JP3492736B2 - Optical isolator - Google Patents
Optical isolatorInfo
- Publication number
- JP3492736B2 JP3492736B2 JP27892693A JP27892693A JP3492736B2 JP 3492736 B2 JP3492736 B2 JP 3492736B2 JP 27892693 A JP27892693 A JP 27892693A JP 27892693 A JP27892693 A JP 27892693A JP 3492736 B2 JP3492736 B2 JP 3492736B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- optical fiber
- optical
- plate
- birefringent plate
- 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
Landscapes
- Optical Integrated Circuits (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は光アイソレータに関し、
特に複屈折結晶による偏光分離素子を利用した偏波無依
存型の光アイソレータに関する。BACKGROUND OF THE INVENTION The present invention relates to an optical isolator,
In particular, the present invention relates to a polarization-independent optical isolator using a polarization splitting element made of a birefringent crystal.
【０００２】[0002]
【従来の技術】光アイソレータは、通常、偏光子、レン
ズ、ファラデー回転子、複屈折素子、１／２波長板等の
個々のバルクの光学素子を組み合わせて構成されるた
め、部品点数が多く且つ大型となると共に、素子の相互
関係の調整が複雑になるなどの問題がある。これに対し
て導波路または光ファイバに直接光アイソレータを組み
込んで光アイソレータを小型化することが提案されてい
る。2. Description of the Related Art An optical isolator usually has a large number of parts because it is constructed by combining individual bulk optical elements such as a polarizer, a lens, a Faraday rotator, a birefringent element, and a half-wave plate. There is a problem that the device becomes large and the adjustment of the mutual relation of the elements becomes complicated. On the other hand, it has been proposed to directly incorporate an optical isolator into a waveguide or an optical fiber to reduce the size of the optical isolator.
【０００３】特公平３−２２９６２号公報には、１本の
光ファイバを一か所以上で切断してそこに誘電体金属多
層膜偏光子、ファラデー回転子板等を直接挿入一体化す
ることによりファイバ一体型の光アイソレータが記載さ
れている。本発明でもこの技術を利用するが、同公報の
ものは偏波依存性である。In Japanese Patent Publication No. 3-22962, one optical fiber is cut at one or more places, and a dielectric metal multilayer film polarizer, a Faraday rotator plate, etc. are directly inserted and integrated therein. A fiber integrated optical isolator is described. The present invention also utilizes this technique, but the one disclosed in the publication is polarization-dependent.
【０００４】特開平３−１７１１０３、特開平３−１９
６１１５号等には、光導波路に偏光分離素子を挿入して
入射光の偏光を２分離して２本の導波路に導き、これら
２本の導波路に挿入されたファアラデー回転子及び１／
２波長板に導き、次いで合成用の偏光分離素子により偏
光を合成するようにした偏波無依存光アイソレータが記
載されている。しかし、この装置では偏光分離用及び合
成用の偏光分離素子の製作が困難である。JP-A-3-171103 and JP-A-3-19
In No. 6115, a polarization separation element is inserted in an optical waveguide to separate the polarized light of incident light into two waveguides, which are guided to two waveguides, and a Faraday rotator and 1/1 inserted in these two waveguides.
A polarization-independent optical isolator is described, which is guided to a two-wave plate and then combined by a polarization separating element for combining. However, with this device, it is difficult to manufacture polarization separation elements for polarization separation and synthesis.
【０００５】特開平４−３０７５１２号及び特開平４−
３４９４２１号には１本の光ファイバを基板に埋め込
み、光ファイバを斜めに切断するスリットを基板に形成
してそこに光アイソレータ素子（３枚のビームスプリッ
タとファラデー回転子、或いは２枚のビームスプリッタ
と１／２波長板とファラデー回転子）が埋め込まれた偏
波無依存光アイソレータが記載されている。光ファイバ
の端面の角度と光アイソレータ素子中の各素子の厚さ等
は、ファイバ傾斜端面から出た光の傾きが各素子により
相殺され、光が見かけ上光ファイバを直進するように定
められると共に、斜め切断のため各素子の端面で反射し
た光が入射側に戻らないようになっている。この技術で
は無調整で容易に組み込み可能な光アイソレータが提供
できるが、光アイソレータ素子がすべて一体化されてい
るために全厚が厚くなり、回折損失が大きくなる欠点が
ある。JP-A-4-307512 and JP-A-4-307512
In 349421, one optical fiber is embedded in a substrate, and a slit for obliquely cutting the optical fiber is formed in the substrate, and an optical isolator element (three beam splitters and a Faraday rotator, or two beam splitters) is provided there. And a polarization independent optical isolator in which a half-wave plate and a Faraday rotator are embedded. The angle of the end face of the optical fiber and the thickness of each element in the optical isolator element are determined so that the inclination of the light emitted from the fiber inclined end surface is canceled by each element and the light apparently goes straight through the optical fiber. The light reflected by the end face of each element is prevented from returning to the incident side due to the oblique cutting. Although this technique can provide an optical isolator that can be easily incorporated without adjustment, it has a drawback that the total thickness is increased and diffraction loss is increased because all the optical isolator elements are integrated.
【０００６】[0006]
【発明が解決しようとする課題】特開平４−３０７５１
２号及び特開平４−３４９４２１号に記載された技術で
は、損失が大きくなる欠点がある。[Patent Document 1] Japanese Patent Application Laid-Open No. 4-30751
The techniques described in Japanese Patent Laid-Open No. 4-349421 and Japanese Patent Laid-Open No. 4-349421 have a drawback that the loss becomes large.
【０００７】[0007]
【０００８】[0008]
【課題を解決するための手段】本発明は、平行に配置さSUMMARY OF THE INVENTION The present invention is arranged in parallel.
れた第１の直線状光導波路と第２の直線状光導波路とA first linear optical waveguide and a second linear optical waveguide
を、または、平行に配置された第１の直線状光ファイバOr a first linear optical fiber arranged in parallel
と第２の直線状光ファイバとを有し、前記２本の平行なAnd a second linear optical fiber, and the two parallel optical fibers
直線状光導波路、または、２本の光ファイバの途中に、In the straight optical waveguide or in the middle of two optical fibers,
順に、第１の複屈折板、１／２波長板とファラデー回転The first birefringent plate, half-wave plate and Faraday rotation
子を組み合わせた素子、及び第２の複屈折板を、前記直The element in which the child is combined and the second birefringent plate
線状光導波路、または、前記光ファイバの光軸に対してLinear optical waveguide, or with respect to the optical axis of the optical fiber
斜めに配置し、順方向から第１の直線状光導波路またはThe first linear optical waveguide is arranged diagonally from the forward direction or
第１の光ファイバに入射した光は、前記第１の複屈折板The light incident on the first optical fiber is the first birefringent plate.
を光が通過する際には、異常光が第１の直線状光導波路When the light passes through the
または第１の光ファイバを直進し、常光が軸ずれして第Or, go straight through the first optical fiber,
２の直線状光導波路または第２の光ファイバに進み、第To the second linear optical waveguide or second optical fiber,
２の複屈折板を光が通過する際には、異常光が直進し、When the light passes through the birefringent plate of 2, the extraordinary light goes straight,
常光が軸ずれして、すべての光が第２の直線状光導波路The ordinary light is off-axis, and all the light is the second linear optical waveguide.
または第２の光ファイバに進むように構成され、逆方向Or configured to go to a second optical fiber and in the opposite direction
から第２の直線状光導波路または第２の光ファイバに入From the second linear optical waveguide or the second optical fiber
射した光は、前記第２の複屈折板を光が通過する際にWhen the light passes through the second birefringent plate,
は、異常光が第２の直線状光導波路または第２の光ファMeans that the extraordinary light is the second linear optical waveguide or the second optical fiber.
イバを直進し、常光が軸ずれして第１の直線状光導波路The first straight optical waveguide, in which the ordinary light is axially displaced and goes straight on
または第１の光ファイバに進み、第１の複屈折板を光がOr go to the first optical fiber and let the light pass through the first birefringent plate.
通過する際には、異常光が直進し、常光が軸ずれして、When passing, the extraordinary light goes straight, the ordinary light is off-axis,
全ての光が第１の直線状光導波路または第１の光ファイAll the light is the first linear optical waveguide or the first optical fiber.
バの光軸を外れた方向に進むように構成されていることBeing configured to move away from the optical axis of the bar
を特徴とする偏波無依存光アイソレータが提供される。A polarization-independent optical isolator is provided.
特に好ましくは、上記において、屈折率が１．４５であParticularly preferably, in the above, the refractive index is 1.45.
る前記光ファイバと、ルチル平行平板である前記第１のThe optical fiber and the first rutile parallel plate
複屈折板及び前記第２の複屈折板と、Ｂｉ置換ガーネッA birefringent plate and the second birefringent plate, and a Bi substitution garnet.
トであるファラデー回転子と、を含み、前記複屈折板のA Faraday rotator that is a
Ｃ軸を前記第１の複屈折板及び前記第２の複屈折板の入The C-axis is inserted into the first birefringent plate and the second birefringent plate.
射面に対して４５度の角度に配置する。この構成によるIt is placed at an angle of 45 degrees to the projection surface. With this configuration
と、順方向の光の回折損失が減少し、無調整で容易に組And the diffraction loss of light in the forward direction is reduced, making it easy to assemble without adjustment.
立が可能であり、また複屈折板と１／２波長板とファラIt is possible to stand, and a birefringent plate, a half-wave plate, and a farr
デー回転子の面で反射する光は導波路または光ファイバThe light reflected by the surface of the day rotator is a waveguide or an optical fiber.
からはずれた方向に向かい入射方向に戻らないので反射Reflects because it goes in the direction away from and does not return in the incident direction
減衰量が大きくなる利点が得られる。The advantage is that the amount of attenuation increases.
【０００９】[0009]
【作用】図１を参照して本発明の基本原理を説明する。
コア３、４をそれぞれ有する光ファイバ１、２は近接し
て平行に配置されている。光ファイバ１、２は別々の３
か所で切断されて溝部が形成され、それらの溝部に第１
の複屈折板５、１／２波長板６、これに密着した回転角
度４５°のファラデー回転子７、及び第２の複屈折板８
が挿入されている。複屈折板５、８は、入射した光のう
ち常光が直進し異常光が軸はずれとなって別の光ファイ
バへ出射するように構成される。この代わりに、以下の
実施例に示すように、入射した光のうち異常光が直進
し、常光が軸はずれとなって他方の光ファイバに出射す
るように構成されてもよい。この場合には複屈折板５、
８の入射面は条件を満足するような角度に傾斜させる必
要がある。１／２波長板６、ファラデー回転子７は接着
一体化されており複屈折板５と常光もしくは異常光で透
過した順方向の光に対しては、偏波面が９０度回転し、
複屈折板８を常光もしくは異常光で透過した逆方向の光
に対しては偏波面が回転しないように構成されてる。The basic principle of the present invention will be described with reference to FIG.
The optical fibers 1 and 2 each having the cores 3 and 4 are arranged in close proximity to each other. Optical fibers 1 and 2 are separate 3
Grooves are formed by cutting in places, and the first grooves are formed in the grooves.
Birefringent plate 5, half-wave plate 6, Faraday rotator 7 having a rotation angle of 45 ° and a second birefringent plate 8 closely attached to the birefringent plate 5.
Has been inserted. The birefringent plates 5 and 8 are configured such that ordinary light of the incident light travels straight and extraordinary light is off-axis and is emitted to another optical fiber. Instead of this, as shown in the following embodiments, the extraordinary light of the incident light may go straight, and the ordinary light may be off-axis and emitted to the other optical fiber. In this case, the birefringent plate 5,
It is necessary to incline the incident surface of No. 8 at an angle that satisfies the conditions. The half-wave plate 6 and the Faraday rotator 7 are bonded and integrated, and the plane of polarization rotates 90 degrees with respect to the birefringent plate 5 and light in the forward direction transmitted by ordinary or extraordinary light.
The plane of polarization is configured not to rotate with respect to light in the opposite direction that has passed through the birefringent plate 8 as ordinary light or extraordinary light.
【００１０】本発明の光アイソレータの作用を説明する
と、図１（ａ）のように、順方向の光に対しては、光フ
ァイバ１から入射した光は第１の複屈折板５で２つに分
かれ、例えば常光は直進して光ファイバ１を進み１／２
波長板６及びファラデー回転子７を透過し偏波面が９０
度回転し、異常光となった光は第２の複屈折板８で軸ず
れを起こして光ファイバ２に出射する。一方、第１の複
屈折板５を出射した異常光は光ファイバ２を進み１／２
波長板６及びファラデー回転子７を透過し偏波面が９０
度回転し、常光となった光は第２の複屈折板８を直進し
て光ファイバ２に出射する。このように、本発明による
と偏波無依存の光アイソレータが得られる。また、２つ
の偏光の光路差は０であるので位相の偏波分散がない。The operation of the optical isolator of the present invention will be described. As shown in FIG. 1A, for the light in the forward direction, the light incident from the optical fiber 1 is divided into two by the first birefringent plate 5. For example, ordinary light goes straight on and goes along the optical fiber 1 for 1/2.
The plane of polarization passes through the wave plate 6 and the Faraday rotator 7 and is 90
The light, which has been rotated by a degree and becomes an extraordinary light, causes an axis shift in the second birefringent plate 8 and is emitted to the optical fiber 2. On the other hand, the extraordinary light emitted from the first birefringent plate 5 travels through the optical fiber 2 and becomes 1/2
The plane of polarization passes through the wave plate 6 and the Faraday rotator 7 and is 90
The light that has been rotated by a degree and becomes ordinary light travels straight through the second birefringent plate 8 and is emitted to the optical fiber 2. Thus, according to the present invention, a polarization-independent optical isolator can be obtained. Further, since the optical path difference between the two polarized lights is 0, there is no phase polarization dispersion.
【００１１】図１（ｂ）のように、逆方向の光に対して
は、光ファイバ２からの戻り光は第２の複屈折板８で２
つに分かれ、常光は直進して光ファイバ２を進み、ファ
ラデー回転子７及び１／２波長板６を透過しても常光で
あり、第２の複屈折板８を経て光ファイバ２を直進す
る。一方、第２の複屈折板８を出射した異常光は光ファ
イバ２を進みファラデー回転子７及び１／２波長板６を
透過しても異常光のままであるから、第１の複屈折板５
で軸ずれを起こして、光ファイバ１には出射しない。As shown in FIG. 1B, with respect to the light in the opposite direction, the return light from the optical fiber 2 is 2 by the second birefringent plate 8.
Ordinary light travels straight through the optical fiber 2 and passes through the Faraday rotator 7 and the half-wave plate 6 and is still ordinary, and travels straight through the optical fiber 2 through the second birefringent plate 8. . On the other hand, the extraordinary light emitted from the second birefringent plate 8 remains as extraordinary light even if it travels through the optical fiber 2 and passes through the Faraday rotator 7 and the half-wave plate 6. 5
The optical axis 1 is misaligned and the light is not emitted to the optical fiber 1.
【００１２】次に、本発明の光アイソレータが低損失で
ある理由を説明する。導波路または光ファイバに溝部を
形成した際に生じる回折損失Ｌ（単位ｄＢ）は、溝幅ｄ
が大きくないときの近似式としてNext, the reason why the optical isolator of the present invention has a low loss will be described. The diffraction loss L (unit: dB) that occurs when a groove is formed in the waveguide or the optical fiber is the groove width d.
As an approximate expression when is not large
【数１】Ｌ＝０．１１λ2 ｄ2 ／ｗ4 （式１）
で表される。λは光の波長、ｗは導波路または光ファイ
バの実効スポットサイズまたは光ファイバのスポットサ
イズ（半径）、ｄは実効的な溝幅であり、溝幅を挿入さ
れる物質の屈折率で割った値である。特開平４−３０７
５１２号及び特開平４−３４９４２１号に示された従来
例では、第１の複屈折板、１／２波長板、ファラデー回
転子、第２の複屈折板を一体化しているため、式１で示
されるｄが大きくなり、損失が増大してしまう。これに
対して、本発明では２本の光ファイバまたは導波路を使
用すると共に素子を別々に挿入しているために損失を低
減できる。例えば、第１の複屈折板、第２の複屈折板を
それぞれ厚さ８５０μｍのルチル板とし、ファラデー回
転子を厚さ３５０μｍののＢｉ置換ガーネット、１／２
波長板を厚さ９２μｍの水晶板、ｗ＝２０μｍ、λ＝
１．５５μｍの場合、上記の従来例では損失Ｌ＝１．４
ｄＢとなるが、本発明では損失がＬ＝０．５ｄＢと大幅
に低減できる。## EQU1 ## L = 0.11λ 2 d 2 / w 4 (Equation 1) λ is the wavelength of light, w is the effective spot size of the waveguide or optical fiber or the spot size (radius) of the optical fiber, d is the effective groove width, and the groove width is divided by the refractive index of the material to be inserted. It is a value. Japanese Patent Laid-Open No. 4-307
In the prior art examples shown in Japanese Patent Application Laid-Open No. 512-2012 and Japanese Patent Application Laid-Open No. 4-349421, the first birefringent plate, the half-wave plate, the Faraday rotator, and the second birefringent plate are integrated, so The indicated d becomes large and the loss increases. On the other hand, in the present invention, since two optical fibers or waveguides are used and the elements are separately inserted, the loss can be reduced. For example, the first birefringent plate and the second birefringent plate are rutile plates each having a thickness of 850 μm, and the Faraday rotator is a Bi-substituted garnet having a thickness of 350 μm.
The wave plate is a quartz plate with a thickness of 92 μm, w = 20 μm, λ =
In the case of 1.55 μm, the loss L = 1.4 in the above conventional example.
However, in the present invention, the loss can be greatly reduced to L = 0.5 dB.
【００１３】[0013]
実施例１
図２は本発明の好ましい実施例を示す。この例が図１と
違う点は光ファイバ１、２に斜めの溝部が形成され、そ
れらの溝部に第１の複屈折板１５、１／２波長板１６、
これに密着した回転角度４５°のファラデー回転子１
７、及び第２の複屈折板１８が挿入されている点であ
る。ここで複屈折板１５、１８を異常光が直進するよう
に斜め角度が設定されている。この時常光は軸ずれを生
じて他方の光ファイバに入射する。また、複屈折板が傾
斜しているために、複屈折板の面からの反射光は入射側
の光ファイバに戻ることはないので、反射減衰量を大き
くすることができる。今一例として、光ファイバの屈折
率を１．４５とし、複屈折板としてルチル平行平板を使
用し、Ｃ軸をルチル板の入出射面に対して４５度の角度
に配置し、常光の屈折率２．４４、異常光の屈折率２．
６９とすると、入射角１２．３°のとき図２のように異
常光が直進する。Embodiment 1 FIG. 2 shows a preferred embodiment of the present invention. This example is different from FIG. 1 in that the optical fibers 1 and 2 are formed with slanting grooves, and the first birefringent plate 15 and the half-wave plate 16 are formed in these grooves.
Faraday rotator 1 with a rotation angle of 45 °
7 and the second birefringent plate 18 is inserted. Here, the oblique angle is set so that the extraordinary light travels straight through the birefringent plates 15 and 18. At this time, the ordinary light is shifted in axis and enters the other optical fiber. Further, since the birefringent plate is inclined, the reflected light from the surface of the birefringent plate does not return to the optical fiber on the incident side, so that the return loss can be increased. As an example, the refractive index of the optical fiber is 1.45, a rutile parallel plate is used as a birefringent plate, and the C axis is arranged at an angle of 45 degrees with respect to the entrance / exit surface of the rutile plate, and the refractive index of ordinary light is set. 2.44, refractive index of extraordinary light
If the incident angle is 69, the extraordinary light goes straight as shown in FIG. 2 when the incident angle is 12.3 °.
【００１４】実施例２
図３は図２に示した実施例１の光ファイバの代わりに、
薄膜技術を利用して基板２０に平行な光導波路１、２を
作り込み、これらの導波路を斜めに切断する溝部を３か
所に設け、それらの溝部に実施例１と同様な関係を満足
するような厚さの第１の複屈折板１５、１／２波長板１
６、これに密着した回転角度４５°のファラデー回転子
１７、及び第２の複屈折板１８を挿入する。この例の光
アイソレータは実施例１と同様に機能する。Example 2 FIG. 3 is a schematic diagram of the optical fiber of Example 1 shown in FIG.
The optical waveguides 1 and 2 parallel to the substrate 20 are formed by using thin film technology, and groove portions for obliquely cutting these waveguides are provided at three places, and the groove portions satisfy the same relationship as that of the first embodiment. First birefringent plate 15 and half-wave plate 1 having a thickness
6, the Faraday rotator 17 having a rotation angle of 45 ° and the second birefringent plate 18 which are in close contact with this are inserted. The optical isolator of this example functions similarly to the first embodiment.
【００１５】実施例１、２の光アイソレータの動作にお
いて、光ファイバ１または光導波路１に入射した順方向
の光のうち異常光は第１の複屈折板１５を直進し、次い
で１／２波長板１６、ファラデー回転子１７を経て常光
になり、最後に第２の複屈折板１８で軸ずれして光ファ
イバ２または導波路２に出射する。一方、光ファイバ１
または導波路１に入射した順方向の光のうち常光は第１
の複屈折板１５で軸ずれして光ファイバ２または光導波
路２に導かれ、次いで１／２波長板１６、ファラデー回
転子１７を経て異常光になり、最後に第２の複屈折板１
８を直進し、光ファイバ２または光導波路２に出射す
る。複屈折板の各面は導波路または光ファイバに対して
傾斜しているからこれらの面での反射光は入射側の光フ
ァイバ１または導波路１に戻ることはない。逆方向の光
に対しては、光ファイバ２からの戻り光は第２の複屈折
板１８で２つに分かれ、異常光は直進して光ファイバ２
を進み、ファラデー回転子７及び１／２波長板６を透過
しても異常光であり、第１の複屈折板１５を経て光ファ
イバ２または導波路２を直進する。一方、第２の複屈折
板８で軸はずれとなった常光は光ファイバ１または導波
路１を進み１／２波長板６及びファラデー回転子７を透
過しても常光のままであるから、第１の複屈折板１５で
軸ずれを起こして、光ファイバ１または導波路１には出
射しない。In the operation of the optical isolators of the first and second embodiments, out of the light in the forward direction incident on the optical fiber 1 or the optical waveguide 1, the extraordinary light travels straight through the first birefringent plate 15 and then has a half wavelength. After passing through the plate 16 and the Faraday rotator 17, the light becomes ordinary light, and finally the second birefringent plate 18 shifts the axis to emit the light to the optical fiber 2 or the waveguide 2. On the other hand, optical fiber 1
Or, of the light in the forward direction incident on the waveguide 1, the ordinary light is the first light.
Is guided by the birefringent plate 15 to the optical fiber 2 or the optical waveguide 2, and then becomes an extraordinary ray through the half-wave plate 16 and the Faraday rotator 17, and finally the second birefringent plate 1
8 goes straight and is emitted to the optical fiber 2 or the optical waveguide 2. Since each surface of the birefringent plate is inclined with respect to the waveguide or the optical fiber, the reflected light on these surfaces does not return to the optical fiber 1 or the waveguide 1 on the incident side. With respect to the light in the opposite direction, the return light from the optical fiber 2 is split into two by the second birefringent plate 18, and the extraordinary light goes straight to the optical fiber 2
Is an extraordinary ray even after passing through the Faraday rotator 7 and the half-wave plate 6, and goes straight through the optical fiber 2 or the waveguide 2 via the first birefringent plate 15. On the other hand, the ordinary light that is off-axis in the second birefringent plate 8 remains ordinary light even if it travels through the optical fiber 1 or the waveguide 1 and passes through the ½ wavelength plate 6 and the Faraday rotator 7. The birefringence plate 15 of No. 1 causes an axis shift and does not emit to the optical fiber 1 or the waveguide 1.
【００１６】[0016]
【効果】本発明によると光ファイバまたは光導波路と一
体化した無調整で容易に組み立て可能な偏波無依存の光
アイソレータが得られる。また、本発明では２本のファ
イバまたは２つの光導波路を使用し、更に、別々の溝部
に別々の素子を挿入するので光の回折損失が少ない。そ
の上、２つの偏波の光路差は０であるので位相の偏波分
散が少ない。更に、素子を斜めに配置することにより反
射減衰量を大きくすることができる。According to the present invention, a polarization-independent optical isolator that is integrated with an optical fiber or an optical waveguide and can be easily assembled without adjustment is obtained. Further, in the present invention, two fibers or two optical waveguides are used, and further, different elements are inserted in different groove portions, so that light diffraction loss is small. Moreover, since the optical path difference between the two polarized waves is 0, the phase polarization dispersion is small. Further, by arranging the elements obliquely, the return loss can be increased.
【図１】本発明の原理を説明する図である。FIG. 1 is a diagram illustrating the principle of the present invention.
【図２】本発明の第１の実施例による光アイソレータを
示す図である。FIG. 2 is a diagram showing an optical isolator according to a first embodiment of the present invention.
【図３】本発明の第２の実施例による光アイソレータを
示す図である。FIG. 3 is a diagram showing an optical isolator according to a second embodiment of the present invention.
１、２：導波路（光ファイバまたは光導波路） ５、１５：第１の複屈折板 ６、１６：１／２波長板 ７、１７：ファラデー回転子 ８、１８：第２の複屈折板 ２０：基板 1, 2: Waveguide (optical fiber or optical waveguide) 5, 15: First birefringent plate 6, 16: 1/2 wave plate 7, 17: Faraday rotator 8, 18: second birefringent plate 20: substrate
フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G02B 27/28 G02B 6/12 ＪＳＴＰｕｌｓ（ＪＯＩＳ)Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) G02B 27/28 G02B 6/12 JSTPuls (JOIS)
Claims (2)
と第２の直線状光導波路とを、または、平行に配置され
た第１の直線状光ファイバと第２の直線状光ファイバと
を有し、 前記２本の平行な直線状光導波路、または、２本の光フ
ァイバの途中に、順に第１の複屈折板、１／２波長板と
ファラデー回転子を組み合わせた素子、及び第２の複屈
折板を、前記直線状光導波路、または、前記光ファイバ
の光軸に対して斜めに配置し、 順方向から第１の直線状光導波路または第１の光ファイ
バに入射した光は、前記第１の複屈折板を光が通過する
際には、異常光が第１の直線状光導波路または第１の光
ファイバを直進し、常光が軸ずれして第２の直線状光導
波路または第２の光ファイバに進み、第２の複屈折板を
光が通過する際には、異常光が直進し、常光が軸ずれし
て、すべての光が第２の直線状光導波路または第２の光
ファイバに進むように構成され、 逆方向から第２の直線状光導波路または第２の光ファイ
バに入射した光は、前記第２の複屈折板を光が通過する
際には、異常光が第２の直線状光導波路または第２の光
ファイバを直進し、常光が軸ずれして第１の直線状光導
波路または第１の光ファイバに進み、第１の複屈折板を
光が通過する際には、異常光が直進し、常光が軸ずれし
て、全ての光が第１の直線状光導波路または第１の光フ
ァイバの光軸を外れた方向に進むように構成されている
ことを特徴とする偏波無依存光アイソレータ。 1. A first linear optical waveguide arranged in parallel.
And the second linear optical waveguide, or arranged in parallel.
A first linear optical fiber and a second linear optical fiber
With two parallel linear optical waveguides or two optical fibers.
In the middle of the fiber, the first birefringent plate, the half-wave plate,
Element combining Faraday rotator and second birefringence
Folded plate, the linear optical waveguide, or the optical fiber
Of the first linear optical waveguide or the first optical fiber from the forward direction.
The light incident on the bar passes through the first birefringent plate.
In this case, the extraordinary light is the first linear optical waveguide or the first light.
Straight line goes through the fiber, and the ordinary light is off axis
Go to the waveguide or the second optical fiber and pass the second birefringent plate
When the light passes, the extraordinary light goes straight and the ordinary light is misaligned.
And all the light is the second linear optical waveguide or the second light.
A second linear optical waveguide or a second optical fiber configured to travel into the fiber from the opposite direction.
The light incident on the bar passes through the second birefringent plate.
In this case, the extraordinary light is the second linear optical waveguide or the second light.
The first straight light is transmitted by going straight through the fiber and shifting the axis of the ordinary light.
Go to the waveguide or the first optical fiber and pass the first birefringent plate
When the light passes, the extraordinary light goes straight and the ordinary light is misaligned.
So that all the light is transmitted through the first linear optical waveguide or the first optical waveguide.
It is configured to move in a direction off the optical axis of the fiber.
A polarization independent optical isolator characterized in that
と、 ルチル平行平板である前記第１の複屈折板及び前記第２
の複屈折板と、 Ｂｉ置換ガーネットであるファラデー回転子と、を含
み、 前記複屈折板のＣ軸を前記第１の複屈折板及び前記第２
の複屈折板の入射面に対して４５度の角度に配置したこ
とを特徴とする請求項１の光アイソレータ。 2. The optical fiber having a refractive index of 1.45.
And the first birefringent plate and the second rutile parallel plate.
And a Faraday rotator that is a Bi-substituted garnet.
Seen, the birefringent said first birefringent plate C-axis of plate and the second
Be placed at an angle of 45 degrees to the entrance surface of the birefringent plate of
The optical isolator according to claim 1, wherein:
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27892693A JP3492736B2 (en) | 1993-10-13 | 1993-10-13 | Optical isolator |
| US08/320,816 US5499307A (en) | 1993-10-13 | 1994-10-11 | Optical isolator and polarization splitter therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27892693A JP3492736B2 (en) | 1993-10-13 | 1993-10-13 | Optical isolator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07110459A JPH07110459A (en) | 1995-04-25 |
| JP3492736B2 true JP3492736B2 (en) | 2004-02-03 |
Family
ID=17604009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27892693A Expired - Fee Related JP3492736B2 (en) | 1993-10-13 | 1993-10-13 | Optical isolator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3492736B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100481716B1 (en) * | 2002-12-12 | 2005-04-11 | 학교법인 청석학원 | Light isolator |
-
1993
- 1993-10-13 JP JP27892693A patent/JP3492736B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07110459A (en) | 1995-04-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5499307A (en) | Optical isolator and polarization splitter therefor | |
| JP2774467B2 (en) | Polarization independent optical isolator | |
| US6487014B2 (en) | High isolation optical switch, isolator or circulator having thin film polarizing beam-splitters | |
| US6040942A (en) | Polarization separator/combiner | |
| EP0552783B1 (en) | Optical isolator device | |
| JPH05224153A (en) | Optical isolator | |
| CA2270733A1 (en) | Optical attenuator | |
| JP4079228B2 (en) | Optical device having optical circulator function | |
| US5377040A (en) | Polarization independent optical device | |
| JP2002023111A (en) | Polarizing beam splitter/combiner | |
| JPH0990279A (en) | Polarization independent type optical isolator and optical circulator | |
| US6014254A (en) | Optical device for splitting an input beam into two orthogonal polarization states | |
| US6246518B1 (en) | Reflection type optical isolator | |
| JP2000241762A (en) | Optical isolator | |
| JP3492736B2 (en) | Optical isolator | |
| JP3228773B2 (en) | Optical isolator | |
| JP3161885B2 (en) | Optical isolator | |
| JP2905847B2 (en) | Optical isolator device | |
| JPH0634915A (en) | Optical isolator, light amplifier provided with the optical isolator, and duplex optical transmission system provided with the optical amplifier | |
| JP3263501B2 (en) | Polarization separation element | |
| JP2775103B2 (en) | Polarizing prism | |
| JP2004226599A (en) | Polarized light separating and composing device | |
| JP2000241763A (en) | Optical isolator | |
| JPS6255766B2 (en) | ||
| JP2000284225A (en) | Optical isolator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20031014 |
|
| LAPS | Cancellation because of no payment of annual fees |