JPH07117603B2 - Anti-reflection film for Faraday rotator - Google Patents
Anti-reflection film for Faraday rotatorInfo
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- JPH07117603B2 JPH07117603B2 JP1303365A JP30336589A JPH07117603B2 JP H07117603 B2 JPH07117603 B2 JP H07117603B2 JP 1303365 A JP1303365 A JP 1303365A JP 30336589 A JP30336589 A JP 30336589A JP H07117603 B2 JPH07117603 B2 JP H07117603B2
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、光アイソレータ，光サーキュレータ等に用い
られるファラデー回転子の磁性ガーネット厚膜に被覆す
る反射防止膜に関し更に詳しくはビスマス（Bi）置換磁
性ガーネット厚膜の反射防止膜に関する。The present invention relates to an antireflection film for coating a magnetic garnet thick film of a Faraday rotator used in optical isolators, optical circulators, etc. More specifically, bismuth (Bi) substitution A magnetic garnet thick film antireflection film.
半導体レーザを用いる光ファイバ通信や光計測等におい
て、光コネクタなどの光学部品からの反射光が再び半導
体レーザに戻るとレーザ発振が不安定になり、周波数特
性の劣化や雑音発生の原因となる。そこで、光レーザ発
振を安定に行わせるために反射戻り光を遮断すめ光アイ
ソレータが必要であるが、特に、最近の高速伝送用とし
て実用化の進んでいるDFB（分布帰環:Distributed Feed
−Back）型半導体レーザは、単一モード発振であるため
に反射光に対して非常に敏感であり、高性能な光アイソ
レータが要求される。これにはファラデー回転子が好適
で、このファラデー回転子には、従来、FZ（フローティ
ング ゾーン）法によって育成するYIG（Y3Fe5O12）の
バルク単結晶が用いられてきたが、近年、大量生産が可
能で安価なLPE（液相エピタキシー）法によって育成す
るBi置換磁性ガーネット厚膜が注目されている。さら
に、Bi置換磁性ガーネット厚膜はYIGのバルク単結晶に
比べて、ファラデー回転係数が大きいために膜厚を薄く
することが可能で光アイソレータを小型化することがで
き、且つ価格低下もできる。Bi置換磁性ガーネット厚膜
は、Gd系、YbTb系共にフラックス成分としてPbO−Bi2O3
−B2O3を用い、基板には（GdCa）３（GaMgZr）5O12を用
いてLPE法により、（GdBi）３（FeAlGa）5O12、または
（YbTbBi）3Fe5O12の約500μｍの単結晶膜を育成したの
ち、両面を光学研磨により、ファラデー回転角が45度に
なるような膜厚にされる。さらに、このBi置換磁性ガー
ネット厚膜には、半導体レーザの反射戻り光を遮断する
ための反射防止膜を施す必要があるが、従来は単層のSi
O2膜が用いられている。この反射率が理論上ゼロになる
単層反射防止膜の屈折率は基板の屈折率の平方根で与え
られるが、基板であるBi置換磁性ガーネット厚膜とし
て、もっぱら使用されている（GdBi）（FeAlGa）5O12お
よび（YbTbBi）3Fe5O12のレーザ波長1.31μｍと1.55μ
ｍに対応する屈折率（ｎ）は前者では2.25,2.22、後者
では2.35,2.34である。従って反射防止膜の、屈折率と
しては前者では1.50、後者では1.53が要求される。これ
に対してSiO2膜ではレーザー波長が1.31μｍに対してｎ
＝1.45,1.55μｍに対してｎ＝1.44であり、要求される
ものより小であるが、（GdBi）３（FeAlGa）5O12の厚膜
に被覆した場合、各波長に対する反射率の理論値は0.11
5％と0.116％であり、（YbTbBi）3Fe5O12の場合は0.309
％と0.364％である。前記したDFB型半導体レーザに用い
る光アイソレーターにおいては、この反射防止膜の反射
率が0.1％以下であることが求められており、且つ地下
通信回線や海底通信回線等に用いられるので高温高湿度
に対する耐久性もあわせて要求されている。In optical fiber communication and optical measurement using a semiconductor laser, when reflected light from an optical component such as an optical connector returns to the semiconductor laser again, laser oscillation becomes unstable, which causes deterioration of frequency characteristics and noise generation. Therefore, it is necessary to use an optical isolator to block the reflected return light in order to stabilize the optical laser oscillation. Especially, the DFB (Distributed Return: Distributed Feed) which has been put into practical use recently for high-speed transmission.
Since the −Back) type semiconductor laser is a single mode oscillation, it is very sensitive to reflected light, and a high performance optical isolator is required. A Faraday rotator is suitable for this purpose. Conventionally, a YIG (Y 3 Fe 5 O 12 ) bulk single crystal grown by the FZ (floating zone) method has been used for this Faraday rotator. Bi-substituted magnetic garnet thick films grown by the LPE (liquid phase epitaxy) method, which can be mass-produced and are inexpensive, are attracting attention. Further, the Bi-substituted magnetic garnet thick film has a large Faraday rotation coefficient as compared with the YIG bulk single crystal, so that the film thickness can be reduced, the optical isolator can be downsized, and the cost can be reduced. The Bi-substituted magnetic garnet thick film contains PbO-Bi 2 O 3 as a flux component in both Gd and YbTb systems.
-B 2 O 3 is used, and (GdCa) 3 (GaMgZr) 5 O 12 is used as the substrate, and by the LPE method, about (GdBi) 3 (FeAlGa) 5 O 12 or (YbTbBi) 3 Fe 5 O 12 After growing a 500 μm single crystal film, both sides are optically polished to a film thickness such that the Faraday rotation angle becomes 45 degrees. Furthermore, this thick Bi-substituted magnetic garnet film must be coated with an antireflection film to block the reflected return light of the semiconductor laser.
An O 2 film is used. The refractive index of a single-layer antireflection film where this reflectance theoretically becomes zero is given by the square root of the refractive index of the substrate, but it is used exclusively as the substrate Bi-substituted magnetic garnet thick film (GdBi) (FeAlGa ) 5 O 12 and (YbTbBi) 3 Fe 5 O 12 laser wavelengths 1.31 μm and 1.55 μm
The refractive index (n) corresponding to m is 2.25,2.22 for the former and 2.35,2.34 for the latter. Therefore, the refractive index of the antireflection film is required to be 1.50 for the former and 1.53 for the latter. On the other hand, for the SiO 2 film, the laser wavelength is 1.31 μm and n
= 1.45, 1.55 μm, n = 1.44, which is smaller than the required value, but when coated with a thick film of (GdBi) 3 (FeAlGa) 5 O 12 the theoretical value of reflectance for each wavelength Is 0.11
5% and 0.116%, 0.309 for (YbTbBi) 3 Fe 5 O 12.
% And 0.364%. In the optical isolator used for the DFB semiconductor laser described above, the reflectance of this antireflection film is required to be 0.1% or less, and since it is used for underground communication lines and submarine communication lines, etc. Durability is also required.
しかしながら、現在用いられている電子ビーム蒸着法に
よるSiO2膜では未だ不十分である。However, the SiO 2 film by the electron beam evaporation method currently used is still insufficient.
上記問題点を解決するために、本発明の目的は反射率が
0.1％以下で、高温高湿度下での耐久性も優秀なファラ
デー回転子のBi置換磁性ガーネット厚膜の反射防止膜を
提供することにある。In order to solve the above problems, the object of the present invention is to improve the reflectance.
It is to provide an antireflection film of a Bi-substituted magnetic garnet thick film of a Faraday rotator, which has an excellent durability under high temperature and high humidity of 0.1% or less.
すなわち、本発明は、 ビスマス置換磁性ガーネット厚膜から成るファラデー回
転子の反射防止膜を前提とし、 上記ビスマス置換磁性ガーネット厚膜の表面に設けられ
る反射防止膜が、 蒸着法により順次成膜された屈折率nAでその光学的膜厚
がnAdAの第１層膜と、屈折率nBでその光学的膜厚がnBdB
の第２層膜及び屈折率nAでその光学的膜厚がnAdAの第３
層膜から成りその屈折率がnEである３層等価膜（但し、
nA＜nE＜nBであり、dAは第１層膜と第３層膜の物理的膜
厚、dBは第２層膜の物理的膜厚を示す）にて構成され、 かつ、上記第１層膜と第３層膜を構成する材料がSiO2で
あり、第２層膜を構成する材料がAl2O3、ZrO2、TiO2、T
a2O5、HfO2及びY2O3の中から選ばれたいずれかの１種で
あると共に、 nA、nB及びnEが下記数式（１）〜（３）を具備すること
を特徴とする。That is, the present invention is premised on an antireflection film of a Faraday rotator composed of a bismuth-substituted magnetic garnet thick film, and the antireflection film provided on the surface of the bismuth-substituted magnetic garnet thick film is sequentially formed by a vapor deposition method. A first layer film having a refractive index n A and an optical film thickness n A d A, and a first layer film having a refractive index n B and an optical film thickness n B d B
Of the second layer and the third layer having a refractive index of n A and an optical film thickness of n A d A
A three-layer equivalent film consisting of a layer film and having a refractive index of n E (however,
n A <n E <n B , d A is the physical film thickness of the first layer film and the third layer film, and d B is the physical film thickness of the second layer film), and , The material forming the first layer film and the third layer film is SiO 2 , and the material forming the second layer film is Al 2 O 3 , ZrO 2 , TiO 2 , T
a 2 O 5 , HfO 2 and Y 2 O 3 and any one of them is selected, and n A , n B and n E have the following formulas (1) to (3). Characterize.
（但し、nAdA/λ＝δA/2π、nBdB/λ＝δB/2πであり、
かつ、λはレーザ光の使用波長を示す。） 〔作 用〕 本発明にて使用することのできるBi置換磁性ガーネット
厚膜はGd系やYbTb系等があげられ、例えば（GdBi）
３（FeAlGa）5O12や（YbTbBi）3Fe5O12等が好適であ
る。これらは（GdCa）３（GaMgZr）5O12を基板に用いて
LPE法でPbO−Bi2O3−B2O3をフラックスとして約500μｍ
の単結晶を育成し、両面を光学研磨して、ファラデー回
転角が45度になるようにしたものであればよい。 (However, n A d A / λ = δ A / 2π, n B d B / λ = δ B / 2π,
In addition, λ indicates the used wavelength of the laser light. ) [Operation] Examples of the Bi-substituted magnetic garnet thick film that can be used in the present invention include Gd-based and YbTb-based films, for example (GdBi)
3 (FeAlGa) 5 O 12 and (YbTbBi) 3 Fe 5 O 12 are suitable. These use (GdCa) 3 (GaMgZr) 5 O 12 as the substrate
About 500 μm with PbO-Bi 2 O 3 -B 2 O 3 as flux by LPE method
Any single crystal may be grown as long as it has a Faraday rotation angle of 45 degrees.
該３層等価膜は「Thin−film optical filters 2nd ed
n」（H.A.Macleod,Bristol Adam Hilger Ltd p.118〜12
2,1986）に述べられているように、２種類の屈折率が異
なる膜ＡおよびＢを用いて、Ａ−Ｂ−Ａ又はＢ−Ａ−Ｂ
なる３層よりなる膜を形成しＡおよびＢの中間的屈折率
を有する膜となすものである。すなわち、低屈折率膜Ａ
の屈折率をnA、高屈折率膜Ｂの屈折率をnBとし必要とす
る屈折率をnEとする。但し、得られる３層等価膜はＡ−
Ｂ−Ａなる構造を有し、nA＜nE＜nBである。１層目と３
層目の光学的膜厚nAdAと２層目のnBdBは下記数式（１）
〜（３）で示すことができる。The three-layer equivalent film is "Thin-film optical filters 2nd ed.
n ”(HAMacleod, Bristol Adam Hilger Ltd p.118-12
2, 1986), two kinds of films A and B having different refractive indexes are used to produce A-B-A or B-A-B.
A film having three layers is formed to form a film having an intermediate refractive index between A and B. That is, the low refractive index film A
, N A , the refractive index of the high refractive index film B is n B, and the required refractive index is n E. However, the obtained three-layer equivalent film is A-
Has a B-A made structure, a n A <n E <n B . 1st layer and 3
The optical film thickness n A d A of the layer and n B d B of the second layer are represented by the following mathematical formula (1)
~ (3) can be shown.
（但し、nAdA/λ＝δA/2π、nBdB/λ＝δB/2πであり、
かつ、λはレーザ光の使用波長を示す。） 本発明では、SiO2で構成される第１層膜並びに第３層膜
と、Al2O3、ZrO2、TiO2、Ta2O5、HfO2、Y2O3の中から選
ばれた１種にて構成される第２層膜との組み合わせによ
る３層等価膜が適当であるが、上記ビスマス置換磁性ガ
ーネット厚膜の表面との親和性や耐高温高湿度性の点
で、第１層膜、第２層膜、第３層膜がSiO2−Al2O3−SiO
2の順で構成される３層等価膜が望ましい。 (However, n A d A / λ = δ A / 2π, n B d B / λ = δ B / 2π,
In addition, λ indicates the used wavelength of the laser light. In the present invention, the first layer film and the third layer film composed of SiO 2 and Al 2 O 3 , ZrO 2 , TiO 2 , Ta 2 O 5 , HfO 2 and Y 2 O 3 are selected. A three-layer equivalent film by combining with the second layer film composed of one kind is suitable, but in terms of affinity with the surface of the above bismuth-substituted magnetic garnet thick film and high temperature and high humidity resistance, The first layer film, the second layer film and the third layer film are SiO 2 —Al 2 O 3 —SiO
A three-layer equivalent film constructed in the order of 2 is desirable.
本発明の３層等価膜は蒸着法で成膜することが重要であ
るが、特にイオンアシスト蒸着法が好適である。該イオ
ンアシスト蒸着法は、真空蒸着中の低エネルギーイオン
ビームを蒸着前または蒸着中に基板に照射する方法であ
り、基板表面の清浄化、薄膜付着力の向上、充填密度の
向上等に有効である。It is important that the three-layer equivalent film of the present invention is formed by a vapor deposition method, but an ion assisted vapor deposition method is particularly preferable. The ion-assisted vapor deposition method is a method of irradiating a substrate with a low-energy ion beam during vacuum vapor deposition before or during vapor deposition, and is effective for cleaning the substrate surface, improving thin film adhesion, and improving packing density. is there.
〔実施例−１〕 エピタキシャル基板として２インチの（GdCa）３（GaMg
Zr）5O12のウェハーと、フラックス成分としてPbO−Bi2
O3−B2O3とを用いてLPE法によりBi置換磁性ガーネット
厚膜（GdBi）３（FeAlGa）5O12および（YbTbBi）3Fe5O
12をそれぞれ約500μｍの厚さに育成した。エピタキシ
ャル基板とBi置換磁性ガーネット厚膜の界面における反
射損失を除くためにエピタキシャル基板を削除したの
ち、両面を光学研磨によりファラデー回転角が45度とな
るような膜厚にした。これらのBi置換磁性ガーネット厚
膜を洗剤，有機洗剤等を用いて超音波洗浄を行った。次
にSiO2とAl2O3蒸着材料をそれぞれハースに入れイオン
アシスト蒸着装置に設置し、準備したBi置換磁性ガーネ
ット厚膜をセットした後、300℃に加熱しながら、３×1
0-6torrまで排気した。Al2O3の蒸着時には、酸素ガスを
１×10-4torrまで導入した。イオン化ガスには酸素また
はアルゴンまたは酸素とアルゴンの混合ガスを用いた。
第１表に示すようにレーザー光の使用波長1.31μｍと1.
55μｍに対応した３層等価膜のそれぞれの光学的膜厚に
合せるように光学的干渉モニターにより各層の膜厚を制
御しSiO2−Al2O3−SiO2からなる膜を作成した。得られ
た反射防止膜のそれぞれの波長における反射率を測定し
たところ、第１表に示すようにいずれの膜でも0.04〜0.
06％と極めて低い結果であった。[Example-1] 2-inch (GdCa) 3 (GaMg) as an epitaxial substrate
Zr) 5 O 12 wafer and PbO-Bi 2 as flux component
Bi-substituted magnetic garnet thick film (GdBi) 3 (FeAlGa) 5 O 12 and (YbTbBi) 3 Fe 5 O by LPE method using O 3 -B 2 O 3
Each 12 was grown to a thickness of about 500 μm. After removing the epitaxial substrate in order to eliminate the reflection loss at the interface between the epitaxial substrate and the Bi-substituted magnetic garnet thick film, both sides were optically polished to a thickness such that the Faraday rotation angle was 45 degrees. These Bi-substituted magnetic garnet thick films were ultrasonically cleaned using detergent, organic detergent, etc. Next, put SiO 2 and Al 2 O 3 vapor deposition materials into the hearth respectively and set them in the ion assisted vapor deposition equipment. After setting the prepared Bi-substituted magnetic garnet thick film, while heating to 300 ° C, 3 × 1
Exhausted to 0 -6 torr. At the time of vapor deposition of Al 2 O 3 , oxygen gas was introduced up to 1 × 10 −4 torr. As the ionized gas, oxygen, argon, or a mixed gas of oxygen and argon was used.
As shown in Table 1, the laser wavelength used is 1.31 μm and 1.
The film thickness of each layer was controlled by an optical interference monitor so as to match the optical film thickness of the three-layer equivalent film corresponding to 55 μm, and a film made of SiO 2 —Al 2 O 3 —SiO 2 was prepared. The reflectance of each of the obtained antireflection films at each wavelength was measured, and as shown in Table 1, 0.04 to 0.
It was a very low result of 06%.
〔実施例−２〕 実施例−１で得られた本発明の反射防止膜と、従来の通
常の電子ビーム蒸着法によるSiO2単層の反射防止膜およ
びイオンアシスト法で得られるSiO2単層の反射防止膜を
準備し、温度85℃，湿度85％の条件下に放置して反射防
止膜の耐久性を測定した。150時間まで放置し、反射防
止膜の中心波長からの移動量を測定した。中心波長は1.
31μｍを用いた。この結果を第１図に示す。 EXAMPLE -2] and the anti-reflection film of the present invention obtained in Example -1, SiO 2 single layer obtained anti-reflection film and the ion-assisted method of SiO 2 single layer by the conventional ordinary electron beam evaporation The antireflection film of No. 1 was prepared, and the durability of the antireflection film was measured by leaving it under the conditions of a temperature of 85 ° C. and a humidity of 85%. After leaving it for 150 hours, the amount of movement from the center wavelength of the antireflection film was measured. The center wavelength is 1.
31 μm was used. The results are shown in FIG.
第１図によれば、本発明のSiO2−Al2O3−SiO反射膜はイ
オンアシスト法によるSiO2単層膜と同一の性能を有する
ことが分る。From FIG. 1, it can be seen that the SiO 2 —Al 2 O 3 —SiO reflective film of the present invention has the same performance as the SiO 2 single layer film by the ion assist method.
本発明の反射防止膜は反射率が0.1％以下と低く、かつ
高温高湿度下における耐久性も優れており、その効果は
大である。The antireflection film of the present invention has a low reflectance of 0.1% or less and excellent durability under high temperature and high humidity, and its effect is great.
【図面の簡単な説明】 第１図は高温高湿度下での反射防止膜の耐久性を示すグ
ラフである。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing durability of an antireflection film under high temperature and high humidity.
Claims (6)
ファラデー回転子の反射防止膜において、 上記ビスマス置換磁性ガーネット厚膜の表面に設けられ
る反射防止膜が、 蒸着法により順次成膜された屈折率nAでその光学的膜厚
がnAdAの第１層膜と、屈折率nBでその光学的膜厚がnBdB
の第２層膜及び屈折率nAでその光学的膜厚がnAdAの第３
層膜から成りその屈折率がnEである３層等価膜（但し、
nA＜nE＜nBであり、dAは第１層膜と第３層膜の物理的膜
厚、dBは第２層膜の物理的膜厚を示す）にて構成され、 かつ、上記第１層膜と第３層膜を構成する材料がSiO2で
あり、第２層膜を構成する材料がAl2O3、ZrO2、TiO2、T
a2O5、HfO2及びY2O3の中から選ばれたいずれかの１種で
あると共に、 nA、nB及びnEが下記数式（１）〜（３）を具備すること
を特徴とするファラデー回転子の反射防止膜。 （但し、nAdA/λ＝δA/2π、nBdB/λ＝δB/2πであり、
かつ、λはレーザ光の使用波長を示す。）1. An antireflection film for a Faraday rotator comprising a bismuth-substituted magnetic garnet thick film, wherein the antireflection film provided on the surface of the bismuth-substituted magnetic garnet thick film has a refractive index n sequentially formed by a vapor deposition method. its optical thickness is a first layer film of n a d a at a, the optical film thickness by the refractive index n B is n B d B
Of the second layer and the third layer having a refractive index of n A and an optical film thickness of n A d A
A three-layer equivalent film consisting of a layer film and having a refractive index of n E (however,
n A <n E <n B , d A is the physical film thickness of the first layer film and the third layer film, and d B is the physical film thickness of the second layer film), and , The material forming the first layer film and the third layer film is SiO 2 , and the material forming the second layer film is Al 2 O 3 , ZrO 2 , TiO 2 , T
a 2 O 5 , HfO 2 and Y 2 O 3 and any one of them is selected, and n A , n B and n E have the following formulas (1) to (3). Anti-reflection film for Faraday rotator. (However, n A d A / λ = δ A / 2π, n B d B / λ = δ B / 2π,
In addition, λ indicates the used wavelength of the laser light. )
ことを特徴とする特許請求の範囲第１項記載のファラデ
ー回転子の反射防止膜。2. The antireflection film for a Faraday rotator according to claim 1, wherein the vapor deposition method is an ion assisted vapor deposition method.
i）３（FeAlGa）5O12であり、かつ、このビスマス置換
磁性ガーネット膜厚の表面に設けられる上記反射防止膜
が、屈折率1.45でその光学的膜厚が0.388のSiO2から成
る第１層膜と、屈折率1.60でその光学的膜厚が0.223のA
l2O3から成る第２層膜及び屈折率1.45でその光学的膜厚
が0.388のSiO2から成る第３層膜にて構成（但し、必要
とする単層反射防止膜の光学的膜厚nd＝λ/4を1.00と
し、ｎ＝1.50、λ＝1.31μｍとする）されることを特徴
とする特許請求の範囲第１項記載のファラデー回転子の
反射防止膜。3. The bismuth-substituted magnetic garnet (GdB
i) 3 (FeAlGa) 5 O 12 , and the antireflection film provided on the surface of this bismuth-substituted magnetic garnet film is made of SiO 2 having a refractive index of 1.45 and an optical film thickness of 0.388. Layer film and A with a refractive index of 1.60 and an optical film thickness of 0.223
Consists of a second layer film made of l 2 O 3 and a third layer film made of SiO 2 having a refractive index of 1.45 and an optical film thickness of 0.388 (however, the required optical film thickness of the single-layer antireflection film). The antireflection film for a Faraday rotator according to claim 1, wherein nd = λ / 4 is 1.00, n = 1.50 and λ = 1.31 μm.
i）３（FeAlGa）5O12であり、かつ、このビスマス置換
磁性ガーネット膜厚の表面に設けられる上記反射防止膜
が、屈折率1.44でその光学的膜厚が0.388のSiO2から成
る第１層膜と、屈折率1.59でその光学的膜厚が0.223のA
l2O3から成る第２層膜及び屈折率1.44でその光学的膜厚
が0.388のSiO2から成る第３層膜にて構成（但し、必要
とする単層反射防止膜の光学的膜厚nd＝λ/4を1.00と
し、ｎ＝1.49、λ＝1.55μｍとする）されることを特徴
とする特許請求の範囲第１項記載のファラデー回転子の
反射防止膜。4. The bismuth-substituted magnetic garnet is (GdB
i) 3 (FeAlGa) 5 O 12 , and the antireflection film provided on the surface of this bismuth-substituted magnetic garnet film is made of SiO 2 having a refractive index of 1.44 and an optical film thickness of 0.388. Layer film and A with a refractive index of 1.59 and an optical film thickness of 0.223
It is composed of a second layer film made of l 2 O 3 and a third layer film made of SiO 2 having a refractive index of 1.44 and an optical film thickness of 0.388 (however, the required optical film thickness of the single-layer antireflection film). nd = λ / 4 is 1.00, n = 1.49, λ = 1.55 μm). The antireflection film for a Faraday rotator according to claim 1, wherein
Bi）3Fe5O12であり、かつ、このビスマス置換磁性ガー
ネット膜厚の表面に設けられる上記反射防止膜が、屈折
率1.45でその光学的膜厚が0.308のSiO2から成る第１層
膜と、屈折率1.60でその光学的膜厚が0.382のAl2O3から
成る第２層膜及び屈折率1.45でその光学的膜厚が0.308
のSiO2から成る第３層膜にて構成（但し、必要とする単
層反射防止膜の光学的膜厚nd＝λ/4を1.00とし、ｎ＝1.
53、λ＝1.31μｍとする）されることを特徴とする特許
請求の範囲第１項記載のファラデー回転子の反射防止
膜。5. The bismuth-substituted magnetic garnet is (YbTb
Bi) 3 Fe 5 O 12 , and the antireflection film provided on the surface of this bismuth-substituted magnetic garnet film is a first layer film made of SiO 2 having a refractive index of 1.45 and an optical film thickness of 0.308. And a second layer film made of Al 2 O 3 having a refractive index of 1.60 and an optical film thickness of 0.382 and an optical film thickness of 0.308 having a refractive index of 1.45.
3rd layer film made of SiO 2 (provided that the optical thickness nd = λ / 4 of the required single-layer antireflection film is 1.00 and n = 1.
53, λ = 1.31 μm). The antireflection film for a Faraday rotator according to claim 1, wherein
Bi）3Fe5O12であり、かつ、このビスマス置換磁性ガー
ネット膜厚の表面に設けられる上記反射防止膜が、屈折
率1.44でその光学的膜厚が0.291のSiO2から成る第１層
膜と、屈折率1.59でその光学的膜厚が0.417のAl2O3から
成る第２層膜及び屈折率1.44でその光学的膜厚が0.291
のSiO2から成る第３層膜にて構成（但し、必要とする単
層反射防止膜の光学的膜厚nd＝λ/4を1.00とし、ｎ＝1.
53、λ＝1.55μｍとする）されることを特徴とする特許
請求の範囲第１項記載のファラデー回転子の反射防止
膜。6. The bismuth-substituted magnetic garnet (YbTb
Bi) 3 Fe 5 O 12 , and the antireflection film provided on the surface of this bismuth-substituted magnetic garnet film is a first layer film made of SiO 2 having a refractive index of 1.44 and an optical film thickness of 0.291. And a second layer film of Al 2 O 3 having a refractive index of 1.59 and an optical film thickness of 0.417 and an optical film thickness of 0.291 having a refractive index of 1.44.
3rd layer film made of SiO 2 (provided that the optical thickness nd = λ / 4 of the required single-layer antireflection film is 1.00 and n = 1.
53, λ = 1.55 μm). The antireflection film for a Faraday rotator according to claim 1, wherein
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1303365A JPH07117603B2 (en) | 1989-11-24 | 1989-11-24 | Anti-reflection film for Faraday rotator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1303365A JPH07117603B2 (en) | 1989-11-24 | 1989-11-24 | Anti-reflection film for Faraday rotator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04230701A JPH04230701A (en) | 1992-08-19 |
| JPH07117603B2 true JPH07117603B2 (en) | 1995-12-18 |
Family
ID=17920115
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1303365A Expired - Fee Related JPH07117603B2 (en) | 1989-11-24 | 1989-11-24 | Anti-reflection film for Faraday rotator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07117603B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013083871A (en) * | 2011-10-12 | 2013-05-09 | Tamron Co Ltd | Antireflection film and manufacturing method of antireflection film |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09265003A (en) * | 1996-03-29 | 1997-10-07 | Shin Etsu Chem Co Ltd | Antireflection film for faraday rotator and optical isolator |
| US6853473B2 (en) | 2002-01-24 | 2005-02-08 | Tdk Corporation | Faraday rotator and optical device comprising the same, and antireflection film and optical device comprising the same |
| CN113093315A (en) * | 2021-03-09 | 2021-07-09 | 深圳莱宝高科技股份有限公司 | Anti-reflection composite film and preparation method thereof |
-
1989
- 1989-11-24 JP JP1303365A patent/JPH07117603B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013083871A (en) * | 2011-10-12 | 2013-05-09 | Tamron Co Ltd | Antireflection film and manufacturing method of antireflection film |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04230701A (en) | 1992-08-19 |
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