JPH04264534A - Production of wavelength converting element - Google Patents
Production of wavelength converting elementInfo
- Publication number
- JPH04264534A JPH04264534A JP3026055A JP2605591A JPH04264534A JP H04264534 A JPH04264534 A JP H04264534A JP 3026055 A JP3026055 A JP 3026055A JP 2605591 A JP2605591 A JP 2605591A JP H04264534 A JPH04264534 A JP H04264534A
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- litao3
- forming
- proton exchange
- conversion element
- 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.)
- Granted
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 32
- 239000000758 substrate Substances 0.000 claims abstract description 78
- 229910012463 LiTaO3 Inorganic materials 0.000 claims abstract description 65
- 230000010287 polarization Effects 0.000 claims abstract description 64
- 238000006243 chemical reaction Methods 0.000 claims abstract description 60
- 238000000034 method Methods 0.000 claims abstract description 30
- 230000005684 electric field Effects 0.000 claims abstract description 27
- 230000000737 periodic effect Effects 0.000 claims abstract description 21
- 208000037516 chromosome inversion disease Diseases 0.000 claims description 54
- 239000013078 crystal Substances 0.000 claims description 31
- 238000010438 heat treatment Methods 0.000 claims description 18
- 150000002500 ions Chemical class 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 description 19
- 239000004065 semiconductor Substances 0.000 description 6
- 229910003327 LiNbO3 Inorganic materials 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 5
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 4
- 230000006378 damage Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229940005657 pyrophosphoric acid Drugs 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000005711 Benzoic acid Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 235000010233 benzoic acid Nutrition 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- 230000010365 information processing Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000008832 photodamage Effects 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000010897 surface acoustic wave method Methods 0.000 description 1
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 1
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
- G02F1/35—Non-linear optics
- G02F1/37—Non-linear optics for second-harmonic generation
- G02F1/377—Non-linear optics for second-harmonic generation in an optical waveguide structure
- G02F1/3775—Non-linear optics for second-harmonic generation in an optical waveguide structure with a periodic structure, e.g. domain inversion, for quasi-phase-matching [QPM]
-
- 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
- G02F1/35—Non-linear optics
- G02F1/355—Non-linear optics characterised by the materials used
- G02F1/3558—Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
-
- 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
- G02F1/35—Non-linear optics
- G02F1/353—Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
- G02F1/3544—Particular phase matching techniques
- G02F1/3548—Quasi phase matching [QPM], e.g. using a periodic domain inverted structure
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Abstract
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、コヒーレント光源を応
用した、光情報処理、光応用計測制御分野に使用される
波長変換素子の製造方法に関するものである。
【０００２】
【従来の技術】誘電体の分極を強制的に反転させる分極
反転は誘電体に周期的な分極反転層を形成することによ
り表面弾性波を利用した光周波数変調器や非線形分極の
分極反転を利用した波長変換素子などに利用される。特
に非線形光学物質の非線形分極を周期的に反転すること
が可能になれば非常に変換効率の高い第二高調波発生素
子を作製することができる。これによって半導体レーザ
などの光を変換すると小型の短波長光源が実現でき、印
刷、光情報処理、光応用計測制御分野などに応用できる
ため盛んに研究が行われている。
【０００３】このような分極反転を利用した従来の波長
変換素子の製造方法としては、例えばＬｉＮｂＯ３基板
表面に周期的な分極反転層を形成して波長変換素子を製
造する方法がある。これは図７に示すようにＬｉＮｂＯ
３基板１００表面に周期的Ｔｉ膜１０１を形成し、Ｔｉ
を基板に拡散することにより、ＬｉＮｂＯ３基板１００
に周期的な分極反転層１０２を形成し、この周期的な分
極反転層１０２を横切るように光導波路１０３を形成し
て波長変換素子を製造する方法である。
【０００４】またＬｉＴａＯ３結晶によって、波長変換
素子を作製する方法として、従来の波長変換素子製造方
法を示す。例えば、（アプライドフィジィックスレター
（Ａｐｐｌ．Ｐｈｙｓ．Ｌｅｔｔ．）１９９０年５６号
Ｐ１５３５の）Ｋｉｙｏｓｈｉ Ｎａｋａｍｕｒａ氏に
よる波長変換素子製造方法がある。図７はこの従来の波
長変換素子製造方法の工程図である。図７において２１
はＬｉＴａＯ３基板、２２はプロトン交換層、２３は分
極反転層である。製造方法は、図８（ｂ）ＬｉＴａＯ３
基板を５９０℃の安息香酸中で熱処理しプロトン交換層
を形成する。（ｃ）ＬｉＴａＯ３基板をキュリー温度（
６００℃）近傍の５７０℃〜５９０℃で熱処理するとＬ
ｉＴａＯ３基板の−Ｃ面表面に分極の反転した層が形成
されるという波長変換素子製造方法である。
【０００５】
【発明が解決しようとする課題】ＬｉＮｂＯ３結晶には
光損傷という問題があり、光のパワー密度を上げるのが
困難なため変換効率の高い波長変換素子を製造するのが
難しいという問題があり、ＬｉＮｂＯ３結晶に結晶構造
が類似しており、かつ高い非線形性を有し、さらに光損
傷にも強いＬｉＴａＯ３結晶に分極反転を形成して波長
変換素子を製造する研究が行われている。またＬｉＴａ
Ｏ３結晶は光学特性に優れており、かつ結晶育成時の不
純物の混入が少なくＬｉＮｂＯ３に比べ結晶性に優れて
いるため光損傷やＤＣドリフトにおいて優れた特性を有
し光ＩＣデバイス用の光学材料として有用な材料である
。しかしながら、上記のような方法ではスラブ状の反転
層は形成できても、ＬｉＴａＯ３結晶に周期的な分極反
転層を形成することができないという問題があった。さ
らに周期的な分極反転層により高効率の波長変換素子を
形成するには、数μｍの周期と光の波長以上の深さの分
極反転層が必要であるという問題があった。
【０００６】本発明は上記課題を解決するもので、Ｌｉ
ＴａＯ３結晶による周期的な分極反転を形成し、数μｍ
という短周期で、かつ深い分極反転層を形成することに
より、変換効率の高い波長変換素子の製造方法を提供す
ることを目的とする。
【０００７】
【課題を解決するための手段】以上の課題を解決するた
め、Ｃ板（結晶のＣ軸に垂直な面で切り出した基板）の
ＬｉＴａＯ３基板の＋Ｃ表面にストライプ状の電極パタ
ーンを形成する工程と、前記ＬｉＴａＯ３基板の裏面に
電極を形成する工程と、前記ストライプ状の電極パター
ンと、前記ＬｉＴａＯ３基板の裏面に形成した電極の間
に電界を印加し、同時に前記ＬｉＴａＯ３基板をＬｉＴ
ａＯ３のキュリー温度以下で加熱する工程とを有する波
長変換素子の製造方法とするものである。
【０００８】またＣ板（結晶のＣ軸に垂直な面）のＬｉ
ＴａＯ３基板の−Ｃ面表面にストライプ状のマスクを形
成する工程と、前記ＬｉＴａＯ３基板本体をプロトン交
換処理して、非マスク部分から前記ＬｉＴａＯ３基板内
のＬｉとＨ＋イオンを交換しプロトン交換層を形成する
工程と、前記ＬｉＴａＯ３基板表面に形成したストライ
プ状のマスクを除去する工程と、前記ＬｉＴａＯ３基板
の表面と裏面に電極を形成する工程と、前記ＬｉＴａＯ
３基板の表裏の電極間に電界を印加し同時にＬｉＴａＯ
３のキュリー温度以下で加熱する分極反転処理工程とを
有する波長変換素子製造方法とするものである。
【０００９】
【作用】本発明は前述した方法により、ＬｉＴａＯ３結
晶基板をキュリー点近傍で加熱することにより基板の分
極はランダムになり、この状態で電界を印加することに
よりＬｉＴａＯ３結晶の分極を周期的に反転させる。こ
れによって波長変換素子を作製できる。
【００１０】また本発明は前述した方法によりＬｉＴａ
Ｏ３結晶にプロトン交換処理を部分的に施すと、プロト
ン交換層はキュリー点が基板より低くなるため、プロト
ン交換層のキュリー点より高く基板のより低い温度で熱
処理することにより、プロトン交換層の分極だけをラン
ダムにできる。そこで電界を印加してプロトン交換層の
分極だけを反転させる。そうすれば、プロトン交換層の
横方向の広がりを電界により制限し、同時に熱処理が行
えるため、周期的な分極反転層が深さ方向により深く形
成され、かつ分極反転層の横方向広がりが低減できる。
このため、深くかつ短周期の分極反転を形成できる。
【００１１】以上の結果、従来実現していなかった、Ｌ
ｉＴａＯ３結晶による周期的な分極反転を形成し、数μ
ｍという短周期で、かつ深い分極反転層を形成すること
により、変換効率の高い波長変換素子を製造することが
できる。
【００１２】
【実施例】図１は、第１の実施例における波長変換素子
製造方法の工程図を示すものである。図１において、１
はＬｉＴａＯ３基板、２はストライプ状の電極、３は電
極、４は分極反転層である。以上のように構成された第
１実施例の波長変換素子製造方法について、以下その製
造方法を説明する。図１（ａ）＋Ｃ板のＬｉＴａＯ３基
板１上にスパッタリング法によりＴａ膜を形成する。（
ｂ）Ｔａ膜上にレジストを塗布した後、フォトリソグラ
フィ法により４μｍ周期ごとに幅２μｍのストライプを
１０ｍｍに渡って基板のＹ伝搬方向に形成する。この周
期はＬｉＴａＯ３における波長０．８μｍの基本波と波
長０．４μｍの第２高調波の位相整合条件より決定した
。位相整合条件とは、高調波出力が 最も大きくなる
周期の長さであり、基板の材質固有の屈折率と、基本波
、高調波の波長によって一義的に決まる距離である。つ
ぎにＣＦ４雰囲気中でドライエッチングを行いストライ
プ状の電極２を形成する。（ｃ）ＬｉＴａＯ３基板の裏
面にも平面電極を設け、ストライプ電極と平面電極間に
直流電界を印加しながら恒温漕中で熱処理を行った。用
いたＬｉＴａＯ３基板のキュリー点が６１０℃であった
ので、熱処理の温度は６００℃で行った。熱処理は電極
の酸化を防止するため窒素中で行った。ここでの熱処理
とは、ＬｉＴａＯ３結晶をキュリー温度近くまで温度を
上げて、一定方向にそろっている結晶の分極を部分的に
反転させる処理である。（ｄ）電極を除去する。作製し
た周期的分極反転層は深さ０．５μｍであった。周期的
分極反転層に直交するように基板表面にプロトン交換導
波路を形成し波長変換素子を作製した。
【００１３】図２に実施例１で製造した波長変換素子の
構成斜視図を示す。１はＬｉＴａＯ３基板、４は分極反
転層、５はプロトン交換導波路、６は波長８００ｎｍの
基本波、７は波長４００ｎｍの第２高調波である。プロ
トン交換導波路は幅２μｍ深さ１μｍである。波長８０
０ｎｍ、出力４０ｍＷの半導体レーザの光６を集光光学
系により集光し作製した波長変換素子に入射した。導波
路より、出射される基本波及び第二高調波７をレンズで
コリメートしパワーメータで測定した。その結果、波長
４００ｎｍの第二高調波の出力は０．１ｍＷであり分極
反転による位相整合がとれていない場合の１０００倍以
上になり高い変換効率が得られた。さらに基本光のパワ
ーを増大させて２００ｍＷまで導波させたが光損傷によ
る変動は観測されなかった。以上の結果安定で高効率の
出力が得られた。
【００１４】なお、本実施例では分極反転層の作製方向
をＹ伝搬方向としたがＸ伝搬方向でも同様な素子が作製
できる。また、本実施例では基板にＬｉＴａＯ３基板を
用いたが他にＭｇＯをドープしたＬｉＴａＯ３基板でも
同様な素子が作製できる。
【００１５】また図３は、第２の実施例における波長変
換素子製造方法の工程図を示すものである。図３におい
て、１はＬｉＴａＯ３基板、８はストライプ状のＴａマ
スク、９はプロトン交換層、１０，１１は白金の電極、
１２は分極反転層である。以上のように構成された第２
実施例の波長変換素子製造方法について、以下その製造
方法を説明する。図３（ａ）−Ｃ板のＬｉＴａＯ３基板
１上にスパッタリング法によりＴａ膜を形成する。（ｂ
）Ｔａ膜上にレジストを塗布した後、フォトリソグラフ
ィ法により４μｍ周期ごとに幅２μｍのストライプを１
０ｍｍに渡って基板のＹ伝搬方向に形成する。この周期
はＬｉＴａＯ３における波長０．８μｍの基本波と波長
０．４μｍの第２高調波の位相整合条件より決定した。
つぎにＣＦ４雰囲気中でドライエッチングを行いストラ
イプ状のマスクパターン８を形成する。（ｃ）２６０℃
のピロ燐酸中で２０分間熱処理し、プロトン交換層９を
形成する。ピロ燐酸は解離度が高く、かつ沸点が高いた
め、高温処理により、深いプロトン交換層が短時間で形
成でき、作製の効率がよい、またプロトン交換の交換率
が高いため、プロトン交換層のキュリー点低下が大きく
かつ、均一なプロトン交換層が形成できる。（ｄ）Ｔａ
マスクをＨＦで除去する。（ｅ）ＬｉＴａＯ３基板の表
面と裏面に白金の電極を設ける。（ｆ）基板の表裏の平
面電極間に直流電界を印加しながら恒温漕中で熱処理を
行った。用いたＬｉＴａＯ３基板のキュリー点が６１０
℃であったので、熱処理の温度は６００℃で１分間行っ
た。このときプロトン交換層のキュリー点は基板より低
く、分極反転層の形成は４６０℃〜６００℃の間で可能
であった。４５０℃以下または６００℃以上では周期的
な反転層の形成は不可能であった。これは４６０℃以下
ではプロトン交換層がキュリー点に達しないため分極の
反転が起こらないためである。また６１０℃以上ではプ
ロトン交換層のみならず基板自体がキュリー点に達する
ため基板全面が分極反転が発生し、周期的な分極反転が
消滅するためである。作製した周期的分極反転層１２は
深さ０．８μｍであった。周期的分極反転層に直交する
ように基板表面にプロトン交換導波路を形成し図２と同
様な波長変換素子を作製した。プロトン交換導波路は幅
２μｍ深さ１μｍである。波長８００ｎｍ、出力４０ｍ
Ｗの半導体レーザの光６を集光光学系により集光し作製
した波長変換素子に入射した。導波路より、出射される
基本波及び第二高調波をレンズでコリメートしパワーメ
ータで測定した。その結果、７の波長４００ｎｍの第二
高調波の出力は０．２ｍＷであり従来の２倍の高効率の
変換が可能となった。
【００１６】なお、本実施例では電界の印加に平面電極
を用いたが、図４に示すように分極反転層を形成しよう
とするところだけにストライプ状の電極１３を用いると
、局部電界がプロトン交換部分のみに選択的に印加され
る。これによってより深い、分極反転層１２が形成され
た、周期４μｍで反転層深さ１μｍとなり、同様な第２
高調波の発生実験を行ったところ０．３ｍＷの出力が得
られ非常に高い効率の変換が可能になった。さらに選択
的に電界を印加することにより、分極反転の周期の短周
期化が可能になり、従来４μｍの周期しかできなかった
が、局部電界の印加により、周期３μｍ深さ０．８μｍ
の分極反転層の作製が可能になり、これによって波長０
．７６μｍの半導体レーザの光を変換したところ、０．
２ｍＷの第２高調波出力が得られ短波長化も可能になっ
た。
【００１７】なお、本実施例では電界の印加に平面電極
を用いたが、図５に示すように櫛形の電極１４，１５を
２つ交互に並べ、一方の電極をプロトン交換層の直上に
形成すると、局部電界がプロトン交換部分９のみに選択
的に印加され、かつ電極間距離が非常に短いためる高い
電界が印加されるこれによって、形成された分極反転層
は周期４μｍで深さ１．５μｍ、と平面電極で形成した
場合に比べ約２倍になった。この反転層をもちいて波長
変換素子を作製すると波長０．８μｍ、４０ｍＷの半導
体レーザの光を入射すると１ｍＷの第二高調波（波長０
．４μｍ）が得られ平面電極で形成した波長変換素子の
約５倍という非常に高い変換効率が得られた。
【００１８】なお、本実施例では分極反転層の作製方向
をＹ伝搬方向としたがＸ伝搬方向でも同様な素子が作製
できる。また、本実施例では、イオン交換にピロ燐酸を
用いたが、他に燐酸、安息香酸、硝酸、塩酸、硫酸、な
ども用いることができる。
【００１９】なお、本実施例では耐イオン化のマスクと
して、Ｔａ膜を用いたが、他にＴａ２Ｏ５、Ｐｔなど耐
酸性を有する膜なら用いることができる。さらに、本実
施例では、基板として、ＬｉＴａＯ３を用いたが、他に
ＭｇＯをドーピングした、ＬｉＴａＯ３基板でも用いる
ことができる。
【００２０】図６に示すように、Ｘ板のＬｉＴａＯ３結
晶上の表面に高さ１μｍ幅２μｍの凸型のストライプを
Ｙ軸方向に形成する形成し、ストライプの両側面に周期
的な電極１６，１７を形成する。この電極に２Ｖの電界
を印加しながら６００℃で１０分間加熱したところ、Ｃ
軸方向を向いている分極を周期的にーＣ方向に反転させ
た。この方法によって凸型のストライプにおいて最低周
期２μｍの周期的な分極反転層を形成できた。さらにス
トライプの両端面を研磨することにより、これを導波路
とし波長変換素子を作製した。作製した波長変換素子に
波長６８０ｎｍの半導体レーザの光２０ｍＷを入射した
ところ、波長３４０ｎｍのＳＨＧ出力が０．１ｍＷ発生
し高出力で短波長の波長変換素子が作製できた。これに
よって、従来分極反転が作製できなかった。Ｘ板または
Ｙ板のＬｉＴａＯ３結晶を用いて波長変換素子が構成で
きる。また凸型の両側面から電界を印加するため、電界
密度を上げることができ、低電圧で分極反転が形成でき
る。さらに側面からの電界印加によって分極反転を形成
するため、短周期で深いの反転層が形成でき高効率でか
つ短波長の波長変換素子が構成できる。
【００２１】なお、本実施例ではＸ板のＬｉＴａＯ３結
晶を用いたがＹ板のＬｉＴａＯ３結晶でも同様な素子が
作製できる、但しその場合は凸型のストライプはＸ軸伝
搬となる。
【００２２】
【発明の効果】以上説明したように、ＬｉＴａＯ３結晶
にストライプ状の電極を形成し電界を印加しながら同時
にキュリー点近傍で熱処理することにより、ＬｉＴａＯ
３結晶の分極を周期的に反転させる。これによって周期
的な分極反転層の形成が可能になり光導波路と組み合わ
せることにより波長変換素子を作製できる。以上の結果
、従来実現していなかった、ＬｉＴａＯ３結晶による周
期的な分極反転を形成し、かつ耐光損傷性に優れるＬｉ
ＴａＯ３結晶により高出力の波長変換素子を製造するこ
とができ、その実用効果は大きい。
【００２３】またＬｉＴａＯ３結晶にプロトン交換処理
を部分的に施した後、電界を印加し、同時にキュリー温
度以下かつキュリー温度近傍で加熱するすことにより、
プロトン交換層の横方向の広がりを電界により制限し、
同時に熱処理が行えるため、周期的な分極反転層が深さ
方向により深く形成され、かつ分極反転層の横方向広が
りが低減できる。以上の結果、従来実現していなかった
ＬｉＴａＯ３結晶を用いて、深くかつ短周期の分極反転
を形成できる。この周期的な分極反転によって波長変換
素子を形成すると高効率の変換が可能になり、かつ耐光
損傷性に優れるＬｉＴａＯ３結晶により高出力の波長変
換素子を製造することができ、その実用効果は大きい。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a wavelength conversion element that applies a coherent light source and is used in the fields of optical information processing and optical applied measurement control. . [0002] Polarization inversion, which forcibly inverts the polarization of a dielectric material, is performed by forming a periodic polarization inversion layer on the dielectric material, and is used as an optical frequency modulator using surface acoustic waves or nonlinear polarization. It is used in wavelength conversion elements that utilize inversion. In particular, if it becomes possible to periodically invert the nonlinear polarization of a nonlinear optical material, a second harmonic generating element with extremely high conversion efficiency can be produced. By converting light from semiconductor lasers and other sources, it is possible to create compact, short-wavelength light sources, which can be applied to fields such as printing, optical information processing, and optical applied measurement and control, and are therefore being actively researched. A conventional method for manufacturing a wavelength conversion element using such polarization inversion includes, for example, a method of manufacturing a wavelength conversion element by forming a periodic polarization inversion layer on the surface of a LiNbO3 substrate. As shown in Figure 7, this is a LiNbO
3. A periodic Ti film 101 is formed on the surface of the substrate 100.
By diffusing into the substrate, the LiNbO3 substrate 100
In this method, a periodic domain-inverted layer 102 is formed, and an optical waveguide 103 is formed across the periodic domain-inverted layer 102 to manufacture a wavelength conversion element. [0004] Furthermore, as a method for manufacturing a wavelength conversion element using LiTaO3 crystal, a conventional method for manufacturing a wavelength conversion element will be described. For example, there is a method for manufacturing a wavelength conversion element by Mr. Kiyoshi Nakamura (Appl. Phys. Lett., 1990, No. 56, P1535). FIG. 7 is a process diagram of this conventional wavelength conversion element manufacturing method. 21 in Figure 7
2 is a LiTaO3 substrate, 22 is a proton exchange layer, and 23 is a polarization inversion layer. The manufacturing method is shown in FIG. 8(b) LiTaO3
The substrate is heat treated in benzoic acid at 590°C to form a proton exchange layer. (c) LiTaO3 substrate at Curie temperature (
When heat treated at 570°C to 590°C near
This is a method for manufacturing a wavelength conversion element in which a layer with inverted polarization is formed on the -C plane surface of an iTaO3 substrate. [0005] Problems to be Solved by the Invention: LiNbO3 crystals have the problem of optical damage, and because it is difficult to increase the optical power density, it is difficult to manufacture wavelength conversion elements with high conversion efficiency. Research is being conducted on manufacturing wavelength conversion elements by forming polarization inversion in LiTaO3 crystal, which has a crystal structure similar to LiNbO3 crystal, has high nonlinearity, and is also resistant to optical damage. Also, LiTa
O3 crystal has excellent optical properties, less contamination with impurities during crystal growth, and superior crystallinity compared to LiNbO3, so it has excellent properties in terms of optical damage and DC drift, and is used as an optical material for optical IC devices. It is a useful material. However, although the above method can form a slab-like inversion layer, there is a problem in that a periodic polarization inversion layer cannot be formed in the LiTaO3 crystal. Furthermore, in order to form a highly efficient wavelength conversion element using a periodic polarization inversion layer, there is a problem in that the polarization inversion layer must have a period of several μm and a depth greater than the wavelength of light. [0006] The present invention solves the above-mentioned problems.
Forms periodic polarization inversion by TaO3 crystal, several μm
It is an object of the present invention to provide a method for manufacturing a wavelength conversion element with high conversion efficiency by forming a deep polarization inversion layer with a short period. [Means for Solving the Problems] In order to solve the above problems, a striped electrode pattern is formed on the +C surface of a LiTaO3 substrate, which is a C plate (a substrate cut in a plane perpendicular to the C axis of the crystal). forming an electrode on the back surface of the LiTaO3 substrate, applying an electric field between the striped electrode pattern and the electrode formed on the back surface of the LiTaO3 substrate, and simultaneously converting the LiTaO3 substrate into LiT.
The method of manufacturing a wavelength conversion element includes a step of heating below the Curie temperature of aO3. [0008] Also, Li of the C plate (plane perpendicular to the C axis of the crystal)
A step of forming a stripe-shaped mask on the surface of the −C plane of the TaO3 substrate, and performing proton exchange treatment on the main body of the LiTaO3 substrate to exchange Li and H+ ions in the LiTaO3 substrate from the non-mask portion to form a proton exchange layer. a step of removing the striped mask formed on the surface of the LiTaO3 substrate; a step of forming electrodes on the front and back surfaces of the LiTaO3 substrate;
An electric field is applied between the front and back electrodes of the three substrates, and at the same time LiTaO
3, a polarization inversion treatment step of heating at a temperature below the Curie temperature. [Operation] According to the method described above, the present invention makes the polarization of the substrate random by heating the LiTaO3 crystal substrate near the Curie point, and by applying an electric field in this state, the polarization of the LiTaO3 crystal becomes periodic. invert it. With this, a wavelength conversion element can be manufactured. The present invention also provides LiTa by the method described above.
When the O3 crystal is partially subjected to proton exchange treatment, the Curie point of the proton exchange layer becomes lower than that of the substrate. Therefore, by heat treatment at a temperature higher than the Curie point of the proton exchange layer and lower than that of the substrate, the polarization of the proton exchange layer is reduced. You can only randomize. Then, an electric field is applied to reverse only the polarization of the proton exchange layer. In this way, the lateral spread of the proton exchange layer can be restricted by an electric field and heat treatment can be performed at the same time, so that the periodic polarization inversion layer can be formed deeper in the depth direction, and the lateral spread of the polarization inversion layer can be reduced. . Therefore, deep and short-period polarization inversion can be formed. As a result of the above, L
Periodic polarization inversion is formed by iTaO3 crystal, and several μ
By forming a deep polarization inversion layer with a short period of m, a wavelength conversion element with high conversion efficiency can be manufactured. Embodiment FIG. 1 shows a process diagram of a method for manufacturing a wavelength conversion element in a first embodiment. In Figure 1, 1
2 is a LiTaO3 substrate, 2 is a striped electrode, 3 is an electrode, and 4 is a polarization inversion layer. The manufacturing method of the wavelength conversion element of the first embodiment configured as described above will be explained below. A Ta film is formed on a LiTaO3 substrate 1 of FIG. 1(a)+C plate by a sputtering method. (
b) After applying a resist on the Ta film, stripes with a width of 2 μm are formed every 4 μm in a length of 10 mm in the Y propagation direction of the substrate by photolithography. This period was determined based on the phase matching condition of the fundamental wave with a wavelength of 0.8 μm and the second harmonic wave with a wavelength of 0.4 μm in LiTaO3. The phase matching condition is the length of the period at which the harmonic output is the largest, and is the distance uniquely determined by the refractive index specific to the material of the substrate and the wavelengths of the fundamental wave and harmonics. Next, dry etching is performed in a CF4 atmosphere to form striped electrodes 2. (c) A planar electrode was also provided on the back surface of the LiTaO3 substrate, and heat treatment was performed in a constant temperature bath while applying a DC electric field between the striped electrode and the planar electrode. Since the Curie point of the LiTaO3 substrate used was 610°C, the temperature of the heat treatment was 600°C. The heat treatment was performed in nitrogen to prevent oxidation of the electrode. The heat treatment here is a treatment in which the temperature of the LiTaO3 crystal is raised to near the Curie temperature and the polarization of the crystal aligned in a certain direction is partially reversed. (d) Remove the electrode. The periodically domain-inverted layer produced had a depth of 0.5 μm. A wavelength conversion element was fabricated by forming a proton exchange waveguide on the substrate surface perpendicular to the periodically poled layer. FIG. 2 shows a perspective view of the structure of the wavelength conversion element manufactured in Example 1. 1 is a LiTaO3 substrate, 4 is a polarization inversion layer, 5 is a proton exchange waveguide, 6 is a fundamental wave with a wavelength of 800 nm, and 7 is a second harmonic wave with a wavelength of 400 nm. The proton exchange waveguide is 2 μm wide and 1 μm deep. wavelength 80
Light 6 from a semiconductor laser with a wavelength of 0 nm and an output of 40 mW was focused by a focusing optical system and made incident on the fabricated wavelength conversion element. The fundamental wave and second harmonic 7 emitted from the waveguide were collimated with a lens and measured with a power meter. As a result, the output of the second harmonic with a wavelength of 400 nm was 0.1 mW, which was more than 1000 times that in the case where phase matching by polarization inversion was not achieved, and high conversion efficiency was obtained. Furthermore, although the power of the fundamental light was increased to 200 mW, no fluctuation due to optical damage was observed. As a result, stable and highly efficient output was obtained. In this example, the polarization inversion layer was fabricated in the Y propagation direction, but a similar device can also be fabricated in the X propagation direction. Furthermore, although a LiTaO3 substrate was used as the substrate in this embodiment, a similar element can also be fabricated using a LiTaO3 substrate doped with MgO. FIG. 3 shows a process diagram of a method for manufacturing a wavelength conversion element in a second embodiment. In FIG. 3, 1 is a LiTaO3 substrate, 8 is a striped Ta mask, 9 is a proton exchange layer, 10 and 11 are platinum electrodes,
12 is a polarization inversion layer. The second
The method of manufacturing the wavelength conversion element of the embodiment will be described below. A Ta film is formed on the LiTaO3 substrate 1 of the FIG. 3(a)-C plate by sputtering. (b
) After applying resist on the Ta film, one stripe with a width of 2 μm is formed every 4 μm period by photolithography.
It is formed over a length of 0 mm in the Y propagation direction of the substrate. This period was determined based on the phase matching condition of the fundamental wave with a wavelength of 0.8 μm and the second harmonic wave with a wavelength of 0.4 μm in LiTaO3. Next, dry etching is performed in a CF4 atmosphere to form a striped mask pattern 8. (c) 260℃
pyrophosphoric acid for 20 minutes to form a proton exchange layer 9. Pyrophosphoric acid has a high degree of dissociation and a high boiling point, so a deep proton exchange layer can be formed in a short time by high temperature treatment, which is highly efficient in production. A uniform proton exchange layer with a large point drop can be formed. (d)Ta
Remove the mask with HF. (e) Platinum electrodes are provided on the front and back surfaces of the LiTaO3 substrate. (f) Heat treatment was performed in a constant temperature bath while applying a DC electric field between the front and back plane electrodes of the substrate. The Curie point of the LiTaO3 substrate used is 610.
℃, the heat treatment temperature was 600°C for 1 minute. At this time, the Curie point of the proton exchange layer was lower than that of the substrate, and the polarization inversion layer could be formed at a temperature between 460°C and 600°C. At temperatures below 450°C or above 600°C, it was impossible to form periodic inversion layers. This is because at temperatures below 460° C., the proton exchange layer does not reach the Curie point, so polarization reversal does not occur. Moreover, at 610° C. or higher, not only the proton exchange layer but also the substrate itself reaches the Curie point, so polarization inversion occurs over the entire surface of the substrate, and periodic polarization inversion disappears. The periodically domain-inverted layer 12 produced had a depth of 0.8 μm. A proton exchange waveguide was formed on the surface of the substrate so as to be perpendicular to the periodic polarization inversion layer, and a wavelength conversion element similar to that shown in FIG. 2 was fabricated. The proton exchange waveguide is 2 μm wide and 1 μm deep. Wavelength 800nm, output 40m
The light 6 from the W semiconductor laser was focused by a focusing optical system and made incident on the fabricated wavelength conversion element. The fundamental wave and second harmonics emitted from the waveguide were collimated with a lens and measured with a power meter. As a result, the output of the second harmonic of 7 with a wavelength of 400 nm was 0.2 mW, making it possible to perform conversion with twice the efficiency of the conventional method. In this example, a planar electrode was used to apply the electric field, but if a striped electrode 13 is used only in the area where the polarization inversion layer is to be formed, as shown in FIG. It is selectively applied only to the replacement part. As a result, a deeper polarization inversion layer 12 was formed, with a period of 4 μm and a depth of 1 μm, and a similar second polarization inversion layer 12 was formed.
When a harmonic generation experiment was conducted, an output of 0.3 mW was obtained, making conversion with extremely high efficiency possible. Furthermore, by selectively applying an electric field, it is possible to shorten the period of polarization inversion. Conventionally, only a period of 4 μm could be achieved, but by applying a local electric field, it is possible to shorten the period of polarization inversion with a period of 3 μm and a depth of 0.8 μm.
It is now possible to fabricate a polarization inversion layer with a wavelength of 0.
．． When the light from a 76 μm semiconductor laser was converted, the result was 0.
A second harmonic output of 2 mW was obtained, making it possible to shorten the wavelength. In this example, a plane electrode was used to apply the electric field, but as shown in FIG. 5, two comb-shaped electrodes 14 and 15 were arranged alternately, and one electrode was formed directly above the proton exchange layer. Then, a local electric field is selectively applied only to the proton exchange portion 9, and since the distance between the electrodes is very short, a high electric field is applied.As a result, the polarization inversion layer formed has a period of 4 μm and a depth of 1.5 μm. , which is about twice as much as when it is formed using a flat electrode. When a wavelength conversion element is fabricated using this inversion layer, when light from a semiconductor laser with a wavelength of 0.8 μm and 40 mW is incident, a second harmonic of 1 mW (wavelength 0
．． 4 μm), and a very high conversion efficiency of about 5 times that of a wavelength conversion element formed with a flat electrode was obtained. In this example, the polarization inversion layer was fabricated in the Y propagation direction, but a similar device can also be fabricated in the X propagation direction. Further, in this example, pyrophosphoric acid was used for ion exchange, but phosphoric acid, benzoic acid, nitric acid, hydrochloric acid, sulfuric acid, etc. can also be used. In this embodiment, a Ta film was used as the ionization-resistant mask, but any other acid-resistant film such as Ta2O5 or Pt may be used. Furthermore, although LiTaO3 is used as the substrate in this embodiment, a LiTaO3 substrate doped with MgO may also be used. As shown in FIG. 6, convex stripes with a height of 1 μm and a width of 2 μm are formed on the surface of the LiTaO3 crystal of the X plate in the Y-axis direction, and periodic electrodes 16, form 17. When this electrode was heated at 600°C for 10 minutes while applying a 2V electric field, C
The polarization pointing in the axial direction was periodically reversed in the -C direction. By this method, a periodic polarization inversion layer with a minimum period of 2 μm could be formed in convex stripes. Furthermore, by polishing both end faces of the stripe, a wavelength conversion element was fabricated using this as a waveguide. When 20 mW of light from a semiconductor laser with a wavelength of 680 nm was incident on the produced wavelength conversion element, an SHG output of 0.1 mW at a wavelength of 340 nm was generated, and a high output and short wavelength wavelength conversion element was fabricated. As a result, polarization inversion could not be produced in the past. A wavelength conversion element can be constructed using an X-plate or Y-plate LiTaO3 crystal. Furthermore, since the electric field is applied from both sides of the convex shape, the electric field density can be increased and polarization inversion can be formed with a low voltage. Furthermore, since polarization inversion is formed by applying an electric field from the side, a deep inversion layer can be formed with a short period, and a wavelength conversion element with high efficiency and a short wavelength can be constructed. Note that although an X-plate LiTaO3 crystal was used in this embodiment, a similar element can also be fabricated using a Y-plate LiTaO3 crystal; however, in that case, the convex stripes will propagate along the X axis. Effects of the Invention As explained above, by forming striped electrodes on LiTaO3 crystal and simultaneously applying an electric field and heat-treating it near the Curie point, LiTaO
3 The polarization of the crystal is periodically reversed. This makes it possible to form a periodic polarization inversion layer, and by combining it with an optical waveguide, a wavelength conversion element can be manufactured. As a result of the above, LiTaO3 crystal can form periodic polarization inversion, which has not been achieved before, and Li has excellent resistance to light damage.
A high-output wavelength conversion element can be manufactured using TaO3 crystal, and its practical effects are great. [0023] Furthermore, after partially subjecting the LiTaO3 crystal to proton exchange treatment, by applying an electric field and simultaneously heating it below the Curie temperature and near the Curie temperature,
The lateral spread of the proton exchange layer is restricted by an electric field,
Since the heat treatment can be performed simultaneously, the periodically domain-inverted layer can be formed deeper in the depth direction, and the lateral spread of the domain-inverted layer can be reduced. As a result of the above, deep and short-period polarization inversion can be formed using LiTaO3 crystal, which has not been realized in the past. When a wavelength conversion element is formed by this periodic polarization inversion, highly efficient conversion becomes possible, and a high-output wavelength conversion element can be manufactured using LiTaO3 crystal which has excellent resistance to light damage, which has great practical effects.
【図１】本発明の実施例の波長変換素子製造方法の工程
断面図である。FIG. 1 is a process cross-sectional view of a method for manufacturing a wavelength conversion element according to an embodiment of the present invention.
【図２】波長変換素子の構成斜視図である。FIG. 2 is a perspective view of the configuration of a wavelength conversion element.
【図３】波長変換素子製造方法の工程断面図である。FIG. 3 is a process cross-sectional view of a method for manufacturing a wavelength conversion element.
【図４】波長変換素子製造方法の斜視図である。FIG. 4 is a perspective view of a method for manufacturing a wavelength conversion element.
【図５】波長変換素子製造方法の斜視図である。FIG. 5 is a perspective view of a method for manufacturing a wavelength conversion element.
【図６】波長変換素子製造方法の斜視図である。FIG. 6 is a perspective view of a method for manufacturing a wavelength conversion element.
【図７】従来の波長変換素子製造方法の工程断面図であ
る。FIG. 7 is a process cross-sectional view of a conventional wavelength conversion element manufacturing method.
【図８】従来の波長変換素子製造方法の工程断面図であ
る。FIG. 8 is a process cross-sectional view of a conventional wavelength conversion element manufacturing method.
１ ＬｉＴａＯ３基板 ２ ストライプ状の電極 ３ 電極 ４ 分極反転層 ５ プロトン交換光導波路 ６ 基本波 ７ 第二高調波 ８ Ｔａマスク出射部 ９ プロトン交換層 １０ 電極 １１ 電極 １２ 分極反転層 １３ ストライプ状の電極 １４ 櫛形電極 １５ 櫛形電極 １６ 電極 １７ 電極 １８ 凸型のストライプ ２１ ＬｉＴａＯ３基板 ２２ プロトン交換層 ２３ 分極反転層 ３１ ＬｉＴａ３基板 1 LiTaO3 substrate 2 Striped electrode 3 Electrode 4 Polarization inversion layer 5. Proton exchange optical waveguide 6 Fundamental wave 7 Second harmonic 8 Ta mask emission part 9. Proton exchange layer 10 Electrode 11 Electrode 12 Polarization inversion layer 13 Striped electrode 14 Comb-shaped electrode 15 Comb-shaped electrode 16 Electrode 17 Electrode 18 Convex stripes 21 LiTaO3 substrate 22 Proton exchange layer 23 Polarization inversion layer 31 LiTa3 substrate
Claims (5)
した基板）のＬｉＴａＯ３基板の＋Ｃ表面にストライプ
状の電極パターンを形成する工程と、前記ＬｉＴａＯ３
基板の裏面に電極を形成する工程と、前記ストライプ状
の電極パターンと、前記ＬｉＴａＯ３基板の裏面に形成
した電極の間に電界を印加し、同時に前記ＬｉＴａＯ３
基板をＬｉＴａＯ３のキュリー温度以下で加熱する工程
とを有することを特徴とする波長変換素子の製造方法。1. A step of forming a striped electrode pattern on the +C surface of a LiTaO3 substrate of a C plate (a substrate cut out perpendicular to the C axis of the crystal);
forming an electrode on the back surface of the substrate; applying an electric field between the striped electrode pattern and the electrode formed on the back surface of the LiTaO3 substrate;
A method for manufacturing a wavelength conversion element, comprising the step of heating a substrate at a temperature below the Curie temperature of LiTaO3.
ライプ状のマスクを形成する工程と、前記ＬｉＴａＯ３
基板本体をプロトン交換処理して、非マスク部分から前
記ＬｉＴａＯ３基板内のＬｉとＨ＋イオンを交換しプロ
トン交換層を形成する工程と、前記ＬｉＴａＯ３基板表
面に形成したストライプ状のマスクを除去する工程と、
前記ＬｉＴａＯ３基板の表面と裏面にそれぞれ平面電極
を形成する工程と、前記平面電極間に電界を印加し同時
に前記ＬｉＴａＯ３基板をＬｉＴａＯ３のキュリー温度
以下で加熱する分極反転処理工程とを有することを特徴
とする波長変換素子の製造方法。2. A step of forming a stripe-shaped mask on the surface of the LiTaO3 substrate of the C plate;
A step of performing proton exchange treatment on the substrate body to exchange Li and H+ ions in the LiTaO3 substrate from the non-mask portion to form a proton exchange layer, and a step of removing the striped mask formed on the surface of the LiTaO3 substrate. ,
It is characterized by comprising a step of forming planar electrodes on the front and back surfaces of the LiTaO3 substrate, respectively, and a polarization inversion treatment step of applying an electric field between the planar electrodes and simultaneously heating the LiTaO3 substrate below the Curie temperature of LiTaO3. A method for manufacturing a wavelength conversion element.
ライプ状のマスクを形成する工程と、前記ＬｉＴａＯ３
基板本体をプロトン交換処理して、非マスク部分から前
記ＬｉＴａＯ３基板内のＬｉとＨ＋イオンを交換してプ
ロトン交換層を形成する工程と、前記ＬｉＴａＯ３基板
表面に形成したストライプ状のマスクを除去する工程と
、前記プロトン交換層上面にのみ電極を形成する工程と
、前記ＬｉＴａＯ３基板の裏面に電極を形成する工程と
、前記ＬｉＴａＯ３基板の表裏の電極間に電界を印加し
同時に前記ＬｉＴａＯ３基板をＬｉＴａＯ３のキュリー
温度以下で加熱する分極反転処理工程とを有することを
特徴とする波長変換素子の製造方法。3. A step of forming a stripe-shaped mask on the surface of the LiTaO3 substrate of the C plate;
A step of performing proton exchange treatment on the substrate body to exchange Li and H+ ions in the LiTaO3 substrate from the non-mask portion to form a proton exchange layer, and a step of removing the striped mask formed on the surface of the LiTaO3 substrate. a step of forming an electrode only on the upper surface of the proton exchange layer; a step of forming an electrode on the back surface of the LiTaO3 substrate; and a step of applying an electric field between the front and back electrodes of the LiTaO3 substrate and simultaneously converting the LiTaO3 substrate into a Curie of LiTaO3. 1. A method for manufacturing a wavelength conversion element, comprising a polarization inversion treatment step of heating at a temperature below temperature.
ライプ状のマスクを形成する工程と、前記ＬｉＴａＯ３
基板本体をプロトン交換処理して、非マスク部分から前
記ＬｉＴａＯ３基板内のＬｉとＨ＋イオンを交換してプ
ロトン交換層を形成する工程と、前記ＬｉＴａＯ３基板
表面に形成したストライプ状のマスクを除去する工程と
、前記プロトン交換層直上に櫛形電極を形成する工程と
、前記櫛形電極に交差しない他の櫛形電極を形成する工
程と、前記両櫛形電極間に電界を印加し、同時に前記Ｌ
ｉＴａＯ３基板をＬｉＴａＯ３のキュリー温度以下で加
熱する分極反転処理工程とを有することを特徴とする波
長変換素子の製造方法。4. A step of forming a stripe-shaped mask on the surface of the LiTaO3 substrate of the C plate;
A step of performing proton exchange treatment on the substrate body to exchange Li and H+ ions in the LiTaO3 substrate from the non-mask portion to form a proton exchange layer, and a step of removing the striped mask formed on the surface of the LiTaO3 substrate. a step of forming a comb-shaped electrode directly above the proton exchange layer; a step of forming another comb-shaped electrode that does not intersect the comb-shaped electrode; applying an electric field between both the comb-shaped electrodes;
A method for manufacturing a wavelength conversion element, comprising a polarization inversion treatment step of heating an iTaO3 substrate below the Curie temperature of LiTaO3.
した基板）またはＹ板（結晶のＹ軸に垂直な面）のＬｉ
ＴａＯ３基板の表面に凸型のストライプを形成する工程
と、前記ストライプの両側面に周期的な電極を形成する
工程と、前記電極間に電界を印加し、同時に前記ＬｉＴ
ａＯ３基板をＬｉＴａＯ３のキュリー温度以下で加熱す
る分極反転処理工程とを有することを特徴とする波長変
換素子の製造方法。5. Li on an X plate (a substrate cut on a plane perpendicular to the X axis of the crystal) or a Y plate (a plane perpendicular to the Y axis of the crystal)
A step of forming convex stripes on the surface of the TaO3 substrate, a step of forming periodic electrodes on both sides of the stripe, applying an electric field between the electrodes, and simultaneously applying the LiT
A method for manufacturing a wavelength conversion element, comprising a polarization inversion treatment step of heating an aO3 substrate below the Curie temperature of LiTaO3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3026055A JPH0812366B2 (en) | 1991-02-20 | 1991-02-20 | Method of manufacturing wavelength conversion element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3026055A JPH0812366B2 (en) | 1991-02-20 | 1991-02-20 | Method of manufacturing wavelength conversion element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04264534A true JPH04264534A (en) | 1992-09-21 |
| JPH0812366B2 JPH0812366B2 (en) | 1996-02-07 |
Family
ID=12183002
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3026055A Expired - Lifetime JPH0812366B2 (en) | 1991-02-20 | 1991-02-20 | Method of manufacturing wavelength conversion element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0812366B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0699934A2 (en) * | 1994-08-31 | 1996-03-06 | Matsushita Electric Industrial Co., Ltd. | Method for manufacturing domain-inverted regions and optical wavelength conversion device with the same |
| EP0718671A1 (en) * | 1994-12-09 | 1996-06-26 | Hewlett-Packard Company | Method for forming domain inversion regions and for fabricating wavelength conversion device |
-
1991
- 1991-02-20 JP JP3026055A patent/JPH0812366B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0699934A2 (en) * | 1994-08-31 | 1996-03-06 | Matsushita Electric Industrial Co., Ltd. | Method for manufacturing domain-inverted regions and optical wavelength conversion device with the same |
| EP0699934A3 (en) * | 1994-08-31 | 1996-08-14 | Matsushita Electric Ind Co Ltd | Method for manufacturing domain-inverted regions and optical wavelength conversion device with the same |
| US5652674A (en) * | 1994-08-31 | 1997-07-29 | Matsushita Electric Industrial Co., Ltd. | Method for manufacturing domain-inverted region, optical wavelength conversion device utilizing such domain-inverted region and method for fabricating such device |
| EP0718671A1 (en) * | 1994-12-09 | 1996-06-26 | Hewlett-Packard Company | Method for forming domain inversion regions and for fabricating wavelength conversion device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0812366B2 (en) | 1996-02-07 |
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