JPH0738049B2 - Optical device - Google Patents
Optical deviceInfo
- Publication number
- JPH0738049B2 JPH0738049B2 JP61187233A JP18723386A JPH0738049B2 JP H0738049 B2 JPH0738049 B2 JP H0738049B2 JP 61187233 A JP61187233 A JP 61187233A JP 18723386 A JP18723386 A JP 18723386A JP H0738049 B2 JPH0738049 B2 JP H0738049B2
- Authority
- JP
- Japan
- Prior art keywords
- optical path
- wave
- optical
- polarization separation
- separation film
- 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
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Description
【発明の詳細な説明】 〔概要〕 平行した二平面で、対角線方向に対向する半面の一方
に、偏光分離膜を他方に全反射膜をそれぞれ形成した平
行ガラス板と、複屈折板とを所望に組合せることによ
り、直交する二方向の光路中に挿入して偏光分離度が高
く、且つ製造容易な光デバイスを提供する。DETAILED DESCRIPTION OF THE INVENTION [Outline] A parallel glass plate in which a polarization splitting film and a total reflection film are respectively formed on one of half surfaces that are diagonally opposed to each other in two parallel planes, and a birefringent plate are desired. By providing the optical device which is inserted into the optical paths in two directions orthogonal to each other, the degree of polarization separation is high and the optical device is easy to manufacture.
本発明は、偏光分離膜を備えた光デバイスの改良に関す
る。The present invention relates to improvement of an optical device including a polarization separation film.
偏波光をＳ波（入射光の電界が入射面に垂直の偏波）
と、Ｐ波（入射光の電界が入射面に平行の偏波）とに分
離するという、偏光分離膜を備えた光デバイスは、互い
に直交する二方向の光通信伝送路に広く使用されてい
る。S-polarized light (polarized light whose electric field is perpendicular to the incident surface)
And an P-wave (an electric field of incident light is polarized parallel to the incident surface) are separated, and an optical device having a polarization separation film is widely used for two-way optical communication transmission lines orthogonal to each other. .
一方、ガラス板に屈折率の異なる光学膜を所定の膜厚
で、交互に積層した偏光分離膜は、入射角を選択する
と、Ｐ波は総て透過し、Ｓ波は大部分が反射し、少ない
一部が透過するという、偏光分離性を有する。On the other hand, in a polarization separation film in which optical films having different refractive indexes are alternately laminated on a glass plate, when the incident angle is selected, all P waves are transmitted and most S waves are reflected, It has a polarized light separating property that a small part is transmitted.
このような光デバイスには、製造が容易であること、偏
光分離度が高いことが要望されている。Such an optical device is required to be easy to manufacture and have a high degree of polarization separation.
第４図の（ａ），（ｂ）はそれぞれ従来の光デバイスの
光路図、第５図の（ａ），（ｂ）はそれぞれ従来の他の
光デバイスの光路図、第６図は従来例を適用した装置の
光路図である。FIGS. 4 (a) and 4 (b) are optical path diagrams of a conventional optical device, FIGS. 5 (a) and 5 (b) are optical path diagrams of other conventional optical devices, and FIG. 6 is a conventional example. It is an optical-path figure of the apparatus to which is applied.
第４図において、光デバイスは平行六面体ガラス板1Aの
平行した二平面の一方の面の全面に、偏光分離膜３が形
成され、直角プリズム２が、その斜辺面が偏光分離膜３
の表面に密着して、平行六面体ガラス板1Aに固着されて
いる。In FIG. 4, an optical device has a polarization separation film 3 formed on the entire surface of one of two parallel two planes of a parallelepiped glass plate 1A.
Is in close contact with the surface of and is fixed to the parallelepiped glass plate 1A.
いま、第４図（ａ）のように、光路10より偏光分離膜３
に45度傾斜した面に直交するように、偏波光を平行六面
体ガラス板1Aに入射させると、大部分のＳ波（図では紙
面に垂直な偏波・で示す）は、偏光分離膜３で反射し、
偏光分離膜３に平行する面に投射され、この面で反射し
て、光路10に並進した点線で示す光路12より出射する。Now, as shown in FIG.
When polarized light is incident on the parallelepiped glass plate 1A so as to be orthogonal to the plane inclined at 45 degrees to, most of the S waves (indicated by the polarization perpendicular to the paper in the figure) are reflected by the polarization separation film 3. Reflected,
The light is projected on a surface parallel to the polarization separation film 3, reflected on this surface, and emitted from an optical path 12 indicated by a dotted line translated in the optical path 10.
Ｐ波（図では紙面に平行な偏波 で示す）は、偏光分離膜３を透過して直進し、直角プリ
ズム２を通過して、実線で示す光路11より出射する。P wave (polarization parallel to the paper surface in the figure (Indicated by) is transmitted through the polarization separation film 3, goes straight, passes through the rectangular prism 2, and is emitted from the optical path 11 indicated by a solid line.
なお、光路11よりは、偏光分離膜３を透過した一部のＳ
波が出射する。In addition, from the optical path 11, a part of S transmitted through the polarization separation film 3 is transmitted.
Waves emerge.
また、第４図（ｂ）のように、光路10に直交する光路20
より直角プリズム２を透して、偏光分離膜３に偏波光を
入射させると、Ｐ波は偏光分離膜３を透過して直進し、
偏光分離膜３に平行する面に投射され、この面で反射し
て、光路12に並進（光路10と光路20とが偏光分離膜３上
で交叉する場合は、光路12に一致する。）した実線で示
す光路21より出射する。In addition, as shown in FIG. 4B, the optical path 20 orthogonal to the optical path 10
When the polarized light is made incident on the polarization separation film 3 through the right-angled prism 2 more, the P wave passes through the polarization separation film 3 and goes straight.
It is projected on a plane parallel to the polarization separation film 3, reflected on this plane, and translated into the optical path 12 (when the optical path 10 and the optical path 20 intersect on the polarization separation film 3, they coincide with the optical path 12). The light is emitted from the optical path 21 indicated by the solid line.
なお、光路21よりは、偏光分離膜３を透過した一部のＳ
波が出射する。In addition, from the optical path 21, a part of the S transmitted through the polarization separation film 3 is transmitted.
Waves emerge.
偏光分離膜３に投射された偏光波の大部分のＳ波は、偏
光分離膜３で反射して、直角プリズム２の他の面から、
光路21に並進（光路10と光路20とが偏光分離膜３上で交
叉する場合は、光路11に一致する。）した点線で示す光
路22より出射する。Most S waves of the polarized waves projected on the polarization separation film 3 are reflected by the polarization separation film 3 and from the other surface of the rectangular prism 2.
The light is emitted from an optical path 22 indicated by a dotted line that is translated to the optical path 21 (matches the optical path 11 when the optical path 10 and the optical path 20 intersect on the polarization separation film 3).
第５図に示す光デバイスは、平行ガラス板１の平行した
二平面の、対角線方向に対向対向するほぼ半面の一方に
偏光分離膜３が、他方に全反射膜４が形成され、直角プ
リズム２が、その斜辺面が偏光分離膜３に密着して、平
行ガラス板１に固着されている。また、直角プリズム５
が、その斜辺面が全反射膜４に密着して、平行ガラス板
１に固着されている。In the optical device shown in FIG. 5, the polarization splitting film 3 is formed on one of the half surfaces of the two parallel planes of the parallel glass plate 1 facing each other in the diagonal direction, and the total reflection film 4 is formed on the other surface. However, the hypotenuse surface is in close contact with the polarization separation film 3 and is fixed to the parallel glass plate 1. In addition, right angle prism 5
However, the hypotenuse surface is in close contact with the total reflection film 4 and is fixed to the parallel glass plate 1.
いま、第５図（ａ）にように、光路10より全反射膜４に
隣接する面から直角プリズム５に偏波光を入射させる
と、直角プリズム５の他の面で反射して、平行ガラス板
１に入り、偏光分離膜３に45度の入射角で入射する。Now, as shown in FIG. 5 (a), when polarized light is made incident on the rectangular prism 5 from a surface adjacent to the total reflection film 4 through the optical path 10, the polarized light is reflected on the other surface of the rectangular prism 5 to form a parallel glass plate. 1, and enters the polarization separation film 3 at an incident angle of 45 degrees.
この際、大部分のＳ波は、偏光分離膜３で反射し、全反
射膜４に投射され、全反射膜４で反射して、直角プリズ
ム２に入り、光路10とは90度の方向の点線で示す光路12
より出射する。At this time, most of the S waves are reflected by the polarization splitting film 3, projected on the total reflection film 4, reflected by the total reflection film 4, enter the right-angle prism 2, and are 90 ° to the optical path 10. Optical path 12 shown by the dotted line
Emit more.
偏光分離膜３に投射された偏光波のＰ波は、偏光分離膜
３を透過して直進し、直角プリズム２に入り、光路12に
並進した実線で示す光路11より出射する。The P wave of the polarized wave projected on the polarization splitting film 3 passes through the polarization splitting film 3, goes straight, enters the right-angled prism 2, and exits from the optical path 11 shown by the solid line translated into the optical path 12.
なお、光路11よりは、偏光分離膜３を透過した一部のＳ
波が出射する。In addition, from the optical path 11, a part of S transmitted through the polarization separation film 3 is transmitted.
Waves emerge.
また、第５図（ｂ）のように、光路10に逆行する光路20
より直角プリズム２に偏波光を入射させると、直角プリ
ズム２を透過して、偏光分離膜３に入射する。In addition, as shown in FIG.
When the polarized light is made incident on the right-angled prism 2 more, it is transmitted through the right-angled prism 2 and is incident on the polarization separation film 3.
この際、Ｐ波は偏光分離膜３を透過して直進し、全反射
膜４で反射して直角プリズム２の他の面から、光路12に
並進（光路10と光路20とが偏光分離膜３上で交叉する場
合は光路12に一致する。）した実線で示す光路21より出
射する。At this time, the P wave passes through the polarization separation film 3 and travels straight, and is reflected by the total reflection film 4 and translated from the other surface of the right-angle prism 2 to the optical path 12 (the optical path 10 and the optical path 20 are polarized. When crossing above, it coincides with the optical path 12.) The light is emitted from the optical path 21 indicated by the solid line.
なお、光路21よりは、偏光分離膜３を透過した一部のＳ
波が出射する。In addition, from the optical path 21, a part of the S transmitted through the polarization separation film 3 is transmitted.
Waves emerge.
一方、大部分のＳ波は、偏光分離膜３で反射して、直角
プリズム２の他の面から、光路21に並進（光路10と光路
20とが偏光分離膜３上で交叉する場合は、光路11に一致
する。）した点線で示す光路22より出射する。On the other hand, most of the S waves are reflected by the polarization separation film 3 and translated from the other surface of the rectangular prism 2 to the optical path 21 (optical path 10 and optical path 21).
When 20 and 20 intersect on the polarization splitting film 3, they coincide with the optical path 11. ) Is emitted from the optical path 22 indicated by the dotted line.
第６図は、第４図に示した一対の光デバイスを前段，後
段に直列に並設して、後段の光デバイスは、偏波切換手
段15を介して、前段の光デバイスに対称に配設した装置
である。FIG. 6 shows that the pair of optical devices shown in FIG. 4 are arranged in series at the front stage and the rear stage in series, and the optical device at the rear stage is symmetrically arranged to the optical device at the front stage via the polarization switching means 15. It is an installed device.
第１の伝送路６より偏光波（光信号）を、光路10に投入
し、また第２の伝送路７より偏光波（光信号）を光路20
に投入する。そして、それぞれ装置の出射路側（後段の
光デバイス）には、光路11に対して第３の伝送路８を、
光路21に対して第４の伝送路９がそれぞれ光結合するよ
うに構成してある。The polarized wave (optical signal) is input to the optical path 10 from the first transmission path 6, and the polarized wave (optical signal) is input to the optical path 20 from the second transmission path 7.
Throw in. Then, on the emission path side (the latter optical device) of the device, the third transmission path 8 is provided with respect to the optical path 11,
The fourth transmission path 9 is optically coupled to the optical path 21.
なお、光路10と光路20とは、偏光分離膜３で交叉するも
のとする。The optical path 10 and the optical path 20 are assumed to intersect with each other by the polarization separation film 3.
ここで偏波切換手段15は、例えば磁気光学効果を利用し
たスイッチであって、磁気光学結晶板（例えばYIG…イ
ットリウム・鉄・ガーネット）よりなり、付与する磁界
の方向を変えることにより、Ｓ波をＰ波に、Ｐ波をＳ波
に変換する機能を有する。Here, the polarization switching means 15 is, for example, a switch utilizing the magneto-optical effect, and is composed of a magneto-optical crystal plate (for example, YIG ... Yttrium, iron, garnet), and changes the direction of the applied magnetic field to generate the S wave. To P waves and P waves to S waves.
第１の伝送路６の出射光は、前段の偏光分離膜３でＳ波
とＰ波に分離されて、それぞれ光路12,光路11を進み、
偏波切換手段15を経て、後段の光デバイスに入射する。The light emitted from the first transmission path 6 is separated into S wave and P wave by the polarization separation film 3 in the preceding stage and travels through the optical path 12 and the optical path 11, respectively.
It is incident on the optical device at the subsequent stage via the polarization switching means 15.
そして、光路12と光路11とは、後段の光デバイスの偏光
分離膜３で交叉し、一体となる。Then, the optical path 12 and the optical path 11 are integrated by intersecting with the polarization separation film 3 of the optical device in the subsequent stage.
即ち、光路12を進んだＳ波は、偏光分離膜３で反射して
第３の伝送路８に入射し、光路11を進んだＰ波は、偏光
分離膜３を透過して、第３の伝送路８に入射する。That is, the S wave traveling through the optical path 12 is reflected by the polarization separation film 3 and is incident on the third transmission path 8, and the P wave traveling through the optical path 11 is transmitted through the polarization separation film 3 and is transmitted to the third transmission path 8. It is incident on the transmission line 8.
第２の伝送路７の出射光は、前段の偏光分離膜３でＳ波
とＰ波に分離されてそれぞれ光路22（光路11に同じ），
光路21（光路12に同じ）を進み、偏波切換手段15を経
て、後段の光デバイスに入射する。The light emitted from the second transmission path 7 is separated into an S wave and a P wave by the polarization separation film 3 in the preceding stage, and is divided into an optical path 22 (same as the optical path 11),
The light travels along the optical path 21 (same as the optical path 12), passes through the polarization switching means 15, and enters the optical device at the subsequent stage.
そして、光路22と光路21とは、後段の光デバイスの偏光
分離膜３で交叉し、一体となる。Then, the optical path 22 and the optical path 21 intersect with each other at the polarization separation film 3 of the optical device in the subsequent stage, and are integrated.
即ち、光路22を進んだＳ波は、偏光分離膜３で反射して
第４の伝送路９に入射し、光路21を進んだＰ波は、偏光
分離膜３を透過して、第４の伝送路９に入射する。That is, the S wave traveling through the optical path 22 is reflected by the polarization separation film 3 and is incident on the fourth transmission path 9, and the P wave traveling through the optical path 21 is transmitted through the polarization separation film 3 to form the fourth wave. It is incident on the transmission line 9.
このような状態で、偏波切換手段15を作動させ、Ｐ波を
Ｓ波に、Ｓ波をＰ波にそれぞれ切換えると、光路11を進
んだ光路10よりのＰ波は、偏波切換手段15によりＳ波と
なり、後段の偏光分離膜３で反射して第４の伝送路９に
入射する。また光路12を進んだＳ波はＰ波になり、偏光
分離膜３を透過して第４の伝送路９に入射する。In such a state, when the polarization switching means 15 is operated to switch the P wave to the S wave and the S wave to the P wave, the P wave from the optical path 10 traveling along the optical path 11 is polarized. Then, it becomes an S wave, is reflected by the polarization separation film 3 in the subsequent stage, and enters the fourth transmission line 9. Further, the S wave traveling along the optical path 12 becomes a P wave, which is transmitted through the polarization separation film 3 and is incident on the fourth transmission path 9.
一方、光路21を進んだ光路20よりのＰ波は、偏波切換手
段15によりＳ波となり、後段の偏光分離膜３で反射して
第３の伝送路８に入射する。また光路22を進んだＳ波は
Ｐ波になり、偏光分離膜３を透過して第４の伝送路９に
入射する。On the other hand, the P wave from the optical path 20 traveling along the optical path 21 becomes an S wave by the polarization switching means 15, is reflected by the polarization separation film 3 in the subsequent stage, and enters the third transmission path 8. Further, the S wave that has traveled along the optical path 22 becomes a P wave, which passes through the polarization separation film 3 and is incident on the fourth transmission path 9.
上述のように、第６図に示した装置は、偏波切換手段15
を操作することにより、第１の伝送路６を第４の伝送路
９に、第２の伝送路７を第３の伝送路８にそれぞれ切換
えることができるという、スイッチ機能を有する装置で
ある。As described above, the device shown in FIG.
It is a device having a switch function that can switch the first transmission line 6 to the fourth transmission line 9 and the second transmission line 7 to the third transmission line 8 by operating.
尚、第５図に示した光デバイスを、組合せることによ
り、説明は省略するが、上述のような切換えスイッチ機
能を有する装置とすることができる。It should be noted that the optical device shown in FIG. 5 may be combined to form an apparatus having the above-described changeover switch function, although the description is omitted.
しかしながら上記従来例の光デバイスは、平行六面体1A
に直角プリズム２を、或いは平行ガラス板１に直角プリ
ズム２と直角プリズム５をそれぞれ固着することが必要
である。そしてこの様に例えば第５図の如く平行ガラス
板にプリズムを固着するのは、プリズムを固着しない場
合より特に偏光分離膜でＳ波とＰ波の分離の程度が約50
％良好となるからである。However, the above-mentioned conventional optical device has a parallelepiped 1A
It is necessary to fix the right-angled prism 2 to the parallel glass plate 1, or the right-angled prism 2 and the right-angled prism 5 to the parallel glass plate 1. In this way, for example, fixing the prism to the parallel glass plate as shown in FIG. 5 is more effective than the case where the prism is not fixed so that the degree of separation of the S wave and the P wave is about 50 by the polarization separation film.
% Is good.
即ち例えばＰ波中にＳ波が混在する程度は偏光分離膜が
直接空気に触れている場合と、プリズムを介在させる場
合とでは後者の場合の消光比が30dB前後であるのに対
し、前者は20dB程度に過ぎない。That is, for example, to the extent that S waves are mixed in P waves, the extinction ratio in the latter case is around 30 dB when the polarization separation film is in direct contact with air and when the prism is interposed, whereas the former is It is only about 20 dB.
そのため偏波光よりＰ波とＳ波とを十分に分離するため
の光デバイスとして偏光分離膜を備える平行六面体また
は平行ガラス板とプリズムとの組合わせを使用してい
る。Therefore, a combination of a parallelepiped or a parallel glass plate provided with a polarization separation film and a prism is used as an optical device for sufficiently separating P waves and S waves from polarized light.
しかしかかる従来の光デバイスでは直角プリズムの接着
作業を必要とし、かつ出射光の平行精度を高くするため
には接着した状態で受光面と出射面との角度を所定の高
精度にしなければならず、高価となり、特にプリズムを
２個接着する場合には、例えば平行ガラス板のみの場合
より約３倍の価格とない、しかも接着剤が高湿・高温あ
るいは大パワーの光入射によって劣化するおそれがあ
り、さらに偏光分離膜は両面で接着されるため残留反射
の問題も有している。However, such a conventional optical device requires the work of adhering the right-angle prism, and in order to increase the parallel accuracy of the emitted light, the angle between the light-receiving surface and the emitting surface must be set to a predetermined high accuracy in the adhered state. However, the cost is high, especially when two prisms are bonded together, the price is not about three times as high as when only a parallel glass plate is used, and the adhesive may deteriorate due to high humidity, high temperature, or high power incident light. In addition, since the polarization separation film is adhered on both sides, there is a problem of residual reflection.
また、偏光分離膜３は、もともとＰ波とＳ波を完全に分
離する機能がなくて、Ｓ波の一部がＰ波の光路に混在し
ている。The polarization separation film 3 does not originally have a function of completely separating the P wave and the S wave, and a part of the S wave is mixed in the optical path of the P wave.
このことに起因して、例えば第６図のような装置に組込
むと、第３の伝送路８に第２の伝送路７のＳ波の一部
が、第４の伝送路９に第１の伝送路６のＳ波の一部がそ
れぞれ混入し、漏話するという問題点がある。Due to this, for example, when incorporated in a device as shown in FIG. 6, a part of the S wave of the second transmission line 7 is transferred to the third transmission line 8 and the first S wave is transferred to the fourth transmission line 9. There is a problem that some of the S waves on the transmission path 6 are mixed and crosstalk occurs.
また、偏波切換手段15を単にオン，オフの機能を有する
スイッチとした場合には、Ｐ波とともにＳ波の一部が混
在していることに起因して、オフ状態でも、この一部の
Ｓ波の光パワーを、オフとすることができない。即ち、
消光比が低いという問題点がある。Further, when the polarization switching means 15 is simply a switch having an on / off function, a part of the S wave is mixed with the P wave, so that even in the off state, this part of the S wave is partially mixed. The optical power of the S wave cannot be turned off. That is,
There is a problem that the extinction ratio is low.
一方光学軸が約45°の複屈折板単体によってＰ波とＳ波
を分離することも周知であり、これは物性によってＰ波
とＳ波の分離を行なうので、消光比は約60dB程度にもな
る。しかし複屈折板によってＰ波とＳ波の十分な分離を
行なうためには複屈折板の厚さは10〜20mm程度の厚さを
必要とするが極めて高価となり、１mm程度の厚さでは分
離は十分ではなくばなく使用出来ないという問題点があ
る。On the other hand, it is also well known that a P-wave and a S-wave are separated by a single birefringent plate having an optical axis of about 45 °. This separates the P-wave and the S-wave depending on the physical properties, so the extinction ratio is about 60 dB. Become. However, in order to sufficiently separate the P wave and the S wave by the birefringence plate, the birefringence plate needs to have a thickness of about 10 to 20 mm, but it is extremely expensive and the separation of about 1 mm does not cause the separation. There is a problem that it cannot be used unless it is sufficient.
上記問題点は本発明により、平行した二平面を有し、対
角線方向に対向するほぼ半面の一方に偏光分離膜（３）
が、他方に全反射膜（４）がそれぞれ形成された平行ガ
ラス板（１）と、平行ガラス板（１）の偏光分離膜
（３）面側に配置され、受光面が平行ガラス板（１）に
対し略45°傾斜し、光学軸が略45°である偏光を分離す
る複屈折板（30）が配置されることを特徴とする光デバ
イスによって解決される。According to the present invention, the above-mentioned problems have two planes parallel to each other, and the polarization splitting film (3) is provided on one of the substantially half surfaces facing each other in the diagonal direction.
However, the parallel glass plate (1) on which the total reflection film (4) is formed on the other side and the polarization separation film (3) surface side of the parallel glass plate (1) are arranged, and the light receiving surface is the parallel glass plate (1). The optical device is characterized by arranging a birefringent plate (30) which separates polarized light having an optical axis of about 45 °, which is tilted at about 45 ° with respect to the optical device.
その場合平行ガラス板（１）と複屈折板（30）の間の選
択した光路中に1/2波長板（35）が配設されるようにし
てもよい。In that case, the half-wave plate (35) may be arranged in the selected optical path between the parallel glass plate (1) and the birefringent plate (30).
上記本発明の手段によれば、第１図（ａ）のように、光
路10より平行ガラス板１に入射した偏波光は、偏光分離
膜３で分離され、大部分のＳ波は偏光分離膜３で反射し
て光路12に進み、さらに全反射膜４で反射して1/2波長
板35に入射する。そして、1/2波長板35によりＰ波に変
換され、複屈折板30に常光として入射し光路12を直進す
る。According to the above-mentioned means of the present invention, as shown in FIG. 1 (a), the polarized light incident on the parallel glass plate 1 through the optical path 10 is separated by the polarization separation film 3 and most of the S waves are separated by the polarization separation film. It is reflected by 3 and advances to the optical path 12, and further reflected by the total reflection film 4 and is incident on the half-wave plate 35. Then, it is converted into P waves by the half-wave plate 35, enters the birefringent plate 30 as ordinary light, and goes straight on the optical path 12.
一方、Ｐ波と一部のＳ波は、偏光分離膜３を透過して光
路11に進み、光学軸が約45°の複屈折板30に入射する。
そして、Ｐ波は常光として光路11を直進する。しかし、
Ｓ波は異常光として複屈折板30に入射するので、屈折し
て光路11に平行ずれした光路11mを進む。即ち、Ｐ波と
Ｓ波とは完全に分離される。On the other hand, the P wave and a part of the S wave pass through the polarization separation film 3 and proceed to the optical path 11, and enter the birefringent plate 30 having an optical axis of about 45 °.
Then, the P wave travels straight along the optical path 11 as ordinary light. But,
Since the S wave enters the birefringent plate 30 as extraordinary light, it is refracted and travels along the optical path 11m which is parallel to the optical path 11. That is, the P wave and the S wave are completely separated.
また、第１図（ｂ）のように、光路20より平行ガラス板
１に入射した偏波光は、偏光分離膜３で分離され、大部
分のＳ波は反射して光路22に進み、複屈折板30に異常光
として入射し、屈折して第１図（ａ）の光路11mと同一
光路の光路22を進む。Further, as shown in FIG. 1 (b), the polarized light incident on the parallel glass plate 1 from the optical path 20 is separated by the polarization separation film 3 and most of the S waves are reflected and proceed to the optical path 22 for birefringence. The light enters the plate 30 as extraordinary light, is refracted, and travels along the optical path 22 of the same optical path as the optical path 11m of FIG.
一方、Ｐ波と一部のＳ波は、偏光分離膜３を透過して、
光路21に進み全反射膜４で反射して1/2波長板35に入射
する。そして1/2波長板35によりそれぞれＳ波,P波に変
換される。この結果、Ｓ波に変換したＰ波は、複屈折板
30に異常光として入射し、屈折して光路21に進み、1/2
波長板35によりＰ波に変換したＳ波は、複屈折板30に常
光として入射し、第１図（ａ）の光路12と同一光路の光
路21mを直進する。即ち、Ｓ波とＰ波に完全に分離す
る。On the other hand, the P wave and a part of the S wave pass through the polarization separation film 3,
The light travels to the optical path 21 and is reflected by the total reflection film 4 to enter the half-wave plate 35. Then, it is converted into S wave and P wave by the half-wave plate 35, respectively. As a result, the P wave converted into the S wave is converted into the birefringent plate.
It enters the 30 as extraordinary light, is refracted and advances to the optical path 21,
The S wave converted into the P wave by the wave plate 35 enters the birefringent plate 30 as ordinary light, and goes straight on the optical path 21m of the same optical path as the optical path 12 of FIG. That is, it is completely separated into S wave and P wave.
したがって、出射側において、光路11及び光路21に伝送
路を光結合させると、漏話する恐れがない。また、光路
11,光路21に、それぞれ偏波切換手段を設けて、オン，
オフのスイッチを機能を持たせると、消光比の高いスイ
ッチとすることができる。Therefore, when the transmission path is optically coupled to the optical path 11 and the optical path 21 on the emission side, there is no risk of crosstalk. Also the optical path
11, the optical path 21 is provided with polarization switching means respectively,
If the off switch has a function, it can be a switch with a high extinction ratio.
上述のように本発明の光デバイスでは平行ガラス板にプ
リズムを付加していない構造であるため、消光比の点で
劣るが、高精度の接着と調整作業を要せず、接着剤の劣
化のおそれもなく、接着面での残留反射も生ずることが
なく、さらに安価となる。As described above, since the optical device of the present invention has a structure in which prisms are not added to the parallel glass plate, it is inferior in terms of extinction ratio, but does not require highly accurate bonding and adjustment work, and deterioration of the adhesive There is no fear, no residual reflection occurs on the adhesive surface, and the cost is further reduced.
一方消光比が極めて優れているが十分な厚さを持たなけ
ればＰ波とＳ波について必要とする分離が不可能である
光学軸45°の複屈折板でも、平行ガラス板に対し45°傾
斜させて配置組合わせることで、数mm程度の厚さでも高
消光比機能が十分に発揮されることになる。On the other hand, the extinction ratio is extremely excellent, but it is impossible to separate the required P and S waves from each other unless it has a sufficient thickness. By arranging and combining them, the high extinction ratio function can be fully exerted even with a thickness of about several mm.
即ち本発明はプリズムの付加されていない平行ガラス板
によって大きくＰ波とＳ波を分離し、光学軸45°の複屈
折板によって、分離後のＰ波,S波の消光比を上げる点に
特徴を有している。That is, the present invention is characterized in that a P-wave and an S-wave are largely separated by a parallel glass plate to which no prism is added, and a birefringent plate having an optical axis of 45 ° increases the extinction ratio of the separated P-wave and S-wave. have.
また、第３図の光デバイスは、第１図の示したものと同
一機能を有する。即ち、光路10よりの偏波光のうち、偏
光分離膜３を透過した一部のＳ波は、複屈折板30Bによ
りＰ波と分離され、光路11mを進み、光路20よりの偏波
光のうち、偏光分離膜３を透過した一部のＳ波は、複屈
折板30AによりＰ波と分離され、光路21mを進む。The optical device shown in FIG. 3 has the same function as that shown in FIG. That is, of the polarized light from the optical path 10, a part of the S wave transmitted through the polarization separation film 3 is separated from the P wave by the birefringent plate 30B, travels along the optical path 11m, and out of the polarized light from the optical path 20. A part of the S wave transmitted through the polarization separation film 3 is separated from the P wave by the birefringent plate 30A and travels along the optical path 21m.
以下図面を参照しながら、本発明を具体的に説明する。
なお、全図を通じて同一符号は同一対象物を示す。The present invention will be specifically described below with reference to the drawings.
The same reference numerals denote the same objects throughout the drawings.
第１図の（ａ），（ｂ）はそれぞれ本発明の一実施例の
光デバイスの光路図、第２図は本発明の光デバイスを適
用した装置の光路図、第３図の（ａ），（ｂ）はそれぞ
れ本発明の他の実施例の光デバイスの光路図である。1 (a) and 1 (b) are optical path diagrams of an optical device of one embodiment of the present invention, FIG. 2 is an optical path diagram of an apparatus to which the optical device of the present invention is applied, and FIG. 3 (a). , (B) are optical path diagrams of optical devices of other embodiments of the present invention.
第１図において、平行ガラス板１の平行した二平面の、
対角線方向に対向するほぼ半面の一方に偏光分離膜３が
形成され、他方に全反射膜４が形成されている。In FIG. 1, of the two parallel planes of the parallel glass plate 1,
The polarization splitting film 3 is formed on one of the approximately half surfaces facing each other in the diagonal direction, and the total reflection film 4 is formed on the other half.
複屈折板30（例えば方解石，ルチル等）は、結晶軸が受
光面に対して45度傾斜している。そして、複屈折板30は
平行ガラス板１の偏光分離膜３側に配設され、受光面が
平行ガラス板１の出射面に対して45度傾斜している。The crystal axis of the birefringent plate 30 (eg, calcite, rutile, etc.) is inclined by 45 degrees with respect to the light receiving surface. The birefringent plate 30 is arranged on the side of the polarization separation film 3 of the parallel glass plate 1, and the light receiving surface is inclined by 45 degrees with respect to the emission surface of the parallel glass plate 1.
平行ガラス板１と複屈折板30の間には、複屈折板30に平
行に、偏波面を90度回転させる1/2波長板35が配設され
ている。この1/2波長板35の長さは、複屈折板30の長さ
のほぼ半分で、全反射膜４で反射される光路、即ち図の
光路12,21上に配設してある。Between the parallel glass plate 1 and the birefringent plate 30, a 1/2 wavelength plate 35 for rotating the plane of polarization by 90 degrees is arranged in parallel with the birefringent plate 30. The length of the half-wave plate 35 is approximately half the length of the birefringent plate 30, and is arranged on the optical path reflected by the total reflection film 4, that is, the optical paths 12 and 21 in the figure.
このような光デバイスが、光路10よりの偏波光のＰ波が
光路11に、大部分のＳ波が光路12に、一部のＳ波が光路
11mに分離され、また光路20よりの偏波光のＰ波が光路2
1に、大部分のＳ波が光路22に、一部のＳ波が光路21mに
分離されることは、前述の通りである。In such an optical device, the P wave of polarized light from the optical path 10 is in the optical path 11, most of the S waves are in the optical path 12, and some of the S waves are in the optical path.
The P wave of the polarized light from the optical path 20 is separated into 11 m and the optical path 2
As described above, 1, most of the S waves are separated into the optical path 22 and some of the S waves are separated into the optical path 21m.
第２図は、第１図に示した一対の光デバイスを前段，後
段に直列に並設して、後段の光デバイスは、並列に配設
した偏波切換手段15A,15Bを介して、前段の光デバイス
に対称に配設した装置である。FIG. 2 shows that the pair of optical devices shown in FIG. 1 are arranged in series at the front stage and the rear stage in series, and the optical devices at the rear stage are connected via the polarization switching means 15A and 15B arranged in parallel to the front stage. This device is arranged symmetrically to the optical device of.
第１の伝送路６より偏波光（光信号）を、光路10に投入
し、また第２の伝送路７より偏波光（光信号）を、光路
20に投入する。そして、それぞれ装置の出射路側（後段
の光デバイス）には、光路11に対して第３の伝送路８
を、光路21に対して第４の伝送路９がそれぞれ光結合す
るように構成してある。Polarized light (optical signal) is input to the optical path 10 from the first transmission path 6, and polarized light (optical signal) is input to the optical path 10 from the second transmission path 7.
Put in 20. The third transmission line 8 is provided with respect to the optical path 11 on the emission path side (the latter optical device) of the device.
Are configured so that the fourth transmission path 9 is optically coupled to the optical path 21.
なお、光路10と光路20とは、前段の光デバイスの偏光分
離膜３で交叉するものとする。The optical path 10 and the optical path 20 are assumed to intersect with each other by the polarization separation film 3 of the optical device in the preceding stage.
ここで、偏波切換手段15A,15Bはそれぞれ光路11,21上に
配設された、例えば磁気光学結晶板（例えばYIG…イッ
トリウム・鉄・ガーネット）よりなり、付与する磁界の
方向を変えることにより、Ｓ波をＰ波に、Ｐ波をＳ波に
変換する機能を有する。Here, the polarization switching means 15A and 15B are, for example, magneto-optical crystal plates (for example, YIG ... yttrium, iron, garnet) provided on the optical paths 11 and 21, respectively, and change the direction of the applied magnetic field. , And has a function of converting an S wave into a P wave and a P wave into an S wave.
第１の伝送路６の出射光は、前段の偏光分離膜３でＳ波
とＰ波に分離され、それぞれ光路12（図示の光路21
m），光路11を進み、また、偏光分離膜３を透過した一
部のＳ波は、光路11mに進む。そして、Ｐ波は偏波切換
手段15Aを経て、Ｓ波は偏波切換手段15Bを経て後段の光
デバイスに入射する。The light emitted from the first transmission path 6 is separated into an S wave and a P wave by the polarization separation film 3 in the preceding stage, and each is separated into an optical path 12 (optical path 21 in the figure.
m), travels along the optical path 11, and part of the S waves that have passed through the polarization separation film 3 travels along the optical path 11m. Then, the P wave passes through the polarization switching means 15A and the S wave passes through the polarization switching means 15B and enters the optical device at the subsequent stage.
光路11を進んだＰ波は、1/2波長板35によりＳ波に変換
され、全反射膜４で反射して、偏光分離膜３に入射し、
偏光分離膜３で反射して、第３の伝送路８に入射する。The P wave traveling along the optical path 11 is converted into an S wave by the half-wave plate 35, reflected by the total reflection film 4, and made incident on the polarization separation film 3.
The light is reflected by the polarization separation film 3 and enters the third transmission line 8.
また、第２の伝送路７の出射光は、前段の偏光分離膜３
でＳ波とＰ波に分離されて、それぞれ光路（図示の光路
11m），光路21を進み、また、偏光分離膜３を透過した
一部のＳ波は、光路21mに進む。この際光路21を進んだ
Ｐ波は前段の光デバイスの1/2波長板35によりＳ波に変
換されて偏波切換手段15Bを経て後段の光デバイスに進
む。The light emitted from the second transmission path 7 is emitted from the polarization separation film 3 in the preceding stage.
Are separated into S wave and P wave by
11 m), traveling along the optical path 21, and a part of the S waves transmitted through the polarization separation film 3 also proceeds toward the optical path 21 m. At this time, the P wave that has traveled along the optical path 21 is converted into an S wave by the half-wave plate 35 of the optical device at the front stage and travels to the optical device at the rear stage through the polarization switching means 15B.
そして、光路21を進んだＳ波に変換されたＰ波は、偏光
分離膜３でで反射して、第４の伝送路９に入射する。Then, the P wave converted into the S wave traveling through the optical path 21 is reflected by the polarization separation film 3 and enters the fourth transmission path 9.
なお、光路11m,光路を進んだ偏波は、後段の光デバイス
の偏光分離膜３を透過して光路21に平行に進むが、光路
21とはずれいるので、第４の伝送路９に入射しない。ま
た光路21m,光路12を進んだ偏波は、後段の光デバイスの
偏光分離膜３を透過して光路11に平行に進むが、光路11
とはずれているので、第３の伝送路８に入射しない。The polarized light traveling along the optical path 11m and the optical path travels in parallel with the optical path 21 after passing through the polarization separation film 3 of the optical device in the subsequent stage.
Since it deviates from 21, it does not enter the fourth transmission line 9. Further, the polarized light traveling through the optical paths 21m and 12 passes through the polarization separation film 3 of the optical device in the subsequent stage and travels in parallel with the optical path 11, but the optical path 11
Therefore, it does not enter the third transmission line 8.
このような状態で、偏波切換手段15A,15Bをそれぞれ作
動させ光路11のＰ波をＳ波に、光路21のＳ波をＰ波にそ
れぞれ切換えると、光路11を進んだ偏波は光路11mを進
んで、第３の伝送路８は勿論のこと第４の伝送路９にも
入射しない。また、光路21を進んだ偏波は光路21mを進
んで、第４の伝送路９は勿論のこと第３の伝送路８にも
入射しない。In such a state, when the polarization switching means 15A and 15B are respectively activated to switch the P wave of the optical path 11 to the S wave and the S wave of the optical path 21 to the P wave, the polarized wave traveling through the optical path 11 is the optical path 11m. Then, the light does not enter not only the third transmission line 8 but also the fourth transmission line 9. Further, the polarized wave that has traveled along the optical path 21 travels along the optical path 21m and does not enter the third transmission path 8 as well as the fourth transmission path 9.
即ち漏話することがなく、且つ消光比が極めて高い。That is, there is no crosstalk and the extinction ratio is extremely high.
第３図において、平行ガラス板１の偏光分離膜３側に、
出射面に45度傾斜して、並列に複屈折板30A,30Bが配設
されている。In FIG. 3, on the polarization separation film 3 side of the parallel glass plate 1,
Birefringent plates 30A and 30B are arranged in parallel at an angle of 45 degrees to the exit surface.
複屈折板30Aは光路11（光路22と同じ）上に、複屈折板3
0Bは光路21（光路12と同じ）上にそれぞれ配設され、そ
の結晶軸は、光路に45度傾斜し、且つ傾斜方向が異な
る。The birefringent plate 30A is located on the optical path 11 (same as the optical path 22) and the birefringent plate 3
0B is arranged on the optical path 21 (same as the optical path 12), and its crystal axis is inclined by 45 degrees to the optical path, and the inclination directions are different.
したがって、光路10より平行ガラス板１に入射した偏波
光は、第３図（ａ）のように、偏光分離膜３で分離さ
れ、大部分のＳ波は偏光分離膜３で反射して光路12に進
み、さらに全反射膜４で反射して複屈折板30Bに入射す
る。そして、複屈折板30Bに異常光として入射し屈折し
て光路12を進む。Therefore, the polarized light incident on the parallel glass plate 1 from the optical path 10 is separated by the polarization separation film 3 as shown in FIG. Then, the light is further reflected by the total reflection film 4 and enters the birefringent plate 30B. Then, it enters the birefringent plate 30B as extraordinary light and is refracted to travel along the optical path 12.
一方、Ｐ波と一部のＳ波は、偏光分離膜３を透過して光
路11に進み、複屈折板30Aに入射する。そして、Ｐ波は
異常光として入射し、屈折して光路11を進む。しかし、
Ｓ波は常光として複屈折板30A入射するので、直進して
光路11mを進む。即ち、Ｐ波とＳ波とは完全に分離され
る。On the other hand, the P wave and a part of the S wave pass through the polarization separation film 3 and proceed to the optical path 11, and enter the birefringent plate 30A. Then, the P wave enters as extraordinary light, is refracted, and travels along the optical path 11. But,
Since the S wave is incident on the birefringent plate 30A as ordinary light, it goes straight along the optical path 11m. That is, the P wave and the S wave are completely separated.
また、光路20より平行ガラス板１に入射した偏波光は、
第３図（ｂ）のように、偏光分離膜３で分離され、大部
分のＳ波は反射して光路22に進み、複屈折板30Aに常光
として入射し、直進して光路22（光路11mに同じ）を進
む。In addition, the polarized light incident on the parallel glass plate 1 from the optical path 20 is
As shown in FIG. 3 (b), most of the S waves separated by the polarization separation film 3 are reflected and proceed to the optical path 22, enter the birefringent plate 30 A as ordinary light, and go straight to the optical path 22 (optical path 11 m Same as above).
一方、Ｐ波と一部のＳ波は、偏光分離膜３を透過して、
光路21に進み全反射膜４で反射して、複屈折板30Bに入
射する。そしてＰ波は常光として複屈折板30Bに入射し
て、直進して光路21を進む。しかし、Ｓ波は異常光とし
て複屈折板30Bに入射するので、屈折して光路21m（光路
12に同じ）を進む。即ち、Ｓ波とＰ波に完全に分離す
る。On the other hand, the P wave and a part of the S wave pass through the polarization separation film 3,
The light travels to the optical path 21, is reflected by the total reflection film 4, and enters the birefringent plate 30B. Then, the P-wave enters the birefringent plate 30B as ordinary light and goes straight along the optical path 21. However, since the S wave enters the birefringent plate 30B as extraordinary light, it is refracted and the optical path 21m (optical path
Same as 12). That is, it is completely separated into S wave and P wave.
上述の光デバイスを、第２図と同様に組合せると、漏話
することがなく、且つ消光比が極めて高いことは勿論で
ある。It goes without saying that, when the above optical devices are combined in the same manner as in FIG. 2, no crosstalk occurs and the extinction ratio is extremely high.
以上説明したように本発明は、偏波光をＰ波とＳ波に完
全に分離することができ、通信伝送路に挿入して漏話が
なく、且つ消光比が高く、さらにまた低コストである
等、実用上で優れた効果がある。INDUSTRIAL APPLICABILITY As described above, the present invention can completely separate polarized light into P wave and S wave, inserts it into a communication transmission line without crosstalk, has a high extinction ratio, and is also low in cost. , Has an excellent effect in practical use.
第１図の（ａ），（ｂ）はそれぞれ本発明の一実施例の
光路図、 第２図は本発明を適用した装置の光路図、 第３図の（ａ），（ｂ）はそれぞれ本発明の他の実施例
光路図、 第４図の（ａ），（ｂ）は従来例の光路図、 第５図の（ａ），（ｂ）は従来の他の例の光路図、 第６図は従来例を適用した装置の光路図である。 図において、 １は平行ガラス板、３は偏光分離膜、４は全反射膜、６
は第１の伝送路、７は第２の伝送路、８は第３の伝送
路、９は第４の伝送路、30,30A,30Bは複屈折板、35は1/
2波長板をそれぞれ示す。1 (a) and 1 (b) are optical path diagrams of an embodiment of the present invention, FIG. 2 is an optical path diagram of an apparatus to which the present invention is applied, and FIGS. 3 (a) and 3 (b) are respectively. Optical path diagram of another embodiment of the present invention, (a) and (b) of FIG. 4 are optical path diagrams of a conventional example, (a) and (b) of FIG. 5 are optical path diagrams of other conventional examples, FIG. 6 is an optical path diagram of an apparatus to which the conventional example is applied. In the figure, 1 is a parallel glass plate, 3 is a polarization separation film, 4 is a total reflection film, 6
Is the first transmission line, 7 is the second transmission line, 8 is the third transmission line, 9 is the fourth transmission line, 30, 30A and 30B are birefringent plates, and 35 is 1 /
Two wavelength plates are shown respectively.
Claims (2)
するほぼ半面の一方に偏光分離膜（３）が、他方に全反
射膜（４）がそれぞれ形成された平行ガラス板（１）
と、 平行ガラス板（１）の偏光分離膜（３）面側に配置さ
れ、受光面が平行ガラス板（１）に対し略45°傾斜し、
光学軸が略45°である偏光を分離する複屈折板（30）が
配置されることを特徴とする光デバイス。1. A parallel glass plate (1) having two parallel planes, each having a polarization splitting film (3) formed on one of substantially half surfaces facing each other diagonally and a total reflection film (4) formed on the other half.
And is arranged on the side of the polarization separation film (3) of the parallel glass plate (1), and the light-receiving surface is inclined by about 45 ° with respect to the parallel glass plate (1),
An optical device comprising a birefringent plate (30) arranged to separate polarized light having an optical axis of about 45 °.
の選択した光路中に1/2波長板（35）が配設されたこと
を特徴とする特許請求の範囲第１項に記載の光デバイ
ス。2. A half-wave plate (35) is arranged in a selected optical path between the parallel glass plate (1) and the birefringent plate (30). The optical device according to the item.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61187233A JPH0738049B2 (en) | 1986-08-09 | 1986-08-09 | Optical device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61187233A JPH0738049B2 (en) | 1986-08-09 | 1986-08-09 | Optical device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6343120A JPS6343120A (en) | 1988-02-24 |
| JPH0738049B2 true JPH0738049B2 (en) | 1995-04-26 |
Family
ID=16202385
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61187233A Expired - Lifetime JPH0738049B2 (en) | 1986-08-09 | 1986-08-09 | Optical device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0738049B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5751480A (en) * | 1991-04-09 | 1998-05-12 | Canon Kabushiki Kaisha | Plate-like polarizing element, a polarizing conversion unit provided with the element, and a projector provided with the unit |
| JP6349410B2 (en) * | 2014-02-26 | 2018-06-27 | ビエン チャン， | System and method for multi-beam laser array with variable beam parameter product |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4566761A (en) * | 1984-09-13 | 1986-01-28 | Gte Laboratories Incorporated | Birefringent optical wavelength multiplexer/demultiplexer |
| JPS61145503A (en) * | 1984-12-20 | 1986-07-03 | Fujitsu Ltd | Prism for optical splitting and mixing |
-
1986
- 1986-08-09 JP JP61187233A patent/JPH0738049B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6343120A (en) | 1988-02-24 |
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