JPH04326781A - Semiconductor laser device - Google Patents
Semiconductor laser deviceInfo
- Publication number
- JPH04326781A JPH04326781A JP9679591A JP9679591A JPH04326781A JP H04326781 A JPH04326781 A JP H04326781A JP 9679591 A JP9679591 A JP 9679591A JP 9679591 A JP9679591 A JP 9679591A JP H04326781 A JPH04326781 A JP H04326781A
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor laser
- laser device
- frequency modulation
- modulation sensitivity
- diffraction grating
- 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
- 239000004065 semiconductor Substances 0.000 title claims abstract description 23
- 230000003287 optical effect Effects 0.000 claims description 4
- 230000001427 coherent effect Effects 0.000 claims description 2
- 230000000737 periodic effect Effects 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract description 20
- 230000000694 effects Effects 0.000 abstract description 6
- 230000008878 coupling Effects 0.000 abstract description 3
- 238000010168 coupling process Methods 0.000 abstract description 3
- 238000005859 coupling reaction Methods 0.000 abstract description 3
- 230000010355 oscillation Effects 0.000 description 6
- 238000002347 injection Methods 0.000 description 5
- 239000007924 injection Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000010363 phase shift Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Semiconductor Lasers (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、周波数変調感度が高く
、広帯域にわたって平坦な特性を有する半導体レーザ装
置に係り、特に光通信に用いて好適な半導体レーザ装置
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device having high frequency modulation sensitivity and flat characteristics over a wide band, and particularly to a semiconductor laser device suitable for use in optical communications.
【０００２】0002
【従来の技術】広帯域にわたって比較的平坦な周波数変
調特性を有する半導体レーザ装置については、１９８９
年電子情報通信学会秋季全国大会、Ｃ−１７４に述べら
れている。2. Description of the Related Art A semiconductor laser device having relatively flat frequency modulation characteristics over a wide band was developed in 1989.
It is stated in the 2011 Autumn National Conference of the Institute of Electronics, Information and Communication Engineers, C-174.
【０００３】0003
【発明が解決しようとする課題】ところが、この半導体
レーザ装置では、１００ＭＨｚ以下の低周波領域におい
て、熱の効果によって周波数変調感度が大きくなるため
に、数＋ＫＨｚから数ＧＨｚの広帯域にわたって、平坦
な周波数変調感度特性を得ることが困難であった。これ
は、キャリア注入による周波数変調感度と熱による周波
数変調感度が同程度であるためである。[Problems to be Solved by the Invention] However, in this semiconductor laser device, the frequency modulation sensitivity increases due to thermal effects in the low frequency region of 100 MHz or less, so it is difficult to maintain a flat frequency over a wide band from several KHz to several GHz. It was difficult to obtain modulation sensitivity characteristics. This is because the frequency modulation sensitivity due to carrier injection and the frequency modulation sensitivity due to heat are approximately the same.
【０００４】本発明では、キャリア注入による周波数変
調感度を高めることにより、熱の効果を除外して、平坦
な周波数変調感度特性を得ることを目的とする。An object of the present invention is to eliminate thermal effects and obtain flat frequency modulation sensitivity characteristics by increasing the frequency modulation sensitivity by carrier injection.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に、本発明では分布帰還型半導体レーザの中央領域と左
右の領域で異なる周期の回折格子を設け、それぞれの領
域に独立の電極を設けた。[Means for Solving the Problems] In order to achieve the above object, in the present invention, diffraction gratings with different periods are provided in the central region and left and right regions of a distributed feedback semiconductor laser, and independent electrodes are provided in each region. Ta.
【０００６】[0006]
【作用】電流注入によるキャリア数の増減によって、レ
ーザの発振波長を変化させることができる。しかし、こ
のプラズマ効果による発振波長の変化はごくわずかで、
数百ＭＨｚ／ｍＡ程度である。電流注入による周波数変
調感度を飛躍的に高めるためには、共振器方向の光強度
分布を変化させる方法が有効であると考えられる。これ
は、光強度分布の変化により、プラズマ効果以上に実効
屈折率を変化させることができるからである。[Operation] The oscillation wavelength of the laser can be changed by increasing or decreasing the number of carriers by current injection. However, the change in the oscillation wavelength due to this plasma effect is very small;
It is approximately several hundred MHz/mA. In order to dramatically increase the frequency modulation sensitivity by current injection, it is thought that a method of changing the light intensity distribution in the resonator direction is effective. This is because the change in the light intensity distribution can change the effective refractive index more than the plasma effect.
【０００７】本発明では、電流注入による光強度分布の
変化を大きくするために、共振器の中央付近と、その左
右の領域で異なる周期の回折格子を設けた。そして、注
入電流量の変化により、光と２つの周期の回折格子の結
合の割合を変化させ、その結果として光強度分布を大き
く変えことるができる。電極を３つに分けて、それぞれ
の電極への電流注入量を変化させると、さらに大きく光
強度分布を変化させることができる。また、レーザ内部
に組込んだ回折格子が位相シフトを有する場合、光と２
つの周期の回折格子の結合の割合を変化させることによ
り、軸方向ホールバーニング量を制御して周波数変調感
度を高めることができる。In the present invention, in order to increase the change in the light intensity distribution due to current injection, diffraction gratings with different periods are provided near the center of the resonator and in the left and right regions thereof. By changing the amount of injected current, the ratio of coupling between light and the two periods of the diffraction grating can be changed, and as a result, the light intensity distribution can be changed significantly. By dividing the electrode into three parts and changing the amount of current injected into each electrode, the light intensity distribution can be changed even more. In addition, if the diffraction grating built into the laser has a phase shift, the light and the
By changing the coupling ratio of the two-period diffraction gratings, it is possible to control the amount of hole burning in the axial direction and increase the frequency modulation sensitivity.
【０００８】[0008]
【実施例】本発明の第１の実施例を図１を用いて説明す
る。ｎ型ＩｎＰ基板１の表面に回折格子２を作製した。
回折格子２は、精密機械刻線により作製したマスター回
折格子からホトマスクを作製し、ホトマスクのパターン
をレーザ光を光源とした密着露光法により作製した。中
央領域の回折格子２の周期は２４１ｎｍ、左右領域の回
折格子２の周期は２４０ｎｍとした。中央領域の回折格
子２には、πラジアンの位相シフト２１をもうけた。回
折格子２を作製後、有機金属気相成長法により、ＩｎＧ
ａＡｓ光ガイド層３、多重量子井戸活性層４、ｐ型Ｉｎ
Ｐクラッド層５を順次エピタキシャル成長した。その後
、ｐ側電極６とｎ側電極７を蒸着によって形成すること
によりレーザ構造とした。左右の電極にそれぞれ２０ｍ
Ａ、中央の電極に５ｍＡの電流を流し、さらに中央の電
極を変調することにより、１０ＧＨｚ／ｍＡの高い周波
数変調感度を得ることができた。さらに、１０ｋＨｚか
ら１０ＧＨｚの帯域で、平坦な感度特性を有ることがで
きた。Embodiment A first embodiment of the present invention will be described with reference to FIG. A diffraction grating 2 was fabricated on the surface of an n-type InP substrate 1. For the diffraction grating 2, a photomask was prepared from a master diffraction grating prepared by precision machine marking, and the pattern of the photomask was prepared by a contact exposure method using a laser beam as a light source. The period of the diffraction grating 2 in the central region was 241 nm, and the period of the diffraction grating 2 in the left and right regions was 240 nm. The diffraction grating 2 in the central region was provided with a phase shift 21 of π radians. After producing the diffraction grating 2, InG
aAs optical guide layer 3, multi-quantum well active layer 4, p-type In
The P cladding layer 5 was epitaxially grown in sequence. Thereafter, a laser structure was obtained by forming a p-side electrode 6 and an n-side electrode 7 by vapor deposition. 20m each for left and right electrodes
A, By applying a current of 5 mA to the central electrode and further modulating the central electrode, a high frequency modulation sensitivity of 10 GHz/mA could be obtained. Furthermore, it was possible to have flat sensitivity characteristics in the band from 10 kHz to 10 GHz.
【０００９】次に、本発明の第２の実施例を図２を用い
て説明する。図２の実施例では、中央の回折格子と左右
の回折格子の周期の差を利用して左右の回折格子の間で
実効的なπラジアンシフトを得るように回折格子２を設
計した点が第一の実施例と異なる。左右の電極にそれぞ
れ２０ｍＡ、中央の電極に５ｍＡの電流を流し、さらに
中央の電極を変調することにより、１０ＧＨｚ／ｍＡの
高い周波数変調感度を得ることができた。さらに、１０
ｋＨｚから１０ＧＨｚの帯域で、平坦な感度特性を得る
ことができた。Next, a second embodiment of the present invention will be explained using FIG. 2. In the example shown in FIG. 2, the diffraction grating 2 is designed to obtain an effective π radian shift between the left and right diffraction gratings by utilizing the difference in period between the center diffraction grating and the left and right diffraction gratings. This is different from the first embodiment. By passing currents of 20 mA through the left and right electrodes and 5 mA through the center electrode, and further modulating the center electrode, a high frequency modulation sensitivity of 10 GHz/mA could be obtained. Furthermore, 10
Flat sensitivity characteristics could be obtained in the band from kHz to 10 GHz.
【００１０】次に、本発明の第３の実施例を図３により
図３では、Ｐ側電極６が１つであることが第１の実施例
と異なる。Ｐ側電極６に５０ｍＡの電流を流し、さらに
変調信号を印加することにより、５ＧＨｚ／ｍＡの高い
周波数変調感度を得ることができた。さらに１０ｋＨｚ
から１０ＧＨｚの帯域で平坦な感度特性を得ることがで
きた。Next, a third embodiment of the present invention is shown in FIG. 3, which differs from the first embodiment in that there is only one P-side electrode 6. In FIG. By passing a current of 50 mA through the P-side electrode 6 and further applying a modulation signal, a high frequency modulation sensitivity of 5 GHz/mA could be obtained. 10kHz more
We were able to obtain flat sensitivity characteristics in the 10 GHz band.
【００１１】以上の実施例では、ＩｎＰ系の材料系につ
いて述べたが、その他の材料系についても適用可能であ
る。また、いかなる横モード制御構造を有する半導体レ
ーザ装置においても適用可能である。[0011] In the above embodiments, an InP material system has been described, but other material systems are also applicable. Further, the present invention can be applied to any semiconductor laser device having any transverse mode control structure.
【００１２】次に、本発明の第４の実施例を図４を用い
て説明する。図４は、波長多重コヒーレント光通信シス
テムのブロック図である。発振波長λ１の半導体レーザ
１０、発振波長λ２の半導体レーザ１１、……と複数の
波長の異なるレーザ光をそれぞれ独立に２．４Ｇｂ／Ｓ
の速さで変調し、一本の光ファイバ１２を通して、１０
０ｋｍの伝送を行なった。この送信側半導体レーザとし
て、本発明の周波数変調感度が高く、広帯域にわたって
平坦な特性を有する半導体レーザを用いた。また、受光
例ではローカル光源１４として波長可変レーザを用い、
任意の波長を選択して復調した。Next, a fourth embodiment of the present invention will be explained using FIG. 4. FIG. 4 is a block diagram of a wavelength division multiplexing coherent optical communication system. A semiconductor laser 10 with an oscillation wavelength λ1, a semiconductor laser 11 with an oscillation wavelength λ2, etc., and a plurality of laser beams with different wavelengths are independently transmitted at 2.4 Gb/S.
modulated at a speed of 10
0km transmission was performed. As this transmission-side semiconductor laser, the semiconductor laser of the present invention having high frequency modulation sensitivity and flat characteristics over a wide band was used. In addition, in the light reception example, a wavelength tunable laser is used as the local light source 14,
An arbitrary wavelength was selected and demodulated.
【００１３】[0013]
【発明の効果】本発明により、広帯域（１０ｋＨｚ〜１
０ＧＨｚ）にわたって、平坦な周波数変調感度特性を得
ることができる。[Effects of the Invention] The present invention provides broadband (10kHz to 1kHz)
0 GHz), flat frequency modulation sensitivity characteristics can be obtained.
【図１】本発明の第１の実施例の側面図。FIG. 1 is a side view of a first embodiment of the invention.
【図２】本発明の第２の実施例の側面図。FIG. 2 is a side view of a second embodiment of the invention.
【図３】本発明の第３の実指令の側面図。FIG. 3 is a side view of a third actual command of the present invention.
【図４】本発明の第４の実施例のブロック図。FIG. 4 is a block diagram of a fourth embodiment of the present invention.
１…ｎ型ＩｎＰ基板、２…回折格子、６…ｐ側電極、１
０…発振波長λ１の半導体レーザ、１１…発振波長λ２
の半導体レーザ。1...n-type InP substrate, 2...diffraction grating, 6...p-side electrode, 1
0...Semiconductor laser with oscillation wavelength λ1, 11...Oscillation wavelength λ2
semiconductor laser.
Claims (5)
光の進行方向に沿って周期的な凹凸を有する半導体レー
ザ装置において、中央領域とその他の領域で凹凸の周期
が異なり、発光層に近い側の電極が、３つ以上に分割さ
れていることを特徴とする半導体レーザ装置。Claim 1: A light-emitting layer or a layer adjacent to the light-emitting layer,
In a semiconductor laser device that has periodic irregularities along the direction of light propagation, the periodicity of the irregularities is different between the central region and other regions, and the electrode near the light emitting layer is divided into three or more parts. Features of the semiconductor laser device.
いて、中央領域の凹凸の位相が、ある特定の部分でほぼ
πラジアン変化していることを特徴とする半導体レーザ
装置。2. The semiconductor laser device according to claim 1, wherein the phase of the unevenness in the central region changes by approximately π radians at a certain portion.
いて、中央領域の凹凸の周期とその他の領域の周期の差
により、左領域と右領域の凹凸の位相がほぼπラジアン
変化していることを特徴とする半導体レーザ装置。3. In the semiconductor laser device according to claim 1, the phase of the asperities in the left region and the right region changes by approximately π radians due to the difference between the period of the asperities in the central region and the period of the other regions. A semiconductor laser device characterized by:
いて、中央の電極に信号電流を注入することを特徴とす
る半導体レーザ装置。4. The semiconductor laser device according to claim 1, wherein a signal current is injected into the central electrode.
体レーザ装置を使用したコヒーレント光通信ステム。5. A coherent optical communication system using the semiconductor laser device according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9679591A JPH04326781A (en) | 1991-04-26 | 1991-04-26 | Semiconductor laser device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9679591A JPH04326781A (en) | 1991-04-26 | 1991-04-26 | Semiconductor laser device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04326781A true JPH04326781A (en) | 1992-11-16 |
Family
ID=14174566
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9679591A Pending JPH04326781A (en) | 1991-04-26 | 1991-04-26 | Semiconductor laser device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04326781A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006019516A (en) * | 2004-07-01 | 2006-01-19 | Fujitsu Ltd | Tunable laser and its control method |
| JP2014150145A (en) * | 2013-01-31 | 2014-08-21 | Japan Oclaro Inc | Semiconductor laser element and optical semiconductor device |
| JP2017152724A (en) * | 2017-04-24 | 2017-08-31 | 日本オクラロ株式会社 | Semiconductor laser element, and optical semiconductor device |
| JPWO2018070432A1 (en) * | 2016-10-12 | 2019-08-08 | 古河電気工業株式会社 | Semiconductor laser element |
-
1991
- 1991-04-26 JP JP9679591A patent/JPH04326781A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006019516A (en) * | 2004-07-01 | 2006-01-19 | Fujitsu Ltd | Tunable laser and its control method |
| JP2014150145A (en) * | 2013-01-31 | 2014-08-21 | Japan Oclaro Inc | Semiconductor laser element and optical semiconductor device |
| JPWO2018070432A1 (en) * | 2016-10-12 | 2019-08-08 | 古河電気工業株式会社 | Semiconductor laser element |
| JP2017152724A (en) * | 2017-04-24 | 2017-08-31 | 日本オクラロ株式会社 | Semiconductor laser element, and optical semiconductor device |
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