JPH09292637A - Second harmonic generating element - Google Patents

Second harmonic generating element

Info

Publication number
JPH09292637A
JPH09292637A JP10811696A JP10811696A JPH09292637A JP H09292637 A JPH09292637 A JP H09292637A JP 10811696 A JP10811696 A JP 10811696A JP 10811696 A JP10811696 A JP 10811696A JP H09292637 A JPH09292637 A JP H09292637A
Authority
JP
Japan
Prior art keywords
formed
waveguide
polarization inversion
forming
inversion regions
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
Application number
JP10811696A
Other languages
Japanese (ja)
Inventor
Shigemasa Ogasawara
茂昌 小笠原
Original Assignee
Kyocera Corp
京セラ株式会社
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kyocera Corp, 京セラ株式会社 filed Critical Kyocera Corp
Priority to JP10811696A priority Critical patent/JPH09292637A/en
Publication of JPH09292637A publication Critical patent/JPH09292637A/en
Application status is Pending legal-status Critical

Links

Abstract

PROBLEM TO BE SOLVED: To make it possible to embody superfine polarization inversion regions having a period below a specific value in order to generate UV light of high output by a primary phase matching condition by forming the plural annular polarization inversion regions along the optical axis of the waveguide formed in a ferroelectric substrate.
SOLUTION: The plural annular polarization inversion regions 3 are formed along the optical axis 2a of the waveguide 2 in the ferroelectric substrate 1 formed with the waveguide 2. The width W of the annular polarization inversion regions is specified to ≤3μm (or the annular width is ≤1μm and the period is ≤2μm), by which the generation of the high-output UV light is made possible. The method for manufacture is executed by patterning a resist by photolithography on the substrate of about 200μm formed as a single domain consisting of lithium niobate, then forming the film of, for example, aluminum, titanium, gold, silver, etc., forming metallic electrodes, thereon by a vapor deposition method and executing lift-off, thereby forming the fine structure periodically formed with the electrodes.
COPYRIGHT: (C)1997,JPO

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【発明の属する技術分野】本発明は、赤色半導体レーザのビームを基本波として、その第2高調波を出力するいわゆる第2高調波発生素子(SHG素子)に関するものであり、特に紫外光波長変換素子に関する。 BACKGROUND OF THE INVENTION The present invention provides a beam of red semiconductor laser as the fundamental wave, relates called second harmonic generation element (SHG element) to output the second harmonic, in particular ultraviolet light wavelength conversion It related to the element. このような第2高調波発生素子はコンパクトな短波長コヒーレント光を得ることによって、光情報システム,レーザプリンタ,計測機器,写真や印刷への応用,生物工学や医療への応用が期待できる。 By such a second harmonic wave generating element to obtain a compact short wavelength coherent light, an optical information system, a laser printer, measurement equipment, application to photographic and printing, application to biotechnology and medical be expected.

【0002】 [0002]

【従来の技術】近年、デジタルビデオディスクなどの高密度光記録に適用させる小型短波長コヒーレント光源として、青色光源に対する要望が高まっており、赤外半導体レーザの波長変換により青色コヒーレント光を実現する第2高調波発生素子が注目されている。 In recent years, as a small short-wavelength coherent light source for applying a high-density optical recording such as a digital video disk, there is an increasing demand for blue light source, the realizing blue coherent light by the wavelength conversion of the infrared semiconductor laser SHG element has attracted attention.

【0003】また、この第2高調波発生素子の基板材料としては、例えばニオブ酸リチウム(LiNbO 3 )、 [0003] As the substrate material of the second harmonic generation device, for example, lithium niobate (LiNbO 3),
タンタル酸リチウム(LiTaO 3 )、チタン酸リン酸カリウム(KTiOPO 4 )、ニオブ酸カリウム(KN Lithium tantalate (LiTaO 3), potassium titanate phosphate (KTiOPO 4), potassium niobate (KN
bO 3 )などの無機酸化物があり、いずれも大きな非線形光学定数を有する点で好適に用いられる。 bO 3) There are inorganic oxides such as, any suitably used in that it has a large nonlinear optical constant. 就中、Li Among other things, Li
NbO 3やLiTaO 3は比較的大きな非線形光学定数を有し、しかも、安価に供給されるので、第2高調波発生素子用材料として大変有望視されている。 NbO 3 and LiTaO 3 has a relatively large nonlinear optical constant, moreover, since it is supplied at low cost, is very promising for the second harmonic generation element material.

【0004】かかる第2高調波発生素子は、角周波数ω [0004] Such second harmonic generation device, the angular frequency ω
の基本波を入射し、これによって角周波数2ωの出力を取り出すという機能部品であって、基本波と出力波との双方の波数を疑似的に整合させ、これにより、その出力を大きくできる、いわゆる周期分極反転領域を利用している。 A functional component of the fundamental wave incident in, thereby extracting an output of the angular frequency 2 [omega, artificially align the wave number of both the fundamental wave and the output wave, thereby, can be increased and the output, so-called It utilizes periodic polarization inversion region.

【0005】 [0005]

【発明が解決しようとする課題】第2高調波発生素子を用いて紫外光を得るためには、約1.5μm 程度の周期を有する超微細分極反転領域を作製すればよいが、これほど微細な周期構造は実現されておらず、せいぜい2. To obtain INVENTION Problems to be Solved ultraviolet light using a second harmonic generation element may but be manufactured ultrafine polarization inversion region having a period of about 1.5 [mu] m, this finer periodic structure has not been realized, at most 2 such.
7μm 周期が限界であった。 7μm period was the limit. すなわち、従来は分極反転用の微細電極は微細加工の限界で最小幅0.5μm 程度であるが、印加させる電界の広がりのため、分極反転領域はこれを大きく越えしまい、実際には電極幅が1.3 That is, the fine electrodes of conventional polarized inversion is the minimum width 0.5μm about at the limit of fine processing, since the spread of the electric field for applied, the polarization inversion region would greatly exceed this, actually electrode width 1.3
μm (周期は2.6μm )を越えてしまうからである。 [mu] m (period 2.6 [mu] m) because it exceeds the.

【0006】また、2次や3次の下記式(1)の位相整合条件を用いて、長い分極反転周期(約3μm )を利用した紫外光発生を試みた場合もあるが(信学技報LQE [0006] The secondary or 3 with the following phase matching condition of the following formula (1), long poling period when trying to ultraviolet light generation using (approximately 3 [mu] m) there is also (IEICE LQE
95−94(1995−11),p. 95-94 (1995-11), p. 7〜12を参照)、2次や3次では高出力が得られない。 Referring to 7-12), the secondary or tertiary not high output can be obtained.

【0007】 Λ = 2mλ/4(n(2ω) −n (ω)) ・・・ (1) (ただし、Λ:周期,m:次数(=1,2,・・・), λ: n(2ω) :実効屈折率(角周波数2ωの場合), n (ω) :実効屈折率(角周波数ωの場合)。 [0007] Λ = 2mλ / 4 (n (2ω) -n (ω)) ··· (1) (However, Λ: period, m: order (= 1,2, ···), λ: n ( 2ω): in the case of the effective refractive index (angular frequency 2ω), n (ω): effective refractive index (in the case of the angular frequency ω).

【0008】そこで、本発明では1次の位相整合条件による高出力の紫外光を発生させるため、従来困難であった2μm 以下の周期を持つ超微細分極反転領域を実現する第2高調波発生素子を提供することを目的とする。 [0008] In order to generate the ultraviolet light of a high output by the primary phase matching conditions in the present invention, the second harmonic generation device for ultra fine domain-inverted region having a conventional which was difficult 2μm or less of the period an object of the present invention is to provide a.

【0009】 [0009]

【課題を解決するための手段】上記課題を解決する本発明の第2高調波発生素子は、導波路が形成された強誘電体基板中に、前記導波路の光軸に沿って環状の分極反転領域が複数形成されていることを特徴とする。 To solve the above problems SUMMARY OF THE INVENTION The second harmonic generation device of the present invention, the ferroelectric during board in which a waveguide is formed, the waveguide polarization annular along the optical axis wherein the inversion region are formed. また、環状の分極反転領域の幅が3μm 以下(もしくは、環幅が1μm 以下,周期が2μm 以下)であることを特徴とする。 The width of the domain-inverted region of annular 3μm or less (or, the ring width of 1μm or less, the period is 2μm or less), characterized in that a.

【0010】ここで、このような微細な分極反転領域を作製するために、基板上に予め形成させた梯子状電極もしくは立体的な波板電極に対して印加させる抑制電流が正負を跨いで振動するように制御を与えた電圧・電流でもって、周期が2μm 以下の分極反転領域を形成させることができる。 [0010] In order to produce such a fine domain inversion regions, inhibition current to applied to a ladder electrode or a three-dimensional wave plate electrodes were pre-formed on the substrate across the positive and negative oscillation with voltage-current gives control so that the period can be formed below the domain-inverted regions 2 [mu] m.

【0011】 [0011]

【発明の実施の形態】以下に、本発明の実施形態について図面に基づき詳細に説明する。 DETAILED DESCRIPTION OF THE INVENTION Hereinafter, will be described embodiments with reference to the drawings in detail of the present invention. 図1は、導波路2が形成された強誘電体の基板1中に、導波路2の光軸2aに沿って環状の分極反転領域3が複数形成されている第2 1, in the substrate 1 of the ferroelectric waveguide 2 is formed, the annular polarization inversion region 3 along the optical axis 2a of the waveguide 2 is formed with a plurality 2
高調波発生素子Sである。 A harmonic generating element S. ここで、環状の分極反転領域の幅Wが3μm 以下(もしくは、環幅が1μm 以下,周期が2μm 以下)となっており、このような、第2高調波発生素子Sは高出力の紫外光を発生させることができる。 Here, the width W of the domain-inverted region of the annular 3μm or less (or, the ring width of 1μm or less, the period is 2μm or less) has a, such second harmonic generation element S is ultraviolet light of a high output it can be generated.

【0012】次に、この第2高調波発生素子Sの作製方法について説明する。 [0012] Next, a method for manufacturing the second harmonic generating element S. 例えば、ニオブ酸リチウムの基板の+Z面に超微細な分極反転領域を作製する場合を例にとり説明する。 For example, it will be described as an example the case of producing a ultra fine domain inversion regions on the + Z face of the lithium niobate substrate. ニオブ酸リチウムから成る単一分域化された約200 μm 程度の基板に対して、フォトリソグラフィによってレジストをパターニングした上で、金属電極となる例えばアルミニウム(Al), チタン(Ti), Versus about 200 [mu] m approximately of substrates single-domain of made of lithium niobate, on which a resist is patterned by photolithography, the metal electrodes such as aluminum (Al), titanium (Ti),
金(Au), 銀(Ag)等を蒸着法によって成膜し、リフトオフを行うことによって電極が周期を成す微細構造となるように形成する。 Gold (Au), silver (Ag) or the like is deposited by evaporation, the electrode is formed such that the microstructure forms a cycle by performing lift-off.

【0013】この際の電極パターンは、一見、梯子状にし、その梯子状電極の幅は50μm 程度でよい。 [0013] electrode pattern in this case, seemingly, the ladder, the width of the ladder-shaped electrode may be about 50 [mu] m. なお、基板の裏面には一様な共通電極を成膜する。 Incidentally, forming a uniform common electrode on the back surface of the substrate. ここで、電極の膜厚はいずれも3000Å前後でよい。 Here, both the thickness of the electrode may be a back and forth 3000 Å. また、梯子状電極の代わりに、立体型のいわゆる波板電極を作製する場合は、リフトオフは行わない。 Further, instead of the ladder electrode, the case of producing a so-called corrugated plate electrode of a three-dimensional type, lift-off is not performed.

【0014】次に、この電極を表裏に配した基板に、パルス状の電圧を図2に示す波形をなすように印加する。 [0014] Next, the substrate which arranged the electrode on the front and back, a pulse voltage is applied so as to form a waveform shown in FIG.
ここで、パルス幅は数百μs,ピーク電圧は22kV程度とする。 Here, the pulse width hundreds .mu.s, the peak voltage is about 22 kV. 流れる電流は、平均して数mA〜数百mAとし、1つのパルス内で正負に振動するように変調をかけるか、もしくは負帰還制御を行う。 The current flowing to the average of several mA~ several hundred mA, or modulates to oscillate between positive and negative, or negative feedback control is carried out in a single pulse.

【0015】次に、上記電極をエッチングして剥離させ、さらに導波路状のパターンができるようにパターニングを行い、タンタル(Ta),白金(Pt),金(A Next, by peeling by etching the electrode, to perform patterning can further waveguide-like pattern, tantalum (Ta), platinum (Pt), gold (A
u),シリカ(SiO 2 )膜等後記する高温のプロトン交換液に耐える金属を成膜し、リフトオフを行った上、 u), silica (SiO 2) forming a metal to withstand proton exchange liquid hot to be described later or the like film, after performing lift-off,
例えば、特にTa膜を成膜した場合は230℃のピロリン酸に15分間浸けることで、プロトン交換導波路が形成される。 For example, in particular Ta film by the dipping 15 minutes pyrophosphate 230 ° C. If it is deposited, a proton exchange waveguide is formed. なお、導波路形成には、プロトン交換液としてリン酸,安息香酸等も使用できる。 Note that the waveguide forming, phosphoric acid as the proton exchange liquid, such as benzoic acid can also be used. そして、しかる後に、Ta膜を成膜した場合には20%のNaOH水溶液で除去し、所望のサイズに基板をカットし、端面を研磨することで第2高調波発生素子が作製される。 Then, thereafter, the the case of forming the Ta film is removed with 20% NaOH aqueous solution, and cutting the substrate into a desired size, the second harmonic wave generating element is produced by polishing the end face.

【0016】ここで、入力光として720nmの赤色半導体レーザを用意すれば、360nmの紫外光が得られるが、この時、ニオブ酸リチウムの基板に作製する超微細分極反転領域の周期は、図3における周期Λ=1.5μ [0016] Here, by preparing a red semiconductor laser of 720nm as the input light, although 360nm ultraviolet light is obtained, the period of this time, the ultrafine domain-inverted region to produce a substrate of lithium niobate, 3 cycle in Λ = 1.5μ
m が必要とされる。 m is required. ここで、λ1とλ2とはほぼ等しく、分極反転領域の幅(Λ+λ1)は3μm 以下とすることができる。 Here, approximately equal to the .lambda.1 and .lambda.2, the width of the domain-inverted regions (Λ + λ1) can be 3μm or less. したがって、作製時の金属電極4の周期は3μm でよい。 Therefore, the period of the metal electrode 4 at the time of manufacturing can be a 3 [mu] m. このような方法で分極反転領域を作製する場合、電極のエッジ直下で電界が集中する効果と、 Case of manufacturing a polarization inversion region in this manner, the effect of the electric field is concentrated immediately below the edge of the electrode,
反転作製時に流れる反転電流が正負に振れることによる効果が相乗されて、電極下でありながら反転しない領域が現れることが判明した。 Switching current flowing at the time of reversal produced is a synergistic effect due to swing positive or negative, a region not reversed that appears found yet under the electrode. これを利用することにより、 By utilizing this,
電極周期の半分の周期を有する超微細分極反転領域が実現できるので、1次の位相整合条件を満足する紫外光を発生させる第2高調波発生素子が可能となる。 Since the ultrafine polarization inversion region having half the period of the electrode period can be realized, a second harmonic generation element for generating ultraviolet light that satisfies the first-order phase matching conditions is possible. そして、 And,
分極反転領域の形状の特徴として環状となるのである。 It become annular as a feature of the shape of the domain-inverted region.

【0017】なお、上記の場合、導波路型プロトン交換層を持つ例を示したが、バルクとして導波路方向に細長くして、これに分極反転を直交させても、第2高調波発生素子となり得るに足りる深い(1.5μm 以上)分極反転ができる。 [0017] Incidentally, in the above case, the example having a waveguide-type proton exchange layer, and elongated in the waveguide direction as a bulk, even this is orthogonal to polarization reversal, it becomes the second harmonic wave generating element deep enough to obtain (1.5 [mu] m or more) can poled.

【0018】また、本発明は上記実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲内で種々の変更や改良等は何ら差し支えない。 Further, the present invention is not limited to the above embodiments, various modifications and improvements, etc. within a scope not departing from the gist of the present invention is no problem. 例えば、上記実施形態では、強誘電体材料の基板としてニオブ酸リチウムを使用したが、その他にタンタル酸リチウム、LiNb For example, in the above embodiment, the use of lithium niobate as the substrate of ferroelectric material, other lithium tantalate, LiNb
x Ta 1-x (0<x <1)、チタン酸リン酸カリウム、ニオブ酸カリウム等の基板を使用しても同様な作用効果が得られる。 x Ta 1-x (0 < x <1), potassium titanate phosphate, the same effects can be obtained by using a substrate such as a potassium niobate.

【0019】 [0019]

【発明の効果】以上詳述したように、本発明の第2高調波発生素子によれば、従来では実現が困難であった周期が2μm 以下の非常に微細な分極反転領域を有するものが容易に作製することが可能となる。 As described above in detail, according to the second harmonic generation device of the present invention, facilitates what period realized is difficult in the conventional has the following very fine domain inversion regions 2μm it is possible to manufacture the.

【0020】これにより、高出力の紫外光を発光する第2高調波発生素子が実現される。 [0020] Thus, the second harmonic generation device that emits ultraviolet light of a high output is realized. また、第2高調波発生素子の作製に用いる微細電極は作製する反転周期の2倍でよいので、ステッパー等の高価な装置を使用することなく、安価な直接露光プロセスで充分に対応が可能となる。 Further, since the fine electrodes for use in the production of the second harmonic generation element may be twice the inversion cycle of producing, without using an expensive apparatus such as a stepper, and can sufficiently cope with inexpensive direct exposure process Become.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】本発明の実施形態の第2高調波発生素子の斜視図である。 1 is a perspective view of a second harmonic generation device of an embodiment of the present invention.

【図2】(a)は分極反転領域を作製するための電圧波形を示す図、(b)は電流波形を示す図である。 Figure 2 (a) is a diagram showing a voltage waveform for producing a domain-inverted region is a diagram showing a (b) is a current waveform.

【図3】分極反転領域と微細電極の相関を説明する平面図である。 3 is a plan view for explaining the correlation of the domain-inverted regions and fine electrodes.

【符号の説明】 DESCRIPTION OF SYMBOLS

1 ・・・ 基板 2 ・・・ 導波路 2a・・・ 光軸 3 ・・・ 分極反転領域 S ・・・ 第2高調波発生素子 1 ... substrate 2 ... waveguide 2a ... optical axis 3 ... poled regions S ... second harmonic generation element

Claims (2)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】 導波路が形成された強誘電体基板中に、 To 1. A ferroelectric in board in which a waveguide is formed,
    前記導波路の光軸に沿って環状の分極反転領域が複数形成されていることを特徴とする第2高調波発生素子。 The second harmonic generation device characterized by cyclic polarization inversion region along the optical axis of the waveguide are formed.
  2. 【請求項2】 請求項1に記載の第2高調波発生素子であって、前記環状の分極反転領域の幅が3μm 以下であることを特徴とする第2高調波発生素子。 2. A second harmonic generation device according to claim 1, the second harmonic wave generating element, wherein the width of the domain-inverted region of the annular is 3μm or less.
JP10811696A 1996-04-26 1996-04-26 Second harmonic generating element Pending JPH09292637A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP10811696A JPH09292637A (en) 1996-04-26 1996-04-26 Second harmonic generating element

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10811696A JPH09292637A (en) 1996-04-26 1996-04-26 Second harmonic generating element

Publications (1)

Publication Number Publication Date
JPH09292637A true JPH09292637A (en) 1997-11-11

Family

ID=14476323

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10811696A Pending JPH09292637A (en) 1996-04-26 1996-04-26 Second harmonic generating element

Country Status (1)

Country Link
JP (1) JPH09292637A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100823901B1 (en) * 2003-08-26 2008-04-21 오끼 덴끼 고오교 가부시끼가이샤 Wavelength conversion element and method for using same
WO2014045658A1 (en) * 2012-09-20 2014-03-27 富士電機株式会社 Wavelength conversion element, light source device, and method for manufacturing wavelength conversion element

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100823901B1 (en) * 2003-08-26 2008-04-21 오끼 덴끼 고오교 가부시끼가이샤 Wavelength conversion element and method for using same
WO2014045658A1 (en) * 2012-09-20 2014-03-27 富士電機株式会社 Wavelength conversion element, light source device, and method for manufacturing wavelength conversion element
JP2014062960A (en) * 2012-09-20 2014-04-10 Fuji Electric Co Ltd Wavelength conversion element, light source device, and manufacturing method of wavelength conversion element

Similar Documents

Publication Publication Date Title
Lim et al. Blue light generation by frequency doubling in periodically poled lithium niobate channel waveguide
Byer Quasi-phasematched nonlinear interactions and devices
Pruneri et al. 49 mW of cw blue light generated by first-order quasi-phase-matched frequency doubling of a diode-pumped 946-nm Nd: YAG laser
US5640405A (en) Multi quasi phase matched interactions in a non-linear crystal
US5875053A (en) Periodic electric field poled crystal waveguides
DE69531917T2 (en) Method of manufacturing inverted domains and an optical wavelength converter using the same
US5193023A (en) Method of controlling the domain of a nonlinear ferroelectric optics substrate
EP0683535B1 (en) A method of forming regions of a selected ferroelectric polarization within a body formed of ferroelectric material
Yamada et al. First‐order quasi‐phase matched LiNbO3 waveguide periodically poled by applying an external field for efficient blue second‐harmonic generation
Kintaka et al. High-efficiency LiNbO/sub 3/waveguide second-harmonic generation devices with ferroelectric-domain-inverted gratings fabricated by applying voltage
US5787102A (en) Light generating device and method using a periodically structured non-linear material and orthogonal optical interaction
EP0759182A1 (en) Fabrication of patterned poled dielectric structures and devices
Mizuuchi et al. Harmonic blue light generation in bulk periodically poled LiTaO3
Harada et al. Bulk periodically poled MgO‐LiNbO3 by corona discharge method
Yamada Electrically induced Bragg-diffraction grating composed of periodically inverted domains in lithium niobate crystals and its application devices
Burns et al. Second harmonic generation in field poled, quasi-phase-matched, bulk LiNbO/sub 3
EP0981067A2 (en) A method for forming a ferroelectric domain-inverted structure
Matsumoto et al. Quasiphase-matched second harmonic generation of blue light in electrically periodically-poled lithium tantalate waveguides
Sugita et al. 31%-efficient blue second-harmonic generation in a periodically poled MgO: LiNbO 3 waveguide by frequency doubling of an AlGaAs laser diode
JP3109109B2 (en) The method of manufacturing an optical device unit having a periodic domain inversion structure
EP0485159A2 (en) Waveguide type second-harmonic generation element and method of producing the same
EP0532969B1 (en) Process for fabricating an optical device for generating a second harmonic optical beam
JP2004219845A (en) Optical waveguide device, coherent light source using the same, and optical apparatus provided with the same
US5253259A (en) Frequency doubler and visible laser source having a heater
FR2684772A1 (en) Optical index network electrically controlled.