JPH0422485B2 - - Google Patents
Info
- Publication number
- JPH0422485B2 JPH0422485B2 JP1630786A JP1630786A JPH0422485B2 JP H0422485 B2 JPH0422485 B2 JP H0422485B2 JP 1630786 A JP1630786 A JP 1630786A JP 1630786 A JP1630786 A JP 1630786A JP H0422485 B2 JPH0422485 B2 JP H0422485B2
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- waveguide
- electrodes
- optical device
- electric field
- 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
- 239000000758 substrate Substances 0.000 claims description 36
- 230000003287 optical effect Effects 0.000 claims description 27
- 230000000694 effects Effects 0.000 claims description 18
- 230000005684 electric field Effects 0.000 description 17
- 239000010936 titanium Substances 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 6
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 5
- 230000010287 polarization Effects 0.000 description 4
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000004020 conductor Substances 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000013078 crystal Substances 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000006903 response to temperature Effects 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
Landscapes
- Optical Integrated Circuits (AREA)
Description
【発明の詳細な説明】
〔概要〕
本発明は、焦電効果を持つ強誘電体基板の表面
に形成された導波路に電界を印加することによつ
て屈折率を変化させる導波路光デバイスにおい
て、電極間に導電性部材を形成し且つ該基板裏面
に接地導体を形成することにより、焦電効果を持
つ該基板の自発分極が温度によつて変化した場合
に、電極に誘起される電荷を前記導電性部材を介
して基板表面に一様に分布させ、且つ接地導体に
よつて基板裏面の電荷を除去するようにすること
によつて、温度変化によつて、電界が変化しない
ようにすることにより特性変動を防止した導波路
光デバイスを提供する。[Detailed Description of the Invention] [Summary] The present invention relates to a waveguide optical device in which the refractive index is changed by applying an electric field to a waveguide formed on the surface of a ferroelectric substrate having a pyroelectric effect. By forming a conductive member between the electrodes and a ground conductor on the back surface of the substrate, it is possible to reduce the charge induced in the electrodes when the spontaneous polarization of the substrate, which has a pyroelectric effect, changes due to temperature. The electric field is prevented from changing due to temperature changes by uniformly distributing the electric charge on the substrate surface through the conductive member and removing the electric charge on the back surface of the substrate by the ground conductor. This provides a waveguide optical device that prevents characteristic fluctuations.
本発明は焦電効果を持つ強誘電体に形成した導
波路に係り、特に光スイツチング素子等に用いら
れる導波路光デバイスに関する。
The present invention relates to a waveguide formed in a ferroelectric material having a pyroelectric effect, and more particularly to a waveguide optical device used in an optical switching element or the like.
導波路型光デバイスは、低駆動電圧、高速動作
が可能で且つ小型集積化も有望である。しかしリ
チウムナイオベイト（LiNbO3）のような焦電効
果すなわち自発分極を有する結晶を基板に用い
て、その基板にチタン（Ti）等の拡散層を形成
して導波路を構成したものにおいては、温度変化
によつて、焦電効果に基づく電荷が表面に発生
し、その電荷分布が一様でないため、導波路型光
デバイスの例えばスイツチング特性等が変動して
しまう。第５図ａには従来の導波路の断面図を示
すもので、Ｚ板LiNbO3からなる基板１にTi拡散
層２を形成して導波路とし、その上面にSiO2か
らなるバツフア層３を形成し、その上面に例えば
アルミニウムからなる複数の電極４を形成する。
この光導波路において昇温すると、第５図ｂに示
すように、焦電効果によりＺ板LiNbO3からなる
基板１は分極の状態を変化させるので、この基板
１の表面側に＋電荷が、裏面側に−電荷が発生す
る。そして基板１の表面側に生じた＋電荷に対応
した、−電荷が電極４の底面に外部から供給され
ることになる。従つて、電極４のない電極間から
電極４へ向けて基板１内を図示の如き電界５が発
生し、また基板１の表裏面に生じた＋−電荷によ
つて表裏面間に図示せぬ電界も発生する。導波路
光デバイスは、電極間に電界を印加することによ
り、Ti拡散層２からなる導波路の屈折率を変化
させて、例えばスイツチング動作等を行せるもの
であるから、昇温によつて、前述の如く電界が発
生すると、導波路光デバイスの動作点例えばスイ
ツチング特性等に大きな影響を与えてしまう。
Waveguide type optical devices are capable of low driving voltage, high speed operation, and are promising for compact integration. However, in a waveguide constructed by using a crystal such as lithium niobate (LiNbO 3 ) that has a pyroelectric effect, that is, spontaneous polarization, as a substrate and forming a diffusion layer of titanium (Ti) on the substrate, Charges based on the pyroelectric effect are generated on the surface due to temperature changes, and the charge distribution is not uniform, resulting in fluctuations in, for example, switching characteristics of the waveguide type optical device. FIG. 5a shows a cross-sectional view of a conventional waveguide, in which a Ti diffusion layer 2 is formed on a substrate 1 made of Z plate LiNbO 3 to form a waveguide, and a buffer layer 3 made of SiO 2 is formed on the top surface. A plurality of electrodes 4 made of aluminum, for example, are formed on the upper surface thereof.
When the temperature rises in this optical waveguide, the polarization state of the substrate 1 made of Z-plate LiNbO 3 changes due to the pyroelectric effect, as shown in FIG. A negative charge is generated on the side. Then, negative charges corresponding to the positive charges generated on the front surface side of the substrate 1 are supplied to the bottom surface of the electrode 4 from the outside. Therefore, an electric field 5 as shown in the figure is generated in the substrate 1 from between the electrodes without the electrode 4 toward the electrode 4, and an electric field 5 (not shown in the figure) is generated between the front and back surfaces of the substrate 1 due to the positive and negative charges generated on the front and back surfaces of the substrate 1. An electric field is also generated. The waveguide optical device is capable of performing, for example, a switching operation by changing the refractive index of the waveguide made of the Ti diffusion layer 2 by applying an electric field between the electrodes. When an electric field is generated as described above, it has a large effect on the operating point of the waveguide optical device, such as the switching characteristics.
従つて、従来はこの特性変動を防止するため
に、導波路の構成及び電極の構成等を温度変化に
鈍感な構成としている場合が多い。 Therefore, conventionally, in order to prevent this characteristic variation, the structure of the waveguide, the structure of the electrodes, etc. are often made insensitive to temperature changes.
しかしながら、上記従来の構成では、素子構造
が限定される上に、昇温効果による導波路光デバ
イスの特性変動を充分には防止できないという問
題があつた。従つて本発明は、簡単な構成によ
り、焦電効果により発生した電荷が導波路光デバ
イスの特性に影響を与えることを充分に防止でき
るようにした導波路光デバイスを提供することを
目的とする。
However, the conventional configuration described above has the problem that not only the element structure is limited, but also characteristic fluctuations of the waveguide optical device due to temperature increase effects cannot be sufficiently prevented. Therefore, an object of the present invention is to provide a waveguide optical device that can sufficiently prevent charges generated by the pyroelectric effect from affecting the characteristics of the waveguide optical device with a simple configuration. .
本発明によれば、焦電効果を持つ強誘電体基板
の表面に形成された導波路と、前記基板表面上の
前記導波路近くに設けられた電界を制御すること
によつて該導波路の屈折率を変化させるための複
数の電極と、前記基板表面上の少なくとも前記電
極間に設けられた電荷が誘起される膜体と、前記
基板裏面上に形成された該基板の接地用導電膜体
とを有することを特徴とする導波路光デバイスを
提供するものである。
According to the present invention, a waveguide is formed on the surface of a ferroelectric substrate having a pyroelectric effect, and the waveguide is controlled by controlling an electric field provided near the waveguide on the surface of the substrate. a plurality of electrodes for changing the refractive index; a film body for inducing charges provided at least between the electrodes on the surface of the substrate; and a conductive film body for grounding the substrate formed on the back surface of the substrate. The present invention provides a waveguide optical device characterized by having the following.
電極間に導電性をわずかに与えた材料を形成す
ることにより、焦電効果により発生した電荷が、
基板表面の電極部および基板裏面に滞留しないよ
うにすることにより、昇温によつて導波路に印加
する電界が変化することを防止し、これによつて
導波路光デバイスの特性が変動することを防止し
たものである。
By forming a slightly conductive material between the electrodes, the charge generated by the pyroelectric effect can be
By preventing the electric field from accumulating on the electrodes on the front surface of the substrate and on the back surface of the substrate, the electric field applied to the waveguide is prevented from changing due to temperature rise, thereby preventing the characteristics of the waveguide optical device from changing. This prevents
以下図面を参照して本発明の実施例を説明す
る。
Embodiments of the present invention will be described below with reference to the drawings.
第２図は、導波路光デバイスの斜視図を示すも
ので、Ｚ板LiNbO3の結晶体よりなる基板１にTi
拡散層よりなる導波路を、例えば互いに交差する
ように形成し、その交差点を組み少なくとも２個
の電極４を配設し、この電極に印加される電界を
変化することにより、導波路の屈折率を変化させ
て光路のスイツチング動作等を行せるものであ
る。 FIG. 2 shows a perspective view of a waveguide optical device, in which a substrate 1 made of a Z-plate LiNbO 3 crystal is coated with Ti.
For example, waveguides made of diffusion layers are formed so as to cross each other, and at least two electrodes 4 are arranged at the intersections, and the refractive index of the waveguide is changed by changing the electric field applied to the electrodes. It is possible to perform optical path switching operations, etc. by changing the .
第１図ａ及びｂは本発明の導波路光デバイスの
１実施例の断面図を示すものであり、第５図ａ，
ｂと同一部分は同一番号を付して説明を省略す
る。基板１の表面にTi拡散層２により導波路を
形成し、その上面に厚さが2000ÅのSiO2膜をバ
ツフア層３として形成し、次に厚さが3000Åのア
ルミニウムからなる電極４を少なくとも２個形成
し、バツフア層３と電極４の上面に1000Å厚さの
SiやITOからなる導電性の膜体６をスパツタリン
グによりコーテイングする。 FIGS. 1a and 1b show cross-sectional views of one embodiment of the waveguide optical device of the present invention, and FIGS.
The same parts as b are given the same numbers and the explanation is omitted. A waveguide is formed on the surface of the substrate 1 by a Ti diffusion layer 2, a SiO 2 film with a thickness of 2000 Å is formed on the top surface as a buffer layer 3, and then at least two electrodes 4 made of aluminum with a thickness of 3000 Å are formed on the top surface of the waveguide. A layer of 1000 Å thick is formed on the top surface of buffer layer 3 and electrode 4.
A conductive film 6 made of Si or ITO is coated by sputtering.
また基板１の裏面全体には3000Å厚さ程度のア
ルミニウム等からなる金属をメタライズし、接地
用導電膜体８を形成する。膜体６を設けた結果ギ
ヤブ5μm、長さ10mmの電極間抵抗を従来の1013Ω
以上から107〜1010Ωと下げることができた。そ
の結果昇温しても第１図ｂに示すように、焦電効
果により基板１の表面側に生じた分極による＋電
荷に対応して、電極４及びSi膜体６に一様に−電
荷が誘起される。従つて電荷の分布が基板１の表
面において一様であるので、電極間から電極に向
かつての電界は発生することはない。このため昇
温しても、それによつて電極４から導波路に及ぼ
される電界は変化しないことになるので、昇温に
よる導波路光デバイスの特性の変動は防止でき
る。 Further, the entire back surface of the substrate 1 is metallized with a metal such as aluminum to a thickness of about 3000 Å to form a grounding conductive film 8. As a result of providing the membrane body 6, the resistance between the electrodes with a gear of 5 μm and a length of 10 mm was reduced from the conventional 10 13 Ω.
From the above, we were able to lower it to 10 7 - 10 10 Ω. As a result, even if the temperature rises, as shown in FIG. is induced. Therefore, since the charge distribution is uniform on the surface of the substrate 1, no electric field is generated from between the electrodes toward the electrodes. Therefore, even if the temperature rises, the electric field applied from the electrode 4 to the waveguide does not change, so that changes in the characteristics of the waveguide optical device due to temperature rise can be prevented.
しかも、導電膜体８を接地された金属システム
に接続して該導波路光デバイスを搭載実装するこ
とにより基板１の裏面が接地されるため、焦電効
果により基板１の裏面側に生じた分極による−電
荷が除去され滞留の防止が図られる。その結果、
基板１の表裏面間の電界の発生も防ぐことがで
き、温度変化による導波路光デバイスの特性の変
動をほぼ完全に無くすことができる。 Moreover, since the back surface of the substrate 1 is grounded by connecting the conductive film body 8 to a grounded metal system and mounting the waveguide optical device, polarization occurs on the back surface side of the substrate 1 due to the pyroelectric effect. - Charges are removed and retention is prevented. the result,
It is also possible to prevent the generation of an electric field between the front and back surfaces of the substrate 1, and it is possible to almost completely eliminate fluctuations in the characteristics of the waveguide optical device due to temperature changes.
なお、膜体６の抵抗は、低すぎると、導波路に
電極４から電界を印加したとき、膜体６を介して
電極４間に大電流が流れてしまいデバイスの破壊
を生じてしまう。従つてこのことを考慮して膜体
６の抵抗値を選択する。 Note that if the resistance of the film body 6 is too low, when an electric field is applied to the waveguide from the electrodes 4, a large current will flow between the electrodes 4 through the film body 6, resulting in destruction of the device. Therefore, the resistance value of the membrane body 6 is selected in consideration of this fact.
第３図には本発明の導波路光デバイスの他の実
施例を示す。SiやITOの膜体７を、バツフア層３
の上面に一様にコーテイングした後、その膜体７
の上面に複数の電極４を形成したものである。こ
の場合も第１図ａ，ｂに示した実施例と同様の効
果を生ずる。 FIG. 3 shows another embodiment of the waveguide optical device of the present invention. The film body 7 of Si or ITO is
After uniformly coating the upper surface of the film body 7
A plurality of electrodes 4 are formed on the upper surface. In this case as well, effects similar to those of the embodiment shown in FIGS. 1a and 1b are produced.
第４図は本発明による実施例と従来例との温度
変化による動作点の変動を対比して示したもの
で、特性Ａは従来の装置に係るもので基板１の表
裏面に膜体６（或は７）と８を形成しなかつた場
合には、温度変化に応じて動作点が大きく変動し
た。 FIG. 4 shows a comparison of operating point fluctuations due to temperature changes between the embodiment according to the present invention and the conventional example. Characteristic A is related to the conventional device, and the film body 6 ( Alternatively, when 7) and 8 were not formed, the operating point varied greatly in response to temperature changes.
また特性Ｂは基板１の表面側に膜体６（或は
７）のみ形成し、裏面側の膜体８を形成しなかつ
た場合で、これは特性Ａに比べ動作点変動が大き
く抑制されているが、まだ十分ではない。 Characteristic B is a case where only the film body 6 (or 7) is formed on the front side of the substrate 1, and the film body 8 is not formed on the back side, and compared to characteristic A, the operating point fluctuation is greatly suppressed. There are, but not enough.
特性Ｃが基板１の表裏面に膜体６（或は７）と
８を両方形成した場合の動作点変動特性であり、
特性Ｂに比べ更に変動が抑制され、温度変化によ
る特性変動がほぼ完全に無くなる。 Characteristic C is the operating point fluctuation characteristic when both the film bodies 6 (or 7) and 8 are formed on the front and back surfaces of the substrate 1,
Fluctuations are further suppressed compared to characteristic B, and characteristic fluctuations due to temperature changes are almost completely eliminated.
上記実施例では膜体６あるいは７としてSiや
ITOを用いたが、電荷を誘起する物質であれば、
SuO2或いはSiO2に金属をドーブしたもの等を用
いても同様の効果がある。さらに膜体６として静
電防止材を塗布してもよい。 In the above embodiment, the film body 6 or 7 is made of Si or
ITO was used, but if it is a substance that induces charge,
A similar effect can be obtained by using SuO 2 or SiO 2 doped with metal. Further, an antistatic material may be applied as the film body 6.
本発明によれば昇温して、焦電効果によつて強
誘電体基板に電荷が変動しても、これによつて基
板及び導波路の電界が変動することを防止できる
ので、昇温による特性の変動を抑制することので
きる導波路光デバイスを提供することができる。
According to the present invention, even if the electric charge changes in the ferroelectric substrate due to the pyroelectric effect due to temperature rise, it is possible to prevent the electric field of the substrate and the waveguide from changing due to the temperature rise. A waveguide optical device that can suppress variations in characteristics can be provided.
第１図ａ及びｂはそれぞれ本発明の一実施例に
係る導波路光デバイスの断面図、第２図は導波路
光デバイスの斜視図、第３図は本発明の導波路光
デバイスの他の実施例の断面図、第４図は本発明
の実施例と従来例との特性を対比して示す特性
図、第５図ａ及びｂは従来の導波路光デバイスの
断面図である。
１……Ｚ板LiNbO3基板、２……Ti拡散層、３
……バツフア層、４……電極、５……電界、６，
７……膜体、８……接地用導電膜体。
1a and 1b are respectively cross-sectional views of a waveguide optical device according to an embodiment of the present invention, FIG. 2 is a perspective view of the waveguide optical device, and FIG. 3 is a cross-sectional view of another waveguide optical device of the present invention. 4 is a characteristic diagram comparing the characteristics of the embodiment of the present invention and a conventional example, and FIGS. 5a and 5b are sectional views of a conventional waveguide optical device. 1...Z plate LiNbO 3 substrate, 2...Ti diffusion layer, 3
... Buffer layer, 4 ... Electrode, 5 ... Electric field, 6,
7... Membrane body, 8... Grounding conductive film body.
Claims (1)
れた導波路と、 前記基板表面上の前記導波路近くに設けられ
た、電界を制御することによつて該導波路の屈折
率を変化させるための複数の電極と、 前記基板表面上の少なくとも前記電極間に設け
られた、電荷が誘起される膜体と、 前記基板裏面上に形成された、該基板の接地用
導電膜体とを有することを特徴とした導波路光デ
バイス。[Scope of Claims] 1. A waveguide formed on the surface of a ferroelectric substrate having a pyroelectric effect, and a waveguide provided near the waveguide on the surface of the substrate. a plurality of electrodes for changing the refractive index of a wave path; a film body in which charge is induced, provided at least between the electrodes on the surface of the substrate; and a grounding member formed on the back surface of the substrate. 1. A waveguide optical device comprising: a conductive film body;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1630786A JPS62173428A (en) | 1986-01-28 | 1986-01-28 | Waveguide optical device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1630786A JPS62173428A (en) | 1986-01-28 | 1986-01-28 | Waveguide optical device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62173428A JPS62173428A (en) | 1987-07-30 |
| JPH0422485B2 true JPH0422485B2 (en) | 1992-04-17 |
Family
ID=11912877
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1630786A Granted JPS62173428A (en) | 1986-01-28 | 1986-01-28 | Waveguide optical device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62173428A (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0247607A (en) * | 1988-08-09 | 1990-02-16 | Fujitsu Ltd | Semiconductor device and its production |
| JP2550730B2 (en) * | 1989-12-29 | 1996-11-06 | 富士通株式会社 | Optical waveguide device and manufacturing method thereof |
| JP2867560B2 (en) * | 1990-03-02 | 1999-03-08 | 富士通株式会社 | Optical waveguide device |
| JP2671586B2 (en) * | 1990-09-05 | 1997-10-29 | 日本電気株式会社 | Light control device |
| US5185823A (en) * | 1990-12-13 | 1993-02-09 | Japan Aviation Electronics Industry Limited | Waveguide type optical device |
| JPH0734049B2 (en) * | 1990-12-13 | 1995-04-12 | 日本航空電子工業株式会社 | Waveguide optical device |
| JPH0593892A (en) * | 1991-10-01 | 1993-04-16 | Nec Corp | Two-layered type optical modulator |
| US5388170A (en) * | 1993-11-22 | 1995-02-07 | At&T Corp. | Electrooptic device structure and method for reducing thermal effects in optical waveguide modulators |
| JP2894961B2 (en) * | 1994-11-18 | 1999-05-24 | 日本電気株式会社 | Light control device |
| US5949944A (en) * | 1997-10-02 | 1999-09-07 | Lucent Technologies Inc. | Apparatus and method for dissipating charge from lithium niobate devices |
| US6583480B1 (en) | 1999-06-28 | 2003-06-24 | Sumitomo Osaka Cement Co., Ltd. | Electro-optical element having protective film on top and side surfaces of buffer layer |
| DE60037251T2 (en) * | 1999-07-02 | 2008-10-09 | Matsushita Electric Industrial Co., Ltd., Kadoma | Arrangement for producing solder bumps on semiconductor substrates with generation of electrical charge, method and arrangement for removing these charges, and electrical charge-generating semiconductor substrate |
| JPWO2002097521A1 (en) | 2001-05-25 | 2004-09-16 | アンリツ株式会社 | Optical modulation device having excellent electrical characteristics by effectively suppressing thermal drift and method of manufacturing the same |
| JP4589354B2 (en) | 2007-03-30 | 2010-12-01 | 住友大阪セメント株式会社 | Light modulation element |
| JP6288145B2 (en) | 2016-04-01 | 2018-03-07 | 住友大阪セメント株式会社 | Optical modulator module |
| JP6705354B2 (en) | 2016-09-30 | 2020-06-03 | 住友大阪セメント株式会社 | Optical modulator module |
-
1986
- 1986-01-28 JP JP1630786A patent/JPS62173428A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62173428A (en) | 1987-07-30 |
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| EXPY | Cancellation because of completion of term |