JPH0741507U - Faraday mirror - Google Patents
Faraday mirrorInfo
- Publication number
- JPH0741507U JPH0741507U JP7565393U JP7565393U JPH0741507U JP H0741507 U JPH0741507 U JP H0741507U JP 7565393 U JP7565393 U JP 7565393U JP 7565393 U JP7565393 U JP 7565393U JP H0741507 U JPH0741507 U JP H0741507U
- Authority
- JP
- Japan
- Prior art keywords
- fiber
- mirror
- faraday
- optical fiber
- faraday rotator
- 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
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- Optical Couplings Of Light Guides (AREA)
Abstract
(57)【要約】
【目的】 従来のファラデーミラーはファイバ,レンズ
が分割されているため、しかも光ファイバは先射研摩さ
れ出射光線はファイバ軸方向に対して斜めに放射されて
いるので、X,Yの平面状態とZ方向の調整およびファ
イバのコア軸を回転中心とした回転位置合わせ、光線放
射角がミラーに対して垂直になるようにファイバを角度
合わせするため、二軸のアオリ角度調整まで含まれ、合
計六軸の調整が必要で結合調整が容易ではなく、部品点
数が増える問題があり、それを解決する。
【構成】 45゜ファラデー回転子5,ミラー6を配置
し、ファラデー回転子を磁化するための永久磁石9を外
挿したファラデーミラーにおいて、光ファイバ1先端に
この光ファイバのコア部と等価で単一な屈折率を有する
同一外径のファイバ2、およびその先端に球状部3を形
成した集束ファイバ端末を対向させ、入出射光を導入出
させたファラデーミラー。
(57) [Summary] [Purpose] In the conventional Faraday mirror, the fiber and lens are divided, and since the optical fiber is pre-polished and the outgoing light beam is emitted obliquely to the fiber axis direction, X , Y plane adjustment and Z direction adjustment, rotational alignment around the fiber core axis, and angle adjustment of the fiber so that the radiation angle is perpendicular to the mirror. It is necessary to adjust the total of 6 axes, and it is not easy to adjust the joint, and there is a problem that the number of parts increases, which is solved. [Construction] In a Faraday mirror in which a 45 ° Faraday rotator 5 and a mirror 6 are arranged, and a permanent magnet 9 for magnetizing the Faraday rotator is externally inserted, the end of the optical fiber 1 is equivalent to the core of the optical fiber. A Faraday mirror in which a fiber 2 having the same outer diameter having a uniform refractive index and a converging fiber terminal having a spherical portion 3 formed at its tip are opposed to introduce and emit light.
Description
【0001】[0001]
本考案は光ファイバ系における偏波変動を補償する光学部品に関する。 The present invention relates to an optical component for compensating for polarization fluctuation in an optical fiber system.
【0002】[0002]
シングルモード光ファイバに生じる偏波変動は光通信や光ファイバ計測系にお いて問題が発生する。例えば偏波モードを用いる光学系では熱変化や機械的な揺 動が光ファイバの複屈折状態を変動させるため、伝播する光線の偏波状態が変化 し、光学系のノイズの原因になる。このため偏波維持ファイバが用いられるが高 価であり使用法が難しいという欠点があり、偏波方向を合わせて固定したり、長 くなると偏波モードが歪んで楕円偏波になるという問題があった。一般にこのよ うなファイバ伝播中に光線の偏波状態が変動することに起因する光線強度の不安 定性は、逆向きに偏波状態の位相が90゜ずれている光線を回帰させると、偏波状 態が安定する作用を適用した45゜回転ファラデー回転子と反射鏡から構成された ファラデーミラーが提案されている。 Polarization fluctuations that occur in single-mode optical fibers cause problems in optical communications and optical fiber measurement systems. For example, in an optical system that uses a polarization mode, thermal changes and mechanical fluctuations change the birefringence state of the optical fiber, which changes the polarization state of the propagating light beam and causes optical system noise. For this reason, polarization-maintaining fibers are used, but they have the drawback of being expensive and difficult to use, and there is the problem that the polarization modes are distorted and become elliptically polarized if the polarization directions are aligned and fixed, or if they become longer. there were. In general, the instability of the light intensity due to the change in the polarization state of the light beam during fiber propagation is caused by the reversal of the light beam whose polarization state is shifted by 90 ° in the opposite direction. A Faraday mirror composed of a 45 ° rotating Faraday rotator and a reflecting mirror has been proposed.
【0003】[0003]
最も簡便な構造としてファラデー回転子とミラーがレンズを介して光ファイバ と連結されていれば光レベルが複屈折による偏波歪が補償され安定する。図2は そのようなファラデーミラー構造の概略図であり、光ファイバから出射された光 線はレンズによってファラデー回転子を透過する際に45゜偏波状態を回転してか ら反射鏡で反射して再び同一経路を光ファイバまで回帰するので偏波状態は90゜ だけ旋回する。 As the simplest structure, if the Faraday rotator and mirror are connected to the optical fiber via a lens, the optical level will be stabilized by compensating for polarization distortion due to birefringence. Fig. 2 is a schematic diagram of such a Faraday mirror structure. The light beam emitted from the optical fiber is rotated by 45 ° in the polarization state when passing through the Faraday rotator by the lens and then reflected by the reflecting mirror. Then, the same path is returned to the optical fiber again, so that the polarization state turns by 90 °.
【0004】 このため光ファイバ伝播中に生じる複屈折変動の影響は、往復する光線の偏波 状態が互いに対角化されるため補償され、偏波状態の変動が見かけ上変化しなく なる。したがって光のコヒーレンス性(位相や振動数の整合性)を用いる計測関 連に適用するとき極めて有効である。この場合光ファイバの複屈折変化が時間的 に光線の往復時間に対して無限長と見なせるほど緩やかであることが条件であり 、回帰された光線が光ファイバ内で同一複屈折状態を伝播するという条件におい て成立する。Therefore, the influence of birefringence fluctuation occurring during the propagation of the optical fiber is compensated because the polarization states of the reciprocating rays are diagonalized to each other, and the fluctuation of the polarization state does not seem to change. Therefore, it is extremely effective when applied to a measurement relationship that uses the coherence of light (matching of phase and frequency). In this case, the condition is that the birefringence change of the optical fiber is so gentle that it can be regarded as an infinite length with respect to the round-trip time of the light beam, and the regressed light beam propagates in the same birefringent state in the optical fiber. It is satisfied under the conditions.
【0005】 すなわち図2の構成において、 ミラーから回帰する光線の結合損失が少ないこと。 ファイバ端面などの近端反射は極力制限すること。 組立が容易なこと。 が挙げられる。現在用いられている構成の場合レンズとファイバが分割され、し かも光ファイバは先射研摩され出射光線はファイバ軸方向に対して斜めに放射さ れているので、結合調整が容易ではない。つまりX,Yの平面状態とZ方向の調 整およびファイバのコア軸を回転中心とした回転位置合わせ、光線放射角がミラ ーに対して垂直になるようにファイバを角度合わせするため、二軸のアオリ角度 調整まで含まれ、合計六軸の調整が必要であった。このように従来のファラデー ミラーはファイバ1,レンズ11が分割されているため調整が難しく、部品点数が 増える問題があった。That is, in the configuration of FIG. 2, the coupling loss of light rays returning from the mirror is small. Limit near-end reflections such as fiber end faces as much as possible. Easy to assemble. Is mentioned. In the currently used configuration, the lens and the fiber are separated, and since the optical fiber is pre-polished and the outgoing light beam is emitted obliquely to the fiber axis direction, coupling adjustment is not easy. In other words, in order to adjust the planar state of X and Y and the Z direction, and to adjust the rotational position with the fiber core axis as the center of rotation, and to adjust the angle of the fiber so that the ray emission angle is perpendicular to the mirror, the biaxial Including the tilt angle adjustment, the total 6 axes had to be adjusted. As described above, in the conventional Faraday mirror, since the fiber 1 and the lens 11 are divided, it is difficult to adjust, and there is a problem that the number of parts increases.
【0006】[0006]
本考案は45゜ファラデー回転子,ミラーを配置し、ファラデー回転子を磁化す るための永久磁石を外挿したファラデーミラーにおいて、光ファイバ先端にこの 光ファイバのコア部と等価で単一な屈折率を有する同一外径のファイバ、および その先端に球状部を形成した集束ファイバ端末を対向させ、入出射光を導入出さ せたものであり、球レンズ部とファイバは一体化されており、先端が球状をなし 、部品点数が少なくなるために結合調整が低減でき、また近端反射は60dB以上に 抑制できる。ミラーは誘電体多層蒸着膜あるいは金やアルミニウムの金属膜で形 成する。 The present invention is a Faraday mirror in which a 45 ° Faraday rotator and a mirror are arranged, and a permanent magnet for magnetizing the Faraday rotator is externally inserted. A fiber with the same outer diameter and a focusing fiber terminal with a spherical portion formed at the tip of the fiber are made to face each other to introduce and emit the incoming and outgoing light.The spherical lens portion and the fiber are integrated, and the tip is Since it has a spherical shape and the number of parts is small, coupling adjustment can be reduced and near-end reflection can be suppressed to 60 dB or more. The mirror is made of a dielectric multilayer vapor deposition film or a metal film of gold or aluminum.
【0007】 45゜ファラデー回転子はガーネット膜間の多重反射や、膜面上の反射光を回避 するため光軸に対して1〜15゜傾斜して取り付けた方が好ましいが、それらの寄 与が小さければ角度をつけなくても作用する。本考案によるファラデーミラーの 調整方法としては、図1に示すようなファイバクリーブカット部1に石英ロッド 2を融着し、石英ロッド2先端をファイバ径より大きい球形3に溶融形成し、先 端球形のステンレスファイバホルダ4に固定し、ファラデー回転子5とミラー6 の組合わせ部品と一体化し、ミラー部分をクランプしてから球状ステンレスファ イバホルダ4の尾端部Aを動かし、反射光の最強位置に調整後、その位置にYA G融着等により固定する。The 45 ° Faraday rotator is preferably attached at an angle of 1 to 15 ° with respect to the optical axis in order to avoid multiple reflection between garnet films and reflected light on the film surface. If is small, it works even if it is not angled. As a method of adjusting the Faraday mirror according to the present invention, a quartz rod 2 is fused to a fiber cleave cut portion 1 as shown in FIG. 1, and the tip of the quartz rod 2 is melted and formed into a spherical shape 3 larger than the fiber diameter. Fixed to the stainless steel fiber holder 4 and integrated with the combination part of the Faraday rotator 5 and the mirror 6, the mirror part is clamped, and the tail end A of the spherical stainless steel fiber holder 4 is moved to the strongest position of the reflected light. After the adjustment, fix it at that position by YAG fusion bonding or the like.
【0008】[0008]
ファラデー回転子を透過すると45゜偏波状態が回転する素子厚みにして、ミラ ーで反射し回帰すると、往復で90゜の偏波回転となり、偏光状態が常時対角成分 と重なり合い、すなわち逆向きの複屈折が同時に発生し、結果として時間軸に対 して安定な偏波状態を維持することになる。 When the element thickness is such that the polarization state rotates through 45 ° when it passes through the Faraday rotator, and when it returns after being reflected by the mirror, it reverts to 90 ° polarization rotation, and the polarization state always overlaps with the diagonal component, that is, in the opposite direction. The birefringence of 2 occurs at the same time, and as a result, a stable polarization state is maintained with respect to the time axis.
【0009】[0009]
図1の構成において石英球レンズの直径は約1.2mmに加工した。このビームウ ェストまでの空間伝播距離は約2.7mmであり、その位置にミラーを設置した。ミ ラーは波長域λ=1.31μmで98%以上の反射率が得られる誘電体多層蒸着膜を採 用した。ファラデー回転子5は小型化するため、LPE法により製作された厚み 約300μmのBi置換希土類鉄ガーネット膜を採用し、ガーネット膜間の多重反射や 、膜面上の反射光を回避するため光線伝播方向に対して4゜角度をつけたファラ デー回転子ホルダー7に固定してある。 In the configuration of FIG. 1, the diameter of the quartz ball lens was processed to about 1.2 mm. The spatial propagation distance to this beam waist is about 2.7 mm, and a mirror was installed at that position. The mirror used a dielectric multi-layer vapor deposition film that gives a reflectance of 98% or more in the wavelength range λ = 1.31 μm. In order to make the Faraday rotator 5 compact, a Bi-substituted rare earth iron garnet film with a thickness of about 300 μm manufactured by the LPE method is adopted, and light is propagated to avoid multiple reflection between garnet films and reflected light on the film surface. It is fixed to a Faraday rotator holder 7 which is angled at 4 ° to the direction.
【0010】 先端に球形部Bを形成したファイバホルダ金属部材4中心貫通孔内にフェルー ル保持部材8を介して、光ファイバ1、および先端にこの光ファイバのコア部と 等価で単一な屈折率を有する同一外径のファイバ2、およびその先端に球状部3 を形成した集束ファイバ一体端末を内挿し、その球状部を突出させ、一方対向し て45゜ファラデー回転子5,ミラー6を配置し、ファラデー回転子を磁化するた めの永久磁石9を外挿したキャップ10により封止した。The fiber holder metal member 4 having the spherical portion B formed at the tip is provided with the optical fiber 1 in the center through hole and the ferrule holding member 8, and a single refraction equivalent to the core portion of the optical fiber at the tip. Fiber 2 having the same outer diameter and a converging fiber integrated end having a spherical portion 3 formed at the tip thereof are inserted, and the spherical portion is projected, while a 45 ° Faraday rotator 5 and a mirror 6 are arranged facing each other. Then, the permanent magnet 9 for magnetizing the Faraday rotator was sealed with a cap 10 having been inserted.
【0011】 球形ステンレスファイバホルダ4の尾端部Aを動かし、ミラー反射が最大にな る位置に角度合わせをする。得られたコリメータファイバの結合効率は0.2dB以 下となり極めて安定している。またファラデー回転子を含めた系全体では0.5dB 以下の損失であり、十分な結合が容易に形成できることが判明した。また本実施 例に用いたコリメータファイバ単独の近端反射(リターンロス)は62dBであり、 ファラデーミラーの効果を低下させることはほとんどなく抑制されていることが 判明し、さらに球レンズ先端の反射防止膜を精度良く形成すれば損失はさらに低 減できる。The tail end portion A of the spherical stainless fiber holder 4 is moved to adjust the angle to the position where the mirror reflection is maximum. The coupling efficiency of the obtained collimator fiber is less than 0.2 dB, which is extremely stable. In addition, it was found that the entire system including the Faraday rotator had a loss of 0.5 dB or less, and sufficient coupling could be easily formed. In addition, the near-end reflection (return loss) of the collimator fiber used in this example alone was 62 dB, and it was found that the effect of the Faraday mirror was hardly reduced and was suppressed. If the film is formed accurately, the loss can be further reduced.
【0012】[0012]
本考案の集束球ファイバ端末を使用した場合、レンズファイバが一体で長期光 軸ズレの心配がなく、小型化の設計ができ、光軸合わせが簡単になり、また全て ステンレスホルダに固定され、コンパクトであると共にYAG固定できるので、 信頼性が極めて高い。 When the focused sphere fiber end of the present invention is used, the lens fiber is integrated, there is no concern about optical axis misalignment for a long time, a compact design is possible, optical axis alignment becomes easy, and all are fixed to a stainless steel holder, making it compact. In addition, YAG can be fixed, so the reliability is extremely high.
【図1】本考案を組み込んだファラデーミラー装置の断
面図。FIG. 1 is a sectional view of a Faraday mirror device incorporating the present invention.
【図2】従来のファラデーミラーの概略図。FIG. 2 is a schematic view of a conventional Faraday mirror.
1 光ファイバ 2 石英ロッドファイバ 3 集束レンズ球部 4 ステンレスファイバホルダ 5 ファラデー回転子 6 ミラー 7 ファラデー回転子ホルダー 8 フェルール保持部材 9 リング状永久磁石 10 キャップ 11 レンズ A ステンレスファイバホルダ尾端部 B ステンレスファイバホルダ球形部 1 Optical fiber 2 Quartz rod fiber 3 Focusing lens sphere 4 Stainless fiber holder 5 Faraday rotator 6 Mirror 7 Faraday rotator holder 8 Ferrule holding member 9 Ring-shaped permanent magnet 10 Cap 11 Lens A Stainless fiber holder tail end B Stainless fiber Holder spherical part
Claims (2)
し、ファラデー回転子を磁化するための永久磁石を外挿
したファラデーミラーにおいて、光ファイバ先端にこの
光ファイバのコア部と等価で単一な屈折率を有する同一
外径のファイバ、およびその先端に球状部を形成した集
束ファイバ端末を対向させ、入出射光を導入出させたこ
とを特徴としたファラデーミラー。1. A Faraday mirror in which a 45 ° Faraday rotator and a mirror are arranged, and a permanent magnet for magnetizing the Faraday rotator is externally inserted, and the end of the optical fiber is equivalent to the core of the optical fiber and is a single unit. A Faraday mirror, characterized in that a fiber having the same outer diameter having a refractive index and a focusing fiber terminal having a spherical portion formed at its tip are opposed to introduce and emit light.
〜15゜傾斜して取付けた請求項1記載のファラデーミラ
ー。2. A 45 ° Faraday rotator with respect to the optical axis
The Faraday mirror according to claim 1, wherein the Faraday mirror is mounted at an angle of -15 °.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7565393U JPH0741507U (en) | 1993-12-28 | 1993-12-28 | Faraday mirror |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7565393U JPH0741507U (en) | 1993-12-28 | 1993-12-28 | Faraday mirror |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0741507U true JPH0741507U (en) | 1995-07-21 |
Family
ID=13582424
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP7565393U Pending JPH0741507U (en) | 1993-12-28 | 1993-12-28 | Faraday mirror |
Country Status (1)
Country | Link |
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JP (1) | JPH0741507U (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002243991A (en) * | 2001-02-15 | 2002-08-28 | Nippon Sheet Glass Co Ltd | Coupled optical system and optical device using the same |
WO2011148634A1 (en) * | 2010-05-27 | 2011-12-01 | アダマンド工業株式会社 | Optical fibre birefringence compensation mirror and current sensor |
-
1993
- 1993-12-28 JP JP7565393U patent/JPH0741507U/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002243991A (en) * | 2001-02-15 | 2002-08-28 | Nippon Sheet Glass Co Ltd | Coupled optical system and optical device using the same |
WO2011148634A1 (en) * | 2010-05-27 | 2011-12-01 | アダマンド工業株式会社 | Optical fibre birefringence compensation mirror and current sensor |
JP5830723B2 (en) * | 2010-05-27 | 2015-12-09 | アダマンド株式会社 | Optical fiber birefringence compensating mirror and current sensor |
US9465053B2 (en) | 2010-05-27 | 2016-10-11 | Adamant Kogyo Co., Ltd. | Optical fibre birefringence compensation mirror and current sensor |
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