域である活性
領域がそれよりも広い禁制帯幅と低い屈折率を有
する半導体を組成としたクラツド領域で埋め込ま
れた構造を有する、いわゆる埋め込み形ダブルヘ
テロ接合レーザ素子は発振閾電流値の低さを発振
モードの安定性とによつて注目されている半導体
レーザ素子である。 Diodes composed of - group compound semiconductor mixed crystals such as GaAlAs or InGaAsP and having a double heterojunction structure are widely used as current injection type semiconductor lasers due to their high efficiency, low power consumption, small size, and light weight. Used in fiber optic communication equipment. Among them, the so-called buried double heterojunction laser device has a structure in which the active region, which is the laser action region, is embedded with a cladding region made of a semiconductor with a wider forbidden band width and a lower refractive index. This semiconductor laser device is attracting attention due to its low oscillation mode stability and low oscillation mode stability.
しかしながら、従来の埋め込み形ダブルヘテロ
接合レーザ素子は、活性領域を埋め込むクラツド
領域が一様な屈折率を有していたために単一のモ
ードで安定な発振を得るためには通常、活性領域
の厚さ0.3μｍに対し幅2μｍ以下という微小幅を高
精度に実現することが必須であつた。このため、
例えば製造上のばらつきにより、活性領域の幅が
上述の大きさを越えたりすると、得られたレーザ
素子は高出力動作時には複数のモードで発振が可
能となり、動作範囲を限定しないとほとんど実用
とならなかつたり、また、微小な活性領域をエツ
チングによつて形成するに際し幅の不均一が生じ
やすく、活性領域界面における光の散乱損失の増
大によつて発振閾電流値の上昇を招くといつた欠
点が見られた。そして何よりも、１〜2μｍとい
う微小幅の活性領域へ選択的に電流を注入するた
めの電流狭窄構造の形成が必ずしも容易ではな
く、従つて理論的に予想される発振閾電流値５〜
10ｍＡ以下に対して通常得られるのは高々20ｍＡ
程度であり、また活性領域の幅が１〜2μｍのレ
ーザ素子においては主として製造上の不完全のた
めに発振の効率も低下し、実用となる動作範囲は
高々出力10ｍＷ程度までという欠点があつた。 However, in conventional buried double heterojunction laser devices, the cladding region that embeds the active region has a uniform refractive index. It was essential to achieve a very small width of 2 μm or less for a width of 0.3 μm with high precision. For this reason,
For example, if the width of the active region exceeds the above-mentioned size due to manufacturing variations, the resulting laser device will be able to oscillate in multiple modes during high-output operation, making it almost impractical unless the operating range is limited. In addition, when a minute active region is formed by etching, the width tends to be non-uniform, and the oscillation threshold current value increases due to increased light scattering loss at the interface of the active region. It was observed. Above all, it is not always easy to form a current confinement structure for selectively injecting current into an active region with a minute width of 1 to 2 μm.
Normally you can get at most 20mA for less than 10mA
Moreover, in laser devices with an active region width of 1 to 2 μm, the oscillation efficiency decreases mainly due to manufacturing imperfections, and the practical operating range is limited to an output of about 10 mW at most. .
本発明の目的は上述の欠点を除去し、高出力動
作時にも安定でかつ製造も容易な埋め込み形ダブ
ルヘテロ接合レーザ素子を提供することにある。 SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a buried double heterojunction laser device that is stable even during high-power operation and easy to manufacture.
本発明によればストライプ状メサ構造を有する
半導体基板と前記ストライプ状メサ構造の上部に
エピタキシヤル成長された活性領域と該活性領域
を埋め込むようにエピタキシヤル成長されたクラ
ツド領域とを含む埋め込み形ダブルヘテロ接合レ
ーザ素子において、前記クラツド領域が屈折率を
異とする少なくとも第一及び第二のクラツド領域
を含み、かつ前記活性領域と接する前記第一のク
ラツド領域が前記活性領域と接する水平方向の部
分において前記活性領域の幅よりも小さな厚さを
有し、かつ前記第一のクラツド領域と接する前記
第二のクラツド領域が前記第一のクラツド領域よ
りも高い屈折率を有することを特徴とする埋め込
み形ダブルヘテロ接合レーザ素子が得られる。 According to the present invention, a buried double semiconductor substrate includes a semiconductor substrate having a striped mesa structure, an active region epitaxially grown on the striped mesa structure, and a cladding region epitaxially grown to bury the active region. In a heterojunction laser device, the cladding region includes at least first and second cladding regions having different refractive indexes, and the first cladding region in contact with the active region is in contact with the active region in a horizontal direction. wherein the second cladding region has a thickness smaller than the width of the active region and the second cladding region in contact with the first cladding region has a higher refractive index than the first cladding region. A type double heterojunction laser device is obtained.
次に図面を参照して本発明を詳細に説明する。
図面は本発明の一実施例に関し、その共振器の軸
を直角方向断面を表わすものである。本実施例は
ストライプ状メサ構造１ａを有する半導体基板１
にエピタキシヤル成長された活性領域２ａを含む
活性半導体層２、第一のクラツド領域３、第二の
クラツド領域４、第三のクラツド領域５及び電極
形成層６、更に半導体基板１及び電極形成層６の
表面に形成されたそれぞれｎ側電極８及びｐ側電
極７から構成されている。半導体基板１は面方位
（100）、導電形ｎ形のInP単結晶で厚さ約70μｍ、
ストライプ状メサ構造１ａはメサ上部の幅3μｍ、
高さ約4μｍ、活性半導体層２は発振波長が1.3μ
ｍ、禁制帯幅0.95eVに相当するIn0.74Ga0.26As0.56
P0.44で厚さ約0.3μｍ、第一のクラツド領域３は禁
制帯幅1.35eVの導電形Ｐ形のInPで平坦部におけ
る厚さ約0.5μｍ、活性領域２ａと接する部分の水
平方向の厚み約0.2μｍ、第二のクラツド領域４は
導電形ｎ形で禁制帯幅1.03eVに相当する組成の
In0.81Ga0.19As0.42P0.58から成り、厚さ3.5〜4μｍ、
第三クラツド領域５は上部表面を平滑するための
もので、導電形ｐ形のInPから成り、厚さ約2μ
ｍ、電極形成層６はｐ側電極７とのオーム性接触
を容易にするためのもので、導電形ｐ形のIn0.74
Ga0.26As0.56P0.44から成る厚さ約0.5μｍのもので
ある。なお、ｐ側電極７はAu−Zn合金、ｎ側電
極８はAu−Sn合金により形成されており、素子
の共振器軸方向長さは約200μｍである。 Next, the present invention will be explained in detail with reference to the drawings.
The drawing relates to an embodiment of the present invention, and shows a section taken in a direction perpendicular to the axis of the resonator. This embodiment is a semiconductor substrate 1 having a striped mesa structure 1a.
An active semiconductor layer 2 including an active region 2a grown epitaxially on the substrate, a first cladding region 3, a second cladding region 4, a third cladding region 5 and an electrode forming layer 6, as well as a semiconductor substrate 1 and an electrode forming layer. It is composed of an n-side electrode 8 and a p-side electrode 7 formed on the surface of 6, respectively. The semiconductor substrate 1 is an InP single crystal with a plane orientation (100) and an n-type conductivity, and has a thickness of about 70 μm.
The striped mesa structure 1a has a width of 3 μm at the top of the mesa,
The height is approximately 4 μm, and the oscillation wavelength of the active semiconductor layer 2 is 1.3 μm.
In 0.74 Ga 0.26 As 0.56 m, equivalent to forbidden band width 0.95eV
The first cladding region 3 is made of P-type InP with a forbidden band width of 1.35 eV, and has a thickness of about 0.5 μm in the flat part and a horizontal thickness of the part in contact with the active region 2a of about 0.3 μm at P 0.44. 0.2 μm, and the second cladding region 4 is of n-type conductivity and has a composition corresponding to a forbidden band width of 1.03 eV.
Consisting of In 0.81 Ga 0.19 As 0.42 P 0.58 , thickness 3.5~4μm,
The third cladding region 5 is for smoothing the upper surface, and is made of p-type InP and has a thickness of approximately 2μ.
m, the electrode forming layer 6 is for facilitating ohmic contact with the p-side electrode 7, and is made of p-type conductivity In 0.74.
It is made of Ga 0.26 As 0.56 P 0.44 and has a thickness of about 0.5 μm. Note that the p-side electrode 7 is formed of an Au-Zn alloy, and the n-side electrode 8 is formed of an Au-Sn alloy, and the length of the element in the resonator axial direction is about 200 μm.
本実施例はその動作時において、第一のクラツ
ド領域３と第二のクラツド領域４の界面に形成さ
れるpn接合がちようど逆方向となつて電流を阻
止し、活性領域２ａへの効率的な電流注入に寄与
している。第二のクラツド領域４の導電形を第一
のクラツド領域３の導電形と同じくしても支障な
いが、この場合には電流注入のための電極を活性
領域２ａの上部のみに限定する必要がある。さ
て、本実施例においては、第二のクラツド領域４
はその組成によつて、第一のクラツド領域３より
も高い屈折率を有し、水平方向に薄い第一のクラ
ツド領域３を通つて滲み出した高次発振モードの
光を水平方向に発散させる。このため高次発振モ
ードに対する共振器損失が著しく増大し、高い電
流注入状態においても高次モードの発振が抑制さ
れ、従つて高出力動作時にも安定な基本モード発
振が得られる。 In this embodiment, during operation, the pn junction formed at the interface between the first cladding region 3 and the second cladding region 4 tends to reverse the flow of current, thereby efficiently directing the current to the active region 2a. This contributes to the current injection. There is no problem even if the conductivity type of the second cladding region 4 is the same as the conductivity type of the first cladding region 3, but in this case, it is necessary to limit the electrode for current injection only to the upper part of the active region 2a. be. Now, in this embodiment, the second cladding region 4
has a higher refractive index than the first cladding region 3 due to its composition, and causes the light of the higher-order oscillation mode seeped through the horizontally thin first cladding region 3 to diverge in the horizontal direction. . Therefore, the resonator loss for the higher-order oscillation mode increases significantly, and the oscillation of the higher-order mode is suppressed even in a high current injection state, so that stable fundamental mode oscillation can be obtained even during high-power operation.
なお活性領域の幅、及び第一のクラツド領域の
水平方向の厚み等に関しては、活性領域、第一の
クラツド領域、第二のクラツド領域それぞれの屈
折率相互の関係によつて最適とする値が変化する
が、1.2〜1.6μｍの範囲を発振波長とする
InGaAsP系混晶の素子では、製造の容易さ等も
考慮して、活性領域の幅が２〜5μｍ、第一のク
ラツド領域の水平方向の厚み0.1〜0.5μｍ程度が
適当であろう。活性領域の幅の広い方が電流狭窄
構造などの点で製造が容易となり、また高出力動
作時において光密度及び電流密度の増大が抑制さ
れ信頼性向上にとつて好ましいが、高次モード発
振の抑制のために第一のクラツド領域の水平方向
の厚みとして小さな値をとる必要がある。上述の
実施例では第一のクラツド領域の組成をInPとし
たが、もちろんこれに限定する必要はなく、活性
領域よりも屈折率が低く、禁制帯幅が大きい範囲
内ならばInGaAsP系混晶とすることも可能であ
る。ところで上述の実施例の構造は〔011〕方向
に形成したストライプ状メサ構造の上に液相エピ
タキシヤル成長を施すことにより、水平方向の厚
みが薄い第一のクラツド領域が制御性良く得るこ
とができる。第二のクラツド領域の成長厚によつ
ては、第一のクラツド領域上にとぎれなく第二の
クラツド領域が形成されるが、この場合には、第
一のクラツド領域へ達する不純物拡散等により、
電流通路を形成する必要がある。 Regarding the width of the active region, the horizontal thickness of the first cladding region, etc., the optimum values are determined by the relationship between the refractive indexes of the active region, the first cladding region, and the second cladding region. Although it varies, the oscillation wavelength is in the range of 1.2 to 1.6 μm.
In the case of an InGaAsP mixed crystal element, considering ease of manufacture, etc., it is appropriate that the width of the active region is 2 to 5 .mu.m and the thickness of the first cladding region in the horizontal direction is about 0.1 to 0.5 .mu.m. A wider active region is preferable because manufacturing is easier in terms of current confinement structure, etc., and increases in optical density and current density are suppressed during high-power operation, which is preferable for improving reliability. For suppression, it is necessary to take a small value for the horizontal thickness of the first cladding region. In the above embodiment, the composition of the first cladding region is InP, but it is not necessarily limited to this, and as long as it has a lower refractive index than the active region and a larger forbidden band width, it can be an InGaAsP mixed crystal. It is also possible to do so. By the way, in the structure of the above-mentioned example, by performing liquid phase epitaxial growth on the striped mesa structure formed in the [011] direction, the first cladding region with a thin horizontal thickness can be obtained with good controllability. can. Depending on the growth thickness of the second cladding region, the second cladding region is formed continuously on the first cladding region, but in this case, due to impurity diffusion that reaches the first cladding region, etc.
It is necessary to form a current path.
最後に本発明が有する特徴を要約すれば、高次
モード発振を抑制し高出力動作時にも安定な埋め
込み形ダブルヘテロ接合レーザ素子が得られるこ
と、広い活性領域幅を許容することにより、高い
製造歩留りが期待できる埋め込み形ダブルヘテロ
接合レーザ素子が得られることである。 Finally, to summarize the features of the present invention, it is possible to obtain a buried double heterojunction laser device that suppresses high-order mode oscillation and is stable even during high-output operation, and allows for a wide active region width, resulting in high manufacturing efficiency. It is possible to obtain a buried type double heterojunction laser device that can be expected to have a high yield.
図面は一実施例の断面図である。図中、１は半
導体基板、１ａはストライプ状メサ構造、２は活
性半導体層、２ａは活性領域、３は第一クラツド
領域、４は第二のクラツド領域、５は第三のクラ
ツド領域、６は電極形成層、７はｐ側電極、８は
ｎ側電極である。
The drawing is a cross-sectional view of one embodiment. In the figure, 1 is a semiconductor substrate, 1a is a striped mesa structure, 2 is an active semiconductor layer, 2a is an active region, 3 is a first cladding region, 4 is a second cladding region, 5 is a third cladding region, 6 is an electrode formation layer, 7 is a p-side electrode, and 8 is an n-side electrode.
Claims (1)
前記ストライプ状メサ構造の上部にエピタキシヤ
ル成長された活性領域と該活性領域を埋め込むよ
うにエピタキシヤル成長されたクラツド領域とを
含む埋め込み形ダブルヘテロ接合レーザ素子にお
いて、前記クラツド領域が屈折率を異とする少な
くとも第一及び第二のクラツド領域を含み、かつ
前記活性領域と接する前記第一のクラツド領域が
前記活性領域と接する水平方向の部分において前
記活性領域の幅よりも小さな厚さを有し、かつ前
記第一のクラツド領域と接する前記第二のクラツ
ド領域が前記第一のクラツド領域よりも高い屈折
率を有することを特徴とする埋め込み形ダブルヘ
テロ接合レーザ素子。 ２ 前記半導体基板がInP単結晶から成り、かつ
前記活性領域及びクラツド領域がInPを含む
InGaAsP系混晶から成ることを特徴とする特許
請求の範囲第１項記載の埋め込み形ダブルヘテロ
接合レーザ素子。 ３ 前記活性領域が2μｍ以上5μｍ以下の幅を有
し、第一のクラツド領域が前記活性領域と接する
水平方向の部分において0.1μｍ以上0.5μｍ以下の
厚さを有することを特徴とする特許請求の範囲第
２項記載の埋め込み形ダブルヘテロ接合レーザ素
子。[Scope of Claims] 1. A semiconductor substrate having a striped mesa structure, an active region epitaxially grown on top of the striped mesa structure, and a cladding region epitaxially grown to bury the active region. In the type double heterojunction laser device, the cladding region includes at least first and second cladding regions having different refractive indexes, and the first cladding region in contact with the active region is in contact with the active region in a horizontal direction. The second cladding region, which has a thickness smaller than the width of the active region at a portion thereof and is in contact with the first cladding region, has a higher refractive index than the first cladding region. Embedded double heterojunction laser device. 2. The semiconductor substrate is made of InP single crystal, and the active region and cladding region contain InP.
The buried double heterojunction laser device according to claim 1, characterized in that it is made of an InGaAsP-based mixed crystal. 3. The active region has a width of 2 μm or more and 5 μm or less, and the first cladding region has a thickness of 0.1 μm or more and 0.5 μm or less in a horizontal portion in contact with the active region. The embedded double heterojunction laser device according to scope 2.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8704980A JPS5712590A (en) | 1980-06-26 | 1980-06-26 | Buried type double heterojunction laser element |
| US06/277,508 US4429397A (en) | 1980-06-26 | 1981-06-26 | Buried heterostructure laser diode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8704980A JPS5712590A (en) | 1980-06-26 | 1980-06-26 | Buried type double heterojunction laser element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5712590A JPS5712590A (en) | 1982-01-22 |
| JPS6318876B2 true JPS6318876B2 (en) | 1988-04-20 |
Family
ID=13904078
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8704980A Granted JPS5712590A (en) | 1980-06-26 | 1980-06-26 | Buried type double heterojunction laser element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5712590A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0267688U (en) * | 1988-11-10 | 1990-05-22 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101750194B1 (en) | 2016-02-15 | 2017-06-22 | 부경대학교 산학협력단 | Wavelength conversion glass, manufacturing method of the wavelength conversion glass, and light emitting device comprising the wavelength conversion glass |
-
1980
- 1980-06-26 JP JP8704980A patent/JPS5712590A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0267688U (en) * | 1988-11-10 | 1990-05-22 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5712590A (en) | 1982-01-22 |
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