JPS597312A - Optical isolator - Google Patents

Optical isolator

Info

Publication number
JPS597312A
JPS597312A JP57115218A JP11521882A JPS597312A JP S597312 A JPS597312 A JP S597312A JP 57115218 A JP57115218 A JP 57115218A JP 11521882 A JP11521882 A JP 11521882A JP S597312 A JPS597312 A JP S597312A
Authority
JP
Japan
Prior art keywords
optical
optical fiber
fiber
diameter
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.)
Pending
Application number
JP57115218A
Other languages
Japanese (ja)
Inventor
Akira Ishikawa
朗 石川
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP57115218A priority Critical patent/JPS597312A/en
Publication of JPS597312A publication Critical patent/JPS597312A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4207—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms with optical elements reducing the sensitivity to optical feedback
    • G02B6/4208—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms with optical elements reducing the sensitivity to optical feedback using non-reciprocal elements or birefringent plates, i.e. quasi-isolators
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4207—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms with optical elements reducing the sensitivity to optical feedback

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Light Guides In General And Applications Therefor (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)

Abstract

PURPOSE:To provide an inexpensive and small sized optical isolator having easy constitution by providing a reflection film having a fine hole of the diameter smaller than the core diameter of an optical transmission body to which light is made incident to the one end of said optical transmission body. CONSTITUTION:The forward end of an optical fiber 100 is polished roughly perpendicularly to the optical axis of the optical fiber and a reflection preventing film 300 is attached to the end face thereof; further a reflection film 200 of Al having a fine hole 201 of about 8mu diameter is vapor deposited thereon. The fiber 100 is a focusing type fiber of 80mu core diameter as a core part 101 is shown by a broken line in the figure. Now, the light emitted from a semiconductor laser is restricted to about 2mu spot size by a lens, and is propagated in the core part 101 of the fiber 100 through the fine hole 201 provided to the film 200, whereby the coupling is accomplished with high efficiency.

Description

【発明の詳細な説明】 この発明は、光ファイバからの反射光が半導体レーザに
帰還するのを防ぐために用いられる光アイソレータ、特
に多モード光ファイバ用の光アイソレータに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical isolator used to prevent reflected light from an optical fiber from returning to a semiconductor laser, particularly an optical isolator for a multimode optical fiber.

光源に半導体レーザ、伝送路に光ファイバを用いる光フ
アイバ伝送システムは、半導体レーザの出力光のうちの
一部が光ファイバの光入出射端面等で反射して、半導体
レーザの活性層に帰還し、出力光に雛音や波形歪が発生
するという問題点を有している。特に、半導体レーザと
光ファイバとの結合効率が高いと、反射光が半導体レー
ザに帰還し易くなり、Ｗ音や波形歪が生じ易かった。そ
こで、反射光が半導体レーザに帰還するのを防ぐ目的で
半導体レーザと光ファイバとの間に挿入される光アイソ
レータが開発されてきている。In an optical fiber transmission system that uses a semiconductor laser as a light source and an optical fiber as a transmission path, a portion of the output light of the semiconductor laser is reflected by the light input/output end face of the optical fiber and returns to the active layer of the semiconductor laser. However, there is a problem that noise and waveform distortion occur in the output light. In particular, when the coupling efficiency between the semiconductor laser and the optical fiber is high, the reflected light tends to return to the semiconductor laser, which tends to cause W sound and waveform distortion. Therefore, optical isolators inserted between a semiconductor laser and an optical fiber have been developed for the purpose of preventing reflected light from returning to the semiconductor laser.

従来この種の光アイソレータとしては、　ＹＩＧ等の結
晶中での光の偏波面のファラデー回転作用を用いたもの
（例えば、関他、昭和５４年電子通信学会総合全国大会
講演論文集　講演番号８３−３）等が多く用いられてい
る。Conventionally, this type of optical isolator uses the Faraday rotation effect of the plane of polarization of light in a crystal such as YIG (for example, Seki et al., Proceedings of the National Conference of the Institute of Electronics and Communication Engineers, 1981, Lecture No. 83- 3) etc. are often used.

しかし、この光アイソレータは、ＹＴＧ等の高価なファ
ラデー回転用結晶や偏光子、検光子等の高価な部品を使
用するということ、部品数が多いために大きな組立工数
が必要であろうえ、実装のだめの工数も多いということ
のため高価であるという欠点を有していた。さらに、０
８μｍ帯の波長域では、ファラデー回転素子とし。However, this optical isolator uses expensive parts such as YTG and other expensive Faraday rotation crystals, polarizers, and analyzers, requires a large number of assembly steps due to the large number of parts, and is difficult to assemble. It has the disadvantage of being expensive because it requires a lot of man-hours. Furthermore, 0
In the 8 μm wavelength range, use a Faraday rotation element.

てＹ　Ｉ　Ｇ結晶は損失が大きくて用いることができな
いため、ベルデ定数がＹ　Ｉ　Ｇ結晶より小さい鉛ガラ
ス等を用いるため、ファラデー回転素子の長さを長くす
るか磁界を強くするために大きな磁石を用いるかする必
要があり、小形な光アイソレータを実現するのが困難で
あるという欠点も有していた。Since the Y I G crystal cannot be used because of its large loss, lead glass, etc., whose Verdet constant is smaller than the Y I G crystal, is used. Therefore, a large magnet is used to increase the length of the Faraday rotation element or to strengthen the magnetic field. This also has the disadvantage that it is difficult to realize a compact optical isolator.

この発明の目的は、上記欠点を除去し、安価で小形な、
特に半導体レーザと多モード光ファイバを用いる光フア
イバ伝送システムに適した光アイソレータを提供すると
とＫある。The purpose of this invention is to eliminate the above-mentioned drawbacks, and to create an inexpensive and compact
Particularly, it is desired to provide an optical isolator suitable for an optical fiber transmission system using a semiconductor laser and a multimode optical fiber.

本発明の光アイソレータけ、光が入射する光伝送体また
はその光伝送体の先端に設はられた光学部材の少なくと
も一方の先端に、前記光伝送体のコア径より小さな直径
の細孔を有する反射膜を設けた構成となっている。The optical isolator of the present invention has a pore having a diameter smaller than the core diameter of the optical transmission body at at least one tip of the optical transmission body into which light enters or the optical member provided at the tip of the optical transmission body. It has a configuration with a reflective film.

以下本発明について、図面を用いて詳細に説明する。The present invention will be explained in detail below using the drawings.

第１図は、この発明の第１の実施例を示すだめの概略図
である。FIG. 1 is a schematic diagram showing a first embodiment of the invention.

光ファイバー００の先端は光ファイバの光軸にはソ垂直
に研磨されており、その端面には、反射防止膜３００が
付けられており、さらにその−ヒに直径約８μｍの細孔
２０１　　を有するアルミニウムの反射膜２００が蒸着
により設けられている。細ン 孔２０１は通常のフォト＋）／グラフィの技術によって
設けた。光ファイバーｏｏはコア径８０μｍ（図中破線
でコア部１０１を示しである）の集束形ファイバである
。以上の構成において、半導体レーザから出射した光は
、レンズにより約２μｍのスポットサイズに絞られ（図
には示していない）、反射膜２００に設けられた細孔２
０１　　を通って光ファイバ１００のコア部１０１を伝
搬する。絞られた光ビームが細孔を通過するときの損失
はほとんど無視できて、高効率の結合が得られる。The tip of the optical fiber 00 is polished perpendicular to the optical axis of the optical fiber, and an anti-reflection coating 300 is attached to the end face, and an aluminum film 300 having a pore 201 with a diameter of about 8 μm is attached to the end face. A reflective film 200 is provided by vapor deposition. The fine holes 201 were formed by conventional photo+)/graphic techniques. The optical fiber oo is a focusing fiber with a core diameter of 80 μm (the core portion 101 is indicated by a broken line in the figure). In the above configuration, the light emitted from the semiconductor laser is narrowed down to a spot size of approximately 2 μm by a lens (not shown in the figure), and is
01 and propagates through the core portion 101 of the optical fiber 100. The losses when the focused light beam passes through the pores are almost negligible, resulting in highly efficient coupling.

また、光ファイバ１００の端面に反射防止膜３００が設
けられているため、この端面がらの半導体レーザへの反
射光の帰還はほとんど無い。Further, since the antireflection film 300 is provided on the end face of the optical fiber 100, there is almost no return of reflected light from this end face to the semiconductor laser.

次に、光ファイバ１００を伝搬する光の後方散乱光や、
光ファイバ１ｏｏの出射端での反射光は、コア部１０１
全体に広がって伝搬してくるのでその１１とんどか反射
膜２００で嚢蔽される（ただし、細孔２０１を通るわず
かな光だけが半導体レーザに帰還する。）ため、反射光
は半導体レーザにほとんど影響を及ぼさず、雑音や波形
歪を発生させるということはほとんど無い。この光アイ
ソレータで挿入損失０．１　ｄｌｌ、フーイソレーショ
ン２０ｄｌｌが得られた。なお、細孔２０１の直径と光
ファイバのコア径の比は大きい程大きなアイソレーショ
ンがとれるが、細孔２０１の直径が半導体レーザの出射
光を絞ったビーム径より小さくなると、光ファイバ１０
０への結合効率が低下し、一部反射膜２００の部分に当
った光は半導体レーザに帰還されることになるのでアイ
ソレーションの低下をも引きおこす。しだがって、細孔
の直径には最適な値がある。この実施例では細孔の直径
を約８μｍとしだ。Next, the backscattered light of the light propagating through the optical fiber 100,
The reflected light at the output end of the optical fiber 1oo is reflected by the core portion 101.
Since it spreads over the whole area and propagates, most of it is covered by the reflective film 200 (however, only a small amount of light that passes through the pores 201 returns to the semiconductor laser), so the reflected light is transmitted to the semiconductor laser. It has almost no effect and almost never generates noise or waveform distortion. With this optical isolator, insertion loss of 0.1 dll and optical isolation of 20 dll were obtained. Note that the larger the ratio between the diameter of the pore 201 and the core diameter of the optical fiber, the greater the isolation can be achieved.
The coupling efficiency to 0 is reduced, and some of the light that has hit the reflective film 200 is returned to the semiconductor laser, resulting in a reduction in isolation. Therefore, there is an optimum value for the pore diameter. In this example, the diameter of the pores is approximately 8 μm.

第２図はこの発明による第２の実施例を示すだめの概略
図である。先の第１図に示した第１の実施例と異なる点
は、光ファイバ１００と第１図に示した反射防止膜３０
０との間に透明な光学部材４００が挿入されている点で
ある。FIG. 2 is a schematic diagram showing a second embodiment of the invention. The difference from the first embodiment shown in FIG. 1 is that the optical fiber 100 and the antireflection coating 30 shown in FIG.
0, a transparent optical member 400 is inserted between the two.

光学部材４００は厚さ２００μｍの両端面が研磨された
石英板で、片側に反射防止膜３００’、および細＋ｔｚ
ｏｉ’を有する反射膜２００′が設けられている。The optical member 400 is a quartz plate with a thickness of 200 μm and both end faces polished, with an antireflection film 300′ on one side and a thin +tz
A reflective film 200' having oi' is provided.

光学部材４００の光ファイバ１００に面する側は光学的
に透明な接着剤で光ファイバ１００の端面に固着されて
いる。The side of the optical member 400 facing the optical fiber 100 is fixed to the end surface of the optical fiber 100 with an optically transparent adhesive.

このような構造にすることによって、反射防止膜３００
’、および細孔２ｏ１′を有する反射膜２００’が、よ
り製作し易いという特徴を有している。By adopting such a structure, the antireflection film 300
', and the reflective film 200' having the pores 2o1' is characterized in that it is easier to manufacture.

光学部材４００として石英析を用いたが、他の光学ガラ
ス板等でも良く、また、光ファイバ１００と同じかより
小さなコア径をもつ光ファイバを用いても良い。Although quartz crystal is used as the optical member 400, other optical glass plates or the like may be used, or an optical fiber having the same or smaller core diameter than the optical fiber 100 may be used.

光学部材４００と光ファイバ１００は融着によって固着
しても良い。The optical member 400 and the optical fiber 100 may be fixed together by fusion.

第３図は、この発明による第３の実ＩＸａ例を示すだめ
の概略図である。先の第１１図に示した第１の実施例と
異なる点は、光フフイバｌＯＯの端面が光軸に対して斜
めに設けられている点および反射防止膜３００を設けて
いない点である。光ファイバ１００の端面は光軸シ（利
して約８°に斜λ）研磨されており、直接細孔２０１“
を有する反射膜２００“が設けられている。FIG. 3 is a schematic diagram showing a third practical IXa example according to the present invention. The difference from the first embodiment shown in FIG. 11 is that the end face of the optical fiber IOO is provided obliquely to the optical axis and that the antireflection film 300 is not provided. The end face of the optical fiber 100 is polished along the optical axis (with an angle λ of approximately 8°), and directly connects the pore 201".
A reflective film 200'' is provided.

このように光ファイバ１００の端部が斜め面になってい
るので、反射光はほとんど牛ｉ＋体し−づに戻ることが
無く、高いアイソレーションが得られるという特徴を有
している。Since the end of the optical fiber 100 has a slanted surface in this way, the reflected light hardly returns to the i+ body, resulting in high isolation.

したがって、また、第１の実施例て示した反射防止膜３
００は設ける必要がなくなるので工数が削減でき、より
安価な元アイソレータが得られるという特徴も有してい
る。Therefore, the antireflection film 3 shown in the first embodiment also
Since there is no need to provide 00, the number of man-hours can be reduced, and a cheaper original isolator can be obtained.

なお、第２の実施例に示したような、光ファイバと細孔
を有する反射膜との間に挿入された光学部利は、細孔を
有する反射膜との間に挿入された光！ギ一部１１は、細
孔をイーする反射膜が設けられた差、：　１ｔｒｉが斜
め面になっていても良い。Incidentally, the optical advantage inserted between the optical fiber and the reflective film having pores as shown in the second embodiment is the same as the light inserted between the optical fiber and the reflective film having pores! The gear part 11 may be provided with a reflective film that covers the pores, and may have an inclined surface.

第１．　ｕｓ　２および第３の実施例において示しだτ
１法がｒは別の値であっても良い。1st. As shown in us 2 and the third example, τ
In the first method, r may be a different value.

細孔２０１　、２０１’　、２０２”の位置は、光ファ
イバのコア′部分に対）ｂする位置であれば光軸からず
れて設けても良い。The positions of the pores 201, 201', and 202'' may be offset from the optical axis as long as they are located in relation to the core' portion of the optical fiber.

この場名も半導体レーザからの出射光は効率よくツー、
ファイバに結合し、半導体レーザに戻る反射光もほとん
ど無く高いアイソレーションが得らｉ］る。１だ、）反
射膜２００．２０９’　、２００“はアルミニ・シム以
外の金属蒸着膜、細孔を設けた金属板、誘電体多属膜等
を用いても良い。The name of this place is also that the light emitted from the semiconductor laser is efficiently
There is almost no reflected light that couples into the fiber and returns to the semiconductor laser, resulting in high isolation. 1) The reflective films 200, 209' and 200'' may be made of a metal vapor deposited film other than aluminum shims, a metal plate with pores, a dielectric multimetallic film, or the like.

＼ 畑らに、たとえ光フアイバ端部の軸ずれ等により、半導
体レーザからの出射光が、反射膜２００゜２００’　、
２００“の部分に当ったとしても、反射膜２００．２０
０”　、２００“の上に反射防止膜を設けることにより
、出射光が半導体レーザに帰還するのを防ぐことができ
る。＼ Hata et al. reported that even if the optical fiber end is misaligned, the emitted light from the semiconductor laser will be reflected by the reflective film 200°200',
Even if it hits the 200" part, the reflective film 200.20
By providing an antireflection film on the 0" and 200", it is possible to prevent the emitted light from returning to the semiconductor laser.

υト、この発明による光アイソレータについて実施例を
用いて詳細に説明したが、この発明による九アイソレー
タけ、光伝送体の先端に細孔を有する反射膜を設けただ
けの簡易なものであるので、極めて安価で、小形な九ア
イソレークがイ！）られるというｌ侍長をれ備しており
、！侍に半導体レーザと多モーＩ゛光ファイバを用いる
光ファイバ伝送シスデノ・に良く適打する。Although the optical isolator according to the present invention has been explained in detail using examples, the isolator according to the present invention is a simple one that only has a reflective film with pores at the tip of the optical transmitter. , Extremely cheap and small 9 isolake is great! ) is prepared for the Lord Chamberlain, who will be! It is well suited for optical fiber transmission systems using semiconductor lasers and multimode I optical fibers.

【図面の簡単な説明】[Brief explanation of drawings]

第１図、第２図、第３ＭＶ［この発明による第１、第２
および第３の実施例を示す概略図である。 図において、１００け光ファイバ、１０１はコア部、２
００．２００’　、２００“は反射膜、２０１．２０１
’　。 ２０１“は細孔、３００は反射防止膜である。 ６９Figures 1, 2, and 3 MV [first and second according to the present invention]
and a schematic diagram showing a third example. In the figure, there are 100 optical fibers, 101 is the core part, 2
00.200', 200" is a reflective film, 201.201
'. 201" is a pore, 300 is an antireflection film. 69

Claims (3)

【特許請求の範囲】[Claims] （１）光が入射する光伝送体またはその光伝送体の先端
に設けられた光学部材の少なくとも一方の先端に１前記
光伝送体のコア径より小さな直径の細孔を有する反射膜
を設けて成ることを特徴とする光アイソレータ。(1) A reflective film having a pore having a diameter smaller than the core diameter of the optical transmitter is provided on at least one tip of the optical member on which light enters or the optical member provided at the tip of the optical transmitter. An optical isolator characterized by: （２）光伝送体または光伝送体の先端に設けられた光学
部材の少なくとも一方の先端を光伝送体の光軸に対して
斜め面に形成した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) Claim 1, characterized in that at least one tip of the optical transmission body or an optical member provided at the tip of the optical transmission body is formed to be oblique with respect to the optical axis of the optical transmission body.
Optical isolator as described in section. （３）反射膜の細（Ｌを光伝送体の光軸に対してずらし
て設けた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。(3) The optical isolator according to claim 1, characterized in that the thin (L) of the reflective film is shifted from the optical axis of the optical transmission body.
JP57115218A 1982-07-02 1982-07-02 Optical isolator Pending JPS597312A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP57115218A JPS597312A (en) 1982-07-02 1982-07-02 Optical isolator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP57115218A JPS597312A (en) 1982-07-02 1982-07-02 Optical isolator

Publications (1)

Publication Number Publication Date
JPS597312A true JPS597312A (en) 1984-01-14

Family

ID=14657281

Family Applications (1)

Application Number Title Priority Date Filing Date
JP57115218A Pending JPS597312A (en) 1982-07-02 1982-07-02 Optical isolator

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63170807U (en) * 1987-04-28 1988-11-07
JPH01255803A (en) * 1988-04-06 1989-10-12 Nec Corp Optical fixed attenuator
EP0360177A2 (en) * 1988-09-20 1990-03-28 Alcatel SEL Aktiengesellschaft Optical transmitting and/or receiving element
US5096301A (en) * 1988-11-29 1992-03-17 British Telecommunications Public Limited Company Fiber alignment device; method of making and using
US8855457B2 (en) 2011-04-13 2014-10-07 Adc Telecommunications, Inc. Optical splitting component
WO2021088387A1 (en) * 2019-11-08 2021-05-14 华为技术有限公司 Ferrule, optical connectors, optical communication element, communication device and preparation method
US11536911B2 (en) 2019-11-08 2022-12-27 Huawei Technologies Co., Ltd. Ferrule, optical connector, optical communication element, communications device, and preparation method

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63170807U (en) * 1987-04-28 1988-11-07
JP2551998Y2 (en) * 1987-04-28 1997-10-27 セイコー電子工業株式会社 Light reflective plug
JPH01255803A (en) * 1988-04-06 1989-10-12 Nec Corp Optical fixed attenuator
EP0360177A2 (en) * 1988-09-20 1990-03-28 Alcatel SEL Aktiengesellschaft Optical transmitting and/or receiving element
US5096301A (en) * 1988-11-29 1992-03-17 British Telecommunications Public Limited Company Fiber alignment device; method of making and using
US8855457B2 (en) 2011-04-13 2014-10-07 Adc Telecommunications, Inc. Optical splitting component
WO2021088387A1 (en) * 2019-11-08 2021-05-14 华为技术有限公司 Ferrule, optical connectors, optical communication element, communication device and preparation method
US11536911B2 (en) 2019-11-08 2022-12-27 Huawei Technologies Co., Ltd. Ferrule, optical connector, optical communication element, communications device, and preparation method
US12038612B2 (en) 2019-11-08 2024-07-16 Huawei Technologies Co., Ltd. Ferrule, optical connector, optical communication element, communications device, and preparation method

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