JP2002107774A - Optical switch - Google Patents
Optical switchInfo
- Publication number
- JP2002107774A JP2002107774A JP2000304071A JP2000304071A JP2002107774A JP 2002107774 A JP2002107774 A JP 2002107774A JP 2000304071 A JP2000304071 A JP 2000304071A JP 2000304071 A JP2000304071 A JP 2000304071A JP 2002107774 A JP2002107774 A JP 2002107774A
- Authority
- JP
- Japan
- Prior art keywords
- polarization
- optical path
- birefringent element
- light
- optical
- 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
Links
Landscapes
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光通信や光計測な
どの分野において、光路切り換えを行うための磁気光学
式の光スイッチに関し、更に詳しく述べると、光路の中
央部にミラーを設け、２個の可変ファラデー回転子を独
立に制御することにより３ポートへの出力切り換えを可
能とした光スイッチに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical switch for switching an optical path in the field of optical communication and optical measurement. More specifically, a mirror is provided at the center of the optical path. The present invention relates to an optical switch capable of switching output to three ports by independently controlling the number of variable Faraday rotators.
【０００２】[0002]
【従来の技術】光スイッチは、例えば入力ポートからの
光を第１出力ポートか、又は第２出力ポートのいずれか
一方へ出力するというような光路切り換え機能を有する
光デバイスである。光路の切り換えには、電磁石により
印加磁界方向が変化する４５度ファラデー回転子を用
い、出力光の偏波面が９０度切り換わるように制御する
ことで行っている。2. Description of the Related Art An optical switch is an optical device having an optical path switching function of, for example, outputting light from an input port to either a first output port or a second output port. The optical path is switched by using a 45-degree Faraday rotator in which the direction of the applied magnetic field is changed by an electromagnet and controlling the polarization plane of the output light to switch by 90 degrees.
【０００３】従来から様々な構成の磁気光学式光スイッ
チが開発されている。その一例として、３個の複屈折素
子を間隔をあけて一列に配列し、それら複屈折素子の間
にそれぞれ４５度可変ファラデー回転子と１／２波長板
の組を挿入し、その配列体の一端側に入力ポートを、他
端側に出力ポートを設ける構成がある。２個の４５度可
変ファラデー回転子の電磁石の印加磁界方向を連動制御
することで、光路切り換えを行う。この構成では、設置
する入力ポートと出力ポートの数によって、１×２型、
２×２型、２×１型の光スイッチを実現できる。Conventionally, magneto-optical switches having various configurations have been developed. As an example, three birefringent elements are arranged in a line with an interval, and a pair of a 45-degree variable Faraday rotator and a half-wave plate are inserted between the birefringent elements. There is a configuration in which an input port is provided at one end and an output port is provided at the other end. Optical path switching is performed by interlockingly controlling the applied magnetic field directions of the electromagnets of the two 45-degree variable Faraday rotators. In this configuration, depending on the number of input and output ports to be installed, 1 × 2 type,
2 × 2 type and 2 × 1 type optical switches can be realized.
【０００４】その他、複数の偏光ビームスプリッタと±
４５度可変ファラデー回転子で構成する光スイッチもあ
る。In addition, a plurality of polarization beam splitters and ±
There is also an optical switch composed of a 45-degree variable Faraday rotator.
【０００５】[0005]
【発明が解決しようとする課題】いずれにしても従来の
磁気光学式の光スイッチは、２方向への出力を切り換え
るものであり、出力を３ポートのいずれかへ切り換えら
れるような構造は開発されていない。勿論、従来タイプ
の光スイッチを２組直列に接続すれば１×３（１入力×
３出力）型を構成することは可能であるが、デバイスは
大型化し、光学的特性（クロストークや挿入損失など）
も低下してしまう。In any case, the conventional magneto-optical switch switches the output in two directions, and a structure capable of switching the output to one of three ports has been developed. Not. Of course, if two sets of conventional optical switches are connected in series, 1 × 3 (1 input ×
Although it is possible to configure a three-output) type, the device becomes larger and optical characteristics (such as crosstalk and insertion loss) increase.
Will also decrease.
【０００６】本発明の目的は、光学的特性を損なうこと
なく、しかも小型でありながら１×３型を実現できる光
スイッチを提供することである。An object of the present invention is to provide an optical switch which can realize a 1 × 3 type without deteriorating optical characteristics and being compact.
【０００７】[0007]
【課題を解決するための手段】本発明は、偏波方向が直
交関係にある同じ光路の光を分離し異なる光路の光を合
成する分離合成用複屈折素子、偏波方向に応じて光路を
制御する第１及び第２の光路制御用複屈折素子、偏波方
向が直交関係にある異なる光路の光を合成する合成用複
屈折素子を、この順序で間隔をおいて配設し、分離合成
用複屈折素子と第１の光路制御用複屈折素子との間に、
第１の±４５度可変ファラデー回転子と両側光路で光学
軸が対称になるように並設した２枚の１／２波長板との
組み合わせからなり、偏波方向を直交から平行に逆方向
については平行から直交に変換する偏波回転切換手段を
配置し、第１の光路制御用複屈折素子と第２の光路制御
用複屈折素子との間に、第２の±４５度可変ファラデー
回転子と一部の光路の光を反射するミラーを備えた偏波
反射切換手段を配置し、第２の光路制御用複屈折素子と
合成用複屈折素子との間に、偏波方向を平行から直交に
変換する偏波回転手段を配置し、それら配列体の分離合
成用複屈折素子側及び合成用複屈折素子側にポートを設
置し、第１の±４５度可変ファラデー回転子と第２の±
４５度可変ファラデー回転子のファラデー回転方向を独
立に切り換えるようにした光スイッチである。SUMMARY OF THE INVENTION The present invention provides a birefringent element for separation / synthesis that separates lights in the same optical path having orthogonal polarization directions and combines lights in different optical paths. The first and second optical path controlling birefringent elements to be controlled, and the combining birefringent elements for combining lights in different optical paths whose polarization directions are orthogonal to each other are arranged at intervals in this order, and are separated and combined. Between the first birefringent element and the first birefringent element for optical path control,
It consists of a combination of a first ± 45 degree variable Faraday rotator and two half-wave plates arranged side by side so that the optical axes are symmetrical on both sides of the optical path. Is provided with a polarization rotation switching means for converting from parallel to orthogonal, and a second ± 45 degree variable Faraday rotator is provided between the first optical path controlling birefringent element and the second optical path controlling birefringent element. And a polarization reflection switching means having a mirror for reflecting light of a part of the optical path, and the polarization direction is changed from parallel to orthogonal between the second optical path controlling birefringent element and the combining birefringent element. Polarization rotator means for converting the array into a birefringent element for separation / synthesis and a port on the birefringent element for synthesization of these arrays, the first ± 45-degree variable Faraday rotator and the second ±
This is an optical switch in which the Faraday rotation direction of the 45-degree variable Faraday rotator is independently switched.
【０００８】偏波反射切換手段と第２の光路制御用複屈
折素子の間に、ミラーのバイパス光に作用して偏波面を
４５度回転させる１／２波長板を挿入すると、偏波方向
が調整されるため、第１の光路制御用複屈折素子と第２
の光路制御用複屈折素子の通過光の進行方向に沿って見
た光学軸の方向を揃えることができ、同じ構造・形状の
複屈折素子が使用可能となる利点が生じる。When a half-wave plate for rotating the polarization plane by 45 degrees by acting on the mirror bypass light is inserted between the polarization reflection switching means and the second optical path controlling birefringent element, the polarization direction is changed. The first optical path controlling birefringent element and the second
In this case, the directions of the optical axes viewed along the traveling direction of the light passing through the birefringent element for controlling the optical path can be made uniform, and there is an advantage that the birefringent element having the same structure and shape can be used.
【０００９】第２の光路制御用複屈折素子と第２の分離
合成用複屈折素子の間に配置する偏波回転手段は、通過
光の一方の偏波面を９０度回転させる１／２波長板を２
枚、異なる通過光の光路に配置した構造でもよいし、片
側光路の光の偏波面を９０度回転させる１／２波長板と
一方の通過光を９０度回転させる１／２波長板との組み
合わせからなる構成でもよい。The polarization rotator disposed between the second optical path controlling birefringent element and the second separating / combining birefringent element is a half-wave plate for rotating one polarization plane of the transmitted light by 90 degrees. 2
A combination of a half-wave plate that rotates the polarization plane of light in one optical path by 90 degrees and a half-wave plate that rotates one passing light by 90 degrees may be used. A configuration consisting of
【００１０】光の進行方向に沿って見た第２の光路制御
用複屈折素子の光学軸の方向が、第１の光路制御用複屈
折素子の光学軸の方向に対して４５度傾いており、且つ
第２の光路制御用複屈折素子への入射光の偏波面に対し
て平行もしくは垂直の関係に設定されている場合、第２
の光路制御用複屈折素子と合成用複屈折素子の間に配置
する偏波回転手段は、全ての通過光の偏波面をを４５度
回転させる１／２波長板を４枚、各光路の各通過光にそ
れぞれ挿入した構造とすればよい。The direction of the optical axis of the second optical path controlling birefringent element as viewed along the traveling direction of light is inclined by 45 degrees with respect to the direction of the optical axis of the first optical path controlling birefringent element. If the relationship is set to be parallel or perpendicular to the plane of polarization of the light incident on the second optical path controlling birefringent element, the second
The polarization rotator disposed between the optical path controlling birefringent element and the combining birefringent element has four half-wave plates for rotating the polarization planes of all the passing lights by 45 degrees, What is necessary is just to make it the structure inserted in each passing light.
【００１１】波長板は、直交する直線偏波成分間に所定
の波長の位相差を与えるものであるが、本明細書におい
て１／２波長板は広義に解釈されるものとし、それぞれ
（１／２＋整数）波長の位相差が生じるものも含まれる
ものとする。なお１／２波長板は、入力光の偏波方向を
その光学軸に関して対称に変換する性質があるので、適
切な方向に光学軸を設定しておくことによって、入力光
の偏波面を所定方向に回転することができる相反性の光
部品である。また、ミラーなど光路の一部に挿入する部
品については、透明体と組み合わせて外形を他の光学部
品と同じに調整して、組み立て易くする構成も本発明に
含まれることはいうまでもない。A wave plate gives a phase difference of a predetermined wavelength between linearly polarized components orthogonal to each other. In this specification, a half-wave plate is to be interpreted in a broad sense, and each of them is (1/1 / (2 + integer) wavelength phase difference is also included. Since the half-wave plate has the property of transforming the polarization direction of the input light symmetrically with respect to its optical axis, the polarization plane of the input light can be set in a predetermined direction by setting the optical axis in an appropriate direction. A reciprocal optical component that can rotate. In addition, it goes without saying that the present invention includes a configuration such as a mirror inserted into a part of the optical path, which is combined with a transparent body and whose outer shape is adjusted to be the same as other optical components to facilitate assembly.
【００１２】[0012]
【実施例】図１は本発明に係る光スイッチの第１の実施
例を示す説明図、図２はその光路説明図であり、１×３
型の光スイッチである。なお各光部品中における矢印
は、光学軸の方向もしくはファラデー回転の方向を示し
ている。また、説明を分かり易くするために、次のよう
な座標軸を設定する。光部品の配列方向をｚ方向（図面
では奥行き方向）とし、それに対して直交する２方向を
ｘ方向（図面では水平方向）、ｙ方向（図面では垂直方
向）とする。また回転方向は、ｚ方向を見て時計回りを
プラス側とする。FIG. 1 is an explanatory view showing a first embodiment of an optical switch according to the present invention, and FIG.
Type optical switch. The arrow in each optical component indicates the direction of the optical axis or the direction of Faraday rotation. Further, the following coordinate axes are set to make the description easy to understand. The arrangement direction of the optical components is defined as the z direction (depth direction in the drawing), and two directions orthogonal thereto are defined as the x direction (horizontal direction in the drawing) and the y direction (vertical direction in the drawing). As for the rotation direction, the clockwise direction when viewed in the z direction is a plus side.
【００１３】偏波方向が直交関係にある同じ光路の光を
ｘ方向に分離しｘ方向で異なる光路の光を合成する分離
合成用複屈折素子１０、偏波方向に応じて常光は直進し
異常光は＋ｙ方向に光路をシフトする第１の光路制御用
複屈折素子１１、同様に偏波方向に応じて常光は直進し
異常光は＋ｙ方向に光路をシフトする第２の光路制御用
複屈折素子１２、偏波方向が直交関係にある異なる光路
の光を合成する合成用複屈折素子１３を、この順序で間
隔をおいてｚ方向に配設する。そこで、ここではｚ方向
に沿って見た光学軸は、分離合成用複屈折素子１０と合
成用複屈折素子１３についてはｘ軸に平行、第１及び第
２の光路制御用複屈折素子１１，１２についてはｙ軸に
平行に設定されている。A birefringent element 10 for separating and combining light in the same optical path having orthogonal polarization directions in the x direction and combining lights in different optical paths in the x direction. The first birefringent element 11 for optical path control that shifts the optical path in the + y direction, and the second birefringence for the second optical path control that similarly shifts the ordinary light straight and the extraordinary light shifts the optical path in the + y direction according to the polarization direction. An element 12 and a combining birefringent element 13 for combining lights in different optical paths whose polarization directions are orthogonal to each other are arranged in the z direction at intervals in this order. Therefore, here, the optic axis viewed along the z-direction is parallel to the x-axis for the birefringent element 10 for separation / synthesis and the birefringent element 13 for synthesis, and the first and second birefringent elements 11 for controlling the optical path. 12 is set parallel to the y-axis.
【００１４】ｚ方向を見て分離合成用複屈折素子１０と
第１の光路制御用複屈折素子１１との間に、偏波方向を
直交から平行に（逆方向では平行から直交に）変換する
偏波回転切換手段１４を設ける。この偏波回転切換手段
１４は、第１の±４５度可変ファラデー回転子１５と、
左右両側光路で光学軸が対称となるように並設した２枚
の１／２波長板１６の組み合わせからなる。なお、第１
の±４５度可変ファラデー回転子１５は、電磁石により
ファラデー素子に外部磁界を印加する構造であり、電磁
石への通電方向を切り換えることによって印加磁界の方
向を制御でき、それによってファラデー回転を＋４５度
あるいは−４５度に切り換えることができる形式であ
る。１／２波長板１６は、図３のＡに示すように、左側
光路は光学軸がｘ方向から−２２．５度傾き、右側光路
は光学軸がｘ方向から２２．５度傾いて、互いにｙ軸に
関し対称となるように一体化したものである。The polarization direction is converted from orthogonal to parallel (in the opposite direction, from parallel to orthogonal) between the separating / combining birefringent element 10 and the first optical path controlling birefringent element 11 looking at the z direction. A polarization rotation switching means 14 is provided. The polarization rotation switching means 14 includes a first ± 45 degree variable Faraday rotator 15,
It consists of a combination of two half-wave plates 16 arranged side by side so that the optical axes are symmetrical in the left and right optical paths. The first
The variable Faraday rotator 15 has a structure in which an external magnetic field is applied to the Faraday element by an electromagnet, and the direction of the applied magnetic field can be controlled by switching the direction of energization to the electromagnet, whereby the Faraday rotation is increased by +45 degrees or This is a format that can be switched to -45 degrees. As shown in FIG. 3A, the half-wave plate 16 has a left optical path whose optical axis is inclined by −22.5 degrees from the x direction, and a right optical path whose optical axis is inclined by 22.5 degrees from the x direction. It is integrated so as to be symmetric with respect to the y-axis.
【００１５】次に、ｚ方向を見て、第１の光路制御用複
屈折素子１１と第２の光路制御用複屈折素子１２との間
に、偏波反射切換手段１８を設置する。ここで偏波反射
切換手段１８は、第２の±４５度可変ファラデー回転子
１９、一部の光路（上段の光路）のｚ方向の光を反射す
るミラー２０からなる。なお、この第２の±４５度可変
ファラデー回転子１９も、電磁石によりファラデー素子
に外部磁界を印加する構造であり、該電磁石への通電方
向を切り換えることによって印加磁界の方向を制御で
き、それによってファラデー回転を＋４５度あるいは−
４５度に切り換えることができる形式である。ここで
は、第１及び第２の±４５度可変ファラデー回転子１
５，１９は、それらのファラデー回転方向が互いに同じ
向きもしくは逆向きになるように独立に切り換え可能に
なっている。Next, looking at the z direction, a polarization reflection switching means 18 is provided between the first optical path controlling birefringent element 11 and the second optical path controlling birefringent element 12. Here, the polarization reflection switching means 18 includes a second ± 45-degree variable Faraday rotator 19 and a mirror 20 that reflects light in the z direction of a part of the optical path (upper optical path). The second ± 45-degree variable Faraday rotator 19 also has a structure in which an external magnetic field is applied to the Faraday element by an electromagnet, and the direction of the applied magnetic field can be controlled by switching the direction of energization to the electromagnet. Faraday rotation +45 degrees or-
This is a format that can be switched to 45 degrees. Here, the first and second ± 45-degree variable Faraday rotators 1
5, 19 can be independently switched so that their Faraday rotation directions are the same or opposite.
【００１６】またｚ方向を見て、偏波反射切換手段１８
と第２の光路制御用複屈折素子１２との間に、ミラー２
０のバイパス光に作用するように（即ち、下段光路に）
偏波面を４５度回転させる１／２波長板２２を挿入す
る。この１／２波長板２２は、図３のＢに示すように、
光学軸がｘ方向から６７．５度傾いているものである。
従って、第２の±４５度可変ファラデー回転子１９で偏
波面が４５度回転した光が、この１／２波長板２２によ
って、出射光の偏波方向を第２の光路制御用複屈折素子
１２の光学軸に対して平行もしくは垂直になる。Looking at the z direction, the polarization reflection switching means 18
Between the mirror and the second optical path controlling birefringent element 12
0 to act on the bypass light (ie, to the lower optical path)
The half-wave plate 22 for rotating the polarization plane by 45 degrees is inserted. As shown in FIG. 3B, the half-wave plate 22
The optical axis is tilted 67.5 degrees from the x direction.
Therefore, the light whose polarization plane is rotated by 45 degrees by the second ± 45 degree variable Faraday rotator 19 is changed by the half-wave plate 22 so that the polarization direction of the outgoing light is changed by the second optical path controlling birefringent element 12. Parallel or perpendicular to the optical axis of
【００１７】更に、第２の光路制御用複屈折素子１２と
合成用複屈折素子１３の間に偏波回転手段を配置する。
この偏波回転手段は、偏波方向を平行から直交に変換す
るもので、ｚ方向に沿って見たときに左上光路と右下光
路の光の偏波面をそれぞれ９０度回転させるように組み
合わせた２枚の１／２波長板２４からなる。この１／２
波長板２４は、図３のＣに示すように、いずれも光学軸
がｘ方向から４５度傾いているものである。Further, a polarization rotating means is disposed between the second optical path controlling birefringent element 12 and the combining birefringent element 13.
This polarization rotation means converts the polarization direction from parallel to orthogonal, and is combined to rotate the polarization planes of the light in the upper left optical path and the lower right optical path by 90 degrees when viewed along the z direction. It consists of two half-wave plates 24. This 1/2
As shown in FIG. 3C, each of the wave plates 24 has an optical axis inclined by 45 degrees from the x direction.
【００１８】このような配列体の分離合成用複屈折素子
１０の側に、ｙ方向にずらせて下段に入力ポートＩ、上
段に第１出力ポートＯ１を、合成用複屈折素子１３の側
に、ｙ方向にずらせて上段に第２出力ポートＯ２、下段
に第３出力ポートＯ３を設定する。The input port I is shifted downward in the y direction, the first output port O1 is shifted upward, and the birefringent element 13 is shifted to the side of the separation / synthesis birefringent element 10 in such an array. The second output port O2 is set at the upper stage and the third output port O3 is set at the lower stage by shifting in the y direction.
【００１９】この光スイッチの動作について説明する。 （入力ポートＩ→第１出力ポートＯ１）まず、第１及び
第２の±４５度可変ファラデー回転子１５，１９を、そ
れらのファラデー回転方向が共にマイナス方向（反時計
方向）に印加磁界を設定する。下段の入力ポートＩから
ｚ方向に入力する光は、分離合成用複屈折素子１０で常
光は直進し、異常光は屈折してｘ方向に光分離する。そ
して第１の偏波回転切換手段１４で、偏波方向が直交か
ら平行の関係に変換される。即ち、偏波方向が直交する
光は、第１の±４５度可変ファラデー回転子１５でそれ
ぞれ偏波方向が−４５度回転し、１／２波長板１６でｘ
軸に垂直となる。それら両光は第１の光路制御用複屈折
素子１１に対しては異常光になっているので、上方に屈
折し上段の光路を進む。そして偏波反射切換手段１８で
反射する。即ち、光は、第２の±４５度可変ファラデー
回転子１９でそれぞれ偏波方向が−４５度回転し、ミラ
ー２０で反射されて−ｚ方向に進み、再び第２の±４５
度可変ファラデー回転子１９に戻ってそれぞれ偏波方向
が更に−４５度回転してｘ軸と平行になる。第１の偏波
回転切換手段１４によって偏波方向が平行から直交の関
係に変換される。即ち、偏波方向が直交する光は、１／
２波長板１６で偏波方向が４５度回転し、第１の±４５
度可変ファラデー回転子１５でそれぞれ偏波方向が−４
５度回転して、両光は互いに直交する関係となる。そし
て、分離合成用複屈折素子１０でｘ方向で光が合成する
ため、上段の第１出力ポートＯ１から出力する。The operation of the optical switch will be described. (Input port I → first output port O1) First, the first and second ± 45-degree variable Faraday rotators 15 and 19 are set to have a magnetic field applied in such a direction that both Faraday rotation directions are negative (counterclockwise). I do. Light input from the lower input port I in the z-direction is split into ordinary light by the birefringent element 10 for separation and synthesis, and extraordinary light is refracted and separated in the x-direction. Then, the first polarization rotation switching means 14 converts the polarization direction from orthogonal to parallel. That is, light whose polarization directions are orthogonal is rotated by −45 degrees in the first ± 45-degree variable Faraday rotator 15, and x in the half-wave plate 16.
Perpendicular to the axis. Both of these lights are extraordinary lights with respect to the first optical path controlling birefringent element 11, so they are refracted upward and travel on the upper optical path. Then, the light is reflected by the polarization reflection switching means 18. That is, the light is rotated by −45 degrees in the polarization direction by the second ± 45-degree variable Faraday rotator 19, is reflected by the mirror 20, travels in the −z direction, and again has the second ± 45 degrees.
Returning to the degree-variable Faraday rotator 19, the polarization direction is further rotated by -45 degrees to be parallel to the x-axis. The polarization direction is converted from parallel to orthogonal by the first polarization rotation switching means 14. That is, light whose polarization directions are orthogonal is 1 /
The polarization direction is rotated by 45 degrees by the two-wavelength plate 16, and the first ± 45
The polarization direction of each of the variable-degree Faraday rotators 15 is -4.
After rotating by 5 degrees, the two lights have a relationship orthogonal to each other. Then, since the light is combined in the x direction by the birefringent element for separation / combination 10, the light is output from the first output port O1 in the upper stage.
【００２０】（入力ポートＩ→第２出力ポートＯ２）次
に、第１及び第２の±４５度可変ファラデー回転子１
５，１９を、ファラデー回転方向が共にプラスとなる向
き（時計方向）に印加磁界を設定する。下段の入力ポー
トＩからｚ方向に入力する光は、分離合成用複屈折素子
１０で常光は直進し、異常光は屈折してｘ方向に光分離
する。そして第１の偏波回転切換手段１４で、偏波方向
が直交から平行の関係に変換される。即ち、偏波方向が
直交する光は、第１の±４５度可変ファラデー回転子１
５でそれぞれ偏波方向が＋４５度回転し、１／２波長板
１６でｘ軸に平行となる。それら両光は第１の光路制御
用複屈折素子１１に対しては常光になっているので、そ
のまま下段光路を直進する。そのため偏波反射切換手段
１８を通過する。即ち、第２の±４５度可変ファラデー
回転子１９でそれぞれ偏波方向が＋４５度回転した後、
ミラー２０をバイパスする。次に、１／２波長板２２で
偏波方向が４５度回転し、ｘ軸に垂直になる。この光は
第２の光路制御用複屈折素子１２に対しては異常光にな
っているので、上方に屈折し上段の光路を進む。そして
１／２波長板２４で、左側光路の光の偏波面は９０度回
転し、右側光路の光はそのままバイパスするために、両
光の偏波方向は直交の関係に変換される。そして合成用
複屈折素子１３でｘ方向で光が合成するため、上段の第
２出力ポートＯ２から出力する。(Input Port I → Second Output Port O2) Next, the first and second ± 45-degree variable Faraday rotators 1
5 and 19, the applied magnetic field is set in a direction (clockwise) in which both the Faraday rotation directions are positive. Light input from the lower input port I in the z-direction is split into ordinary light by the birefringent element 10 for separation and synthesis, and extraordinary light is refracted and separated in the x-direction. Then, the first polarization rotation switching means 14 converts the polarization direction from orthogonal to parallel. That is, light whose polarization directions are orthogonal to each other is transmitted to the first ± 45 degree variable Faraday rotator 1.
5, the polarization direction is rotated by +45 degrees, and the half-wave plate 16 becomes parallel to the x-axis. Both of these lights are ordinary light with respect to the first birefringent element 11 for controlling the optical path, and thus go straight on the lower optical path. Therefore, the light passes through the polarization reflection switching means 18. That is, after the polarization direction is rotated by +45 degrees by the second ± 45-degree variable Faraday rotator 19,
The mirror 20 is bypassed. Next, the polarization direction is rotated by 45 degrees by the half-wave plate 22, and becomes perpendicular to the x-axis. This light is extraordinary light with respect to the second optical path controlling birefringent element 12, so it is refracted upward and travels along the upper optical path. Then, in the half-wave plate 24, the polarization plane of the light in the left optical path is rotated by 90 degrees, and the light in the right optical path is bypassed as it is. Then, since light is combined in the x direction by the combining birefringent element 13, the light is output from the second output port O2 in the upper stage.
【００２１】（入力ポートＩ→第３出力ポートＯ３）第
１の±４５度可変ファラデー回転子１５は、ファラデー
回転方向がプラスとなる向き（時計方向）に、第２の±
４５度可変ファラデー回転子１９は、ファラデー回転方
向がマイナスとなる向き（反時計方向）に印加磁界を設
定する。下段の入力ポートＩからｚ方向に入力する光
は、分離合成用複屈折素子１０で常光は直進し、異常光
は屈折してｘ方向に光分離する。そして第１の偏波回転
切換手段１４で、偏波方向が直交から平行の関係に変換
される。即ち、偏波方向が直交する光は、第１の±４５
度可変ファラデー回転子１５でそれぞれ偏波方向が＋４
５度回転し、１／２波長板１６でｘ軸に平行となる。そ
れら両光は第１の光路制御用複屈折素子１１に対しては
常光になっているので、そのまま下段の光路を直進す
る。そのため偏波反射切換手段１８を通過する。即ち、
第２の±４５度可変ファラデー回転子１９でそれぞれ偏
波方向が−４５度回転し、ミラー２０をバイパスする。
次に、１／２波長板２２で偏波方向が４５度回転し、ｘ
軸に平行になる。この光は第２の光路制御用複屈折素子
１２に対しては常光になっているので、そのまま下段の
光路を直進する。そして１／２波長板２４で、左側光路
の光はそのままバイパスし、右側光路の光の偏波面は９
０度回転するために、両光の偏波方向は直交の関係に変
換される。そして合成用複屈折素子１３でｘ方向で光が
合成するため、下段の第３出力ポートＯ３から出力す
る。(Input Port I → Third Output Port O3) The first ± 45-degree variable Faraday rotator 15 rotates the second ± 45 ° in a direction in which the Faraday rotation direction is positive (clockwise).
The 45-degree variable Faraday rotator 19 sets the applied magnetic field in a direction in which the Faraday rotation direction is negative (counterclockwise). Light input from the lower input port I in the z-direction is split into ordinary light by the birefringent element 10 for separation and synthesis, and extraordinary light is refracted and separated in the x-direction. Then, the first polarization rotation switching means 14 converts the polarization direction from orthogonal to parallel. That is, the light whose polarization direction is orthogonal is the first ± 45
The polarization direction is +4 by the Faraday rotator 15
It rotates by 5 degrees and becomes parallel to the x-axis by the half-wave plate 16. Both of these lights are ordinary light for the first optical path control birefringent element 11, so they proceed straight through the lower optical path. Therefore, the light passes through the polarization reflection switching means 18. That is,
The polarization direction is rotated by −45 degrees by the second ± 45-degree variable Faraday rotator 19, and bypasses the mirror 20.
Next, the polarization direction is rotated 45 degrees by the half-wave plate 22, and x
Be parallel to the axis. Since this light is ordinary light for the second optical path controlling birefringent element 12, it travels straight through the lower optical path as it is. The half-wave plate 24 bypasses the light in the left optical path as it is, and the polarization plane of the light in the right optical path is 9
To rotate by 0 degrees, the polarization directions of both lights are converted to an orthogonal relationship. Then, since the light is combined in the x direction by the combining birefringent element 13, the light is output from the third output port O3 in the lower stage.
【００２２】このようにして、第１及び第２の±４５度
可変ファラデー回転子１５，１９の印加磁界を独立に切
り換えることによって、入力ポートＩからの入力光を、
第１出力ポートＯ１、第２出力ポートＯ２、第３出力ポ
ートＯ３のいずれかへ出力するという１×３型の光スイ
ッチが実現できる。入出力の結合関係と可変ファラデー
回転子の印加磁界の関係を表１に示す。In this way, the input light from the input port I is changed by independently switching the applied magnetic field of the first and second ± 45-degree variable Faraday rotators 15 and 19.
It is possible to realize a 1 × 3 optical switch that outputs to any one of the first output port O1, the second output port O2, and the third output port O3. Table 1 shows the relationship between the input / output coupling relationship and the applied magnetic field of the variable Faraday rotator.
【００２３】[0023]
【表１】 [Table 1]
【００２４】図４は上記実施例で用いることができる偏
波回転手段の変形例を示す説明図である。第２の光路制
御用複屈折素子と合成用複屈折素子の間に配置する偏波
回転手段は、片側光路の光の偏波面を９０度回転させる
１／２波長板と一方の通過光の偏波面を９０度回転させ
る１／２波長板との組み合わせからなる。ここでは、下
段の光路のみに挿入する１／２波長板３０と左側光路の
みに挿入する１／２波長板３２との組み合わせである。
従って、左下光路を通る光は、両方の１／２波長板３
０，３２を通過することになる。なお、図５に示すよう
に、両方の１／２波長板３０，３２の光学軸は、ｚ方向
に沿って見たときにｘ方向に対して−４５度傾いた向き
とする。なお、１／２波長板３０と１／２波長板３２の
ｚ方向についての配列順序は逆でもよい。FIG. 4 is an explanatory view showing a modification of the polarization rotating means which can be used in the above embodiment. The polarization rotating means disposed between the second optical path controlling birefringent element and the combining birefringent element includes a half-wave plate for rotating the polarization plane of the light of one side optical path by 90 degrees and a polarization of one of the passing lights. It consists of a combination with a half-wave plate that rotates the wavefront by 90 degrees. Here, a combination of a half-wave plate 30 inserted only in the lower optical path and a half-wave plate 32 inserted only in the left optical path is used.
Therefore, light passing through the lower left optical path is transmitted to both the half-wave plates 3.
0, 32. As shown in FIG. 5, the optical axes of both the half-wave plates 30 and 32 are inclined at −45 degrees with respect to the x direction when viewed along the z direction. The arrangement order of the half-wave plate 30 and the half-wave plate 32 in the z direction may be reversed.
【００２５】入力ポートから第２出力ポートに向かう上
段光路の光については、前記実施例と同様、左側光路の
光の偏波面は１／２波長板３２で９０度回転し、右側光
路の光はそのまま１／２波長板３２をバイパスするため
に、両光の偏波方向は直交の関係に変換される。入力ポ
ートから第３出力ポートに向かう下段光路の光について
は、左側光路の光の偏波面は１／２波長板３０で９０度
回転し、次の１／２波長板３２で９０度回転するため、
結局元の状態に戻り、右側光路の光の偏波面は１／２波
長板３０で９０度回転するために、両光の偏波方向は直
交の関係に変換される。このような偏波状態は、前記第
１実施例の場合と全く同じである。従って、第１実施例
における１／２波長板２４と置き換えることができる。For the light in the upper optical path from the input port to the second output port, the polarization plane of the light in the left optical path is rotated 90 degrees by the half-wave plate 32, and the light in the right optical path is In order to bypass the half-wave plate 32 as it is, the polarization directions of both lights are converted into an orthogonal relationship. For the light in the lower optical path from the input port to the third output port, the polarization plane of the light in the left optical path is rotated by 90 degrees by the half-wave plate 30 and 90 degrees by the next half-wave plate 32. ,
Eventually, the light returns to the original state, and the polarization plane of the light in the right optical path is rotated by 90 degrees by the half-wave plate 30, so that the polarization directions of both lights are converted into an orthogonal relationship. Such a polarization state is exactly the same as that of the first embodiment. Therefore, the half-wave plate 24 in the first embodiment can be replaced.
【００２６】図６は本発明に係る光スイッチの第２の実
施例を示す説明図、図７はその光路説明図であり、１×
３型の光スイッチである。ここでも各光部品中における
矢印は、光学軸の方向もしくはファラデー回転の方向を
示している。また、説明を分かり易くするために、同様
の座標軸を設定する。この第２実施例が前記の第１実施
例と異なる点は、偏波反射切換手段と第２の光路制御用
複屈折素子の間の１／２波長板が無く、第２の光路制御
用複屈折素子はｚ方向に沿って見たときの光学軸の向き
がｘ方向に対して４５度傾いており、更に偏波回転手段
が４分割の１／２波長板の組み合わせからなる点であ
る。FIG. 6 is an explanatory view showing a second embodiment of the optical switch according to the present invention, and FIG. 7 is an explanatory view of the optical path thereof.
This is a type 3 optical switch. Again, the arrows in each optical component indicate the direction of the optical axis or the direction of Faraday rotation. In addition, similar coordinate axes are set for easy understanding. This second embodiment differs from the first embodiment in that there is no half-wave plate between the polarization reflection switching means and the second optical path controlling birefringent element, and the second optical path controlling birefringent element. The refracting element is characterized in that the direction of the optical axis when viewed along the z direction is inclined by 45 degrees with respect to the x direction, and that the polarization rotating means is formed of a combination of quartered half-wave plates.
【００２７】偏波方向が直交関係にある同じ光路の光を
ｘ方向に分離しｘ方向で異なる光路の光を合成する分離
合成用複屈折素子４０、偏波方向に応じて常光は直進し
異常光は＋ｙ方向に光路をシフトする第１の光路制御用
複屈折素子４１、同様に偏波方向に応じて常光は直進し
異常光は＋ｙ方向に光路をシフトする第２の光路制御用
複屈折素子４２、偏波方向が直交関係にある異なる光路
の光を合成する合成用複屈折素子４３を、この順序で間
隔をおいてｚ方向に配設する。ここでは、ｚ方向に沿っ
て見た光学軸は、分離合成用複屈折素子４０及び合成用
複屈折素子４３についてはｘ軸に平行、第１光路制御用
複屈折素子４１についてはｙ軸に平行、第２の光路制御
用複屈折素子４２についてはｘ軸に対して４５度傾斜す
るように設定されている。A birefringent element 40 for separating and combining light in the same optical path whose polarization directions are orthogonal to each other in the x direction and combining lights in different optical paths in the x direction. The first birefringent element 41 for controlling the light path shifts the optical path in the + y direction. Similarly, the birefringence for the second optical path control shifts the ordinary light straight and the extraordinary light shifts the optical path in the + y direction according to the polarization direction. An element 42 and a combining birefringent element 43 for combining lights in different optical paths whose polarization directions are orthogonal to each other are arranged in the z direction at intervals in this order. Here, the optical axis viewed along the z direction is parallel to the x axis for the birefringent element 40 for separation / synthesis and the birefringent element 43 for synthesis, and parallel to the y axis for the birefringent element 41 for the first optical path control. The second birefringent element 42 for controlling the optical path is set so as to be inclined by 45 degrees with respect to the x-axis.
【００２８】ｚ方向を見て分離合成用複屈折素子４０と
第１の光路制御用複屈折素子４１との間に、偏波方向を
直交から平行に（逆方向では平行から直交に）変換する
偏波回転切換手段４４を設ける。この偏波回転切換手段
４４は、第１の±４５度可変ファラデー回転子４５と、
左右両側光路で光学軸が対称となるように並設した２枚
の１／２波長板４６の組み合わせからなる。なお、第１
の±４５度可変ファラデー回転子４５は、電磁石により
ファラデー素子に外部磁界を印加する構造であり、電磁
石への通電方向を切り換えることによって印加磁界の方
向を制御でき、それによってファラデー回転を＋４５度
あるいは−４５度に切り換えることができる形式であ
る。１／２波長板４６は、図３のＡに示すのと同様、左
側光路は光学軸がｘ方向から−２２．５度傾き、右側光
路は光学軸がｘ方向から２２．５度傾いて、互いにｙ軸
に関し対称となるように一体化したものである。The polarization direction is converted from orthogonal to parallel (in the opposite direction, from parallel to orthogonal) between the separating / combining birefringent element 40 and the first optical path controlling birefringent element 41 looking at the z direction. A polarization rotation switching means 44 is provided. This polarization rotation switching means 44 includes a first ± 45 degree variable Faraday rotator 45,
It consists of a combination of two half-wave plates 46 arranged side by side so that the optical axes are symmetrical in the left and right optical paths. The first
The ± 45 degree variable Faraday rotator 45 has a structure in which an external magnetic field is applied to the Faraday element by an electromagnet, and the direction of the applied magnetic field can be controlled by switching the direction of energization to the electromagnet, whereby the Faraday rotation is increased by +45 degrees or This is a format that can be switched to -45 degrees. The half-wave plate 46 has a left optical path whose optical axis is inclined at −22.5 degrees from the x direction and a right optical path whose optical axis is inclined at 22.5 degrees from the x direction, as shown in FIG. They are integrated so as to be symmetric with respect to the y-axis.
【００２９】次に、ｚ方向を見て、第１の光路制御用複
屈折素子４１と第２の光路制御用複屈折素子４２との間
に、偏波反射切換手段４８を設置する。ここで偏波反射
切換手段４８は、第２の±４５度可変ファラデー回転子
４９、一部の光路（上段の光路）のｚ方向の入力光を反
射するミラー５０からなる。なお、この第２の±４５度
可変ファラデー回転子４９も、電磁石によりファラデー
素子に外部磁界を印加する構造であり、該電磁石への通
電方向を切り換えることによって印加磁界の方向を制御
でき、それによってファラデー回転を＋４５度あるいは
−４５度に切り換えることができる形式である。ここで
は、第１及び第２の±４５度可変ファラデー回転子４
５，４９は、それらのファラデー回転方向が互いに同じ
向きもしくは逆向きになるように独立に切り換え可能に
なっている。Next, a polarization reflection switching means 48 is provided between the first optical path controlling birefringent element 41 and the second optical path controlling birefringent element 42 as viewed in the z direction. Here, the polarization reflection switching means 48 includes a second ± 45-degree variable Faraday rotator 49 and a mirror 50 that reflects input light in the z-direction of a part of the optical path (upper optical path). The second ± 45-degree variable Faraday rotator 49 also has a structure in which an external magnetic field is applied to the Faraday element by an electromagnet, and the direction of the applied magnetic field can be controlled by switching the direction of energization to the electromagnet. This is a format in which the Faraday rotation can be switched to +45 degrees or -45 degrees. Here, the first and second ± 45-degree variable Faraday rotators 4
5, 49 can be switched independently so that their Faraday rotation directions are the same or opposite.
【００３０】更に、第２の光路制御用複屈折素子４２と
合成用複屈折素子４３の間に、偏波方向を平行から直交
に変換する偏波回転手段を配置する。この偏波回転手段
は、ｚ方向に沿って見たときに左上、右上、左下、右下
の各光路の光の偏波面をそれぞれ４５度回転させるよう
に組み合わせた４枚の１／２波長板５４からなる。この
１／２波長板５４は、図８に示すように、光学軸がｘ方
向から±２２．５度傾いているものである。Further, between the second optical path controlling birefringent element 42 and the synthesizing birefringent element 43, a polarization rotating means for converting the polarization direction from parallel to orthogonal is arranged. This polarization rotating means is composed of four half-wave plates combined so as to rotate the polarization plane of light in each of the upper left, upper right, lower left, and lower right optical paths by 45 degrees when viewed along the z direction. It consists of 54. The half-wave plate 54 has an optical axis inclined ± 22.5 degrees from the x direction, as shown in FIG.
【００３１】このような配列体の分離合成用複屈折素子
１０の側に、ｙ方向にずらせて下段に入力ポートＩ、上
段に第１出力ポートＯ１を、合成用複屈折素子１３の側
に、ｙ方向にずらせて上段に第２出力ポートＯ２、下段
に第３出力ポートＯ３を設定する。The input port I in the lower stage and the first output port O1 in the upper stage are shifted to the side of the separating / synthesizing birefringent element 10 in the y direction, and the combining birefringent element 13 is located in the upper stage. The second output port O2 is set at the upper stage and the third output port O3 is set at the lower stage by shifting in the y direction.
【００３２】この光スイッチの動作について説明する。 （入力ポートＩ→第１出力ポートＯ１）この動作は、前
記の第１実施例と全く同様である。第１及び第２の±４
５度可変ファラデー回転子４５，４９を、ファラデー回
転方向が共にマイナスとなる向き（反時計方向）に印加
磁界を設定する。下段の入力ポートＩからｚ方向に入力
する光は、分離合成用複屈折素子４０で常光は直進し、
異常光は屈折してｘ方向に光分離する。そして第１の偏
波回転切換手段４４で、偏波方向が直交から平行の関係
に変換される。即ち、偏波方向が直交する光は、第１の
±４５度可変ファラデー回転子４５でそれぞれ偏波方向
が−４５度回転し、１／２波長板４６でｘ軸に垂直とな
る。それら両光は第１の光路制御用複屈折素子４１に対
しては異常光になっているので、上方に屈折し上段の光
路を進む。そして偏波反射切換手段４８で反射する。即
ち、光は、第２の±４５度可変ファラデー回転子４９で
それぞれ偏波方向が−４５度回転し、ミラー５０で反射
されて−ｚ方向に進み、再び第２の±４５度可変ファラ
デー回転子４９に戻ってそれぞれ偏波方向が更に−４５
度回転してｘ軸と平行になる。そして、第１の偏波回転
切換手段４４によって偏波方向が平行から直交の関係に
変換される。即ち、偏波方向が直交する光は、１／２波
長板４６で偏波方向が４５度回転し、第１の±４５度可
変ファラデー回転子４５でそれぞれ偏波方向が−４５度
回転して、両光は互いに直交する関係となる。そして、
第１の分離合成用複屈折素子４０でｘ方向で光が合成す
るため、上段の第１出力ポートＯ１から出力する。The operation of the optical switch will be described. (Input port I → first output port O1) This operation is exactly the same as in the first embodiment. First and second ± 4
The magnetic field applied to the 5-degree variable Faraday rotators 45 and 49 is set so that the Faraday rotation directions are both negative (counterclockwise). The light input from the lower input port I in the z-direction travels straight through the birefringent element 40 for separation / combination.
The extraordinary light is refracted and separated in the x direction. Then, the first polarization rotation switching means 44 converts the polarization direction from orthogonal to parallel. That is, light whose polarization directions are orthogonal to each other is rotated by −45 degrees in the first ± 45-degree variable Faraday rotator 45, and is perpendicular to the x-axis in the half-wave plate 46. Both of these lights are extraordinary lights with respect to the first optical path control birefringent element 41, so they are refracted upward and travel on the upper optical path. The light is reflected by the polarization reflection switching means 48. That is, the light is rotated by −45 degrees in the polarization direction by the second ± 45-degree variable Faraday rotator 49, is reflected by the mirror 50 and travels in the −z direction, and is again subjected to the second ± 45-degree variable Faraday rotation. Returning to the element 49, the polarization direction is further -45.
Rotate by degrees to be parallel to the x-axis. Then, the polarization direction is changed from parallel to orthogonal by the first polarization rotation switching means 44. That is, for the light whose polarization directions are orthogonal, the polarization direction is rotated 45 degrees by the half-wave plate 46, and the polarization direction is rotated -45 degrees by the first ± 45 degree variable Faraday rotator 45, respectively. , The two lights are orthogonal to each other. And
Since the light is combined in the x direction by the first birefringent element 40 for separation / combination, the light is output from the first output port O1 in the upper stage.
【００３３】（入力ポートＩ→第２出力ポートＯ２）次
に、第１及び第２の±４５度可変ファラデー回転子４
５，４９を、ファラデー回転方向が共にプラスとなる向
き（時計方向）に印加磁界を設定する。下段の入力ポー
トＩから＋ｚ方向に入力する光は、分離合成用複屈折素
子４０で常光は直進し、異常光は屈折してｘ方向に光分
離する。そして第１の偏波回転切換手段４４で、偏波方
向が直交から平行の関係に変換される。即ち、偏波方向
が直交する光は、第１の±４５度可変ファラデー回転子
４５でそれぞれ偏波方向が＋４５度回転し、１／２波長
板４６でｘ軸に平行となる。それら両光は第１の光路制
御用複屈折素子４１に対しては常光になっているので、
そのまま下段の光路を直進する。そのため偏波反射切換
手段４８を通過する。即ち、第２の±４５度可変ファラ
デー回転子４９でそれぞれ偏波方向が＋４５度回転し、
ミラー５０をバイパスする。従って、この光は偏波方向
がｘ軸に対して４５度回転しているが、第２の光路制御
用複屈折素子４２の光学軸がｚ方向に沿って見たときに
ｘ方向に対して４５度傾いているので、結局、この光は
第２の光路制御用複屈折素子４２に対しては異常光にな
っている。従って、斜め上方に屈折し上段の光路を進
む。そして１／２波長板５４で、左側光路及び右側光路
の光の偏波面は逆にそれぞれ４５度回転するために、両
光の偏波方向は直交の関係に変換される。そして合成用
複屈折素子４３でｘ方向で光が合成するため、上段の第
２出力ポートＯ２から出力する。(Input port I → second output port O2) Next, the first and second ± 45-degree variable Faraday rotators 4
5 and 49, the applied magnetic field is set in a direction (clockwise) in which both the Faraday rotation directions are positive. The light input from the lower input port I in the + z direction is divided into ordinary light by the birefringent element 40 for separation and synthesis, and extraordinary light is refracted and separated in the x direction. Then, the first polarization rotation switching means 44 converts the polarization direction from orthogonal to parallel. That is, the light whose polarization directions are orthogonal to each other is rotated by +45 degrees in the first ± 45-degree variable Faraday rotator 45 and becomes parallel to the x-axis in the half-wave plate 46. Since both of these lights are ordinary light with respect to the first optical path control birefringent element 41,
Continue straight down the lower optical path. Therefore, the light passes through the polarization reflection switching means 48. That is, the polarization direction is rotated by +45 degrees with the second ± 45-degree variable Faraday rotator 49, respectively.
The mirror 50 is bypassed. Therefore, although the polarization direction of this light is rotated by 45 degrees with respect to the x-axis, when the optical axis of the second optical path controlling birefringent element 42 is viewed along the z-direction, Since the light is tilted by 45 degrees, the light eventually becomes abnormal light with respect to the second optical path controlling birefringent element 42. Therefore, the light is refracted obliquely upward and travels along the upper optical path. Then, since the polarization planes of the light in the left optical path and the right optical path are rotated by 45 degrees, respectively, in the half-wave plate 54, the polarization directions of the two lights are converted into an orthogonal relationship. Then, since light is combined in the x direction by the combining birefringent element 43, the light is output from the second output port O2 in the upper stage.
【００３４】（入力ポートＩ→第３出力ポートＯ３）第
１の±４５度可変ファラデー回転子４５を、ファラデー
回転方向がプラスとなる向き（時計方向）に、第２の±
４５度可変ファラデー回転子４９は、ファラデー回転方
向がマイナスとなる向き（反時計方向）に印加磁界を設
定する。下段の入力ポートＩからｚ方向に入力する光
は、分離合成用複屈折素子４０で常光は直進し、異常光
は屈折してｘ方向に光分離する。そして第１の偏波回転
切換手段４４で、偏波方向が直交から平行の関係に変換
される。即ち、偏波方向が直交する光は、第１の±４５
度可変ファラデー回転子４５でそれぞれ偏波方向が＋４
５度回転し、１／２波長板４６でｘ軸に平行となる。そ
れら両光は第１の光路制御用複屈折素子４１に対しては
常光になっているので、そのまま下段の光路を直進す
る。そのため偏波反射切換手段４８を通過する。即ち、
第２の±４５度可変ファラデー回転子４９でそれぞれ偏
波方向が−４５度回転し、ミラー５０をバイパスする。
従って、この光は偏波方向がｘ軸に対して４５度回転し
ているが、第２の光路制御用複屈折素子４２の光学軸が
ｚ方向に沿って見たときにｘ方向に対して４５度傾いて
いるので、結局、この光は第２の光路制御用複屈折素子
４２に対しては常光になっている。従って、下段の光路
を直進する。そして１／２波長板５４で、左側光路及び
右側光路の光の偏波面は逆にそれぞれ４５度回転するた
め、両光の偏波方向は直交の関係に変換される。そして
合成用複屈折素子４３でｘ方向で光が合成するため、下
段の第３出力ポートＯ３から出力する。(Input port I → third output port O3) The first ± 45-degree variable Faraday rotator 45 is rotated in the direction (clockwise) in which the Faraday rotation direction is positive (clockwise).
The 45-degree variable Faraday rotator 49 sets the applied magnetic field in a direction in which the Faraday rotation direction is negative (counterclockwise). The light input from the lower input port I in the z direction travels straight in the birefringent element 40 for separation / combination, and the extraordinary light is refracted and separated in the x direction. Then, the first polarization rotation switching means 44 converts the polarization direction from orthogonal to parallel. That is, the light whose polarization direction is orthogonal is the first ± 45
The polarization direction is +4 by the degree variable Faraday rotator 45
It rotates 5 degrees and becomes parallel to the x-axis by the half-wave plate 46. Since both of these lights are ordinary lights for the first optical path control birefringent element 41, they travel straight through the lower optical path as it is. Therefore, the light passes through the polarization reflection switching means 48. That is,
The second ± 45-degree variable Faraday rotator 49 rotates the polarization direction by −45 degrees, and bypasses the mirror 50.
Therefore, although the polarization direction of this light is rotated by 45 degrees with respect to the x-axis, when the optical axis of the second optical path controlling birefringent element 42 is viewed along the z-direction, Since the light is inclined by 45 degrees, the light is eventually ordinary light with respect to the second optical path controlling birefringent element 42. Therefore, the light travels straight down the lower optical path. Then, since the polarization planes of the light in the left optical path and the right optical path are rotated by 45 degrees, respectively, in the half-wave plate 54, the polarization directions of both lights are converted into an orthogonal relationship. Since the light is combined in the x direction by the combining birefringent element 43, the light is output from the lower third output port O3.
【００３５】このようにして、第１実施例の場合と同
様、第１及び第２の±４５度可変ファラデー回転子４
５，４９の印加磁界の切り換えによって、入力ポートＩ
からの入力光を、第１出力ポートＯ１、第２出力ポート
Ｏ２、第３出力ポートＯ３のいずれかへ出力するという
１×３型の光スイッチが実現できる。Thus, similarly to the case of the first embodiment, the first and second ± 45-degree variable Faraday rotators 4
By switching the applied magnetic field of 5, 49, the input port I
1 × 3 type optical switch that outputs the input light from the first to the first output port O1, the second output port O2, or the third output port O3.
【００３６】[0036]
【発明の効果】本発明は上記のように、光路の中央部に
ミラーを設け、２個の可変ファラデー回転子を独立に制
御するように構成したことによって、光学的特性が損な
われることなく、しかも小型でありながら１×３型の光
スイッチを実現することが可能となる。As described above, according to the present invention, the mirror is provided at the center of the optical path, and the two variable Faraday rotators are independently controlled, so that the optical characteristics are not impaired. Moreover, it is possible to realize a 1 × 3 optical switch while being small.
【図１】本発明に係る光スイッチの第１実施例を示す説
明図。FIG. 1 is an explanatory view showing a first embodiment of an optical switch according to the present invention.
【図２】その光路説明図。FIG. 2 is an explanatory view of an optical path.
【図３】それに用いる１／２波長板の光学軸の向きを示
す説明図。FIG. 3 is an explanatory diagram showing the direction of the optical axis of a half-wave plate used for the plate.
【図４】偏波回転手段の変形例を示す説明図。FIG. 4 is an explanatory view showing a modification of the polarization rotation means.
【図５】それに用いる１／２波長板の光学軸の向きを示
す説明図。FIG. 5 is an explanatory diagram showing the direction of an optical axis of a half-wave plate used for the plate.
【図６】本発明に係る光スイッチの第２実施例を示す説
明図。FIG. 6 is an explanatory view showing a second embodiment of the optical switch according to the present invention.
【図７】その光路説明図。FIG. 7 is an explanatory view of an optical path.
【図８】その偏波回転手段である１／２波長板の光学軸
の向きを示す説明図。FIG. 8 is an explanatory view showing the direction of the optical axis of a half-wave plate as the polarization rotating means.
１０ 分離合成用複屈折素子 １１ 第１の光路制御用複屈折素子 １２ 第２の光路制御用複屈折素子 １３ 合成用複屈折素子 １４ 偏波回転切換手段 １５ 第１の±４５度可変ファラデー回転子 １６ １／２波長板 １８ 偏波反射切換手段 １９ 第２の±４５度可変ファラデー回転子 ２０ ミラー ２４ １／２波長板 Reference Signs List 10 Birefringent element for separation / combination 11 Birefringent element for first optical path control 12 Birefringent element for second optical path 13 Birefringent element for combination 14 Polarization rotation switching means 15 First ± 45 degree variable Faraday rotator 16 1/2 wave plate 18 Polarization reflection switching means 19 Second ± 45 degree variable Faraday rotator 20 Mirror 24 1/2 wave plate
───────────────────────────────────────────────────── フロントページの続き (72)発明者 井村 智和 東京都港区新橋５丁目36番11号 富士電気 化学株式会社内 (72)発明者 小野 博章 東京都港区新橋５丁目36番11号 富士電気 化学株式会社内 (72)発明者 徳増 次雄 東京都港区新橋５丁目36番11号 富士電気 化学株式会社内 Ｆターム(参考） 2H079 AA03 BA01 CA05 CA11 HA11 KA14 KA17 KA20 2K002 AA02 AA04 AB04 BA11 DA01 EA11 EA30 GA10 HA09 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomokazu Imura 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd. (72) Inventor Hiroaki Ono 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Within Electrochemical Co., Ltd. (72) Inventor Tsugio Tokumasu 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. F-term (reference) 2H079 AA03 BA01 CA05 CA11 HA11 KA14 KA17 KA20 2K002 AA02 AA04 AB04 BA11 DA01 EA11 EA30 GA10 HA09
Claims (5)
を分離し異なる光路の光を合成する分離合成用複屈折素
子、偏波方向に応じて光路を制御する第１及び第２の光
路制御用複屈折素子、偏波方向が直交関係にある異なる
光路の光を合成する合成用複屈折素子を、この順序で間
隔をおいて配設し、 分離合成用複屈折素子と第１の光路制御用複屈折素子と
の間に、第１の±４５度可変ファラデー回転子と両側光
路で光学軸が対称になるように並設した２枚の１／２波
長板との組み合わせからなり、偏波方向を直交から平行
に逆方向については平行から直交に変換する偏波回転切
換手段を配置し、 第１の光路制御用複屈折素子と第２の光路制御用複屈折
素子との間に、第２の±４５度可変ファラデー回転子と
一部の光路の光を反射するミラーを備えた偏波反射切換
手段を配置し、 第２の光路制御用複屈折素子と合成用複屈折素子との間
に、偏波方向を平行から直交に変換する偏波回転手段を
配置し、 それら配列体の分離合成用複屈折素子側と合成用複屈折
素子側にポートを設置し、第１の±４５度可変ファラデ
ー回転子と第２の±４５度可変ファラデー回転子のファ
ラデー回転方向を独立に切り換えるようにしたことを特
徴とする光スイッチ。1. A birefringent element for separating and combining light of the same optical path whose polarization directions are orthogonal to each other and combining light of different optical paths, and first and second birefringent elements for controlling the optical path according to the polarization direction. An optical path controlling birefringent element and a combining birefringent element for combining lights in different optical paths whose polarization directions are orthogonal to each other are arranged at intervals in this order. A combination of a first ± 45-degree variable Faraday rotator and two half-wave plates arranged side by side so that the optical axes are symmetrical on both side optical paths, between the optical path controlling birefringent element, A polarization rotation switching means for converting the polarization direction from orthogonal to parallel and in the opposite direction from parallel to orthogonal is disposed, and between the first optical path controlling birefringent element and the second optical path controlling birefringent element. Equipped with a second ± 45-degree variable Faraday rotator and a mirror that reflects light in some optical paths And a polarization rotation switching means for converting the polarization direction from parallel to orthogonal between the second optical path controlling birefringent element and the combining birefringent element. Ports are installed on the birefringent element side for separating and synthesizing the body and the birefringent element side for synthesizing, and the Faraday rotation directions of the first ± 45 degree variable Faraday rotator and the second ± 45 degree variable Faraday rotator are independently set. An optical switch characterized by switching.
屈折素子の間に、ミラーのバイパス光に作用して偏波面
を４５度回転させる１／２波長板を挿入し、偏波方向を
調整した請求項１記載の光スイッチ。2. A half-wave plate, which acts on a bypass light of a mirror and rotates a polarization plane by 45 degrees, is inserted between the polarization reflection switching means and the second birefringent element for optical path control. The optical switch according to claim 1, wherein the direction is adjusted.
屈折素子の間に配置する偏波回転手段は、通過光の一方
の偏波面を９０度回転させる１／２波長板を２枚、異な
る通過光の光路に配置した構造からなる請求項２記載の
光スイッチ。3. The polarization rotating means disposed between the second optical path controlling birefringent element and the synthesizing birefringent element includes a half-wave plate for rotating one polarization plane of the transmitted light by 90 degrees. 3. The optical switch according to claim 2, wherein the optical switch has a structure in which a plurality of light beams are arranged in different light paths.
屈折素子の間に配置する偏波回転手段は、片側光路の光
の偏波面を９０度回転させる１／２波長板と一方の通過
光の偏波面を９０度回転させる１／２波長板との組み合
わせからなる請求項２記載の光スイッチ。4. A polarization rotating means disposed between the second optical path controlling birefringent element and the synthesizing birefringent element comprises a half-wave plate for rotating the polarization plane of light in one optical path by 90 degrees and one of the two. 3. The optical switch according to claim 2, comprising a combination with a half-wave plate for rotating the polarization plane of the transmitted light by 90 degrees.
行方向に沿って見た光学軸の方向が入射光の偏波面に対
して平行もしくは垂直の関係に設定され、第２の光路制
御用複屈折素子と合成用複屈折素子の間に配置する偏波
回転手段は、全ての通過光の偏波面を４５度回転させる
１／２波長板を４枚、各光路の各通過光にそれぞれ挿入
した請求項１記載の光スイッチ。5. The birefringent element for controlling an optical path, wherein a direction of an optical axis viewed along a traveling direction of light is set to be parallel or perpendicular to a plane of polarization of incident light. The polarization rotator disposed between the optical path controlling birefringent element and the synthesizing birefringent element includes four half-wave plates for rotating the polarization planes of all the transmitted light by 45 degrees, and each passing light in each optical path. 2. The optical switch according to claim 1, wherein the optical switch is inserted into each of the optical switches.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000304071A JP2002107774A (en) | 2000-10-03 | 2000-10-03 | Optical switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000304071A JP2002107774A (en) | 2000-10-03 | 2000-10-03 | Optical switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002107774A true JP2002107774A (en) | 2002-04-10 |
Family
ID=18785178
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000304071A Pending JP2002107774A (en) | 2000-10-03 | 2000-10-03 | Optical switch |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002107774A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002372696A (en) * | 2001-06-15 | 2002-12-26 | Fdk Corp | Variable branching ratio optical splitter |
| JP2007127988A (en) * | 2005-11-07 | 2007-05-24 | Fdk Corp | Branching ratio switching type optical splitter |
| CN113777810A (en) * | 2021-08-10 | 2021-12-10 | 青岛浦芮斯光电技术有限公司 | Magneto-optical switch |
-
2000
- 2000-10-03 JP JP2000304071A patent/JP2002107774A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002372696A (en) * | 2001-06-15 | 2002-12-26 | Fdk Corp | Variable branching ratio optical splitter |
| JP4591940B2 (en) * | 2001-06-15 | 2010-12-01 | Ｆｄｋ株式会社 | Variable splitting ratio optical splitter |
| JP2007127988A (en) * | 2005-11-07 | 2007-05-24 | Fdk Corp | Branching ratio switching type optical splitter |
| CN113777810A (en) * | 2021-08-10 | 2021-12-10 | 青岛浦芮斯光电技术有限公司 | Magneto-optical switch |
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