JPH0668585B2 - Optical isolator - Google Patents
Optical isolatorInfo
- Publication number
- JPH0668585B2 JPH0668585B2 JP59243313A JP24331384A JPH0668585B2 JP H0668585 B2 JPH0668585 B2 JP H0668585B2 JP 59243313 A JP59243313 A JP 59243313A JP 24331384 A JP24331384 A JP 24331384A JP H0668585 B2 JPH0668585 B2 JP H0668585B2
- Authority
- JP
- Japan
- Prior art keywords
- birefringent
- deflecting
- light
- plates
- plate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は光通信等に用いられる光アイソレータに関する
ものである。TECHNICAL FIELD The present invention relates to an optical isolator used for optical communication and the like.
光通信において、光源が半導体レーザである場合、発振
器であるレーザからの反射によって再びレーザに戻され
ると発振に不安定性を生じたり、雑音を伴う不具合を生
ずる。このため反射光を阻止して前記不具合を防止する
ために光アイソレータが用いられる。In optical communication, when the light source is a semiconductor laser, when it is returned to the laser by reflection from the laser which is the oscillator, instability occurs in the oscillation or a problem accompanied by noise occurs. Therefore, an optical isolator is used to prevent reflected light and prevent the above-mentioned problems.
従来の光アイソレータは第３図ａに示す如く偏光子１と
検光子２との間にＹＩＧ等の４５°ファラデー回転子３
を挿入配置したもの、あるいは第３図ｂに示す如く偏光
子１と検光子２に複屈折偏向板を用いたものがある。そ
して両者共偏光子１と検光子２の偏光面を４５°くいち
がわせて固定してあり、偏光子１の方から入る光は４５
°ファラデー回転子３で偏光面を４５°回転させられる
ので検光子３を通過することができる。一方、検光子２
の方から入る光は４５°ファラデー回転子３で偏光面を
４５°回転させられるが、その方向が偏光子１の偏光面
と９０°の角度をなすため偏光子１を通過することがで
きない。このようにして一方からのみ光を通し、他方か
らの光は阻止しアイソレータとしての機能を発揮するこ
とができる。この場合ＹＩＧを用いた４５°ファラデー
回転子の消光比が４０ｄＢ程度であるため、さらに消光
比を高めるように第４図の如く前記の構成を２組用いた
ものが案出されている。なお同図において、４，５，
６，７は複屈折偏向板、８，９は４５°ファラデー回転
子である。As shown in FIG. 3a, the conventional optical isolator has a 45 ° Faraday rotator 3 such as a YIG between a polarizer 1 and an analyzer 2.
There are those in which the birefringence deflector is used for the polarizer 1 and the analyzer 2 as shown in FIG. 3b. The polarization planes of the polarizer 1 and the analyzer 2 are fixed at 45 ° so that the light entering from the polarizer 1 is 45 °.
Since the plane of polarization can be rotated by 45 ° by the Faraday rotator 3, it can pass through the analyzer 3. On the other hand, analyzer 2
The light entering from the direction (1) can rotate the polarization plane by 45 ° by the 45 ° Faraday rotator 3, but cannot pass through the polarizer 1 because its direction makes an angle of 90 ° with the polarization plane of the polarizer 1. In this way, it is possible to allow light to pass from only one side and block the light from the other side to exert the function as an isolator. In this case, since the extinction ratio of the 45 ° Faraday rotator using YIG is about 40 dB, one using two sets of the above-mentioned constitutions has been devised so as to further increase the extinction ratio. In the figure, 4, 5,
Reference numerals 6 and 7 are birefringent deflecting plates, and 8 and 9 are 45 ° Faraday rotators.
上記構成のものにあっては、複屈折テーパー板を４個必
要とし、部品点数が多くなるという問題がある。The structure described above requires four birefringent taper plates, resulting in a large number of parts.
本発明は、上記問題点を解消した光アイソレータを提供
するもので、その手段は、常光と異常光を、複屈折物質
からなり偏光に応じて進路が異なるように光の進行方向
を変えるテーパ状の第１、第２、第３の３つの複屈折偏
向板と、前記第１、第２の複屈折偏向板間および前記第
２、第３の複屈折偏向板間に挿入された第１および第２
の４５°ファラデー回転子とで構成され、前記第１およ
び第２の複屈折偏向板を構成する結晶の光学軸方位は何
れも偏向板の光が入射する面に平行であり、第１および
第２の複屈折偏向板を構成する結晶の前記光学軸方位は
相互に４５°の角度をなし、かつ、前記第２および第３
の複屈折偏向板を構成する結晶の光学軸方位は何れも偏
向板の光が入射する面に平行であり、第２および第３の
複屈折偏向板を構成する結晶の前記光学軸方位は相互に
４５°の角度をなしており、前記テーパ状の３つの複屈
折偏向板のうち、２つの偏向板は先端の向きおよびテー
パ形状を構成する平面のなす角度が同一であり、残りの
１つの偏向板は先端の向きが前記２つの偏向板に対して
逆方向で、かつ、テーパ形状を構成する平面のなす角度
が２倍であることを特徴とする光アイソレータによって
なされる。The present invention provides an optical isolator which solves the above-mentioned problems, and its means is a taper shape that changes the traveling direction of ordinary light and extraordinary light so as to change the traveling direction so that the path is different depending on the polarization. First, second, and third birefringent deflectors, and the first and second birefringent deflectors inserted between the first and second birefringent deflectors and between the second and third birefringent deflectors. Second
45 ° Faraday rotator, and the optical axes of the crystals forming the first and second birefringent deflecting plates are both parallel to the plane of incidence of light on the deflecting plate. The optical axes of the crystals constituting the second birefringent deflection plate form an angle of 45 ° with each other, and the second and third optical axes
The optical axes of the crystals forming the birefringent deflector are parallel to the plane of the deflecting plate on which light is incident, and the optical axes of the crystals forming the second and third birefringent deflectors are mutually parallel. Of the three tapered birefringent deflecting plates, the two deflecting plates have the same tip direction and the same angle between the planes forming the tapered shape, and the remaining one The deflecting plate is made by an optical isolator characterized in that the direction of its tip is opposite to that of the two deflecting plates, and that the angle between the planes forming the tapered shape is doubled.
上記光アイソレータは、３つの偏光子のうちの２つが常
光・異常光を並進または屈折分離する向きおよび大きさ
が等しく、残りの１つが他の２つに対して向きが反対で
且つ大きさが２倍としたことにより、順方向の光は常光
・異常光とも屈折が打ち消され、入力光と同じ方向へ出
力し、逆方向の光は、屈折が打ち消されず進む方向が変
るため、光アイソレータとしての消光比は向上される。
また偏光子の数が３個で良いので、部品点数が少なくな
る。In the optical isolator, two of the three polarizers have the same direction and size for translational or refraction separation of ordinary and extraordinary light, and the other one has the opposite direction to the other two and has the size. By doubling the light, the forward light is refracted by both ordinary and extraordinary light and is output in the same direction as the input light, while the light in the opposite direction is refracted and the traveling direction is changed. The extinction ratio of is improved.
Moreover, since the number of polarizers may be three, the number of parts is reduced.
以下、図面を参照して本発明の実施例を詳細に説明す
る。Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
第１図は本発明の一実施例を説明するための図である。
同図において、１１，１２，１３は複屈折偏向板、１
４，１５は４５°ファラデー回転子をそれぞれ示してい
る。FIG. 1 is a diagram for explaining one embodiment of the present invention.
In the figure, reference numerals 11, 12, 13 denote birefringent deflecting plates, 1
Reference numerals 4 and 15 denote 45 ° Faraday rotators, respectively.
本実施例は第１図に示す如く、第１，第２，第３の３個
の複屈折偏向板１１，１２，１３と、第１，第２の複屈
折偏向板１１，１２との間および第２，第３の複屈折偏
向板１２，１３との間にそれぞれ挿入配置された４５°
ファラデー回転子１４，１５とより構成され、前記第１
および第３の複屈折偏向板１１，１３は常光・異常光を
屈折分離する大きさおよび向きが等しく、第２の複屈折
偏向板１２は他の２つに比し常光・異常光を屈折分離す
る大きさが２倍で且つ向きが反対となるように形成配置
されている。In the present embodiment, as shown in FIG. 1, between the first, second, and third birefringent deflecting plates 11, 12, and 13 and the first and second birefringent deflecting plates 11, 12, And 45 ° inserted between the second and third birefringent deflection plates 12 and 13, respectively.
The Faraday rotator 14, 15 and the first
The third birefringence deflecting plates 11 and 13 have the same size and direction for refracting and separating ordinary and extraordinary rays, and the second birefringent deflecting plate 12 refracts and separates ordinary and extraordinary rays as compared with the other two. They are formed and arranged so that the size to be doubled and the directions are opposite.
このように構成された本実施例の動作を第２図を用いて
説明する。同図において、第１図と同一部分は同一符号
を付して示した。また光線１６の実線，破線はそれぞれ
複屈折偏向板内での常光・異常光を表わしている。The operation of this embodiment configured as described above will be described with reference to FIG. In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals. Further, the solid line and the broken line of the light beam 16 respectively represent ordinary and extraordinary light in the birefringent deflection plate.
第２図ａは光線１６が順方向（図の左から右へ）に入射
する場合の光路を示しており、常光・異常光とも屈折が
打ち消されて入力光と同じ方向へ出力する。光線１６が
逆方向から入射する場合は第２図ｂの如く、第３の複屈
折偏向板１３を出た常光は第２の４５°ファラデー回転
子１５によって第２の複屈折偏向板の異常光となり、第
２の複屈折偏向板１２で屈折されたのち、第１の４５°
ファラデー回転子１４で第１の複屈折偏向板の常光とな
り第１の複屈折偏向板１１から矢印Ａ方向に出射する。
また第３の複屈折偏向板１３で屈折された異常光は第２
の４５°ファラデー回転子１５で第２の複屈折偏向板の
常光となり、第２の複屈折偏向板１２を通過したのち、
第１の４５°ファラデー回転子１４で第１の複屈折偏向
板の異常光となり第１の複屈折偏向板１１で屈折されて
矢印Ｂ方向に出射する。このように逆方向の光線は常光
・異常光とも入射方向と異なった方向に屈折され、出射
するためレンズ１７によって光ファイバ１８への結合が
できずアイソレータとなり、またファラデー回転子を２
個使用しているため消光比を向上することができる。な
お本実施例においては常光・異常光を屈折分離するため
に複屈折偏向板を用いたが、これは常光・異常光を並進
させる複屈折平板の偏光子を用いても同様の効果が得ら
れる。また３つの偏光子の機能は相互に入れ換えること
も可能である。FIG. 2a shows the optical path when the light ray 16 is incident in the forward direction (from left to right in the figure). The refraction of both ordinary and extraordinary light is canceled and the light is output in the same direction as the input light. When the light ray 16 is incident from the opposite direction, the ordinary light emitted from the third birefringent deflection plate 13 is an extraordinary light of the second birefringent deflection plate by the second 45 ° Faraday rotator 15 as shown in FIG. 2b. After being refracted by the second birefringent deflector 12, the first 45 °
The Faraday rotator 14 becomes the ordinary light of the first birefringence deflecting plate and emits it from the first birefringence deflecting plate 11 in the arrow A direction.
The extraordinary light refracted by the third birefringent deflector 13 is
After becoming the ordinary light of the second birefringent deflecting plate by the 45 ° Faraday rotator 15 and passing through the second birefringent deflecting plate 12,
The first 45 ° Faraday rotator 14 becomes extraordinary light of the first birefringence deflecting plate, refracted by the first birefringence deflecting plate 11, and emitted in the direction of arrow B. In this way, the rays in the opposite directions are refracted in directions different from the incident direction for both ordinary and extraordinary rays and are emitted, so that they cannot be coupled to the optical fiber 18 by the lens 17 and become an isolator, and the Faraday rotator
Since they are used individually, the extinction ratio can be improved. In the present embodiment, the birefringent deflector is used to refract and separate the ordinary and extraordinary rays. However, the same effect can be obtained by using a birefringent plate polarizer that translates the ordinary and extraordinary rays. . Further, the functions of the three polarizers can be interchanged with each other.
以上説明したように本発明によれば、４５°ファラデー
回転子を用いた光アイソレータを２段に重ねた光アイソ
レータにおいて、その偏光子として複屈折の平板または
テーパー板が３個で良く、従来４個を必要としたのに対
し部品点数が節減される。As described above, according to the present invention, in the optical isolator in which the optical isolators using the 45 ° Faraday rotator are stacked in two stages, the number of birefringent flat plates or tapered plates may be three as the polarizer. The number of parts is reduced while the number of parts was required.
第１図は本発明の光アイソレータの一実施例を説明する
ための図、第２図は本発明の実施例の動作を説明するた
めの図、第３図および第４図は従来の光アイソレータを
説明するための図である。 図中、１１，１２，１３は複屈折偏向板、１４，１５は
４５°ファラデー回転子をそれぞれ示す。FIG. 1 is a diagram for explaining one embodiment of the optical isolator of the present invention, FIG. 2 is a diagram for explaining the operation of the embodiment of the present invention, and FIGS. 3 and 4 are conventional optical isolators. It is a figure for explaining. In the figure, 11, 12 and 13 are birefringent deflecting plates, and 14 and 15 are 45 ° Faraday rotators, respectively.
Claims (2)
に応じて進路が異なるように光の進行方向を変えるテー
パ状の第１、第２、第３の３つの複屈折偏向板と、前記
第１、第２の複屈折偏向板間および前記第２、第３の複
屈折偏向板間に挿入された第１および第２の４５°ファ
ラデー回転子とで構成され、 前記第１および第２の複屈折偏向板を構成する結晶の光
学軸方位は何れも偏向板の光が入射する面に平行であ
り、第１および第２の複屈折偏向板を構成する結晶の前
記光学軸方位は相互に４５°の角度をなし、かつ、前記
第２および第３の複屈折偏向板を構成する結晶の光学軸
方位は何れも偏向板の光が入射する面に平行であり、第
２および第３の複屈折偏向板を構成する結晶の前記光学
軸方位は相互に４５°の角度をなしており、 前記テーパ状の３つの複屈折偏向板のうち、２つの偏向
板は先端の向きおよびテーパ形状を構成する平面のなす
角度が同一であり、残りの１つの偏向板は先端の向きが
前記２つの偏向板に対して逆方向で、かつ、テーパ形状
を構成する平面のなす角度が２倍であることを特徴とす
る光アイソレータ。1. Tapered first, second, and third birefringent deflecting plates made of a birefringent material and changing the traveling directions of the ordinary light and the extraordinary light so that their paths differ depending on the polarized light. A first and a second 45 ° Faraday rotator inserted between the first and second birefringent deflection plates and between the second and third birefringent deflection plates, and the first and second The optical axes of the crystals forming the second birefringent deflecting plate are all parallel to the plane of the deflecting plate on which light is incident, and the optical axis directions of the crystals forming the first and second birefringent deflecting plates are the same. Form an angle of 45 ° with each other, and the optical axes of the crystals forming the second and third birefringent deflecting plates are both parallel to the light incident surface of the deflecting plate. The optical axis directions of the crystals forming the third birefringent deflection plate form an angle of 45 ° with each other. Of the three tapered birefringent deflecting plates, the two deflecting plates have the same tip direction and the same angle formed by the planes forming the tapered shape, and the remaining one deflecting plate has the two tip directions. An optical isolator characterized in that a plane forming a tapered shape is doubled in a direction opposite to a plate.
先端の方向およびテーパ形状を構成する平面をなす角度
が同一である前記２つの偏向板が、前記第１および第３
の複屈折偏向板であることを特徴とする特許請求の範囲
第１項記載の光アイソレータ。2. Among the three birefringent deflecting plates, the two deflecting plates having the same direction of the tip of the deflecting plate and the angle forming a plane forming the tapered shape are the first and the third deflecting plates.
The optical isolator according to claim 1, which is a birefringent deflector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59243313A JPH0668585B2 (en) | 1984-11-20 | 1984-11-20 | Optical isolator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59243313A JPH0668585B2 (en) | 1984-11-20 | 1984-11-20 | Optical isolator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61122624A JPS61122624A (en) | 1986-06-10 |
| JPH0668585B2 true JPH0668585B2 (en) | 1994-08-31 |
Family
ID=17101973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59243313A Expired - Lifetime JPH0668585B2 (en) | 1984-11-20 | 1984-11-20 | Optical isolator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0668585B2 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2796315B2 (en) * | 1988-10-07 | 1998-09-10 | 並木精密宝石株式会社 | Polarization-independent optical circuit and device therefor |
| US5402509A (en) * | 1991-09-12 | 1995-03-28 | Fujitsu Limited | Optical fiber coupling device including lenses and magnetooptics |
| EP0634844A1 (en) * | 1993-07-15 | 1995-01-18 | AT&T Corp. | Non-reciprocal optical diplexer |
| US5726801A (en) * | 1994-12-21 | 1998-03-10 | E-Tek Dynamics, Inc. | Reduced optical isolator module for a miniaturized laser diode assembly |
| US6278547B1 (en) * | 1998-05-06 | 2001-08-21 | Hughes Electronics Corporation | Polarization insensitive faraday attenuator |
| US6049427A (en) * | 1999-02-19 | 2000-04-11 | Jds Uniphase Corporation | Optical device arrangements utilizing simultaneous orthogonal walkoff elements |
| US6178044B1 (en) * | 1999-08-31 | 2001-01-23 | Oplink Communications, Inc. | Method and system for providing an optical circulator |
| US6288826B1 (en) * | 2000-01-05 | 2001-09-11 | Jds Uniphase Inc. | Multi-stage optical isolator |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5868718A (en) * | 1981-10-21 | 1983-04-23 | Nippon Telegr & Teleph Corp <Ntt> | Light isolator |
-
1984
- 1984-11-20 JP JP59243313A patent/JPH0668585B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61122624A (en) | 1986-06-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6014475A (en) | Fiber optic circulator | |
| US5682446A (en) | Polarization mode dispersion-free circulator | |
| US5574595A (en) | Optical isolator | |
| US5923472A (en) | 3-port optical circulator/switch with mirror | |
| JPS6158809B2 (en) | ||
| US6061167A (en) | Optical isolator | |
| US5267078A (en) | Optical isolator | |
| JPH0668585B2 (en) | Optical isolator | |
| US6246518B1 (en) | Reflection type optical isolator | |
| US6366402B1 (en) | Method and system for providing an in-line optical circulator | |
| JPH0668584B2 (en) | Optical isolator | |
| JP3161885B2 (en) | Optical isolator | |
| US20030053209A1 (en) | Dual stage optical isolator with reduced polarization mode dispersion and beam offset | |
| JP2930431B2 (en) | Polarization-independent optical isolator | |
| US6476967B2 (en) | Compact optical circulator with three ports | |
| JP2905847B2 (en) | Optical isolator device | |
| CA2328564C (en) | Multi-stage optical isolator | |
| JP2777262B2 (en) | Optical isolator device | |
| JP2989983B2 (en) | Optical isolator | |
| JPH0820623B2 (en) | Optical isolator | |
| JPH02173613A (en) | Polarizing device | |
| RU2082190C1 (en) | Optical insulator | |
| JPS60238813A (en) | Optical isolator | |
| JPH0532826Y2 (en) | ||
| JPH04140709A (en) | Optical isolator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |