JPH01270035A - Optical modulator - Google Patents
Optical modulatorInfo
- Publication number
- JPH01270035A JPH01270035A JP10111188A JP10111188A JPH01270035A JP H01270035 A JPH01270035 A JP H01270035A JP 10111188 A JP10111188 A JP 10111188A JP 10111188 A JP10111188 A JP 10111188A JP H01270035 A JPH01270035 A JP H01270035A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- emitter
- quantum well
- waveguide
- multiple quantum
- 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
- 230000003287 optical effect Effects 0.000 title claims description 15
- 230000001902 propagating effect Effects 0.000 claims abstract 2
- 239000004065 semiconductor Substances 0.000 claims abstract 2
- 238000005253 cladding Methods 0.000 claims description 13
- 239000000969 carrier Substances 0.000 claims description 11
- 239000000470 constituent Substances 0.000 claims 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 abstract description 6
- 239000000758 substrate Substances 0.000 abstract description 4
- 239000004020 conductor Substances 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 8
- 230000004888 barrier function Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- 230000005641 tunneling Effects 0.000 description 4
- 230000006798 recombination Effects 0.000 description 3
- 238000005215 recombination Methods 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000002019 doping agent Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
- G02F1/31—Digital deflection, i.e. optical switching
- G02F1/313—Digital deflection, i.e. optical switching in an optical waveguide structure
- G02F1/3137—Digital deflection, i.e. optical switching in an optical waveguide structure with intersecting or branching waveguides, e.g. X-switches and Y-junctions
- G02F1/3138—Digital deflection, i.e. optical switching in an optical waveguide structure with intersecting or branching waveguides, e.g. X-switches and Y-junctions the optical waveguides being made of semiconducting materials
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、光通信、光情報処理分野において用いられ
る光信号の変調装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical signal modulation device used in the fields of optical communication and optical information processing.
第４図は例えばエレクトロニクス レターズ。 Figure 4 is an example of Electronics Letters.
２０巻、 （１９８４） 、２２Ｂ頁（Ｅｌｅｃｔｒｏ
ｎｉｃｓ Ｌｅｔｔｅｒｓ Ｖｏｌ、２０、 （１９８
４） 、 ｐ、２２８）に示された従来の光変調装置を
示す上面図、第５図は第４図のＡ−Ａ断面図である。こ
れら図において、３は光入射口、７はＧａＡｓ基板、１
４はｎ−Ａｌ、Ｇａ、−ＸＡｓクラッド層、１５はｎ−
ＧａＡｓ光ガイド層、１６はｐ−Ａ ｌＸＧａ、−ＸＡ
ｓクラッド層、１７は電極である。Volume 20, (1984), page 22B (Electro
nics Letters Vol, 20, (198
4), p, 228) are top views showing the conventional optical modulation device, and FIG. 5 is a sectional view taken along line AA in FIG. In these figures, 3 is a light entrance, 7 is a GaAs substrate, 1
4 is n-Al, Ga, -XAs cladding layer, 15 is n-
GaAs light guide layer, 16 is p-A lXGa, -XA
s cladding layer, 17 is an electrode.
図に示すように、光ガイドＮ１５には角度２θでＸ字状
に交叉しているりフジ形導波路１５ が形成されている
。またその交叉部においてはクラッド層１４．光ガイド
層１５．クラッド１ｉ１６によりｎ Ａ １ ｘ Ｇ
ａ ＋ −Ｘ Ａ ｓ ／ ｎ Ｇ ａ Ａ ｓ
／ ｐＡ ＩＸ Ｇａｐ−ＸＡｓダブルへテロ構造が形
成されており、光ガイド層１５の部分の屈折率は等制約
にそれ以外の部分よりも高くなる。入射光はボート３か
ら素子内に入り、ボート３′、または３から出射する。As shown in the figure, the optical guide N15 is formed with a Fuji-shaped waveguide 15 that intersects in an X-shape at an angle of 2θ. Moreover, at the intersection part, the cladding layer 14. Light guide layer 15. n A 1 x G by cladding 1i16
a + −X A s / n G a A s
/pA IX Gap-XAs double heterostructure is formed, and the refractive index of the light guide layer 15 portion is higher than that of the other portions under equal constraints. The incident light enters the element from the boat 3 and exits from the boat 3' or 3.
キャリアが電極１７からｐｎ接合を介して光ガイド層１
５に注入されると、キャリアが注入された部分の屈折率
はプラズマ効果により低下する。Carriers are transferred from the electrode 17 to the light guide layer 1 via the pn junction.
5, the refractive index of the portion into which carriers are injected decreases due to the plasma effect.
たとえば入射光の波長が０．９μｍ、注入されたキャリ
ア密度ΔＮがｌ ＸＩＯ”Ｃ１１−”のとき、屈折率変
化Δｎはおよそ５Ｘ１０−３である。For example, when the wavelength of the incident light is 0.9 μm and the injected carrier density ΔN is lXIO"C11-", the refractive index change Δn is approximately 5X10-3.
今、レーザビームがボート３から入射したとする。交叉
角２θが２〜３°よりも小さいとき、ガイド層１５の交
叉領域へのｌ ｘｌＱｌａｃｆｌＩ−３程度のキャリア
注入により入射光を全反射させてボート３″から出射さ
せることが可能となる。一方、キャリアを注入しないと
きは、レーザ光はボート３′ から出射する。このよう
にガイド層１５の交叉領域へのキャリア注入量を制御す
ることにより、入射光のスイッチングを行なうことがで
きる。Assume now that a laser beam is incident from boat 3. When the intersection angle 2θ is smaller than 2 to 3 degrees, by injecting carriers of about lxlQlacflI-3 into the intersection region of the guide layer 15, it becomes possible to totally reflect the incident light and emit it from the boat 3''. When carriers are not injected, the laser beam is emitted from the boat 3'. By controlling the amount of carriers injected into the intersection region of the guide layer 15 in this way, the incident light can be switched.
従来の光変調装置は以上のように構成されており、この
ようなダブルへテロ構造では電流注入を停止した後もキ
ャリア再結合によって電子が消費されるまでは電子が導
波路に存在するため、スイッチング速度は、ｐｎ接合部
の注入キャリアの寿命、即ちキャリア再結合時間（これ
は通常数ナノセ、りのオーダである）で制限され、１
ｆＪｚ以下となるため、高速変調ができないという問題
点があった。Conventional optical modulators are configured as described above, and in such a double heterostructure, electrons remain in the waveguide even after current injection is stopped until they are consumed by carrier recombination. The switching speed is limited by the lifetime of the injected carriers at the p-n junction, i.e. the carrier recombination time (which is typically on the order of a few nanoseconds);
fJz or less, there was a problem that high-speed modulation was not possible.
この発明は上記のような問題点を解消するためになされ
たもので、屈折率可変領域へキャリアを高速に注入した
り、高速で取り去ったりすることができる光変調装置を
得ることを目的とする。This invention was made to solve the above-mentioned problems, and its purpose is to obtain an optical modulation device that can rapidly inject carriers into a variable refractive index region and remove them at high speed. .
この発明に係る光変調装置は、光ガイド層の屈折率可変
領域を多重量子井戸構造により形成し、これをベース層
とし、該ベース層を挟んで形成された、該ベース層の量
子井戸に形成される電子のｎ＝１の量子準位と等しいか
あるいはやや小さいエネルギー位置に伝導帯底が一致す
る第１のクラフト層及び第２のクラッド層をそれぞれエ
ミッタ及びコレクタ層とするトランジスタ構造にしたも
のである。In the optical modulator according to the present invention, the refractive index variable region of the light guide layer is formed with a multiple quantum well structure, this is used as a base layer, and the quantum wells of the base layer are formed with the base layer sandwiched therebetween. A transistor structure in which the first craft layer and the second cladding layer, whose conduction band bottoms coincide with an energy position equal to or slightly lower than the n=1 quantum level of electrons, are used as emitter and collector layers, respectively. It is.
この発明においては、上述の構成として、屈折率可変領
域へのキャリアの注入は共鳴トンネリング現象を利用し
て制御するようにしたから、屈折率可変領域へキャリア
を高速に注入したり、高速で取り去ったりすることがで
きる。In this invention, as described above, since the injection of carriers into the variable refractive index region is controlled using the resonant tunneling phenomenon, carriers can be injected into the variable refractive index region at high speed and removed at high speed. You can
以下、この発明の一実施例を図について説明する。 An embodiment of the present invention will be described below with reference to the drawings.
第１図は本発明の一実施例による光変調装置を示す上面
図であり、図において、１はＸ字形のｎＡ ｌ ＊ Ｇ
ａ ＋−ｗ Ａ ｓ光ガイド層、２はｎ−Ａｌ。FIG. 1 is a top view showing an optical modulation device according to an embodiment of the present invention, and in the figure, 1 is an X-shaped nA l * G
a + -w As light guide layer, 2 is n-Al.
Ｇａｐ−、Ａｓクラッド層、３は光入射口、４はエミッ
タ電極、５はベース電極である。Gap-, As clad layer, 3 is a light entrance, 4 is an emitter electrode, and 5 is a base electrode.
第２図は第１図のＡ−Ａ断面図であり、図において、６
はコレクタ電極、７はｎ−ＧａＡｓ基板、８はｎ Ａ
１１ｌ Ｇａｐ−ｘＡｓコレクタ層、９は多重量子井戸
のｐ−ＡＩ、Ｇａｐ−、Ａｓバリア層、１０は多重量子
井戸のｐ−ＧａＡｓウェル層、１１はベース電極５とオ
ーミック接合をとるためのｐ型ドーパント拡散層である
。FIG. 2 is a sectional view taken along line A-A in FIG.
is the collector electrode, 7 is the n-GaAs substrate, and 8 is the nA
11l Gap-xAs collector layer; 9 is a multi-quantum well p-AI, Gap-, As barrier layer; 10 is a multi-quantum well p-GaAs well layer; 11 is a p-type for making an ohmic contact with the base electrode 5; This is a dopant diffusion layer.
また、第３図は光ガイド層１とクラッド層２により構成
されたｎ−ＡｌｘＧａ、−ＸＡｓエミッタ層１２と、多
重量子井戸よりなるベース領域、及びコレクタ層８から
なるトランジスタ構造において、電子がベース領域に注
入されているときのバンドダイアグラムを表す図であり
、図において、１３はウェル層１０内に形成されるｎ＝
１電子量子準位である。FIG. 3 also shows that in a transistor structure consisting of an n-AlxGa, -XAs emitter layer 12 constituted by an optical guide layer 1 and a cladding layer 2, a base region consisting of a multiple quantum well, and a collector layer 8, electrons are 13 is a diagram showing a band diagram when implanted into a region, and in the diagram, 13 is formed in the well layer 10 where n=
It is a one-electron quantum level.
エミッタ層１２の伝導帯底は多重量子井戸ウェル層１０
に形成されるｎ−１量子率位１３に等しいかあるいはや
や小さい値に設定されている。例えば、バリア層９の組
成がｙ＝＝ｌとすると量子準位１３のエネルギーは、ウ
ェル層１０の伝導帯底からはかって０．０８ｅＶとなる
。このときのエミッタ７１１２とコレクタ層８の組成は
ｘ ＝０．８５とすればよい、第３図（ａ）に示したキ
ャリア注入時はこのような条件が満たされているので、
エミッタ層１２の電子は量子準位１３に共鳴トンネリン
グすることができる。同様に、量子準位１３とコレクタ
層８の間にも共鳴トンネリング条件が満たされているの
で、ベース層に注入された電子はコレクタ層８に流れ込
む。一方、電子の注入を停止させるには、エミッタ・ベ
ース間の順方向バイアス電圧を調節して、第３図（ｂｌ
に示すようにエミッタ層１２の伝導帯底が量子準位１３
よりもエネルギー的に高くなるようにすればよい、この
ときはトンネル条件が満たされないため、電子はウェル
層１０に注入されなくなる。一方、ベース・コレクタ間
には逆バイアスを印加しているので、共鳴トンネリング
条件は保持され、ベース層内の電子は速やかに光ガイド
領域から取り除かれる。このため電子が注入されな（な
ってから屈折率可変領域より電子が存在しなくなるまで
の時間は、キャリア再結合による電子消費による場合に
比して大幅に短縮され、光の高速変調が可能となる。The conduction band bottom of the emitter layer 12 is the multi-quantum well well layer 10.
It is set to a value equal to or slightly smaller than the n-1 quantum rate 13 formed in . For example, if the composition of the barrier layer 9 is y==l, the energy of the quantum level 13 will be 0.08 eV from the bottom of the conduction band of the well layer 10. At this time, the composition of the emitter 7112 and the collector layer 8 should be x = 0.85. Since these conditions are satisfied when carriers are injected as shown in FIG. 3(a),
Electrons in the emitter layer 12 can resonantly tunnel to the quantum level 13. Similarly, since the resonant tunneling condition is also satisfied between the quantum level 13 and the collector layer 8, the electrons injected into the base layer flow into the collector layer 8. On the other hand, to stop electron injection, adjust the forward bias voltage between the emitter and base as shown in Figure 3 (bl
As shown in , the conduction band bottom of the emitter layer 12 is at the quantum level 13.
In this case, since the tunneling condition is not satisfied, electrons are no longer injected into the well layer 10. On the other hand, since a reverse bias is applied between the base and the collector, resonant tunneling conditions are maintained and electrons in the base layer are quickly removed from the light guide region. Therefore, the time from when electrons are not injected until they no longer exist in the variable refractive index region is significantly shorter than when electrons are consumed by carrier recombination, making it possible to modulate light at high speed. Become.
なお、上記実施例では、ベース層となるバリア層９とウ
ェル層１０をともにｐ型としたが、バリア層９のみ、あ
るいはウェルＮ１０のみをｐ型としてもよい。In the above embodiment, both the barrier layer 9 serving as the base layer and the well layer 10 are p-type, but only the barrier layer 9 or only the well N10 may be p-type.
以上のように、この発明によれば、屈折率可変領域を多
重量子井戸構造により構成しこれをベース層とし、該ベ
ース層を挟んで形成された、該ベース層の量子井戸に形
成される電子のｎ＝１の量子準位と等しいかあるいはや
や小さいエネルギー位置に伝導帯底が一致する第１のク
ラッド層及び第２のクラッド層をそれぞれエミッタ及び
コレクタ層とするトランジスタ構造とし、共鳴トンネリ
ングにより上記屈折率可変領域に電子を注入するように
構成したので、光信号の高速変調が達成できる効果があ
る。As described above, according to the present invention, the refractive index variable region is configured with a multiple quantum well structure, which is used as a base layer, and the electrons formed in the quantum wells of the base layer are formed with the base layer sandwiched therebetween. A transistor structure is used in which the first cladding layer and the second cladding layer, whose conduction band bottoms coincide with an energy position equal to or slightly lower than the n=1 quantum level of Since the configuration is such that electrons are injected into the variable refractive index region, there is an effect that high-speed modulation of optical signals can be achieved.
第１図はこの発明の一実施例による光変調装置を示す上
面図、第２図は第１図のＡ−Ａ断面図、第３図（ａ）は
屈折率可変領域へのキャリア注入時のバンドダイヤグラ
ムを示す図、第３図（ｂ）はキャリア注入停止時のバン
ドダイヤグラムを示す図、第４図は従来の光変調装置を
示す上面図、第５図は第４図のＡ−Ａ断面図である。
１はｒｌ Ａ ｌ ｘ Ｇ ａ Ｉ−Ｘ Ａ ３光ガ
イド層、２はｎ Ａ Ｉ Ｘ Ｇ ａ ｌ−Ｘ Ａ
ｓクラッド層、３は光入射口、４はエミッタ電極、５は
ベース電極、６はコレクタ電極、７はｎ−ＧａＡｓ基板
、８はｎ−ＡｌＸＧａ、−、ｌＡｓコレクタ層、９はｐ
−ＡＩ、Ｇａｔ−、Ａｓバリア層、ＩＯはｐ −Ｇ ａ
Ａ ５ウ工ル層、１１はｐ型ドーパント拡散層、１２
はｎ−Ａｌ、ＩＧａ、−Ｘ、Ａｓエミッタ層、１３はｎ
＝１電子量子準位。
なお図中同一符号は同−又は相当部分を示す。FIG. 1 is a top view showing an optical modulation device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and FIG. A diagram showing a band diagram, FIG. 3(b) is a diagram showing a band diagram when carrier injection is stopped, FIG. 4 is a top view showing a conventional optical modulation device, and FIG. 5 is a cross section taken along the line AA in FIG. 4. It is a diagram. 1 is rl A l x G a I-X A 3 light guide layer, 2 is n A I X G a l-X A
s cladding layer, 3 is a light entrance, 4 is an emitter electrode, 5 is a base electrode, 6 is a collector electrode, 7 is an n-GaAs substrate, 8 is an n-AlXGa, -, lAs collector layer, 9 is a p
-AI, Gat-, As barrier layer, IO is p -Ga
A 5 aluminum layer, 11 p-type dopant diffusion layer, 12
is n-Al, IGa, -X, As emitter layer, 13 is n
= 1 electron quantum level. Note that the same reference numerals in the figures indicate the same or equivalent parts.
Claims (1)
を有し、該導波路の交叉部にキャリアを注入することに
よって屈折率を変化させ、上記導波路を伝搬する導波光
の強度を変化させるようにした光変調装置において、 上記導波路はｐ型多重量子井戸構造からなる主導波層と
、該主導波層を挟むように形成された、第２のクラッド
層および上記主導波路を構成する量子井戸よりもバンド
ギャップが大きくかつこの量子井戸に形成される電子の
ｎ＝１量子準位と等しいか或いはやや小さいエネルギ位
置に伝導帯底が一致する第１のクラッド層とを備え、 上記主導波層をベース層、第１クラッド層をエミッタ層
、第２クラッド層をコレクタ層としてベース・エミッタ
間にバイアス電圧を印加したときエミッタ層の伝導帯底
は上記ｎ＝１量子準位より大きいエネルギ位置にシフト
するものであることを特徴とする光変調装置。(1) It has multi-layered semiconductor layers constituting a waveguide that intersects in an X-shape, and the refractive index is changed by injecting carriers into the intersection of the waveguide, and the intensity of the guided light propagating through the waveguide is In the optical modulator, the waveguide includes a main wave layer having a p-type multiple quantum well structure, a second cladding layer formed to sandwich the main wave layer, and the main waveguide. a first cladding layer having a larger band gap than the constituent quantum wells and whose conduction band bottom coincides with an energy position equal to or slightly smaller than the n=1 quantum level of electrons formed in the quantum well; When a bias voltage is applied between the base and emitter with the above-mentioned main wave layer as the base layer, the first cladding layer as the emitter layer, and the second cladding layer as the collector layer, the conduction band bottom of the emitter layer is lower than the above n=1 quantum level. 1. A light modulation device that shifts to a high energy position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10111188A JPH01270035A (en) | 1988-04-22 | 1988-04-22 | Optical modulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10111188A JPH01270035A (en) | 1988-04-22 | 1988-04-22 | Optical modulator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01270035A true JPH01270035A (en) | 1989-10-27 |
Family
ID=14291964
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10111188A Pending JPH01270035A (en) | 1988-04-22 | 1988-04-22 | Optical modulator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01270035A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2663161A1 (en) * | 1990-06-08 | 1991-12-13 | Thomson Csf | Optical waveguide with integrated transistor structure and applications to the production of laser modulators and optical couplers |
-
1988
- 1988-04-22 JP JP10111188A patent/JPH01270035A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2663161A1 (en) * | 1990-06-08 | 1991-12-13 | Thomson Csf | Optical waveguide with integrated transistor structure and applications to the production of laser modulators and optical couplers |
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