JPH0379693B2 - - Google Patents
Info
- Publication number
- JPH0379693B2 JPH0379693B2 JP15920684A JP15920684A JPH0379693B2 JP H0379693 B2 JPH0379693 B2 JP H0379693B2 JP 15920684 A JP15920684 A JP 15920684A JP 15920684 A JP15920684 A JP 15920684A JP H0379693 B2 JPH0379693 B2 JP H0379693B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- layer
- wavelength
- semiconductor laser
- optical
- 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
- 239000004065 semiconductor Substances 0.000 claims description 19
- 230000010355 oscillation Effects 0.000 claims description 8
- 239000006096 absorbing agent Substances 0.000 claims description 4
- 230000007704 transition Effects 0.000 claims description 4
- 230000001678 irradiating effect Effects 0.000 claims description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 13
- 238000010521 absorption reaction Methods 0.000 description 9
- 230000003287 optical effect Effects 0.000 description 6
- 238000005253 cladding Methods 0.000 description 4
- 239000000758 substrate Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Semiconductor Lasers (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は外部からの光照射による半導体レー
ザの出力光制御を果す高速光−光スイツチング素
子に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-speed light-to-light switching device that controls the output light of a semiconductor laser by external light irradiation.
外部からの光入射により、光を出力する光−光
スイツチング素子の基本構成を第１図に示す。
FIG. 1 shows the basic configuration of a light-to-light switching element that outputs light upon input of light from the outside.
光スイツチング素子は、ある波長λ1の光を入射
させると、波長λ2の光を出力するものである。λ1
＝λ2であれば、波長λ2の出力光を別の素子の波長
λ1の入力光として用いることにより、素子と素子
の接続が可能となるが、従来はλ1≠λ2である。 The optical switching element outputs light with a wavelength λ 2 when light with a certain wavelength λ 1 is input thereto. λ 1
= λ 2 , it is possible to connect the elements by using the output light with the wavelength λ 2 as the input light with the wavelength λ 1 of another element, but conventionally, λ 1 ≠ λ 2 .
従来の光−光スイツチング素子の一例として、
光パルス励起による半導体レーザがある。すなわ
ち、半導体レーザの発振波長より十分短い波長の
光パルスを半導体レーザの活性層に入射させる
と、価電子帯の電子は光エネルギを吸収して、導
電体に励起される。そして、反転分布状態に至る
と、半導体レーザはパルス発振する。 As an example of a conventional optical-optical switching element,
There is a semiconductor laser that uses optical pulse excitation. That is, when a light pulse having a wavelength sufficiently shorter than the oscillation wavelength of the semiconductor laser is made incident on the active layer of the semiconductor laser, electrons in the valence band absorb the light energy and are excited into the conductor. When the population inversion state is reached, the semiconductor laser oscillates in pulses.
ところが、この方法では、発振に必要な反転分
布状態を達成するために、活性層での吸収が大き
い、つまり、発振波長より十分短い波長の入射光
を用いる必要がある。
However, in this method, in order to achieve the population inversion state necessary for oscillation, it is necessary to use incident light that is highly absorbed in the active layer, that is, has a wavelength sufficiently shorter than the oscillation wavelength.
このように、入射光と出力光の波長が異なつて
いるので、光集積回路等で要求される素子の多段
接続ができない。 As described above, since the wavelengths of the incident light and the output light are different, it is not possible to connect elements in multiple stages as required in optical integrated circuits and the like.
そこでこの発明の目的は、入射光と出力光を同
一波長にするものであり、素子の多段接続による
光−光論理回路等を実現しうる高速光−光スイツ
チング素子を堤供するにある。
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-speed optical-optical switching device which makes the incident light and output light the same wavelength, and which can realize an optical-optical logic circuit or the like by connecting devices in multiple stages.
この目的を達成するためにこの発明は、半導体
レーザの活性層の禁制帯幅より狭い禁制帯幅を持
つ直接遷移形半導体層を、可飽和吸収体として半
導体レーザ共振器内部に設け、半導体レーザの発
振波長と同じ波長の光を、外部から可飽和吸収体
に照射することにより光スイツチング動作をする
高速光−光スイツチング素子を構成したことを特
徴とする。
In order to achieve this object, the present invention provides a direct transition type semiconductor layer having a forbidden band width narrower than the forbidden band width of the active layer of the semiconductor laser as a saturable absorber inside the semiconductor laser resonator. The present invention is characterized by configuring a high-speed light-to-light switching element that performs a light switching operation by externally irradiating a saturable absorber with light having the same wavelength as the oscillation wavelength.
この発明による素子の一例を第２図に示す。 An example of a device according to the invention is shown in FIG.
光−光スイツチング素子20は以下の如く構成さ
れる。１はGaAs層であり所定厚さとされ入射光
側に設けられている。２は活性層、３はＰ型クラ
ツド層、４はｎ型クラツド層、５はＰ型Ga As
層、６はｎ型Ga As基板であり夫々積層されて
いる。そして前記ｎ型Ga As基板６の外側には
負電極７が、また前記Ｐ型Ga As層５の外側に
は正電極８が設けられる。そして、第２図に示す
如く、光−光スイツチング素子20の図において右
側には入射光用レンズ９が、また左側には出力光
用レンズ１０が配置されている。 The optical-optical switching element 20 is constructed as follows. A GaAs layer 1 has a predetermined thickness and is provided on the incident light side. 2 is an active layer, 3 is a P-type cladding layer, 4 is an n-type cladding layer, and 5 is a P-type GaAs.
Layer 6 is an n-type GaAs substrate and is laminated. A negative electrode 7 is provided on the outside of the n-type GaAs substrate 6, and a positive electrode 8 is provided on the outside of the P-type GaAs layer 5. As shown in FIG. 2, an incident light lens 9 is disposed on the right side of the optical-optical switching element 20, and an output light lens 10 is disposed on the left side.
通常のAl Ga Asダブルヘテロ構造半導体レー
ザの片方の出力端に、活性層より狭い禁制帯幅を
持つ直接遷移形半導体層として適当な厚さのGa
As層１を設ける。 At one output end of an ordinary Al Ga As double heterostructure semiconductor laser, a Ga film with an appropriate thickness is added as a direct transition type semiconductor layer with a narrower bandgap than the active layer.
An As layer 1 is provided.
活性層とGa As層１との屈折率の差は小さい
ので、活性層とGa As層１の界面での光の反射
は少ない。従つて、半導体レーザの共振器を構成
する二鏡面は、Ga As層１を設けていない側の
出力面とGa As層１の外側の面となる。 Since the difference in refractive index between the active layer and the Ga As layer 1 is small, there is little reflection of light at the interface between the active layer and the Ga As layer 1. Therefore, the two mirror surfaces constituting the resonator of the semiconductor laser are the output surface on the side where the Ga As layer 1 is not provided and the outer surface of the Ga As layer 1.
一般に、禁制帯幅がEgの直接遷移形半導体に、
λ≦hc／Eg（ｈ：プランク定数，ｃ：光速度）の
関係がある適当な波長λの光を入射させると価電
子帯の電子は光子エネルギを吸収して導電帯に励
起される。このことにより、入射光は吸収される
が、入射光強度を上げていくと、励起されうる電
子状態の減少により、それ以上はもう吸収できな
い状態、いわゆる吸収飽和の状態に至る。この吸
収飽和の状態では、λより長い波長の光に対して
吸収をおこなわない。 In general, for direct transition semiconductors with a forbidden band width of Eg,
When light of a suitable wavelength λ with the relationship λ≦hc/Eg (h: Planck's constant, c: speed of light) is incident, electrons in the valence band absorb photon energy and are excited into the conductive band. As a result, the incident light is absorbed, but as the intensity of the incident light is increased, the number of excited electronic states decreases, leading to a state where no more absorption is possible, a so-called absorption saturation state. In this state of absorption saturation, light with a wavelength longer than λ is not absorbed.
素子の活性層としてAl0.05 Ga0.95 Asを用い
ると禁制帯幅は約1.46eVであり、発振波長は約
850nmとなる。約1.43eVの禁制帯幅を持つGaAs
層１は、850nm程度の波長の光に対して高い吸収
係数を持ち、約850nmの光パルス照射により、比
較的容易に吸収飽和状態に至る。 When Al 0.05 Ga 0.95 As is used as the active layer of the device, the forbidden band width is approximately 1.46 eV and the oscillation wavelength is approximately
It becomes 850nm. GaAs with a forbidden band width of approximately 1.43eV
Layer 1 has a high absorption coefficient for light with a wavelength of about 850 nm, and reaches absorption saturation relatively easily by irradiation with a light pulse of about 850 nm.
素子に発振しきい値より少し少ない程度の電流
を流しておき、Ga As層１が吸収飽和状態に至
る強度で約850nmの波長の光パルスをGa As層
１に照射すると、共振器内光伝搬損失の急激な減
少により、発振利得が損失を上回り、素子はパル
ス発振する。 When a current slightly lower than the oscillation threshold is passed through the device and a light pulse with a wavelength of approximately 850 nm is applied to the GaAs layer 1 at an intensity that brings the absorption saturation state to the GaAs layer 1, light propagation within the cavity Due to the rapid decrease in loss, the oscillation gain exceeds the loss, and the device oscillates in pulses.
照射する光パルスの強度は、Ga As層１の厚
さに依存する。Ga As層１での励起電子の寿命
約2nsecより十分短い時間、たとえば5psecで光パ
ルス照射を行うとすると、Ga As層１の厚さが
約10μmでは、約8.4×10-5J／cm2の強度で約
850nmの波長の光パルス照射を行なえばよい。 The intensity of the irradiated light pulse depends on the thickness of the GaAs layer 1. Assuming that the light pulse irradiation is performed for a time sufficiently shorter than the lifetime of excited electrons in the Ga As layer 1 of about 2 nsec, for example, 5 psec, if the thickness of the Ga As layer 1 is about 10 μm, it will be about 8.4×10 -5 J/cm 2 with an intensity of approx.
Light pulse irradiation with a wavelength of 850 nm may be performed.
活性層内の光子密度と励起電子密度の時間に関
する微分方程式を用いた計算によると、この素子
は光パルス照射後、約10psecの遅れ時間で、半値
幅約4psecのパルス発振を行うと予想され、きわ
めて高速な光スイツチングが実現される。Ga
As層１の厚さ及び、素子に流す電流値を変化さ
せることにより、より高速化も可能である。 According to calculations using differential equations related to the photon density and excited electron density in the active layer over time, this device is expected to emit pulses with a half-value width of about 4 psec with a delay time of about 10 psec after irradiation with a light pulse. Extremely fast optical switching is achieved. Ga
By changing the thickness of the As layer 1 and the value of the current flowing through the element, higher speeds can be achieved.
素子への照射光パルスを二つにし、その強度を
適当な値に設定することで、光のANDまたはOR
論理回路が実現できる。 By dividing the light pulses irradiated to the element into two and setting the intensity to an appropriate value, it is possible to perform AND or OR of light.
Logic circuits can be realized.
すなわち、AND回路では、一つの光パルス照
射では吸収飽和状態に至らないが、二つの光パル
スを同時に照射することにより吸収飽和状態に至
るように、照射光パルス強度とGa As層１の厚
さを設定する。 In other words, in the AND circuit, the intensity of the irradiated light pulse and the thickness of the GaAs layer 1 are adjusted so that the absorption saturation state cannot be reached with one light pulse irradiation, but the absorption saturation state can be reached with the simultaneous irradiation of two light pulses. Set.
OR回路では、二つの光パルスのうち、どちら
か一つの光パルス照射により吸収飽和状態に至る
ように照射光パルス強度とGa As層１の厚さを
設定する。 In the OR circuit, the irradiated light pulse intensity and the thickness of the Ga As layer 1 are set so that absorption saturation is reached by irradiation with one of the two light pulses.
この素子により実現される光AND及びOR回路
は、すべて同一波長を用いているので、素子と素
子の多段接続ができ、複雑な論理回路も実現しう
る。 Since the optical AND and OR circuits realized by this element all use the same wavelength, elements can be connected in multiple stages, and complex logic circuits can also be realized.
Ga As層１の厚さと素子に流す電流値を適当
に設定すれば、光増幅器が実現できる。 By appropriately setting the thickness of the GaAs layer 1 and the value of the current flowing through the element, an optical amplifier can be realized.
なお、この発明は、Al Ga As系半導体レーザ
だけではなくIn Ga As Ｐ系半導体レーザなど
他の半導体レーザにも適用できるのは勿論であ
る。 Note that the present invention is of course applicable not only to Al Ga As semiconductor lasers but also to other semiconductor lasers such as In Ga As P semiconductor lasers.
第１図は光−光スイツチング素子の基本構成を
示す。第２図はこの本発明の実施例を示す。
図中、１はGa As層、２は活性層、３はＰ型
クラツド層、４はｎ型クラツド層、５はＰ型Ga
As層、６はｎ型Ga As基板、７は負電極、８は
正電極、９は入射光用レンズ、１０は出力光用レ
ンズである。
FIG. 1 shows the basic configuration of an optical-optical switching element. FIG. 2 shows an embodiment of this invention. In the figure, 1 is a GaAs layer, 2 is an active layer, 3 is a P-type cladding layer, 4 is an n-type cladding layer, and 5 is a P-type Ga layer.
6 is an n-type GaAs substrate, 7 is a negative electrode, 8 is a positive electrode, 9 is a lens for incident light, and 10 is a lens for output light.
Claims (1)
制帯幅を持つ直接遷移形半導体層を、可飽和吸収
体として半導体レーザ共振器内部に設け、半導体
レーザの発振波長と同じ波長の光を、外部から可
飽和吸収体に照射することにより光スイツチング
動作をする高速光−光スイツチング素子。1. A direct transition type semiconductor layer having a bandgap narrower than the bandgap of the active layer of the semiconductor laser is provided inside the semiconductor laser resonator as a saturable absorber, and light with the same wavelength as the oscillation wavelength of the semiconductor laser is emitted from the outside. A high-speed light-to-light switching device that performs a light switching operation by irradiating a saturable absorber with light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15920684A JPS6138935A (en) | 1984-07-31 | 1984-07-31 | High speed light-light switching element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15920684A JPS6138935A (en) | 1984-07-31 | 1984-07-31 | High speed light-light switching element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6138935A JPS6138935A (en) | 1986-02-25 |
| JPH0379693B2 true JPH0379693B2 (en) | 1991-12-19 |
Family
ID=15688637
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15920684A Granted JPS6138935A (en) | 1984-07-31 | 1984-07-31 | High speed light-light switching element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6138935A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2516349B2 (en) * | 1987-01-08 | 1996-07-24 | 富士通株式会社 | Optical communication system |
| JP2996225B2 (en) | 1998-03-13 | 1999-12-27 | 日本電気株式会社 | Saturable absorption type optical switch and control method thereof |
| JPH11258559A (en) | 1998-03-13 | 1999-09-24 | Nec Corp | Optical switch, control method therefor, and storage medium in which it is written |
-
1984
- 1984-07-31 JP JP15920684A patent/JPS6138935A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6138935A (en) | 1986-02-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3328881B2 (en) | Semiconductor optical pulse compression waveguide device and semiconductor optical pulse generating laser | |
| JPH11163458A (en) | Semiconductor laser device | |
| GB1594656A (en) | Optical integrated semicxonductor circuits | |
| US3654497A (en) | Semiconductor lasers utilizing internal saturable absorbers | |
| JPS63244783A (en) | Wavelength conversion element | |
| US5177752A (en) | Optical pulse generator using gain-switched semiconductor laser | |
| Elsässer et al. | Subpicosecond switch-off and switch-on of a semiconductor laser due to transient hot carrier effects | |
| JPH0379693B2 (en) | ||
| KR100519920B1 (en) | High Speed Optical Processing including Saturable Absorber and Gain-Clamped Optical Amplifier | |
| JPH0943646A (en) | Short optical pulse waveform shaping device | |
| JPH04247676A (en) | Surface light-emitting semiconductor mode lock laser | |
| JPS58202581A (en) | Controller for laser diode beam | |
| FR2337449A1 (en) | INTEGRATED OPTICAL CIRCUIT OF THE WAVEGUIDE TYPE WITH MULTIPLE HETEROGENOUS STRUCTURES AND ITS MANUFACTURING PROCESS | |
| US5007061A (en) | Bistable semiconductor laser diode device | |
| Kawanaka et al. | Strained single quantum well AlGaInP laser diodes with an asymmetric waveguiding layer. | |
| Goldobin et al. | Generation of single optical pulses of less than 10 psec duration in a two-section heterojunction laser | |
| JPWO2005096463A1 (en) | Surface emitting laser and driving method thereof | |
| AKSAKAL et al. | Comparative theoretical investigation of passively mode-locked diode lasers with different cavity configurations Farklı kavite konfigürasyonlarına sahip pasif mod kilitli diyot lazerlerin karşılaştırmalı teorik incelenmesi | |
| JPS6155276B2 (en) | ||
| JP2814810B2 (en) | Q switch laser | |
| JPS63173381A (en) | Semiconductor laser device | |
| JPS5950589A (en) | Functional light emitting element with controlled spontaneous emission | |
| JPS63185086A (en) | Tunable semiconductor laser | |
| JPS6432693A (en) | Semiconductor optical functional light-emitting element | |
| KR100343946B1 (en) | Waveguide-type optical thyristor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |