JPH0731287B2 - Method of forming optical element - Google Patents
Method of forming optical elementInfo
- Publication number
- JPH0731287B2 JPH0731287B2 JP61136498A JP13649886A JPH0731287B2 JP H0731287 B2 JPH0731287 B2 JP H0731287B2 JP 61136498 A JP61136498 A JP 61136498A JP 13649886 A JP13649886 A JP 13649886A JP H0731287 B2 JPH0731287 B2 JP H0731287B2
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- optical element
- forming
- acid
- linbo
- 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 - Fee Related
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
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Integrated Circuits (AREA)
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使用する光情報処理分野ある
いは光通信、光応用計測制御分野に使用される光導波路
およびマイクロレンズなどに用いる光素子形成方法に関
するものである。TECHNICAL FIELD The present invention relates to a method for forming an optical element used for an optical waveguide and a microlens used in the field of optical information processing using coherent light, or in the fields of optical communication and optical applied measurement control. It is a thing.
従来の技術 従来、強誘電体であるLiNbO3基板を160℃〜250℃程度の
安息香酸溶液中で熱処理を行いLiNbO3基板のLiと安息香
酸中のＨを交換させ高屈折率層（最大屈折率差Δｎ＝0.
13程度）を形成し光導波路としていた。「ジェー・エル
・ジャッケル，シー・イー・ライス及びジェー・ジエー
・ベセルカ“プロトン イクスチェンジ フオー ハイ
−インデックス ウェイブガイドカイン LiNbO3"アプ
ライドフィジクス レター,41巻,7号607−608頁（198
2）（J.L.Jackel,C.E,Rice and J.J.Veselka,“Proton
exchange for high−index waveguides in LiNbO3,"App
l Phys.Lett,Vol41,No.7.PP607−608（1982））」参
照。Conventional technology Conventionally, a LiNbO 3 substrate, which is a ferroelectric material, is heat-treated in a benzoic acid solution at about 160 ° C to 250 ° C to exchange Li of the LiNbO 3 substrate with H in benzoic acid, and thus a high refractive index layer Rate difference Δn = 0.
13) was formed as an optical waveguide. "J. El Jacquel, C. E. Rice and J. J. Beselka" Proton Exchange Change High Index Waveguide Cain LiNbO 3 "Applied Physics Letters, Vol. 41, No. 7, pp. 607-608 (198).
2) (JLJackel, CE, Rice and JJVeselka, “Proton
exchange for high−index waveguides in LiNbO 3 , "App
l Phys. Lett, Vol 41, No. 7, PP607-608 (1982)) ".
以下光素子として光導波路を例にとりその形成方法につ
いて説明する。第２図に従来の溶液中でのプロトン交換
方法を用いた光導波路形成法の具体的構成図を示す。１
は強誘電体基板であるLiNbO3基板、４′はAlによる保護
マスク、５はフォトプロセスおよびエッチングにより保
護マスク４′上に形成されたスリットである。上記保護
マスク４′スリット５が形成されたLiNbO3基板１を安息
香酸の溶液６′中に浸す。溶液６′はヒータ７′により
加熱されたビーカ10を介して一定温度200℃に保たれて
いる。この溶液６′中でLiNbO3基板１を60分熱処理を行
った後、メタノールにより洗浄を行う。こうして安息香
酸溶液６′中のＨとLiNbO3基板１中のLiが交換し高屈折
率層９が形成される。この高屈折率層９が厚み0.5μｍ
程度の光導波路となる。An optical waveguide will be taken as an example of the optical element, and a method of forming the optical waveguide will be described below. FIG. 2 shows a concrete configuration diagram of an optical waveguide forming method using a conventional proton exchange method in a solution. 1
Is a LiNbO 3 substrate which is a ferroelectric substrate, 4'is a protective mask made of Al, and 5 is a slit formed on the protective mask 4'by photoprocess and etching. The LiNbO 3 substrate 1 having the above-mentioned protective mask 4 ′ slit 5 is dipped in a benzoic acid solution 6 ′. The solution 6'is kept at a constant temperature of 200 DEG C. via the beaker 10 heated by the heater 7 '. The LiNbO 3 substrate 1 is heat-treated in this solution 6 ′ for 60 minutes and then washed with methanol. In this way, H in the benzoic acid solution 6'is exchanged with Li in the LiNbO 3 substrate 1 to form the high refractive index layer 9. This high refractive index layer 9 has a thickness of 0.5 μm
It becomes an optical waveguide of a degree.
発明が解決しようとする問題点 このような溶液中での光素子の形成方法は以下に示すよ
うな問題点を有していた。Problems to be Solved by the Invention The method for forming an optical element in such a solution has the following problems.
（１） 0.8μｍ以下の短波長領域において光損傷を生
じる。(1) Optical damage occurs in a short wavelength region of 0.8 μm or less.
（２） 安息香酸をビーカ中に入れ撹拌されるため溶液
中に不純物が溶け込みLiNbO3中に入り光損傷がさらに助
長される。(2) Since benzoic acid is put in a beaker and stirred, impurities are dissolved in the solution and enter LiNbO 3 to further promote photodamage.
問題点を解決するための手段 本発明は上記問題点を解消するもので、光素子の形成方
法に新たな工夫を加えることにより光損傷を大幅に低減
させたものである。すなわち本発明の光素子の形成方法
は、LiNbxTa(1-x)O3（０≦ｘ≦１）基板表面を外拡散す
る工程と、前記基板の表面に、ピロ燐酸を主成分とする
酸を塗布する工程と、前記基板を熱処理し、前記塗布し
た酸の直下の前記基板に、高屈折率部を形成する工程と
を有するものである。Means for Solving the Problems The present invention solves the above problems and significantly reduces optical damage by adding new measures to the method for forming an optical element. That is, the method for forming an optical element of the present invention comprises a step of out-diffusing the surface of a LiNbxTa (1- x ) O 3 (0 ≦ x ≦ 1) substrate, and an acid containing pyrophosphoric acid as a main component on the surface of the substrate. And a step of heat-treating the substrate to form a high refractive index portion on the substrate directly below the applied acid.
作用 本発明は上記手段により溶液中への不純物の溶け込みを
防止するという効果とともに、外拡散によりさらに光損
傷に強い光素子の形成を可能とする。Action The present invention makes it possible to form an optical element that is more resistant to optical damage due to outdiffusion, in addition to the effect of preventing the dissolution of impurities in the solution by the above means.
実 施 例 本発明の光素子の形成方法の第１の実施例を第１図に示
す。この第１の実施例では光素子の形成方法としてLiNb
O3基板上にピロ燐酸（H4P2O7）を塗布し光導波路を形成
する方法について説明する。第１図（ａ）で１は＋Ｚ板
（−Ｚ軸に垂直に切り出された基板）であるLiNbO3基
板、ＺはLiNbO3基板１の＋Ｚ面３上に形成された外拡散
層である。この外拡散層２は1000℃、２時間、酸素中で
LiNbO3基板１を熱処理を行った結果、表面のLi2Oが外拡
散されて形成されたもので厚み70μｍ程度となってい
る。また４はTaによる保護マスク、５はフォトプロセス
およびリフトオフにより保護マスク４に形成されたスリ
ットである。同図（ｂ）において純度95％のピロ燐酸６
をスピンナーを用いて塗布を行った。具体的には回転数
300rpmで20秒スピンコートを行った。Example 1 A first example of the method for forming an optical element of the present invention is shown in FIG. In this first embodiment, LiNb is used as a method for forming an optical element.
A method of forming an optical waveguide by coating pyrophosphoric acid (H 4 P 2 O 7 ) on an O 3 substrate will be described. In FIG. 1 (a), reference numeral 1 denotes a LiNbO 3 substrate which is a + Z plate (a substrate cut out perpendicularly to the −Z axis), and Z denotes an outer diffusion layer formed on the + Z surface 3 of the LiNbO 3 substrate 1. The outer diffusion layer 2 is 1000 ° C. for 2 hours in oxygen.
As a result of heat-treating the LiNbO 3 substrate 1, the Li 2 O on the surface is formed by out-diffusion, and the thickness is about 70 μm. Further, 4 is a protective mask made of Ta, and 5 is a slit formed in the protective mask 4 by a photo process and lift-off. In the same figure (b), pyrophosphoric acid 6 with a purity of 95%
Was applied using a spinner. Specifically, the number of revolutions
Spin coating was performed at 300 rpm for 20 seconds.
次に同図（ｃ）のように200℃に加熱されたオーブン７
中で60分間熱処理を行った。８は温度の均一化を図るた
めのAlプレートである。最後にAlプレート８ごとオーブ
ン７より取り出し冷却を行った後、水酸化ナトリウム系
の溶液でTaによる保護マスク４を除去したのが同図
（ｄ）である。スリット５の直下にプロトン交換により
高屈折率層９が形成された。この高屈折率層９の厚みは
0.5μｍであり波長1.3μｍ以下の光が導波可能な光導波
路となる。He−Neレーザ光（波長0.633μｍ）を導波さ
せたところ10mWでも光損傷が生じなかった。このように
外拡散層２を形成することにより光損傷のしきい値が１
桁以上アップし短波用光導波路として非常に有効である
ことがわかる。またピロ燐酸処理により形成した高屈折
率層９のLiNbO3基板１との最大屈折率差は0.145と安息
香酸の溶液処理に比べ10％以上高く光の閉じ込めの大き
な光導波路の形成が可能となる。またピロ燐酸６は安息
香酸などに比べ極端に蒸発量が少いことおよび一度の光
素子作製に使用する量が1cc以下と非常に少いことなど
のため安全面および溶液の交換などの保守の面を考えた
場合、作業性が飛躍的に向上する。またTaはピロ燐酸な
どの燐酸系でエッチングされない上パターン形成も簡単
に行え保護マスクとして有効であると思われる。Next, as shown in Figure (c), oven 7 heated to 200 ° C
Heat treatment was carried out for 60 minutes. Reference numeral 8 is an Al plate for achieving uniform temperature. Finally, the Al plate 8 is taken out from the oven 7 and cooled, and then the protective mask 4 made of Ta is removed with a sodium hydroxide-based solution, as shown in FIG. The high refractive index layer 9 was formed immediately below the slit 5 by proton exchange. The thickness of this high refractive index layer 9 is
The optical waveguide has a wavelength of 0.5 μm and a wavelength of 1.3 μm or less can be guided. When He-Ne laser light (wavelength 0.633 μm) was guided, optical damage did not occur even at 10 mW. By forming the outer diffusion layer 2 in this manner, the threshold value of optical damage is 1
It can be seen that it is extremely effective as a short-wave optical waveguide by increasing the order of magnitude. Further, the maximum refractive index difference of the high refractive index layer 9 formed by the pyrophosphoric acid treatment with the LiNbO 3 substrate 1 is 0.145, which is more than 10% higher than that of the benzoic acid solution treatment, and it is possible to form an optical waveguide with a large light confinement. . In addition, pyrophosphoric acid 6 has an extremely smaller amount of evaporation than benzoic acid, and the amount used for making an optical element at one time is 1 cc or less, so safety and maintenance such as solution replacement are required. Considering the aspect, workability is dramatically improved. Further, Ta is considered to be effective as a protective mask because it is not etched by phosphoric acid such as pyrophosphoric acid and can easily form a pattern.
なお実施例では200℃で熱処理を行ったが100℃〜300℃
程度の温度範囲で熱処理が可能である。また90℃以上で
の塗布は基板の割れなどを生じ易い。また＋Ｚ板を用い
て光素子の形成を行ったが−Ｚ板などでも、他のX,Y板
等に比べ化学損傷が無く良質の光素子の形成が可能であ
る。また外拡散は500℃以上の温度で行うのが量産性，
制御性の点で良い。In the example, heat treatment was performed at 200 ° C, but 100 ° C to 300 ° C
Heat treatment is possible within a temperature range of about. Also, coating at 90 ° C or higher tends to cause substrate cracking. Further, although the optical element is formed by using the + Z plate, a high-quality optical element can be formed even with the -Z plate and the like without chemical damage as compared with other X, Y plates and the like. In addition, out diffusion is performed at a temperature of 500 ° C or higher for mass production,
Good in terms of controllability.
発明の効果 以上のように本発明の光素子の形成方法によれば、LiNb
xTa(1-x)O3（０≦ｘ≦１）基板表面を外拡散後、基板表
面にピロ燐酸を主成分とする酸を塗布し、この基板を熱
処理することで、酸を塗布した領域の直下に入射部を形
成できるので、簡単に制御性良く光損傷に強い光素子の
形成が可能となる。さらに熱処理における不純物混入を
防ぐことも可能となる。As described above, according to the method for forming an optical element of the present invention, LiNb
xTa (1- x ) O 3 (0 ≦ x ≦ 1) After the substrate surface is out-diffused, an acid containing pyrophosphoric acid as a main component is applied to the substrate surface, and the substrate is heat-treated to form an acid-coated region. Since the incident portion can be formed immediately below, it becomes possible to easily form an optical element having good controllability and high resistance to optical damage. Further, it becomes possible to prevent impurities from being mixed in during the heat treatment.
第１図は本発明の一実施例における光素子の形成方法の
工程断面図、第２図は従来の光素子の形成方法を説明す
る構成図である。 １……LiNbO3基板、２……外拡散層、４……保護マス
ク、６……ピロ燐酸、９……高屈折率層。FIG. 1 is a process cross-sectional view of a method for forming an optical element according to an embodiment of the present invention, and FIG. 2 is a configuration diagram for explaining a conventional method for forming an optical element. 1 ... LiNbO 3 substrate, 2 ... Outer diffusion layer, 4 ... Protective mask, 6 ... Pyrophosphoric acid, 9 ... High refractive index layer.
Claims (3)
外拡散する工程と、前記基板の表面に、ピロ燐酸を主成
分とする酸を塗布する工程と、 前記基板を熱処理し、前記塗布した酸の直下の前記基板
に、高屈折率部を形成する工程と を有する光素子の形成方法。1. A step of outdiffusing a LiNbxTa (1- x ) O 3 (0 ≦ x ≦ 1) substrate surface; a step of applying an acid containing pyrophosphoric acid as a main component to the surface of the substrate; A step of heat-treating the substrate to form a high refractive index portion on the substrate directly below the applied acid.
板または−ｚ板である特許請求の範囲第１項記載の光素
子の形成方法。2. A LiNbxTa (1- x ) O 3 (0 ≦ x ≦ 1) substrate is + z.
The method for forming an optical element according to claim 1, which is a plate or a -z plate.
に、酸を塗布する工程の前に、 前記基板表面にTaによる保護マスクパターンを形成する
工程を有する 特許請求の範囲第１項記載の光素子の形成方法。3. A step of forming a protective mask pattern of Ta on the surface of the LiNbxTa (1- x ) O 3 (0 ≦ x ≦ 1) substrate prior to the step of applying an acid to the substrate. The method for forming an optical element according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61136498A JPH0731287B2 (en) | 1986-06-12 | 1986-06-12 | Method of forming optical element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61136498A JPH0731287B2 (en) | 1986-06-12 | 1986-06-12 | Method of forming optical element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62293206A JPS62293206A (en) | 1987-12-19 |
| JPH0731287B2 true JPH0731287B2 (en) | 1995-04-10 |
Family
ID=15176571
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61136498A Expired - Fee Related JPH0731287B2 (en) | 1986-06-12 | 1986-06-12 | Method of forming optical element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0731287B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11275701A (en) * | 1998-03-18 | 1999-10-08 | Atex Co Ltd | Controller of motor-driven vehicle |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5442719A (en) * | 1993-07-21 | 1995-08-15 | Litton Systems, Inc., A Delaware Corporation | Electro-optic waveguides and phase modulators and methods for making them |
| CN104852271A (en) * | 2015-05-29 | 2015-08-19 | 南京信息工程大学 | Preparation method of waveguide laser |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS607403A (en) * | 1983-06-28 | 1985-01-16 | Canon Inc | Forming method of thin film type optical waveguide |
| JPS60133405A (en) * | 1983-12-22 | 1985-07-16 | Canon Inc | Formation of pattern |
| JPS6170541A (en) * | 1984-09-14 | 1986-04-11 | Canon Inc | Thin film type optical element and its manufacture |
-
1986
- 1986-06-12 JP JP61136498A patent/JPH0731287B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11275701A (en) * | 1998-03-18 | 1999-10-08 | Atex Co Ltd | Controller of motor-driven vehicle |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62293206A (en) | 1987-12-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |