JPS63210903A - Production of optical waveguide element - Google Patents
Production of optical waveguide elementInfo
- Publication number
- JPS63210903A JPS63210903A JP4550887A JP4550887A JPS63210903A JP S63210903 A JPS63210903 A JP S63210903A JP 4550887 A JP4550887 A JP 4550887A JP 4550887 A JP4550887 A JP 4550887A JP S63210903 A JPS63210903 A JP S63210903A
- Authority
- JP
- Japan
- Prior art keywords
- optical waveguide
- deposition
- substrate
- refractive index
- plzt
- 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 abstract description 44
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- 239000010409 thin film Substances 0.000 claims abstract description 37
- 239000000758 substrate Substances 0.000 claims abstract description 28
- 230000008021 deposition Effects 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 10
- 150000001875 compounds Chemical class 0.000 claims abstract description 4
- 238000000151 deposition Methods 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 13
- 238000004544 sputter deposition Methods 0.000 claims description 4
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 claims description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 239000002131 composite material Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 239000010408 film Substances 0.000 abstract description 19
- 230000008878 coupling Effects 0.000 abstract description 5
- 238000010168 coupling process Methods 0.000 abstract description 5
- 238000005859 coupling reaction Methods 0.000 abstract description 5
- 230000005284 excitation Effects 0.000 abstract description 5
- 230000007423 decrease Effects 0.000 abstract description 4
- 238000009826 distribution Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 229910052594 sapphire Inorganic materials 0.000 description 3
- 239000010980 sapphire Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- HTUMBQDCCIXGCV-UHFFFAOYSA-N lead oxide Chemical compound [O-2].[Pb+2] HTUMBQDCCIXGCV-UHFFFAOYSA-N 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229910000464 lead oxide Inorganic materials 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000000427 thin-film deposition Methods 0.000 description 1
Landscapes
- Optical Integrated Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、光通信、光応用計測、光制御の分野にかかわ
る光導波路素子の製造方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing an optical waveguide element related to the fields of optical communication, optical applied measurement, and optical control.
従来の技術
光通信等の要のデバイスとなることが期待される光導波
路素子の作製は、例えば基板に何層かの薄膜を堆積させ
て行われている。特に電気光学特性に優れた材料として
、少なくとも鉛、ランタニウム、ジルコニウム、チタニ
ウムの組み合わせから成る複合酸化物であるＰＬＺＴ化
合物が光導波路素子用材料として注目されてきた。上記
材料の薄膜光導波路素子作製は例えば基板にＰＬＺＴ薄
膜を高周波スパッタリングにより堆積し、場合によって
はその上に電極による散乱を防ぐためのパフ７７層をや
はシスバッタリングにより堆積して行われる。ＰＬＺＴ
薄膜堆積の際には基板温度をａｏｏ’ｃ程度に上げて、
結晶質の膜を形成する。2. Description of the Related Art Optical waveguide devices, which are expected to become key devices in optical communications, are manufactured by, for example, depositing several layers of thin films on a substrate. In particular, as a material with excellent electro-optic properties, a PLZT compound, which is a composite oxide consisting of a combination of at least lead, lanthanium, zirconium, and titanium, has attracted attention as a material for optical waveguide elements. A thin film optical waveguide device made of the above-mentioned material is produced, for example, by depositing a PLZT thin film on a substrate by high frequency sputtering, and in some cases, depositing a puff 77 layer thereon to prevent scattering by electrodes by cis sputtering. PLZT
When depositing a thin film, raise the substrate temperature to about aoo'c.
Forms a crystalline film.
第２図にこのようにして作製した光導波路素子の断面図
およびその屈折率分布図を示す。サファイア基板１１（
屈折率１．７）上にＰＬＺＴ薄膜２１（屈折率２．６）
およびその上にＴａ２０６薄膜２２（屈折率２．１）が
形成されている。導波光は基板１１、ＰＬＺＴ系薄膜２
１、Ｔ ａ ２０６薄膜２２の屈折率差により、ＰＬＺ
Ｔ系薄膜２１内に閉じ込められて伝搬する。従来の例で
はこれらの中で最も少ない屈折率差（ＰＬＺＴ薄膜（２
、６） Ｔａ ２０５薄膜（２，１）でも０．５と大
きく、ＰＬＺＴ膜厚の厚み方向ＴＥレシンルモード条件
は、波長０．８μｍで、約３００ ｎｍ弱と薄いもので
ある。（東野他。FIG. 2 shows a cross-sectional view of the optical waveguide device manufactured in this manner and its refractive index distribution diagram. Sapphire substrate 11 (
PLZT thin film 21 (refractive index 2.6) on top of (refractive index 1.7)
A Ta206 thin film 22 (refractive index 2.1) is formed thereon. The guided light is a substrate 11, a PLZT thin film 2
1. Due to the refractive index difference of the T a 206 thin film 22, PLZ
It is confined within the T-based thin film 21 and propagates. In the conventional example, the refractive index difference (PLZT thin film (2
, 6) The Ta 205 thin film (2,1) is also as large as 0.5, and the TE resin mode condition in the thickness direction of the PLZT film is as thin as approximately 300 nm at a wavelength of 0.8 μm. (Higashino et al.
ｒＰＬＺＴ薄膜光導波路を用いた全反射型光スイノチコ
電子通信学会技術研究報告、０ＱＥ８４−１６゜発明が
解決しようとする問題点
光スイツチ装置の動作安定性を確保するためには、膜厚
方向にシングルモード、多くとも２モードである必要が
ある。従来では、膜厚方向の光閉じ込めのための屈折率
差が材料上の制約から０．５と大きく、従って、導波層
の膜厚が０．３μｍ程度と制限され、厚くできない。光
スイツチ装置に光を導波させる際に、導波層膜厚が薄い
と、実現容易な端面励振が困難となり、プリズム結合等
の他の方法を取らねばならず光の入出力結合が複雑かつ
、工数のかかるものになるという問題点を有していた。Total reflection optical switch using rPLZT thin film optical waveguide Technical research report, Institute of Electronics and Communication Engineers, 0QE84-16゜Problems to be solved by the invention In order to ensure the operational stability of the optical switch device, it is necessary to mode, at most two modes. Conventionally, the refractive index difference in the film thickness direction for optical confinement is as large as 0.5 due to material constraints, and therefore the film thickness of the waveguide layer is limited to about 0.3 μm, which cannot be increased. When guiding light to an optical switch device, if the waveguide layer is thin, it becomes difficult to achieve end-face excitation, which is easy to achieve, and other methods such as prism coupling must be used, making the input/output coupling of light complicated and complicated. , which has the problem of requiring a lot of man-hours.
また、ＰＬＺＴ系薄膜２１と基板１１あるいはバッファ
層２２との屈折率差がそれぞれ０．９あるいは０．５と
大きく、また、薄いＰＬＺＴ系薄膜２１中に光を閉じ込
めるために、ＰＬＺＴ系薄膜の界面の電界強度が強く、
界面での散乱が大きく、損−失を小さくできないという
問題点を有していた。Furthermore, the refractive index difference between the PLZT thin film 21 and the substrate 11 or the buffer layer 22 is as large as 0.9 or 0.5, respectively. The electric field strength is strong,
There was a problem in that the scattering at the interface was large and the loss could not be reduced.
問題点を解決するための手段
上記問題点を解決するため本発明の光導波路素子の製造
方法は、ＰＬＺＴ系材料のような鉛を含む酸化物誘電体
薄膜の光導波層を堆積させる際に、堆積初期と堆積終期
の基板温度を堆積中間時の基板温度より高めて行うとい
うものである。Means for Solving the Problems In order to solve the above problems, the method for manufacturing an optical waveguide device of the present invention includes the following steps when depositing an optical waveguide layer of a lead-containing oxide dielectric thin film such as a PLZT-based material. The substrate temperature at the beginning and end of the deposition is higher than the substrate temperature at the middle of the deposition.
作 用
導波光は屈折率の高い層を導波するが、上下層との屈折
率差が小さいため膜方向にシングルモード条件を満足す
る導波層膜厚を数μｍ〜１０μｍ程度と厚くすることが
可能となり、光の端面励振が行いやすく、光の入出力結
合が簡単かつ量産性に富むものとなる。更に、導波層の
膜厚が厚くなることと、導波層界面での屈折率差が小さ
くなることにより、界面での散乱が少なくなり、導波損
失が小さくなる。Function Guided light is guided through a layer with a high refractive index, but since the difference in refractive index between the upper and lower layers is small, the thickness of the waveguide layer in the film direction must be increased to several μm to 10 μm to satisfy the single mode condition. This makes it possible to easily perform end-face excitation of light, and facilitates optical input/output coupling and facilitates mass production. Furthermore, as the thickness of the waveguide layer increases and the difference in refractive index at the interface between the waveguide layers decreases, scattering at the interface decreases and waveguide loss decreases.
実施例
鉛を含む酸化物薄膜を基板温度を高めて堆積させる場合
、酸化鉛あるいは鉛の蒸気圧が異常に高いため薄膜表面
からの再蒸発が起こり、基板温度が高い程鉛元素が薄膜
から抜けて膜の屈折率が少し小さくなるということを本
発明者等は長年の実験から経験してきた。そこで前記方
法で基板温度のコントロールを行い薄膜を堆積させると
、薄膜中間層の屈折率が上下層の屈折率よりも少し高く
なり、良好な光導波路を容易に実現できたという本発明
者等の発見に基づき本発明は成された。Example: When depositing a lead-containing oxide thin film at a higher substrate temperature, lead oxide or lead vapor pressure is abnormally high, causing re-evaporation from the thin film surface, and the higher the substrate temperature, the more lead element escapes from the thin film. The present inventors have experienced through many years of experiments that the refractive index of the film becomes slightly smaller. Therefore, by controlling the substrate temperature and depositing a thin film using the above method, the refractive index of the thin film intermediate layer became slightly higher than that of the upper and lower layers, and the inventors of the present invention were able to easily realize a good optical waveguide. The present invention was made based on this discovery.
本発明を電気光学効果の大きいＰＬＺＴ系材料に応用す
ると、種々の良好な光導波路素子が作製され特に有益と
なる。−また単に堆積膜の屈折率を変える方法としては
膜組成を変化させる幾つかの方法があるが、装置が複雑
となシかつ作製が煩雑である。本発明は通常の高周波ス
パッタリング装置を用いて薄膜を堆積させる際に、基板
温度をコントロールするだけで容易に所望の屈折率変化
をつけることができ、量産性に富んだものである。When the present invention is applied to PLZT-based materials that have a large electro-optic effect, various good optical waveguide elements can be produced, which is particularly beneficial. -Also, as a method of simply changing the refractive index of a deposited film, there are several methods of changing the film composition, but these methods require complicated equipment and are complicated to manufacture. The present invention allows a desired refractive index change to be easily made by simply controlling the substrate temperature when depositing a thin film using a conventional high-frequency sputtering device, and is highly suitable for mass production.
ＰＬＺＴ系化合物のうち、ジルコニウムを含まＬａ
Ｔｉ
ないＰｂＯ，７５０，２８０，９３ｏ３の組成の材料を
ターゲットとして高周波マグネトロンスパッタリングに
より得られる薄膜は、特に透光性に優れかつ電気光学特
性を十分持つ材料であシ、光導波路素子に適している。Among PLZT compounds, La containing zirconium
A thin film obtained by high-frequency magnetron sputtering using a material with a composition of Ti-free PbO, 750, 280, 93o3 as a target is a material that has particularly excellent translucency and sufficient electro-optical properties, and is suitable for optical waveguide devices. .
サファイアＣ面を基板として用いると薄膜をエピタキシ
ャル成長させることが可能である。この際基板温度６８
０°Ｃで堆積させた膜の屈折率゛は２．６００であシ、
基板温度６００°Ｃで堆積させた膜の屈折率は２，５９
８であるということがエリプンメータ測定により分かっ
た。そこでＰＬＺＴ薄膜堆積初期と終期の基板温度を６
００″Ｃ堆積中間時の基板温度を６８０°Ｃにコントロ
ールして作製を行った。Using sapphire C-plane as a substrate allows epitaxial growth of thin films. At this time, the substrate temperature is 68
The refractive index of the film deposited at 0°C is 2.600,
The refractive index of the film deposited at a substrate temperature of 600°C is 2,59.
It was found by measurement with an ellipse meter that it was 8. Therefore, the substrate temperature at the initial and final stages of PLZT thin film deposition was set to 6
The fabrication was carried out by controlling the substrate temperature at 680°C during the 00″C deposition.
第１（２）はこのようにして作製された光導波路素子の
断面図およびその屈折率分布図である。光導波層となる
ＰＬＺＴ薄膜（屈折率２，６００ ） １２がこれより
少し屈折率の小さいＰＬＺＴ薄膜（屈折率２，５９８）
１３ａ 、１３ｂで挾まれている。この際ＰＬＺＴ薄膜
層１２を膜厚方向シングルモード光が導波する条件は膜
厚が５μｍとなる。従って従来のシングルモード光導波
膜厚０．３μｍよりもかなり広い膜厚の光導波路素子が
実現できた。Part 1 (2) is a cross-sectional view of the optical waveguide device manufactured in this manner and its refractive index distribution diagram. PLZT thin film (refractive index 2,600) that becomes the optical waveguide layer 12 is a PLZT thin film with a slightly smaller refractive index (refractive index 2,598)
It is sandwiched between 13a and 13b. At this time, the condition for single mode light in the film thickness direction to be guided through the PLZT thin film layer 12 is that the film thickness is 5 μm. Therefore, an optical waveguide element with a film thickness considerably wider than the conventional single mode optical waveguide film thickness of 0.3 μm was realized.
この光導波路素子の端部をダイヤモンドカッターにて切
断した後、端面研磨を行い、波長０．８３μｍで、５μ
ｍのビーム径の光を用い端面励振を行ったところ、端面
でのフレネル反射損失を除いた結合損失は、約２．５
ｄＢと小さく、従来の約１０ｄＢに較べ極めて小さな値
が得られた。また伝搬損失も従来４ｄＢ／ｃＷＬであっ
たものが、約０．５ ｄＢ／ｃｔｎ低減した。After cutting the end of this optical waveguide element with a diamond cutter, the end face was polished to 5μm at a wavelength of 0.83μm.
When end face excitation was performed using light with a beam diameter of m, the coupling loss excluding Fresnel reflection loss at the end face was approximately 2.5
dB, which is much smaller than the conventional value of about 10 dB. Furthermore, the propagation loss, which was conventionally 4 dB/cWL, has been reduced by about 0.5 dB/ctn.
ＰＬＺＴ薄膜光導波路作製の際の温度変化幅ΔＴとして
は、５°Ｃ未満ではあまシ効来がなくまた２００°Ｃ以
上も温度を高めるとペロプスカイト構造のエピタキシャ
ル膜を得るのが困難となシ、５°Ｃ≦ΔＴ≦２００℃が
最適であることを本発明者等は合わせて確認した。また
本発明の製造方法では、階段状の屈折分布だけでなく徐
々に屈折率変化させたグレイデッドインデックス型の光
導波路素子も、基板温度プログラムを行うだけで容易に
作製することができる。Regarding the temperature change width ΔT when producing a PLZT thin film optical waveguide, it is difficult to obtain an epitaxial film with a perovskite structure when the temperature is less than 5°C, and it is not effective. The present inventors have also confirmed that 5°C≦ΔT≦200°C is optimal. Further, according to the manufacturing method of the present invention, not only a stepped refractive distribution but also a graded index type optical waveguide element in which the refractive index is gradually changed can be easily manufactured by simply performing a substrate temperature program.
発明の効果
以上のように本発明の光導波路素子の製造方法は、従来
光導波膜厚が薄くて端面励振および伝搬損失に問題があ
った薄膜光導波路素子の新しい製造法、すなわち厚い導
波膜厚でも動作可能な光導波路素子を容易に製造する方
法を提供するものであシ、本発明の工業的価値は高い。Effects of the Invention As described above, the method for manufacturing an optical waveguide device of the present invention is a new method for manufacturing a thin-film optical waveguide device, which conventionally had a thin optical waveguide film and had problems with end-face excitation and propagation loss. The industrial value of the present invention is high because it provides a method for easily manufacturing an optical waveguide element that can operate even if it is thick.
第１図ａ、ｂは本発明の一実施例において作製された光
導波路素子の断面図および屈折率分布図、第２図ａ、ｂ
は従来の光導波路素子の断面図および屈折率分布図であ
る。
１１・・・・・・サファイア基板、１２・・・・・・Ｐ
ＬＺＴ薄膜（屈折率２．６０（１）層、１３ａ 、 １
ａｂ・−・−ＰＬＺＴ薄Ｍ（屈折率２，５９８）層、２
１ ・・−・・−ＰＬＺＴ薄膜、２２・・・・・・Ｔａ
２０５バッファ層。
代理人の氏名 弁理士 中 尾 敏 男 ほか１名１１
−−−サファイ〜→阪ｔ（
／２−−−ＰＬｚＴｉ＊（ｍｌ’ｒ＊２６ｍ）第１図
１３θ１３ｂ−ＰＬＸＴ簿）ＩＩ（ｉｌＦｒｆｌ
Ｐ２．６？、？）（ｂ） 屈ｖｒ牟
２ｌ−−−ＰＬＺＴ傳ｐ良Figures 1a and b are a cross-sectional view and a refractive index distribution diagram of an optical waveguide device manufactured in an embodiment of the present invention, and Figures 2a and b are
are a cross-sectional view and a refractive index distribution diagram of a conventional optical waveguide element. 11...Sapphire substrate, 12...P
LZT thin film (refractive index 2.60 (1) layer, 13a, 1
ab...-PLZT thin M (refractive index 2,598) layer, 2
1...-PLZT thin film, 22...Ta
205 buffer layer. Name of agent: Patent attorney Toshio Nakao and 1 other person11
---Sapphi ~ → Sakat (/2---PLzTi*(ml'r*26m) Fig. 1
13θ13b-PLXT Book) II (ilFrfl
P2.6? ,? )(b) くVR剟2l---PLZT傳悳平
Claims (4)
なる光導波層を堆積させる際に、堆積初期と堆積終期の
基板温度を堆積中間時の基板温度より高めて行うことを
特徴とする光導波路素子の製造方法。(1) When depositing an optical waveguide layer made of an oxide dielectric thin film containing at least lead on a substrate, the temperature of the substrate at the beginning and end of the deposition is higher than the substrate temperature during the middle of the deposition. A method for manufacturing an optical waveguide device.
ム、チタニウムの組み合わせで構成される複合酸化物（
ＰＬＺＴ）であることを特徴とする特許請求の範囲第１
項記載の光導波路素子の製造方法。(2) A composite oxide whose thin film is composed of a combination of at least lead, lanthanium, zirconium, and titanium (
PLZT) Claim 1
A method for manufacturing an optical waveguide device according to section 1.
度の幅ΔＴが５℃≦ΔＴ≦２００℃の範囲にあることを
特徴とする特許請求の範囲第１項記載の光導波路素子の
製造方法。(3) The method for manufacturing an optical waveguide element according to claim 1, wherein the thin film is made of a PLZT material, and the width ΔT of the substrate temperature to be changed is in the range of 5°C≦ΔT≦200°C.
波スパッタリングにより行うことを特徴とする特許請求
の範囲第１項記載の光導波路素子の製造方法。(4) The method for manufacturing an optical waveguide device according to claim 1, wherein the thin film is deposited by high-frequency sputtering using an oxide compound target.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4550887A JPS63210903A (en) | 1987-02-27 | 1987-02-27 | Production of optical waveguide element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4550887A JPS63210903A (en) | 1987-02-27 | 1987-02-27 | Production of optical waveguide element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63210903A true JPS63210903A (en) | 1988-09-01 |
Family
ID=12721347
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4550887A Pending JPS63210903A (en) | 1987-02-27 | 1987-02-27 | Production of optical waveguide element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63210903A (en) |
-
1987
- 1987-02-27 JP JP4550887A patent/JPS63210903A/en active Pending
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