JP3368863B2 - Optical coupler and optical router - Google Patents
Optical coupler and optical routerInfo
- Publication number
- JP3368863B2 JP3368863B2 JP05465799A JP5465799A JP3368863B2 JP 3368863 B2 JP3368863 B2 JP 3368863B2 JP 05465799 A JP05465799 A JP 05465799A JP 5465799 A JP5465799 A JP 5465799A JP 3368863 B2 JP3368863 B2 JP 3368863B2
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- JP
- Japan
- Prior art keywords
- optical
- light
- router
- optical coupler
- light intensity
- 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.)
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- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
- Use Of Switch Circuits For Exchanges And Methods Of Control Of Multiplex Exchanges (AREA)
- Optical Communication System (AREA)
- Optical Integrated Circuits (AREA)
Description
【０００１】[0001]
【発明が属する技術分野】本発明は、光結合器及び光ル
ータに関し、特に、送信信号の光強度を変えることで、
光結合器の屈折率を変化させ、岐路変更を行う光結合器
及び光ルータに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupler and an optical router, and more particularly, by changing the light intensity of a transmission signal,
Optical coupler that changes the crossing path by changing the refractive index of the optical coupler
And optical router.
【０００２】[0002]
【従来の技術】近年、コンピュータ技術は急速に高速化
してきており、一部には光を取り入れてさらに高速化を
図る動きもある。光はすでに通信の領域では、１０Ｇｂ
ｐｓを越える伝送容量を得ており、その高速性、伝送距
離の点から大いにメリットを発揮する。その一方で光を
用いるためには、いったん電気信号を光信号へ変換ある
いは、光信号を電気信号へ変換しなければならず、レイ
テンシの面およびハードウェア増加の面からデメリット
もあわせもっていた。そこで、スイッチなど高速な機能
を要求される部品については、光電変換を行わずに、光
のまま信号を取り扱い、スイッチング、ルーティングな
どを行うことが将来的には必須となる状況である。2. Description of the Related Art In recent years, computer technology has been rapidly increasing in speed, and there is a movement to further increase the speed in part by incorporating light. Light is already 10Gb in the area of communication
It has a transmission capacity exceeding ps, and shows great advantages in terms of its high speed and transmission distance. On the other hand, in order to use light, it is necessary to once convert an electric signal into an optical signal or convert an optical signal into an electric signal, which has disadvantages in terms of latency and increase in hardware. Therefore, in the future, it will be essential to handle signals as they are and perform switching, routing, etc. without performing photoelectric conversion on components such as switches that require high-speed functions.
【０００３】図５は、波長ルータの一例の概念図であ
り、アレイ回折格子の導波路で構成され、入力した波長
多重信号を波長ごとに分波したり、その逆の機能を担う
ことができる。つまり、波長多重伝送（ＷＤＭ）におい
て、伝送信号に波長情報を重畳させておけばこのルータ
を透過させることで、そのままルーティングできること
になる。この技術に関しては、多くの文献が出されてお
り、ＩＥＥＥ Ｐｈｏｔｏｎｉｃｓ Ｌｅｔｔｅｒｓ
Ｖｏｌ．３ ｐｐ．８９６−８９９（１９９１）のＣ．
Ｄｒａｇｏｎｅらによる論文、Ｅｌｅｃｔｒｏｎｉｃｓ
ＬｅｔｔｅｒｓＶｏｌ．３１ ｐｐ．５８１−５８２
（１９９５）のＭ．Ｚｉｒｎｇｉｂｌらによる論文等が
ある。FIG. 5 is a conceptual diagram of an example of a wavelength router, which is composed of a waveguide of an array diffraction grating, and can demultiplex an input wavelength-multiplexed signal for each wavelength or have the opposite function. . In other words, in wavelength division multiplex transmission (WDM), if wavelength information is superimposed on a transmission signal, it can be routed as it is by passing through this router. There are many publications on this technology, including IEEE Photonics Letters.
Vol. 3 pp. 896-899 (1991).
The paper by Dragone et al., Electronics
Letters Vol. 31 pp. 581-582
(1995). There is a paper by Zirngibl et al.
【０００４】又、図６に示すように、特開平４−１２０
９９８号公報（「時分割・波長分割融合スイッチ」）
は、波長可変光メモリの必要個数を低減することができ
る時分割・波長分割融合スイッチが開示されている。具
体的には、時分割多重度ｎ＝８、波長多重度（ハイウエ
イ数）ｍ＝４の時分割・波長分割融合スイッチにおい
て、波長可変光メモリ１７の個数が、ｎ×ｍ2個ですむ
ように分波器１４、１×ｍ光スイッチ１５、ｍ×ｎ光ス
イッチ１６、ｎ×１光スイッチ１８、結合器１９が配置
されている。Further, as shown in FIG.
Publication No. 998 (“Time Division / Wavelength Division Fusion Switch”)
Discloses a time division / wavelength division fusion switch capable of reducing the required number of wavelength tunable optical memories. Specifically, in a time division / wavelength division fusion switch with time division multiplicity n = 8 and wavelength multiplicity (highway number) m = 4, the number of wavelength tunable optical memories 17 is demultiplexed to be n × m 2. An optical switch 14, a 1 × m optical switch 15, an m × n optical switch 16, an n × 1 optical switch 18, and a coupler 19 are arranged.
【０００５】[0005]
【発明が解決しようとする課題】しかし、図５に示した
波長ルータにおいては、ＷＤＭにおける光信号の波長間
隔は０．８ｎｍ程度と小さく、ルータの温度など様々な
ファクタを制御していかないと回折条件がずれてきて、
ルーティングがうまくいかなくなってしまうという欠点
があった。また、光源としてさまざまな波長の光源を用
意する必要があり、ハードウェア量の増加につながって
いた。However, in the wavelength router shown in FIG. 5, the wavelength interval of the optical signal in WDM is as small as about 0.8 nm, and the diffraction is caused unless various factors such as the temperature of the router are controlled. Conditions are shifting,
The drawback was that the routing wouldn't work. In addition, it was necessary to prepare light sources of various wavelengths as a light source, which led to an increase in the amount of hardware.
【０００６】又、図６に示した時分割・波長分割融合ス
イッチに置いても、波長多重技術を使う関係上、上記の
ハードウェア量の問題は同じであった。また、波長可変
の光メモリが必要であり、この技術自体がかなり困難な
ものであった。Even when the time division / wavelength division fusion switch shown in FIG. 6 is used, the above-mentioned problem of the amount of hardware is the same because of the use of the wavelength division multiplexing technique. In addition, a wavelength tunable optical memory is required, and this technique itself is quite difficult.
【０００７】そこで、本発明は、光結合器を用いた簡易
な構成で、送信されてくるデータの光強度に応じて、デ
ータの経路変更（ルーティング）を行うことを課題とし
ている。Therefore, an object of the present invention is to change the data route according to the light intensity of transmitted data with a simple structure using an optical coupler.
【０００８】[0008]
【課題を解決するための手段】上記の課題を解決するた
めの本発明の光結合器は、Ｎを２以上の整数として、Ｎ
個の分岐経路上にそれぞれ互いに異なる周期を有する回
折格子を設け、該回折格子は光強度依存の屈折率変化を
誘起し、入力光強度に対応した特定の回折格子のみが入
力光と結合し、これを透過することによって該特定の回
折格子が設けられた分岐経路へ入力光を結合する。ま
た、本発明の光ルータは、前記光結合器を、Ｍを２以上
の整数としてＭ個備え、Ｍ個の入力チャンネルをＮ個の
出力チャンネルにルーティングしている。Optical coupler of the present invention to solve the above problems BRIEF SUMMARY OF THE INVENTION may, where N is an integer of 2 or more, N
Times with different periods on each branch path
A diffraction grating is provided, and the diffraction grating changes the refractive index depending on the light intensity.
Induced, and only a specific diffraction grating corresponding to the input light intensity enters.
By combining with the light and transmitting it,
The input light is coupled to the branch path provided with the folding grating. Further, in the optical router of the present invention , M is 2 or more in the optical coupler.
M integer channels are provided, and M input channels are routed to N output channels.
【０００９】すなわち、本発明においては、送信信号の
光強度を変えることで、光結合器の屈折率を変化させ、
岐路変更を行う。That is, in the present invention, the refractive index of the optical coupler is changed by changing the light intensity of the transmission signal,
Change the crossroads.
【００１０】[0010]
【発明の実施の形態】以下、図面を参照して本発明の実
施の形態について説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.
【００１１】図１は、本発明の光ルータの基本的要素で
ある光結合器１１の機能を説明するための図である。入
力伝送路を１２として、基本動作について説明を行う。
経路変更を行わない場合は、そのデータ（送信信号）の
光強度をある閾値レベルより小さいＩ０という値に設定
する。また、経路変更を行う場合は、送信信号の光強度
をある閾値レベルより大きいＩ１という値に設定する。
光結合器の結合部の光強度依存の屈折率変化により、経
路の結合が生じて、光信号は出力伝送路１３へ行くか、
１４へ行くかが決定される。上記の光強度がＩ０の送信
信号の場合、屈折率が所望の変化を生じないため、経路
はそのままで１３へ出力される。また、光強度がＩ１の
光強度の場合、屈折率の変化量が大きくなり、伝送路間
の結合が起きて、光信号は出力経路１４へと出力され
る。FIG. 1 is a diagram for explaining the function of an optical coupler 11 which is a basic element of the optical router of the present invention. The basic operation will be described assuming that the input transmission path is 12.
When the route is not changed, the light intensity of the data (transmission signal) is set to a value I0 smaller than a certain threshold level. Further, when the route is changed, the light intensity of the transmission signal is set to a value of I1 which is higher than a certain threshold level.
Whether the optical signal goes to the output transmission line 13 due to the coupling of the paths due to the change in the refractive index depending on the light intensity of the coupling part of the optical coupler.
It is decided whether to go to 14. In the case of the transmission signal with the light intensity of I0, the refractive index does not change as desired, so that the route is output to 13 as it is. When the light intensity is I1, the amount of change in the refractive index becomes large, coupling occurs between the transmission paths, and the optical signal is output to the output path 14.
【００１２】図２は、光結合器１１の内部構成を示す図
である。光結合器１１の結合部には伝送に用いられる光
波長に位相が同調するように回折格子が設けられてお
り、送信信号の光強度レベルがＩ０の場合には屈折率は
経路１３に最適であり、経路１４へ向いた部分の屈折率
は送信の光波長に対して位相がずれており、光が減衰す
るように設定されている。送信信号の光強度をＩ１とす
ることで、結合部の屈折率が変化し、経路１３への屈折
率の位相が光波長に対してずれるために、経路１３へ向
かう光が減衰し、今度は経路１４へ向かう経路で位相が
最適化されるため、光は経路１４へ向かうことになる。FIG. 2 is a diagram showing the internal structure of the optical coupler 11. The coupling part of the optical coupler 11 is provided with a diffraction grating so that the phase is tuned to the wavelength of light used for transmission, and when the light intensity level of the transmission signal is I0, the refractive index is optimum for the path 13. The refractive index of the portion directed to the path 14 is out of phase with the wavelength of the transmitted light and is set so that the light is attenuated. By setting the light intensity of the transmission signal to I1, the refractive index of the coupling portion changes and the phase of the refractive index to the path 13 deviates from the optical wavelength, so the light going to the path 13 is attenuated, and this time. Since the phase is optimized on the path toward the path 14, the light is directed toward the path 14.
【００１３】図２に示すように、回折格子２１と２２は
各々異なった光強度に対する特性を示す。これは光強度
に応じて屈折率変化が異なるためである。その様子を図
２の光強度と透過光量のグラフにまとめてある。As shown in FIG. 2, the diffraction gratings 21 and 22 have different characteristics for different light intensities. This is because the refractive index changes depending on the light intensity. The situation is summarized in the graph of light intensity and transmitted light amount in FIG.
【００１４】回折格子は原理上、ある程度の幅をもつ
が、この幅に応じて光結合器の入力が複数となった場合
は必要な光強度の幅が決まってくる。In principle, the diffraction grating has a certain width, but the width of the required light intensity is determined depending on this width when there are multiple inputs to the optical coupler.
【００１５】ここで、閾値以上の光信号で一度光結合器
の結合部の屈折率が変化すれば次のデータで”０”が続
いても変化は維持される。しばしば用いられる８Ｂ１０
Ｂ変換による符号訂正では、０は最大でも５ビットしか
連続しないので、本発明の適用には問題ない。より注意
するなら、ヘッダの部分に連続した”１”のビットを入
れるようにすればよい。あるいは、閾値以上の場合に
は、”０”の場合でも閾値を超えるように設定しておけ
ばよい。ただし、この場合、伝送信号の消光比が落ちる
というデメリットは生じる。Here, if the refractive index of the coupling part of the optical coupler changes once with an optical signal above the threshold value, the change is maintained even if "0" continues in the next data. 8B10 often used
In code correction by B conversion, 0 is continuous for only 5 bits at the maximum, so there is no problem in applying the present invention. To be more careful, it is sufficient to put consecutive "1" bits in the header part. Alternatively, if it is equal to or more than the threshold value, the threshold value may be set to exceed the threshold value even if it is “0”. However, in this case, there is a demerit that the extinction ratio of the transmission signal decreases.
【００１６】ここでは、１入力２出力の場合についての
説明を行ったが、さらにシステムを拡張したい場合に
は、本実施例で用いたルータの出力分岐数を増やせばよ
い。Although the case of one input and two outputs has been described here, if it is desired to further expand the system, the number of output branches of the router used in this embodiment may be increased.
【００１７】図３は、Ｎを２以上の整数としてＮ分岐の
光結合器１Ｎの機能を説明するための図である。各々の
経路３１〜３Ｎで回折格子の周期を異ならせ、屈折率変
化を生じたときの位相がＮ通りの光強度に対して最適と
なるようにする。FIG. 3 is a diagram for explaining the function of the N-branch optical coupler 1N , where N is an integer of 2 or more . The periods of the diffraction gratings are made different in each of the paths 31 to 3N so that the phase when the refractive index is changed is optimum for N kinds of light intensities.
【００１８】たとえば光強度Ｉ１の信号に対しては、経
路３１の位相が合うように屈折率変化が最適となるよう
に設定し、光強度ＩＮの信号に対しては、経路３Ｎが最
適となるようにすればよい。For example, for the signal of the light intensity I1, the change in the refractive index is set to be optimum so that the phase of the path 31 is in phase, and for the signal of the light intensity IN, the path 3N is optimum. You can do it like this.
【００１９】ただし、Ｎ分岐を行うと、理想的には一本
の経路が選択されてすべての光信号がそちらへ進むので
あるが、完全には透過されないため分岐分だけ損失を生
じることになる。本来進むべき経路以外に進んだ光は回
折格子で完全に散乱されるため、雑音となる可能性は低
い。また、回折格子以降の伝送路では、挿入損失を生じ
る可能性が高いため、この部分を導波路技術を用いて、
低損失に抑えることが重要である。However, if N branches are performed, ideally one path is selected and all the optical signals proceed to that path, but since it is not completely transmitted, a loss corresponding to the branch is generated. . Light that has traveled to a path other than the original path is completely scattered by the diffraction grating, and is unlikely to become noise. In addition, since there is a high possibility that insertion loss will occur in the transmission line after the diffraction grating, this portion is
It is important to keep the loss low.
【００２０】図４は、Ｎ分岐光ルータ１Ｎを、Ｍを２以
上の整数としてＭ個用いる本発明の光ルータのブロック
図である。このルータによって、Ｍ個の入力をルーティ
ングしてＮ個の出力を得る。FIG. 4 shows an N-branch optical router 1N with M of 2 or more.
It is a block diagram of the optical router of this invention which uses M pieces as an above integer . This router routes M inputs to get N outputs.
【００２１】以上、本発明の一つの実施形態について説
明したが、本発明は光結合器を構成要素とする光ルータ
に限らず、光強度に応じて位相の変化するデバイスを構
成要素としてもよい。Although one embodiment of the present invention has been described above, the present invention is not limited to an optical router having an optical coupler as a constituent element, and a device whose phase changes according to the light intensity may be a constituent element. .
【００２２】[0022]
【発明の効果】以上説明した本発明によれば、光信号の
光強度のみに依存して経路変更が可能であり、光のみの
制御のシステムを構築することが可能となる。光制御の
みのシステムでは、光を電気、電気を光に変換する遅延
を取り除くことができるので、レーテンシー低減が達成
できる。また、光電変換部分のハードウェア量が削減で
きるため、コスト的にも有利となる。同時に、光源の光
強度を変えるだけで制御できることから、波長多重技術
のように送信部のハードウェア量の増加も防げることに
なる。According to the present invention described above, it is possible to change the route depending only on the light intensity of the optical signal, and it is possible to construct a system for controlling only light. In an optical control only system, the delay in converting light into electricity and converting electricity into light can be eliminated, so that latency reduction can be achieved. Further, the amount of hardware of the photoelectric conversion portion can be reduced, which is advantageous in terms of cost. At the same time, since the control can be performed only by changing the light intensity of the light source, it is possible to prevent an increase in the amount of hardware of the transmitter as in the wavelength multiplexing technique.
【図１】本発明の光ルータに使用する光結合器の機能を
説明するための図FIG. 1 is a diagram for explaining the function of an optical coupler used in an optical router of the present invention.
【図２】光結合器の内部構成を説明するための図FIG. 2 is a diagram for explaining an internal configuration of an optical coupler.
【図３】N分岐光結合器の機能を説明するための図FIG. 3 is a diagram for explaining the function of an N-branch optical coupler.
【図４】本発明の光ルータのブロック図FIG. 4 is a block diagram of an optical router of the present invention.
【図５】従来の波長ルータの光路図FIG. 5: Optical path diagram of conventional wavelength router
【図６】従来の時分割・波長分割融合スイッチFIG. 6 Conventional time division / wavelength division fusion switch
１１、１Ｎ、４１、４Ｍ 光結合器
１２、 入力
１３、１４、３１、３２、３３、３Ｎ、４１１、４１
２、４１Ｎ 出力
２１、２２、３０１、３０２、３０３、３０Ｎ 回折格
子11, 1N, 41, 4M Optical coupler 12, Input 13, 14, 31, 32, 33, 3N, 411, 41
2, 41N output 21, 22, 301, 302, 303, 30N diffraction grating
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平10−177115（ＪＰ，Ａ) 特開 平９−74577（ＪＰ，Ａ) 特開 平11−32354（ＪＰ，Ａ) 特開 平３−293303（ＪＰ，Ａ) 特開 平10−115701（ＪＰ，Ａ) Ｍ．Ｃａｄａ ｅｔ ａｌ．，Ａｐｐ ｌｉｅｄ Ｐｈｙｓｉｃｓ Ｌｅｔｔｅ ｒｓ，Ｖｏｌ．59，Ｎｏ．19，ｐｐ. 2366−2368（1991) 蒲国勝 他，1994年電子情報通信学会 秋季大会講演論文集 第４分冊（エレク トロニクスＩ），280頁 (58)調査した分野(Int.Cl.7，ＤＢ名) G02F 1/00 - 7/00 G02B 6/00 - 6/34 ＩＮＳＰＥＣ（ＤＩＡＬＯＧ) ＪＩＣＳＴファイル（ＪＯＩＳ) ＷＰＩ（ＤＩＡＬＯＧ)─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-177115 (JP, A) JP-A-9-74577 (JP, A) JP-A-11-32354 (JP, A) JP-A-3- 293303 (JP, A) JP-A-10-115701 (JP, A) M.K. Cada et al. , Applied Physics Letters, Vol. 59, No. 19, pp. 2366-2368 (1991) Kamakuni, et al., Proceedings of the 1994 Autumn Meeting of the Institute of Electronics, Information and Communication Engineers, 4th volume (Electronics I), 280 (58) Fields investigated (Int.Cl. 7 , DB name) ) G02F 1/00-7/00 G02B 6/00-6/34 INSPEC (DIALOG) JISST file (JOIS) WPI (DIALOG)
Claims (2)
路上にそれぞれ互いに異なる周期を有する回折格子を設
け、該回折格子は光強度依存の屈折率変化を誘起し、入
力光強度に対応した特定の回折格子のみが入力光と結合
し、これを透過することによって該特定の回折格子が設
けられた分岐経路へ入力光を結合する光結合器。1. N branching diameters, where N is an integer of 2 or more.
Diffraction gratings with different periods are installed on the road.
However, the diffraction grating induces a change in the refractive index depending on the light intensity, and
Only a specific diffraction grating corresponding to the intensity of light is coupled with the input light
Then, the specific diffraction grating is set by transmitting this.
An optical coupler that couples input light to the stripped branch path .
上の整数としてＭ個備え、Ｍ個の入力チャンネルをＮ個
の出力チャンネルにルーティングする光ルータ。2. The optical coupler according to claim 1 , wherein M is 2 or more.
An optical router that has M integers as the upper integer and routes M input channels to N output channels.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05465799A JP3368863B2 (en) | 1999-03-02 | 1999-03-02 | Optical coupler and optical router |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05465799A JP3368863B2 (en) | 1999-03-02 | 1999-03-02 | Optical coupler and optical router |
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| Publication Number | Publication Date |
|---|---|
| JP2000249858A JP2000249858A (en) | 2000-09-14 |
| JP3368863B2 true JP3368863B2 (en) | 2003-01-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05465799A Expired - Fee Related JP3368863B2 (en) | 1999-03-02 | 1999-03-02 | Optical coupler and optical router |
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| Country | Link |
|---|---|
| JP (1) | JP3368863B2 (en) |
-
1999
- 1999-03-02 JP JP05465799A patent/JP3368863B2/en not_active Expired - Fee Related
Non-Patent Citations (2)
| Title |
|---|
| Ｍ．Ｃａｄａ ｅｔ ａｌ．，Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃｓ Ｌｅｔｔｅｒｓ，Ｖｏｌ．５９，Ｎｏ．１９，ｐｐ．２３６６−２３６８（１９９１） |
| 蒲国勝 他，１９９４年電子情報通信学会秋季大会講演論文集 第４分冊（エレクトロニクスＩ），２８０頁 |
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| Publication number | Publication date |
|---|---|
| JP2000249858A (en) | 2000-09-14 |
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