JP2590807B2 - Manufacturing method of optical waveguide - Google Patents
Manufacturing method of optical waveguideInfo
- Publication number
- JP2590807B2 JP2590807B2 JP60204715A JP20471585A JP2590807B2 JP 2590807 B2 JP2590807 B2 JP 2590807B2 JP 60204715 A JP60204715 A JP 60204715A JP 20471585 A JP20471585 A JP 20471585A JP 2590807 B2 JP2590807 B2 JP 2590807B2
- Authority
- JP
- Japan
- Prior art keywords
- ion exchange
- optical waveguide
- mask
- thickness
- manufacturing
- 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
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/13—Integrated optical circuits characterised by the manufacturing method
- G02B6/134—Integrated optical circuits characterised by the manufacturing method by substitution by dopant atoms
- G02B6/1345—Integrated optical circuits characterised by the manufacturing method by substitution by dopant atoms using ion exchange
Description
【発明の詳細な説明】 産業上の利用分野 本発明はコヒーレント光を利用する光情報処理分野、
あるいは光応用計測制御分野に使用する光導波路の製造
方法に関するものである。The present invention relates to the field of optical information processing using coherent light,
Alternatively, the present invention relates to a method for manufacturing an optical waveguide used in the field of optical measurement and control.
従来の技術 LiNbO3などの強誘電体基板をイオン交換溶液である安
息香酸などの酸中で熱処理を行うことにより作成される
イオン交換光導波路は基板に対する屈折率差が大きく各
種デバイスを構成する上で非常に重要である〔ジェー・
エル・ジャッケル，シー・イー・ライス及びジェー・ジ
ェー・ベセルカ“プロトンイクスチェンジフォーハイ−
インデックスウェイブガイドインLiNbO3"アプライドフ
ィジクスレター,41巻,7号607−608頁（1982）（J.L.Jac
kel,C.E.Rice and J.J.Veselka,“Proton exchange for
high−index waveguides in LiNbO3",Appl.Phys.Lett,
Vol.41,No.7,PP.607−608（1982））参照〕。このイオ
ン交換法により作成された三次元光導波路は横方向散乱
のため伝搬損失が大きく、このため逆リッジ形にして伝
搬損失を低減する必要がある。第２図に三次元光導波路
と逆リッジ形光導波路の厚みに対する伝搬損失の比較を
示す。20は三次元光導波路の特性、21は逆リッジ形光導
波路の特性である。逆リッジ形光導波路は横方向に対す
る閉じ込めが弱く伝搬損失も三次元光導波路に比べ極端
に少なくなる。2. Description of the Related Art An ion-exchange optical waveguide formed by heat-treating a ferroelectric substrate such as LiNbO 3 in an acid such as benzoic acid as an ion-exchange solution has a large refractive index difference with respect to the substrate and constitutes various devices. Is very important in [J.
El Jackel, CEE Rice and JJ Veselka “Proton Exchange For High
Index Wave Guide in LiNbO 3 "Applied Physics Letter, Vol. 41, No. 7, pp. 607-608 (1982) (JLJac
kel, CERice and JJ Veselka, “Proton exchange for
high-index waveguides in LiNbO 3 ", Appl.Phys.Lett,
Vol.41, No.7, PP.607-608 (1982)). The three-dimensional optical waveguide formed by this ion exchange method has a large propagation loss due to lateral scattering, and therefore, it is necessary to reduce the propagation loss by forming an inverted ridge. FIG. 2 shows a comparison of the propagation loss with respect to the thickness of the three-dimensional optical waveguide and the thickness of the inverted ridge optical waveguide. 20 is the characteristic of the three-dimensional optical waveguide, and 21 is the characteristic of the inverted ridge type optical waveguide. The inverted ridge type optical waveguide has weak confinement in the lateral direction, and the propagation loss is extremely reduced as compared with the three-dimensional optical waveguide.
第３図に従来の逆リッジ形光導波路の製造方法を示
す。同図ａで１は強誘電体基板であるLiNbO3基板、２′
はイオン交換の際保護マスクとなるAl膜、３はフォトプ
ロセスにより形成された窓、4aは第１のイオン交換によ
り形成された高屈折率層である。次に同図ｂのようにAl
膜２をエッチングで除去する。次に割れ防止のためイオ
ン交換処理温度とLiNbO3基板１の温度を同温度にするた
めのベーキングを行い、安息香酸中230℃で第２のイオ
ン交換を行う。このようにして同図ｃのように窓３直下
の高屈折率層4aの厚みd1がAl膜２直下の高屈折率層4bの
厚みd2より大きい逆リッジ形光導波路が形成される。FIG. 3 shows a method of manufacturing a conventional inverted ridge optical waveguide. In FIG. 2A, reference numeral 1 denotes a LiNbO 3 substrate which is a ferroelectric substrate, and 2 ′
Is an Al film serving as a protective mask during ion exchange, 3 is a window formed by a photo process, and 4a is a high refractive index layer formed by the first ion exchange. Next, as shown in FIG.
The film 2 is removed by etching. Next, baking is performed to make the temperature of the ion exchange treatment and the temperature of the LiNbO 3 substrate 1 the same to prevent cracking, and the second ion exchange is performed at 230 ° C. in benzoic acid. In this way, the window 3 immediately below the thickness d 2 is greater than the inverse ridge Katachikoshirube waveguide thickness d 1 of the high refractive index layer 4a is Al film 2 immediately below the high refractive index layer 4b as shown in FIG c is formed.
発明が解決しようとする問題点 上記のようにイオン交換を二度に分けて行い逆リッジ
形光導波路を製造する方法では途中でベーキングが入る
ために光導波路の屈折率および光導波路厚みが変化し、
設計とは異なった光導波路が作製されるという問題があ
った。またAl膜除去工程におい硝酸などの酸を使用する
ため光導波路表面に対する化学損傷による伝搬損失の増
加が問題となっていた。Problems to be Solved by the Invention As described above, in the method of manufacturing an inverted ridge type optical waveguide by performing ion exchange twice and changing the refractive index and the optical waveguide thickness of the optical waveguide due to baking in the middle. ,
There is a problem that an optical waveguide different from the design is manufactured. Also, since an acid such as nitric acid is used in the Al film removing step, an increase in propagation loss due to chemical damage to the optical waveguide surface has been a problem.
問題点を解決するための手段 本発明の光導波路の製造方法は上記問題点を解決する
ため、強誘電体基板上に、その一部に窓が開けられ、か
つイオン交換溶液によりエッチング可能なマスクを形成
する工程と、前記イオン交換溶液中でイオン交換を行う
工程とを有し、前記イオン交換を行う工程では、前記窓
直下をイオン交換し、かつ前記マスクは前記イオン交換
途中でエッチングされ、その後は前記マスク直下もイオ
ン交換されることで、前記窓直下に厚みd1である高屈折
率層を、前記マスク直下には厚みd2である高屈折率層を
形成し、前記厚みd1が前記厚みd2より大である逆リッジ
形光導波路が形成されるものである。Means for Solving the Problems The method for manufacturing an optical waveguide of the present invention solves the above-mentioned problems by providing a mask on a ferroelectric substrate, in which a window is partially opened and which can be etched by an ion exchange solution. Forming a, and a step of performing ion exchange in the ion exchange solution, in the step of performing the ion exchange, ion exchange immediately below the window, and the mask is etched during the ion exchange, Thereafter, the ion exchange is also performed immediately below the mask to form a high-refractive-index layer having a thickness d1 immediately below the window and a high-refractive-index layer having a thickness d2 directly below the mask, and the thickness d1 is equal to the thickness. An inverted ridge type optical waveguide having a size larger than d2 is formed.
作用 本発明は上記手段により一度のイオン交換で逆リッジ
形光導波路を形成でき、ベーキングおよびマスク除去の
工程を省き光導波路の形状変化および化学損傷を避ける
ことができる。According to the present invention, the reverse ridge-shaped optical waveguide can be formed by one ion exchange by the above means, and the steps of baking and mask removal can be omitted to avoid the shape change and chemical damage of the optical waveguide.
実 施 例 本発明の光導波路の製造方法の第１の実施例を第１図
に示す。同図ａで１は強誘電体基板であるLiNbO3基板、
10はCVDおよびフォトプロセスによりパターニングされ
た幅２μｍの窓３を持つマスク、具体的には厚み450Å
のSiO2膜である。このLiNbO3基板１を230℃に加熱され
たイオン交換溶液であるリン酸中でイオン交換を行う。
同図ｂは５分後のLiNbO3基板１を示したもので窓３の直
下でLiとＨのイオン交換が起り高屈折率部4aが形成され
る。この際、SiO2膜10はリン酸によりエッチングされ15
0Åの厚みとなっている。SiO2膜10のエッチングレート
は60Å/minである。７分30秒後にはSiO2膜10は完全にエ
ッチングされ、イオン交換に対するマスクとしての効果
を失いこのマスク直下もイオン交換される。同図ｃは10
分後リン酸中より引き出したLiNbO3基板１の断面を示し
たものであり、窓３直下の形成された高屈折率層4aの厚
みd1は0.5μm,SiO2膜10直下に形成された高屈折率層4b
の厚みd2は0.25μｍであった。He−Neレーザ光を端面よ
り入射させた場合He−Neレーザ光は高屈折率層4bの部分
にしみ出しながら高屈折率層4aの部分を伝搬しその伝搬
損失は0.8dB/cmであった。このように本発明によると、
マスク除去工程を必要としないため化学損傷を受けず伝
搬損失の低減が図れる。またリン酸を用いることにより
LiNbO3基板１にリン酸が与える化学損傷は極めて少いた
めより伝搬損失が低減する。またSiO2膜２は膜質を変え
ることによりエッチングレートを変化させることができ
任意のリッジ比（d2/d1）の光導波路が形成できる。Embodiment 1 FIG. 1 shows a first embodiment of the method for manufacturing an optical waveguide according to the present invention. In FIG. 2A, reference numeral 1 denotes a LiNbO 3 substrate which is a ferroelectric substrate,
Reference numeral 10 denotes a mask having a window 3 having a width of 2 μm patterned by CVD and photo processes, specifically, a thickness of 450 mm.
This is the SiO 2 film. The LiNbO 3 substrate 1 is subjected to ion exchange in phosphoric acid, which is an ion exchange solution heated to 230 ° C.
FIG. 5B shows the LiNbO 3 substrate 5 after 5 minutes, in which ion exchange between Li and H occurs immediately below the window 3 to form a high refractive index portion 4a. At this time, the SiO 2 film 10 is etched by phosphoric acid
It has a thickness of 0 mm. The etching rate of the SiO 2 film 10 is 60 ° / min. After 7 minutes and 30 seconds, the SiO 2 film 10 is completely etched, loses its effect as a mask for ion exchange, and is ion-exchanged immediately below the mask. FIG.
5 shows a cross section of the LiNbO 3 substrate 1 pulled out from the phosphoric acid after a minute, and the thickness d 1 of the high refractive index layer 4 a formed immediately below the window 3 is 0.5 μm, formed just below the SiO 2 film 10. High refractive index layer 4b
Had a thickness d 2 of 0.25 μm. When the He-Ne laser light was incident from the end face, the He-Ne laser light propagated through the high refractive index layer 4a while oozing into the high refractive index layer 4b, and the propagation loss was 0.8 dB / cm. . Thus, according to the present invention,
Since no mask removing step is required, propagation loss can be reduced without chemical damage. Also, by using phosphoric acid
Since the chemical damage caused by phosphoric acid to the LiNbO 3 substrate 1 is extremely small, the propagation loss is further reduced. The etching rate of the SiO 2 film 2 can be changed by changing the film quality, and an optical waveguide having an arbitrary ridge ratio (d 2 / d 1 ) can be formed.
本発明の光導波路の製造方法の第２の実施例について
以下説明を行う。本例では1000Åの厚みのAl膜をLiNbO3
上にパターニングしこはく酸中でイオン交換を行った。
220℃,20分熱処理を行うことにより実施例１と同様の課
程で厚み0.45μｍの逆リッジ形光導波路が形成された。
伝搬損失は1.5dB/cmであった。A second embodiment of the method for manufacturing an optical waveguide according to the present invention will be described below. In this example, an Al film having a thickness of 1000 mm is formed of LiNbO 3
Ion exchange was performed in succinic acid patterned on top.
By performing heat treatment at 220 ° C. for 20 minutes, an inverted ridge optical waveguide having a thickness of 0.45 μm was formed in the same process as in Example 1.
The propagation loss was 1.5dB / cm.
なお実施例では強誘電体基板としてLiNbO3基板を使用
したがLiNbxTa(1-x)O3（０≦ｘ≦１）などイオン交換導
波路形成可能な基板であれば良い。また酸としてリン
酸，こはく酸を使用したが安息香酸，ホウ酸などこれに
限ることはない。またマスクとして酸化膜であるSiO2,A
lを使用したがSi3N4,Cr,Tiなどイオン交換溶液中でエッ
チング可能であればこれに限ることはない。In the embodiment, the LiNbO 3 substrate is used as the ferroelectric substrate, but any substrate such as LiNb x Ta (1-x) O 3 (0 ≦ x ≦ 1) on which an ion exchange waveguide can be formed may be used. In addition, phosphoric acid and succinic acid were used as the acid, but it is not limited to benzoic acid, boric acid and the like. In addition, SiO 2 , A
Although l was used, it is not limited to this as long as it can be etched in an ion exchange solution such as Si 3 N 4 , Cr, and Ti.
発明の効果 本発明の光導波路の製造方法によればイオン交換溶液
中でのマスクのエッチングにより、イオン交換層の厚み
に差を設けることで逆リッジ光導波路を一度のイオン交
換処理により製造できる。これによりベーキングによる
光導波路の形状変化およびマスク除去の際の光学損傷を
防止し、さらに工程の大幅な短縮が可能となる。According to the method for manufacturing an optical waveguide of the present invention, a reverse ridge optical waveguide can be manufactured by a single ion exchange process by providing a difference in the thickness of an ion exchange layer by etching a mask in an ion exchange solution. This prevents a change in the shape of the optical waveguide due to baking and optical damage at the time of removing the mask, and makes it possible to significantly reduce the number of steps.
第１図は本発明の光導波路の製造方法の一実施例を示す
工程図、第２図は三次元光導波路と逆リッジ形光導波路
との伝搬損失を比較して示す特性図、第３図は従来の逆
リッジ形光導波路の製造方法を示す工程図である。 １……LiNbO3基板、３……窓、４……高屈折率層、10…
…マスク。FIG. 1 is a process chart showing an embodiment of a method of manufacturing an optical waveguide according to the present invention, FIG. 2 is a characteristic diagram showing a comparison between propagation loss between a three-dimensional optical waveguide and an inverted ridge optical waveguide, and FIG. FIG. 3 is a process diagram showing a method for manufacturing a conventional inverted ridge optical waveguide. 1 LiNbO 3 substrate 3 Window 3 High refractive index layer 10
…mask.
Claims (4)
れ、かつイオン交換溶液によりエッチング可能なマスク
を形成する工程と、前記イオン交換溶液中でイオン交換
を行う工程とを有し、前記イオン交換を行う工程では、
前記窓直下をイオン交換し、かつ前記マスクは前記イオ
ン交換途中でエッチングされ、その後は前記マスク直下
もイオン交換されることで、前記窓直下に厚みd1である
高屈折率層を、前記マスク直下には厚みd2である高屈折
率層を形成し、前記厚みd1が前記厚みd2より大である逆
リッジ形光導波路が形成されることを特徴とする光導波
路の製造方法。1. A method comprising the steps of: forming a mask on a part of a ferroelectric substrate, a window of which is opened and capable of being etched by an ion exchange solution; and performing an ion exchange in the ion exchange solution. In the step of performing the ion exchange,
The ion exchange is performed immediately below the window, and the mask is etched during the ion exchange.After that, the ion exchange is performed immediately below the mask, so that the high refractive index layer having a thickness d1 immediately below the window is directly under the mask. Forming a high refractive index layer having a thickness d2, and forming an inverted ridge type optical waveguide having the thickness d1 larger than the thickness d2.
ｘ≦１）を用いてなる特許請求の範囲第１項記載の光導
波路の製造方法。2. A ferroelectric substrate comprising LiNb x Ta (1-x) O 3 (0 ≦
2. The method for manufacturing an optical waveguide according to claim 1, wherein x ≦ 1).
特許請求の範囲第１項記載の光導波路の製造方法。3. The method for manufacturing an optical waveguide according to claim 1, wherein phosphoric acid is used as the ion exchange solution.
の範囲第１項記載の光導波路の製造方法。4. The method according to claim 1, wherein an oxide film is used as a mask.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60204715A JP2590807B2 (en) | 1985-09-17 | 1985-09-17 | Manufacturing method of optical waveguide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60204715A JP2590807B2 (en) | 1985-09-17 | 1985-09-17 | Manufacturing method of optical waveguide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6263904A JPS6263904A (en) | 1987-03-20 |
| JP2590807B2 true JP2590807B2 (en) | 1997-03-12 |
Family
ID=16495107
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60204715A Expired - Lifetime JP2590807B2 (en) | 1985-09-17 | 1985-09-17 | Manufacturing method of optical waveguide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2590807B2 (en) |
-
1985
- 1985-09-17 JP JP60204715A patent/JP2590807B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6263904A (en) | 1987-03-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5785874A (en) | Optical waveguide device bonded through direct bonding and a method for fabricating the same | |
| JP2002350659A (en) | Optical waveguide element and manufacturing method for optical waveguide element | |
| US4711514A (en) | Product of and process for forming tapered waveguides | |
| JP2590807B2 (en) | Manufacturing method of optical waveguide | |
| CN115951449A (en) | Low-loss lithium niobate waveguide and preparation method thereof | |
| KR101789026B1 (en) | Method of manufacturing of LiNbO3 substrate for optical modulator | |
| US6650819B1 (en) | Methods for forming separately optimized waveguide structures in optical materials | |
| JP3898585B2 (en) | Method for manufacturing member with optical waveguide | |
| EP0518059B1 (en) | Manufacturing of LiNbO3 channel optical guides | |
| JPH0313907A (en) | Production of substrate type optical waveguide | |
| US5000774A (en) | Method of masked two stage lithium niobate proton exchange | |
| JPH0774843B2 (en) | Optical element manufacturing method | |
| JP4137680B2 (en) | Manufacturing method of light control element | |
| JPH10239544A (en) | Optical waveguide element and manufacture thereof | |
| JPS63303308A (en) | Production of light guide | |
| JP2003114346A (en) | Method for manufacturing optical waveguide element | |
| JPH06174908A (en) | Production of waveguide type diffraction grating | |
| JPH1114850A (en) | Manufacture of optical element | |
| JPH03191332A (en) | Production of optical waveguide and optical wavelength converting element | |
| JPH0797170B2 (en) | Optical element manufacturing method | |
| JP2570822B2 (en) | Manufacturing method of optical waveguide | |
| JPH07270634A (en) | Manufacture of optical waveguide and optical waveguide substrate | |
| JPS6263903A (en) | Production of optical waveguide | |
| JPH11258440A (en) | Optical waveguide channel element and its manufacture | |
| JPH0943442A (en) | Optical circuit and its production |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |