JPH0827447B2 - Optical waveguide device - Google Patents
Optical waveguide deviceInfo
- Publication number
- JPH0827447B2 JPH0827447B2 JP61286840A JP28684086A JPH0827447B2 JP H0827447 B2 JPH0827447 B2 JP H0827447B2 JP 61286840 A JP61286840 A JP 61286840A JP 28684086 A JP28684086 A JP 28684086A JP H0827447 B2 JPH0827447 B2 JP H0827447B2
- Authority
- JP
- Japan
- Prior art keywords
- optical waveguide
- electrodes
- optical
- groove
- modulator
- 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 - Lifetime
Links
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
- G02F1/01—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 intensity, phase, polarisation or colour
- G02F1/21—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 intensity, phase, polarisation or colour by interference
- G02F1/225—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 intensity, phase, polarisation or colour by interference in an optical waveguide structure
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
Description
【発明の詳細な説明】 〔概要〕 光導波路デバイスにおいて、２本の光導波路の間に溝
を設け、その溝の底部に電極を配置して、変調に要する
印加電圧の低減と変調器の性能を維持するものである。DETAILED DESCRIPTION [Outline] In an optical waveguide device, a groove is provided between two optical waveguides, and an electrode is arranged at the bottom of the groove to reduce the applied voltage required for modulation and to improve the performance of a modulator. Is to maintain.
本発明は光変調器などに用いられる光導波路デバイス
に関する。The present invention relates to an optical waveguide device used for an optical modulator or the like.
光導波路デバイスとしてのマッハツェンダ型の光導波
路変調器は例えば、LiNbO3の基板にTiを蒸着して分岐し
た２本の導波路を設け、その上にバッファ層を作成し、
さらにその上の分岐された導波路部分に対応する位置
に、電極を配置している。この２つの電極間に電圧を印
加すると、従来型のマッハツェンダ型の光導波路変調器
の断面図を示す第３図における矢印のような電気力線を
与える電界が生ずる。この電界により光導波路２におけ
る光の屈折率が電気光学効果によって変化し、導波路２
を伝送する光の位相を変化させる。この変化が正電極側
（右側）と負電極側（左側）で逆に作用するので２倍の
効果となり、分岐された２本の導波路が再び合体すると
２つの光は互いに干渉し、その結果光が変調される。A Mach-Zehnder type optical waveguide modulator as an optical waveguide device is, for example, provided with two waveguides branched by depositing Ti on a LiNbO 3 substrate, and forming a buffer layer on the waveguide.
Further, electrodes are arranged at positions corresponding to the branched waveguide portions on the electrodes. When a voltage is applied between the two electrodes, an electric field is generated which gives a line of electric force as indicated by an arrow in FIG. 3, which is a sectional view of a conventional Mach-Zehnder type optical waveguide modulator. This electric field changes the refractive index of light in the optical waveguide 2 due to the electro-optic effect,
To change the phase of the light transmitted. This change has the opposite effect on the positive electrode side (right side) and the negative electrode side (left side), resulting in a double effect. When the two branched waveguides are combined again, the two lights interfere with each other, resulting in The light is modulated.
この変調のため電極に印加する電圧は高電圧を必要と
するので、これの低減が非常に求められており、実現す
るための試みがなされている。すなわち、光導波路２の
間隔を小さくし同時に電極５の間隔を小さくして、同じ
印加電圧に対してより強力な電界を得るようにしている
が、分岐した２つの光導波路２をあまり近づけると、分
岐した２つの光が結合し、消光比の劣化を招くという問
題が発生する。Since the voltage applied to the electrodes for this modulation requires a high voltage, there is a great demand for reduction of this voltage, and attempts have been made to realize it. That is, the distance between the optical waveguides 2 is made small and at the same time the distance between the electrodes 5 is made small so as to obtain a stronger electric field for the same applied voltage. A problem arises in which the two branched lights are combined and the extinction ratio deteriorates.
前述の従来技術における問題点にかんがみ、本発明の
目的は、変調器の性能、すなわち消光比は劣化させず
に、変調のため電極に印加する駆動電圧を低減すること
にある。In view of the aforementioned problems in the prior art, it is an object of the present invention to reduce the driving voltage applied to the electrodes for modulation without degrading the performance of the modulator, that is, the extinction ratio.
第１図のように、光導波路基板１に設けられた２本の
光導波路２の間に溝３を設け、その溝３の底部に外部と
電気的に絶縁された金属膜を配置する。As shown in FIG. 1, a groove 3 is provided between two optical waveguides 2 provided on an optical waveguide substrate 1, and a metal film electrically insulated from the outside is arranged at the bottom of the groove 3.
前述の手段を用いれば、電極５の間の静電容量は中間
電極４が中間に存在するから２つの静電容量の直列回路
と等価となって電極間における金属以外の部分の距離が
非常に小さくなり、それにより光導波路における電界は
強くなる。また２つの分岐された光導波路２の間に溝３
が設けられ分岐した２つの光の結合が妨げられる。また
溝３および中間電極４により電界の向きが基板表面に対
し垂直な方向に近づき（第２図参照）、例えばＺカット
LiNbO3基板を用いTM光を適用した場合、電界がより有効
に利用される。If the above-mentioned means is used, the capacitance between the electrodes 5 is equivalent to a series circuit of two capacitances because the intermediate electrode 4 exists in the middle, and the distance between the electrodes other than the metal is very large. It becomes smaller, which results in a stronger electric field in the optical waveguide. In addition, a groove 3 is provided between the two branched optical waveguides 2.
Is provided to prevent the coupling of two branched lights. Moreover, the direction of the electric field approaches the direction perpendicular to the substrate surface due to the groove 3 and the intermediate electrode 4 (see FIG. 2), for example, Z cut
When TM light is applied using a LiNbO 3 substrate, the electric field is used more effectively.
本発明の一実施例としてのマッハツェンダ型光導波路
変調器の斜視図が第１図に、第１図の変調器の線II−II
についての断面図が第２図に示される。A perspective view of a Mach-Zehnder type optical waveguide modulator as an embodiment of the present invention is shown in FIG. 1, and a line II-II of the modulator shown in FIG.
A cross-sectional view of is shown in FIG.
光導波路基板１はＺカットLiNbO3基板にTiを熱拡散し
て光導波路２を作製する。光導波路２は中央付近で２本
に分岐される。２本の光導波路２の間の基板１に溝３を
エッチング等の方法を用いて作製する。金属電極（Auま
たはAl等を用いる）による光の吸収を防ぐために、前述
のように加工された基板１にバッファ層６を設ける。The optical waveguide substrate 1 is prepared by thermally diffusing Ti into a Z-cut LiNbO 3 substrate to form the optical waveguide 2. The optical waveguide 2 is branched into two near the center. The groove 3 is formed in the substrate 1 between the two optical waveguides 2 by using a method such as etching. The buffer layer 6 is provided on the substrate 1 processed as described above in order to prevent light absorption by the metal electrode (using Au or Al or the like).
次いで、電極を光導波路上と溝３の底部に蒸着等によ
って作製する。溝３の底部に設けられた電極は中間電極
４となり、光導波路２の上に設けられた電極５は駆動電
圧を印加するためのものとなる。電極５の一方は接地さ
れ、他方は電圧Ｖが印加される。中間電極４には電圧は
印加されない。光は太い矢印の方向に伝送される。Ｚカ
ット基板はＣ軸が第１図に矢印で示した方向（厚さ方
向）となるよう加工されている。Next, electrodes are formed on the optical waveguide and the bottom of the groove 3 by vapor deposition or the like. The electrode provided on the bottom of the groove 3 serves as the intermediate electrode 4, and the electrode 5 provided on the optical waveguide 2 serves to apply a driving voltage. One of the electrodes 5 is grounded and the other is applied with a voltage V. No voltage is applied to the intermediate electrode 4. Light is transmitted in the direction of the thick arrow. The Z-cut substrate is processed so that the C axis is in the direction (thickness direction) indicated by the arrow in FIG.
第２図を参照すると、中間電極４を設けたことによ
り、正側電極５と中間電極４で１つの静電容量を構成
し、負側電極５と中間電極４で他の１つの静電容量を構
成し、電極５の間における金属以外の部分の距離が小さ
くなる。このことは光導波路２の２本に分岐された部分
において電界強度が増加することになる。従って低い駆
動電圧を電極５に印加しても従来型と同等な光変調を得
ることが可能となる。Referring to FIG. 2, by providing the intermediate electrode 4, the positive electrode 5 and the intermediate electrode 4 constitute one capacitance, and the negative electrode 5 and the intermediate electrode 4 constitute another capacitance. And a distance between the electrodes 5 other than the metal is reduced. This means that the electric field strength increases in the part of the optical waveguide 2 which is branched into two. Therefore, even if a low driving voltage is applied to the electrode 5, it is possible to obtain the light modulation equivalent to that of the conventional type.
第３図の従来型の光変調器では矢印を付した電気力線
の基板１の中を通過する距離が大きいから、同じ印加電
圧で得られる電界が弱い。In the conventional optical modulator shown in FIG. 3, since the electric line of force indicated by the arrow passes through the substrate 1 for a long distance, the electric field obtained at the same applied voltage is weak.
第２図と第３図の矢印で示される電気力線の方向を比
較すると、中間電極４のため第２図の電気力線が基板面
に対し垂直方向、すなわちＣ軸方向成分が増加する傾向
にあり、電気光学効果の大きくなるTM光を用いた場合、
電界が光導波路に対して一層有効に作用するようにな
る。また分岐された２つの光導波路間には溝３が設けら
れたので、分岐した２つの光の結合のおそれも少ない。Comparing the directions of the electric lines of force indicated by the arrows in FIGS. 2 and 3, the electric lines of force in FIG. 2 tend to increase in the direction perpendicular to the substrate surface, that is, the C-axis direction component due to the intermediate electrode 4. When using TM light, which has a large electro-optic effect,
The electric field acts more effectively on the optical waveguide. Further, since the groove 3 is provided between the two branched optical waveguides, there is little risk of coupling the two branched lights.
本発明によれば、変調器の性能、すなわち消光比は劣
化させずに、変調のため電極に印加する駆動電圧を低減
することができる。According to the present invention, the driving voltage applied to the electrodes for modulation can be reduced without degrading the performance of the modulator, that is, the extinction ratio.
第１図は本発明の一実施例としてのマッハツェンダ型光
導波路変調器の斜視図、 第２図は第１図の変調器の線II−IIについての断面図、
および 第３図は従来例のマッハツェンダ型光導波路変調器の第
２図と同様な断面図である。 図において、 １……光導波路基板、２……光導波路、３……溝、４…
…中間電極、５……電極、６……バッファ層。1 is a perspective view of a Mach-Zehnder type optical waveguide modulator as an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of the modulator of FIG. 1,
And FIG. 3 is a sectional view similar to FIG. 2 of a conventional Mach-Zehnder type optical waveguide modulator. In the figure, 1 ... Optical waveguide substrate, 2 ... Optical waveguide, 3 ... Groove, 4 ...
... intermediate electrode, 5 ... electrode, 6 ... buffer layer.
Claims (1)
導波路と、該光導波路上にそれぞれ設けられ、該光導波
路に電界を印加するための電極と、該２本の導波路およ
び電極間に設けられた溝と、該溝内に設けられ外部と電
気的に絶縁された金属膜とを有することを特徴とする光
導波路デバイス。1. An optical-optical crystal substrate having two optical waveguides, electrodes provided on the optical waveguides for applying an electric field to the optical waveguides, the two optical waveguides, and An optical waveguide device comprising a groove provided between electrodes and a metal film provided in the groove and electrically insulated from the outside.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61286840A JPH0827447B2 (en) | 1986-12-03 | 1986-12-03 | Optical waveguide device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61286840A JPH0827447B2 (en) | 1986-12-03 | 1986-12-03 | Optical waveguide device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63141021A JPS63141021A (en) | 1988-06-13 |
| JPH0827447B2 true JPH0827447B2 (en) | 1996-03-21 |
Family
ID=17709713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61286840A Expired - Lifetime JPH0827447B2 (en) | 1986-12-03 | 1986-12-03 | Optical waveguide device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0827447B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6448021A (en) * | 1987-08-19 | 1989-02-22 | Nippon Telegraph & Telephone | Optical device |
| JP3603977B2 (en) * | 1996-09-06 | 2004-12-22 | 日本碍子株式会社 | Traveling waveform optical modulator and method of manufacturing the same |
| US5886807A (en) * | 1997-01-24 | 1999-03-23 | California Institute Of Technology | Traveling-wave reflective electro-optic modulator |
| US6556742B2 (en) * | 1998-11-04 | 2003-04-29 | Fujitsu Limited | Optical wavelength division multiplexed system using wavelength splitters |
| WO2005045512A1 (en) * | 2003-11-10 | 2005-05-19 | Matsushita Electric Industrial Co., Ltd. | Optical modulator and communication system |
| JP2008052103A (en) * | 2006-08-25 | 2008-03-06 | Anritsu Corp | Optical modulator |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5227649A (en) * | 1975-08-27 | 1977-03-02 | Nippon Telegr & Teleph Corp <Ntt> | Waveguide type optical modulator |
| FR2399736A1 (en) * | 1977-08-05 | 1979-03-02 | Thomson Csf | METHOD OF MANUFACTURING AN ELECTRO-OPTICAL STRUCTURE INCLUDING AN INTEGRATED ELECTRODE AND OPTOELECTRONIC COMPONENT USING THE SAID STRUCTURE |
-
1986
- 1986-12-03 JP JP61286840A patent/JPH0827447B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63141021A (en) | 1988-06-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |