JPS6286781A - Distributed feedback type semiconductor laser - Google Patents
Distributed feedback type semiconductor laserInfo
- Publication number
- JPS6286781A JPS6286781A JP60226000A JP22600085A JPS6286781A JP S6286781 A JPS6286781 A JP S6286781A JP 60226000 A JP60226000 A JP 60226000A JP 22600085 A JP22600085 A JP 22600085A JP S6286781 A JPS6286781 A JP S6286781A
- Authority
- JP
- Japan
- Prior art keywords
- active layer
- layer
- semiconductor laser
- missing part
- type
- 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.)
- Pending
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
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/12—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
-
- 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
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
-
- 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
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/1053—Comprising an active region having a varying composition or cross-section in a specific direction
- H01S5/1057—Comprising an active region having a varying composition or cross-section in a specific direction varying composition along the optical axis
-
- 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
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/12—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
- H01S5/124—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers incorporating phase shifts
Abstract
Description
【発明の詳細な説明】
〔概要〕
本発明は、分布帰還型半導体レーザに於いて、活性層の
中央近傍に欠如部分を形成して共振器の光強度が大であ
る部分に電流が注入されることを阻止するようにしたこ
とに依り、高出力を取り出す場合にも安定に単一軸モー
ドの発振を継続できるようにしたものである。[Detailed Description of the Invention] [Summary] The present invention provides a distributed feedback semiconductor laser in which a missing portion is formed near the center of the active layer so that current is injected into the portion of the resonator where the light intensity is high. By preventing this from occurring, single-axis mode oscillation can be stably continued even when high output is extracted.
本発明は、単一軸モードの発振をさせるのに好適な構成
を有する分布帰還（ｄｉｓｔｒｊｂｕｔｅｄ ｆｅｅ
ｄｂａｃｋ：ＤＦＢ）型半導体レーザに関する。The present invention provides a distributed feedback system having a configuration suitable for producing single-axis mode oscillation.
dback: DFB) type semiconductor laser.
一般に、活性層に沿って回折格子、即ち、グレーティン
グ（ｇｒａｔｉｎｇ）を形成して共振器に波長選択性を
もたせたＤＦＢ型半導体レーザが知られている。Generally, a DFB semiconductor laser is known in which a resonator has wavelength selectivity by forming a diffraction grating, ie, a grating, along an active layer.
こ（７）ＤＦＢ型半導体レーザでは、グレーティングに
依り、利得スペクトル幅の範囲内で一つの波長の光が選
択的に反射され単一軸モード発振するとされている。In this (7) DFB type semiconductor laser, light of one wavelength is selectively reflected within the range of the gain spectrum width by the grating, and oscillation occurs in a single axis mode.
従来、前記ＤＦＢ型半導体レーザに於いて、発振開始以
後の単一軸モード発振安定化に関しては充分に検討され
ていない。Conventionally, in the DFB type semiconductor laser, stabilization of single-axis mode oscillation after the start of oscillation has not been sufficiently studied.
従って、製造後、良品と判定されたものであっても、高
出力を取り出すような場合には、２モードで発振するよ
うな状態がしばしば発生する。Therefore, even if a device is determined to be a good product after manufacturing, when a high output is to be extracted, a state where oscillation occurs in two modes often occurs.
本発明は、高出力時にも安定な単一軸モード発振が得ら
れるような構成にしたＤＦＢ型半導体レーザを提供する
ものである。The present invention provides a DFB type semiconductor laser configured to provide stable single-axis mode oscillation even at high output.
前記したように高出力時に発振モードが複数になるのは
、当初の発振モードに対する利得が飽和することに起因
している。As described above, the reason why there are multiple oscillation modes at high output is that the gain for the initial oscillation mode is saturated.
このような利得の飽和は、半導体レーザに於ける共振器
内の光強度分布が関連することは当然であり、その光強
度が大である部分が問題になる。Naturally, such gain saturation is related to the light intensity distribution within the resonator of the semiconductor laser, and the portion where the light intensity is high becomes a problem.
通常、この光強度分布は、半導体レーザの中央部分で最
も大になり且つ両端では小さくなっている。これは、電
界分布が中央部分で最も高く、両端に向かうにつれて低
くなることからも理解できる。Normally, this light intensity distribution is greatest at the center of the semiconductor laser and is smaller at both ends. This can be understood from the fact that the electric field distribution is highest at the center and becomes lower toward both ends.
そこで、本発明のＤＦＢ型半導体レーザでは、共振器の
光強度が大である部分に電流が注入されることを阻止す
るため中央近傍に欠如部分（例えば欠如部分５Ａ）が形
成された活性層（例えば活性層５）と、該活性層並びに
前記欠如部分に沿って形成されたコルゲーション（例え
ばコルゲーション２）とを備えてなる構成を採っている
。Therefore, in the DFB type semiconductor laser of the present invention, an active layer (for example, a missing portion 5A) is formed in the vicinity of the center to prevent current from being injected into a portion of the resonator where the light intensity is high. For example, the active layer 5) and a corrugation (for example, corrugation 2) formed along the active layer and the missing portion are employed.
前記手段に依ると、ＤＦＢ型半導体レーザ内に於ける光
強度が大になるであろう部分には活性層が存在しないの
で、そこでは電流の注入が行われず、その結果、光強度
は全長に互って略平坦になり、利得飽和の影響は低減さ
れ、高出力を取り出す場合にも安定な単一軸モード発振
を維−持することができる。According to the above means, since there is no active layer in the part of the DFB semiconductor laser where the light intensity would be high, current is not injected there, and as a result, the light intensity is not increased over the entire length. They become substantially flat, the influence of gain saturation is reduced, and stable single-axis mode oscillation can be maintained even when high output is extracted.
図は本発明一実施例を説明する為の要部切断側面図を表
している。The figure shows a cutaway side view of essential parts for explaining one embodiment of the present invention.
図に於いて、ｌはｎ型１ｎＰ基板、２は基板Ｉの表面に
形成されたコルゲーション、２Ａはコルゲーション２の
λ／４シフト部分、３はｎ型ＩｎＧａＡｓＰガイド層、
４はｎ型ＩｎＰ分Ｎｉ層、５はＩｎＧａＡｓＰ活性層、
５Ａは活性層５の欠如部分、６はｐ型ＩｎＰクラッド層
、７はｐ型ＩｎＧａＡｓＰキャップ層、８は反射防止膜
、９はｐ側ストライプ電極、ＩＯはｎ側電極、ｌは活性
層５に於ける欠如部分５Ａの長さをそれぞれ示している
。In the figure, l is an n-type 1nP substrate, 2 is a corrugation formed on the surface of the substrate I, 2A is a λ/4 shifted portion of the corrugation 2, 3 is an n-type InGaAsP guide layer,
4 is an n-type InP Ni layer, 5 is an InGaAsP active layer,
5A is the missing part of the active layer 5, 6 is the p-type InP cladding layer, 7 is the p-type InGaAsP cap layer, 8 is the antireflection film, 9 is the p-side stripe electrode, IO is the n-side electrode, and l is the active layer 5. The lengths of the missing portions 5A are shown respectively.
図示例の各部分に関する諸データを例示すると次の通り
である。Examples of data regarding each part of the illustrated example are as follows.
（１）基板１について
不純物濃度： ２Ｘ Ｉ Ｑ ” （ａｍ−’）（２）
コルゲーション２について
深さ：５００ ［人〕
ピッチ：２０００ （人〕
（３）ガイド層３について
厚さ：０．１５（μｍ〕
不純物濃度：５Ｘ１０１７（ロー３〕
（４）分離層４について
厚さ：０．ＩＣμｍ〕
不純物濃度： ５ Ｘ １０１７（ｃｍ−’）（５）
活性層５について
厚さ：０．１５（μｍ〕
（６）欠如部分５Ａについて
ｌ ：５０（μｍ〕
（７）クラッド層６について
厚さ：２〜．３ 〔μｍ〕
不純物濃度： Ｉ Ｘ １０１８（ｃｍ−’）（８）
キャップ層７について
厚さ：０．２Ｃμｍ〕
（９）ｐ側ストライプ電極９について
材料： Ｔ ｉ ／ Ｐ ｔ ／ Ａ ｕ幅：２〔μｍ
〕
ａω ｎ側電極１０について
材料：Ａｕ−Ｇｅ／Ａｕ
尚、図示例に於ける共振器長は４００〔μｍ〕である。(1) Impurity concentration for substrate 1: 2X IQ''(am-') (2)
Depth for corrugation 2: 500 [people] Pitch: 2000 (people) (3) Thickness for guide layer 3: 0.15 (μm) Impurity concentration: 5X1017 (Rho 3) (4) Thickness for separation layer 4: 0.IC μm] Impurity concentration: 5 x 1017 (cm-') (5)
Thickness of active layer 5: 0.15 (μm) (6) Thickness of missing portion 5A: 50 (μm) (7) Thickness of cladding layer 6: 2 to .3 [μm] Impurity concentration: I x 1018 ( cm-') (8)
Thickness of cap layer 7: 0.2 Cμm] (9) Material of p-side stripe electrode 9: T i / P t / A u width: 2 [μm]
] Material of the aω n-side electrode 10: Au-Ge/Au The resonator length in the illustrated example is 400 [μm].
図から判るように、このＤＦＢ型半導体レーザでは、活
性層５の中央近傍には欠如部分５Ａが形成されていて、
このようにすると、利得飽和の影響が低減され、高出力
時に於ける単一軸モードの安定性が改善される。As can be seen from the figure, in this DFB type semiconductor laser, a missing portion 5A is formed near the center of the active layer 5.
This reduces the effects of gain saturation and improves single-axis mode stability at high power.
欠如部分５Ａを形成するには、活性層５がＩｎＧａＡｓ
Ｐである場合、エッチャントとして（Ｈ２ｓｏ、＋Ｈ２
Ｏ２）を用いれば、下地のｎ型ＩｎＰ分離層４がエツチ
ング・ストッパとなるから、通常のフォト・リソグラフ
ィ技術にて、容易に活性層５の選択的除去が可能であり
、また、欠如部分５Ａの長さｌは活性層５に於ける全長
の約１０〔％〕程度にすると好結果が得られる。In order to form the missing portion 5A, the active layer 5 is made of InGaAs.
P, as an etchant (H2so, +H2
If O2) is used, the underlying n-type InP isolation layer 4 serves as an etching stopper, so the active layer 5 can be easily selectively removed using normal photolithography technology, and the missing portion 5A can be removed easily. Good results can be obtained by setting the length l to about 10% of the total length of the active layer 5.
本発明に依るＤＦＢ型半導体レーザでは、共振器の光強
度が大である部分に電流が注入されることを阻止するた
め中央近傍に欠如部分が形成された活性層と、該活性層
並びに前記欠如部分に沿って形成されたコルゲーション
とを備えた構成を採っている。The DFB semiconductor laser according to the present invention includes an active layer in which a cutout is formed near the center to prevent current from being injected into a portion of the resonator where the light intensity is high, and the active layer and the cutout. The structure includes corrugations formed along the sections.
この構成に依ると、ＤＦＢ型半導体レーザ内で光強度が
大になるであろう部分には活性層が存在せず、従って、
そこでは電流が注入されないので、光強度はレーザ内の
全長に亙って略平坦になり、利得飽和の影響は低減され
、高出力を取り出しても単一軸モード発振が多軸モード
発振に移行することはなくなる。According to this configuration, there is no active layer in the portion where the light intensity would be high in the DFB semiconductor laser, and therefore,
Since no current is injected there, the optical intensity is approximately flat over the entire length of the laser, reducing the effects of gain saturation, and even at high outputs, single-axis mode oscillation transitions to multi-axis mode oscillation. That will no longer be the case.
図は本発明一実施例の要部切断側面図を表している。
図に於いて、１はｎ型ＩｎＰ基板、２は基板１の表面に
形成されたコルゲーション、２Ａはコルゲーション２の
λ／４シフト部分、３はｎ型ＩｎＧａＡｓＰガイド層、
４はｎ型１ｎＰ分Ｎ７１．５はＩ ｎＧａＡｓ Ｐ活性
層、５Ａは活性層５の欠如部分、６はｐ型１ｎＰクラッ
ド層、７はｐ型ＩｎＧａＡｓＰキャップ層、８は反射防
止膜−１９はｐ側ストライプ電極、１０！、ｔｎ側電極
、ｌは活性層５に於ける欠如部分５Ａの長さをそれぞれ
示している。The figure shows a cutaway side view of essential parts of an embodiment of the present invention. In the figure, 1 is an n-type InP substrate, 2 is a corrugation formed on the surface of the substrate 1, 2A is a λ/4 shifted portion of the corrugation 2, 3 is an n-type InGaAsP guide layer,
4 is an n-type 1nP layer, N71.5 is an InGaAsP active layer, 5A is a missing part of the active layer 5, 6 is a p-type 1nP cladding layer, 7 is a p-type InGaAsP cap layer, 8 is an anti-reflection film, and 19 is a p-type InGaAsP cap layer. Side stripe electrode, 10! , tn side electrode, and l indicate the length of the missing portion 5A in the active layer 5, respectively.
Claims (1)
を阻止するため中央近傍に欠如部分が形成された活性層
と、 該活性層並びに前記欠如部分に沿って形成されたコルゲ
ーションと を備えてなることを特徴とする分布帰還型半導体レーザ
。[Scope of Claims] An active layer in which a missing portion is formed near the center to prevent current from being injected into a portion of the resonator where the light intensity is high; and along the active layer and the missing portion. A distributed feedback semiconductor laser comprising a corrugation formed therein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60226000A JPS6286781A (en) | 1985-10-12 | 1985-10-12 | Distributed feedback type semiconductor laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60226000A JPS6286781A (en) | 1985-10-12 | 1985-10-12 | Distributed feedback type semiconductor laser |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6286781A true JPS6286781A (en) | 1987-04-21 |
Family
ID=16838219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60226000A Pending JPS6286781A (en) | 1985-10-12 | 1985-10-12 | Distributed feedback type semiconductor laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6286781A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1191651A1 (en) * | 2000-09-06 | 2002-03-27 | Nec Corporation | Distributed feedback semiconductor laser |
| JP2015056515A (en) * | 2013-09-12 | 2015-03-23 | 日本オクラロ株式会社 | Semiconductor optical element and optical communication module |
-
1985
- 1985-10-12 JP JP60226000A patent/JPS6286781A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1191651A1 (en) * | 2000-09-06 | 2002-03-27 | Nec Corporation | Distributed feedback semiconductor laser |
| JP2015056515A (en) * | 2013-09-12 | 2015-03-23 | 日本オクラロ株式会社 | Semiconductor optical element and optical communication module |
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