JP2775103B2 - Polarizing prism - Google Patents
Polarizing prismInfo
- Publication number
- JP2775103B2 JP2775103B2 JP63323977A JP32397788A JP2775103B2 JP 2775103 B2 JP2775103 B2 JP 2775103B2 JP 63323977 A JP63323977 A JP 63323977A JP 32397788 A JP32397788 A JP 32397788A JP 2775103 B2 JP2775103 B2 JP 2775103B2
- Authority
- JP
- Japan
- Prior art keywords
- prism
- light
- birefringent crystal
- parallel
- 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.)
- Expired - Lifetime
Links
Landscapes
- Optical Elements Other Than Lenses (AREA)
- Polarising Elements (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は偏光プリズムに関し，より詳細には光通信等
に用いる小型且つ消光比の高い偏光プリズムに関する。Description: TECHNICAL FIELD The present invention relates to a polarizing prism, and more particularly, to a small-sized polarizing prism having a high extinction ratio used for optical communication and the like.
（従来技術） 電気光学効果や磁気光学効果などの偏光を利用する光
スイッチ，光アイソレータなどでは光の偏光度を検出す
るために偏光ビームスプリッタを用いている。(Prior Art) A polarization beam splitter is used in an optical switch, an optical isolator, or the like that uses polarization such as an electro-optic effect or a magneto-optic effect to detect the degree of polarization of light.
該偏光ビームスリッタは互いの光軸が直交するように
２つのプリズムを組合せた所謂ローション，セナルモ
ン，ウォーラストン等に代表されるものと,2つのプリズ
ム接合面に偏光分離膜（以下PB膜と云う）を用いてＰ偏
光とＳ偏光とに分離するものが一般的であり，これらの
うち近年は光学部品をはじめ各種光学機器の小型化の要
求が高まっているため第４図に示す如くPB膜を用いＰ偏
光とＳ偏光の出射方向が同一方向となるよう構成したも
のが多用されつつある。The polarizing beam slitter is represented by a so-called lotion, a Senarmon, a Wollaston, or the like in which two prisms are combined so that their optical axes are orthogonal to each other, and a polarization splitting film (hereinafter, referred to as a PB film) is formed on a joint surface of the two prisms. ) Is generally used to separate the light into P-polarized light and S-polarized light. Of these, the demand for miniaturization of various optical devices including optical components has recently been increasing, and as shown in FIG. The structure in which the emission directions of the P-polarized light and the S-polarized light are made to be the same direction has been widely used.
しかしながらPB膜を用いて偏光分離を行なう場合，一
般に要求される消光比を10-2程度満たすには前記PB膜は
10層以上のものが必要であり製造コストが高く且つ比較
的高い消光比を得ることが困難であると云う欠点があっ
た。However, when polarization separation is performed using a PB film, the PB film is required to satisfy the generally required extinction ratio of about 10 −2.
There are drawbacks that ten or more layers are required, the production cost is high, and it is difficult to obtain a relatively high extinction ratio.
（発明の目的） 本発明は上述した欠点に鑑みなされたものであって，
消光比が高く光学機器の小型化に適した偏光プリズムを
提供することを目的とする。(Object of the Invention) The present invention has been made in view of the above-mentioned drawbacks,
It is an object of the present invention to provide a polarizing prism having a high extinction ratio and suitable for downsizing an optical device.
（発明の概要） この目的を達成するために本発明の偏光プリズムは複
屈折性結晶から成るプリズムの背面に複屈折性結晶から
成る平行平面基板を前記プリズムの光学軸と該平行平面
基板の光学軸とが直交するよう接着せしめ，該基板と空
気との境界面にて入射した光が全反射するよう構成す
る。(Summary of the Invention) In order to achieve this object, a polarizing prism of the present invention comprises a parallel plane substrate made of a birefringent crystal on the back of a prism made of a birefringent crystal, and an optical axis of the prism and an optical axis of the parallel plane substrate. Adhesion is made so that the axis is perpendicular to the axis, and the light incident on the boundary surface between the substrate and air is totally reflected.
（実施例） 以下図面に示した実施例に基づき詳細に説明する。(Example) Hereinafter, a detailed description will be given based on an example shown in the drawings.
第１図は本発明の一実施例を示す図であって,1は入射
光軸に対し垂直且つ紙面と平行な光学軸をもつ複屈折性
結晶により構成されたプリズムであって，該プリズム１
の出射面側に同じく複屈折性結晶により構成され紙面に
垂直な方向に光学軸をもつ平行平面板２を光学接着剤に
て貼合せたものである。FIG. 1 is a view showing an embodiment of the present invention, wherein 1 is a prism formed of a birefringent crystal having an optical axis perpendicular to the incident optical axis and parallel to the paper surface.
A parallel flat plate 2 also made of a birefringent crystal and having an optical axis in a direction perpendicular to the paper surface is bonded to the light exit surface side with an optical adhesive.
このように構成した光学系に於いて光源３より光を照
射するとプリズム１に入射した光は常光線，異常光線と
もに同一方向に進むが次段の平行平面板２に入射するこ
とにより常光線は異常光線に，異常光線は常光線に変わ
り夫々異なった方向に進み，該平行平面板の空気と接す
る側の面で全反射し，再びプリズム１を透過し常光線，
異常光線が平行に出射する。When light is emitted from the light source 3 in the optical system thus configured, the light incident on the prism 1 travels in the same direction for both ordinary and extraordinary rays. The extraordinary ray is changed to an ordinary ray and travels in different directions.
Extraordinary rays are emitted in parallel.
即ち，光軸が互いに直交するように複屈折性結晶によ
り構成したプリズム及び平行平面板を組合せ，常光線と
異常光線とに分離し，更に該平行平面板２に於いて前記
２光線を全反射させるようにその材質，入射角度を選定
し，例えばプリズム１及び平行平面板２を共にルチル
（TiO2）にて構成した場合には前記平行平面板の空気と
接する側の面に20゜10′以上の入射角にて入射するよう
設定すればよく，また常光線及び異常光線の分離巾をｄ
とすれば平行平面板の板厚ｔとの関係は ｄ＝3.10×10-1×ｔ と表すことができる。That is, a prism and a plane-parallel plate made of a birefringent crystal are combined so that the optical axes are orthogonal to each other, separated into ordinary rays and extraordinary rays, and the two rays are totally reflected by the plane-parallel plate 2. The material and the incident angle are selected so that the prism 1 and the parallel plane plate 2 are both made of rutile (TiO 2 ). What is necessary is just to set it so that it is incident at the above incident angle.
Then, the relation with the plate thickness t of the parallel flat plate can be expressed as d = 3.10 × 10 −1 × t.
このようにPB膜を用いず複屈折性結晶の特性により偏
光分離を行なうため高い消光比の偏光プリズムを構成す
ることができると共に常光線，異常光線の出射光の方向
が同一となるため光学機器を小型化することが可能であ
る。As described above, a polarization prism having a high extinction ratio can be constructed because polarization splitting is performed based on the characteristics of a birefringent crystal without using a PB film, and the directions of outgoing light of ordinary light and extraordinary light are the same. Can be reduced in size.
第２図は本発明の変形実施例を示す図であって，ダブ
ルウォーラストンプリズムに於ける第３プリズムを平行
平面板４に置換し，該平行平面板にて全反射せしめるよ
う構成したもので，このように構成することにより常光
線と異常光線との分離巾ｄを増加することができ，又，
前記第１図に示したプリズム１の光学軸を第３図に示す
如く45゜回転させることにより平行平面板に入射した光
を３成分に分離することが可能となる。FIG. 2 is a view showing a modified embodiment of the present invention, in which the third prism in the double Wollaston prism is replaced by a plane-parallel plate 4 so that the total reflection is performed by the plane-parallel plate. With this configuration, the separation width d between the ordinary ray and the extraordinary ray can be increased, and
By rotating the optical axis of the prism 1 shown in FIG. 1 by 45 ° as shown in FIG. 3, it becomes possible to separate the light incident on the plane-parallel plate into three components.
尚，本発明の実施例ではウォーラストン型のプリズム
を主に用いたがこれに限定されるものではなく，まず複
屈折性結晶はルチル（TiO2）の例を掲げて説明したが他
の複屈折性結晶，例えばCaCO3結晶或は水晶等を用いて
もよい。In the embodiment of the present invention, a Wollaston type prism is mainly used. However, the present invention is not limited to this. First, the birefringent crystal has been described with an example of rutile (TiO 2 ). Refractive crystals such as CaCO 3 crystals or quartz may be used.
更に本実施例では偏光プリズムを分波素子として用い
たが合波素子として用いることが可能なことは云うまで
もない。Further, in this embodiment, the polarizing prism is used as a demultiplexing element, but it goes without saying that it can be used as a multiplexing element.
（発明の効果） 本発明は上述した如く構成し且つ機能するものである
から高い消光比を得ることができ光通信等に使用するこ
とができるのみならず,PB膜を使用しないため製造コス
トを低減し安価に部品を提供するうえで著しい効果を発
揮する。(Effects of the Invention) Since the present invention is constructed and functions as described above, it can obtain a high extinction ratio and can be used for optical communication and the like. It has a remarkable effect in providing components at reduced cost and at low cost.
第１図は本発明の一実施例を示す図，第２図及び第３図
は本発明の変形実施例を示す図，第４図は従来の偏光プ
リズムを示す図である。 １……複屈折性プリズム,2,4……平行平面板,3……光
源，FIG. 1 is a view showing an embodiment of the present invention, FIGS. 2 and 3 are views showing a modified embodiment of the present invention, and FIG. 4 is a view showing a conventional polarizing prism. 1 ... birefringent prism, 2, 4 ... parallel plane plate, 3 ... light source,
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) G02B 5/30 G02B 5/04──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. 6 , DB name) G02B 5/30 G02B 5/04
Claims (2)
屈折結晶から成る厚さｔの平行平面基板を双方の光学軸
が直交するよう接着せしめ、前記プリズムに入射した光
が前記基板との接着面を通過し、前記基板の接着面と対
向する面にて全反射し、再び前記プリズムに入射しこれ
を通過して出射する光が分離幅ｄ＝3.10×10-1×ｔにて
平行となるよう前記平行平面基板の板厚ｔを設定したこ
とを特徴とする偏光プリズム。1. A parallel plane substrate having a thickness of t made of a birefringent crystal is adhered to the back surface of a prism made of a birefringent crystal such that both optical axes are orthogonal to each other. Light that passes through the bonding surface, is totally reflected on the surface facing the bonding surface of the substrate, is incident on the prism again, and exits through this light is parallel with a separation width d = 3.10 × 10 −1 × t. The thickness t of the parallel plane substrate is set so that
屈折結晶から成る平行平面基板を接着したものであっ
て、双方の光学軸が互いに直交し、且つ、前記プリズム
の光学軸を入射面に於いて45゜回転したものであること
を特徴とする偏光プリズム。2. A parallel flat substrate made of a birefringent crystal is adhered to a back surface of a prism made of a birefringent crystal. A polarizing prism characterized by being rotated by 45 °.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63323977A JP2775103B2 (en) | 1988-12-22 | 1988-12-22 | Polarizing prism |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63323977A JP2775103B2 (en) | 1988-12-22 | 1988-12-22 | Polarizing prism |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02168204A JPH02168204A (en) | 1990-06-28 |
| JP2775103B2 true JP2775103B2 (en) | 1998-07-16 |
Family
ID=18160741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63323977A Expired - Lifetime JP2775103B2 (en) | 1988-12-22 | 1988-12-22 | Polarizing prism |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2775103B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04328339A (en) * | 1991-04-30 | 1992-11-17 | Canon Inc | Optical head for plural beams |
| US5822118A (en) * | 1995-12-26 | 1998-10-13 | Lucent Technologies Inc. | Walk-off device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5129955A (en) * | 1974-09-06 | 1976-03-13 | Asahi Chemical Ind | ITONOHINSHITSUHYOKASOCHI |
| JPS62299906A (en) * | 1986-06-20 | 1987-12-26 | Fujitsu Ltd | Polarized light separating element |
-
1988
- 1988-12-22 JP JP63323977A patent/JP2775103B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02168204A (en) | 1990-06-28 |
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