JPH0777367B2 - Two-way optical communication network - Google Patents
Two-way optical communication networkInfo
- Publication number
- JPH0777367B2 JPH0777367B2 JP62201914A JP20191487A JPH0777367B2 JP H0777367 B2 JPH0777367 B2 JP H0777367B2 JP 62201914 A JP62201914 A JP 62201914A JP 20191487 A JP20191487 A JP 20191487A JP H0777367 B2 JPH0777367 B2 JP H0777367B2
- Authority
- JP
- Japan
- Prior art keywords
- optical
- subscribers
- distribution network
- network
- tree
- 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
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
-
- 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
- G02B6/4215—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Communication System (AREA)
Description
【発明の詳細な説明】 〔概 要〕 ツリー形光分配網を備えた光通信網であって、光分配を
受ける複数の加入者同士で双方向通信が行える双方向光
通信網に関し、 ハードウェア規模が小さくて済み、また拡張の楽なツリ
ー形光分配網を用いて構成できる双方向光通信網を提供
することを目的とし、 複数の２×２光カプラを多段に従属接続してなるツリー
形光分配網からなり、双方向通信すべき複数の加入者を
少なくともカバーする１つの２×２光カプラが全反射膜
付きの終端ポートを備えるように構成する。DETAILED DESCRIPTION OF THE INVENTION [Outline] A bidirectional optical communication network including a tree type optical distribution network, in which a plurality of subscribers receiving optical distribution can perform bidirectional communication, A tree consisting of a plurality of 2 × 2 optical couplers cascade-connected in order to provide a bidirectional optical communication network that can be constructed using a tree-type optical distribution network that is small in scale and easy to expand. One 2 × 2 optical coupler, which is composed of an optical distribution network and covers at least a plurality of subscribers to be bidirectionally communicated, is provided with a termination port with a total reflection film.
本発明はツリー形光分配網を備えた光通信網であって、
光分配を受ける複数の加入者同士で双方向通信が行える
双方向光通信網に関する。The present invention is an optical communication network including a tree type optical distribution network,
The present invention relates to a bidirectional optical communication network capable of bidirectional communication among a plurality of subscribers receiving optical distribution.
地域内情報サービスとしてCATV等のネットワークが普及
している。従来はCATV網等のネットワークを構成するた
めに電気信号を伝送する同軸ケーブルが用いられてい
る。しかし近年の情報の多様化，豊富化に対処すべく、
光ファイバを用いた光信号によるネットワーク（以下、
CATV網）が普及し始めている。この光CATV網はツリー形
光分配網によって構成されるのが普通である。ところ
が、さらに諸サービスの要請が高まり、例えば加入者同
士でのパソコン通信も実現しなければならない状況とな
っている。これは双方向光通信網の実現を意味するが、
従来からのツリー形光分配網をそのまま用いたのでは、
双方向性は実現不可能である。本発明は、双方向性をツ
リー形光分配網で実現した光通信網について言及する。Networks such as CATV are widely used as information services in the area. Conventionally, coaxial cables that transmit electric signals have been used to configure networks such as CATV networks. However, in order to cope with the recent diversification and enrichment of information,
Network by optical signal using optical fiber (hereinafter,
CATV network) is beginning to spread. This optical CATV network is usually composed of a tree type optical distribution network. However, the demand for various services has further increased, and for example, personal computer communication between subscribers must be realized. This means the realization of a two-way optical communication network,
If the conventional tree-type optical distribution network is used as it is,
Bidirectionality is not feasible. The present invention refers to an optical communication network in which bidirectionality is realized by a tree type optical distribution network.
第３図は本発明が適用される双方向光通信網の一般的な
概要を示す図である。本図において双方向光通信網10
は、複数の加入者11−1,11−２…11−Ｎと、往復の光フ
ァイバ12−1,12−２…12−Ｎを介しこれらに接続する光
分配網13と、光CATV網であれば光分配網12に情報を送出
するセンター14がある。FIG. 3 is a diagram showing a general outline of a bidirectional optical communication network to which the present invention is applied. In this figure, the bidirectional optical communication network 10
Is a plurality of subscribers 11-1, 11-2 ... 11-N, an optical distribution network 13 connected to them via reciprocating optical fibers 12-1, 12-2 ... 12-N, and an optical CATV network. There is a center 14 for sending information to the optical distribution network 12, if any.
第４図は光分配網として一般的なツリー形光分配網を示
す図であり、例えばCATV網のセンター14から、ツリー形
光分配網21を介して、各加入者11−1,11−２…11−Ｎに
情報が送信される。このツリー形光分配網21は１入力×
Ｎ出力のスターカプラからなり、効率良く多数の加入者
に情報を分配できる。しかしながら、この分配は一方向
であり、本発明で意図している双方向性を満足すること
ができない。FIG. 4 is a diagram showing a general tree type optical distribution network as an optical distribution network. For example, from the center 14 of the CATV network, through the tree type optical distribution network 21, each of the subscribers 11-1, 11-2. The information is transmitted to 11-N. This tree type optical distribution network 21 has 1 input ×
It consists of an N output star coupler and can efficiently distribute information to a large number of subscribers. However, this distribution is unidirectional, and the bidirectionality intended in the present invention cannot be satisfied.
上記のようにツリー形光分配網では一方向の通信（セン
ター→加入者）しか行えず、双方向の通信には、そのま
まの形では適用できない。As described above, the tree-type optical distribution network can perform only one-way communication (center → subscriber), and cannot be applied as it is to two-way communication.
第５図は双方向光通信網の従来の構成例を示す図であ
り、双方向光分配網31は（Ｎ＋１）×（Ｎ＋１）光カプ
ラからなる。すなわちカプラ31は（Ｎ＋１）の入力と
（Ｎ＋１）の出力を持つ。ただし、入力の１つ（ポー
ト）はセンター14からのものであり、出力の１つ（ポー
ト）は光学的に終端される。ここに、波長多重（WDM）
または光周波数多重（FDM）による双方向光通信を考え
ると、第１の入力に波長λ１、第2,第3,…第Ｎ＋１の入
力にそれぞれ波長λ2,λ３…λN+1を割り当てるものと
すれば、いずれかの加入者にもλ１からλN+1までの全
ての光信号情報が印加される。したがってその中から所
望の１つのフイルタで取り出せば、加入者間で双方向の
光通信が可能となる。FIG. 5 is a diagram showing a conventional configuration example of a bidirectional optical communication network. The bidirectional optical distribution network 31 is composed of (N + 1) × (N + 1) optical couplers. That is, the coupler 31 has (N + 1) inputs and (N + 1) outputs. However, one of the inputs (port) is from the center 14 and one of the outputs (port) is optically terminated. Here, wavelength division multiplexing (WDM)
Or considering the two-way optical communication by optical frequency division multiplexed (FDM), the wavelength lambda 1 to the first input, second, third, ... each wavelength lambda 2 to the N + 1 inputs, the lambda 3 ... lambda N + 1 If allotted, all optical signal information from λ 1 to λ N + 1 is applied to any of the subscribers. Therefore, if the desired one filter is taken out from among them, the two-way optical communication between the subscribers becomes possible.
ところで（Ｎ＋１）×（Ｎ＋１）光カプラ31についてみ
ると、これはかなり大形且つ複雑な構成となる。第6A〜
6C図は光カプラの構成例を示す図であり、２×２光カプ
ラ、４×４光カプラおよび８×８光カプラの場合をそれ
ぞれ示す。いずれの光カプラも２×２光カプラが最小単
位となる。なお、２×２光カプラにおいて点線で示すと
おり、各々の内部は光導波路（光ファイバ）が各入力よ
り２分岐し、各出力で合流している。内側の光導波路は
クロスしており、その交点は相互に融着せしめられてい
る。By the way, regarding the (N + 1) × (N + 1) optical coupler 31, this has a considerably large and complicated configuration. No. 6A ~
FIG. 6C is a diagram showing a configuration example of an optical coupler, and shows a case of a 2 × 2 optical coupler, a 4 × 4 optical coupler, and an 8 × 8 optical coupler, respectively. The minimum unit of any optical coupler is a 2 × 2 optical coupler. In the 2 × 2 optical coupler, as shown by the dotted line, inside each of them, an optical waveguide (optical fiber) is branched into two from each input and merges at each output. The inner optical waveguides are crossed, and their intersections are fused to each other.
２×2,4×4,8×８等の光カプラを用いると、双方向通信
を実現できる。しかし光CATV網では膨大な数の加入者が
存在し、例えば512の加入者があれば513×512光カプラ
を構成しなければならないという問題がある。また、加
入者が月日を追って増加する場合、その需要増に柔軟に
対処することが容易でない、という問題もある。Bidirectional communication can be realized by using optical couplers such as 2 × 2, 4 × 4, 8 × 8. However, an optical CATV network has a huge number of subscribers, and if there are 512 subscribers, for example, there is a problem that a 513 × 512 optical coupler must be configured. In addition, when the number of subscribers increases with the passage of time, it is not easy to flexibly deal with the increase in demand.
本発明はハードウェア規模が小さくて済み、また拡張の
楽なツリー形光分配網を用いて構成できる双方向光通信
網を提供することを目的とする。It is an object of the present invention to provide a bidirectional optical communication network that can be configured using a tree-type optical distribution network that requires a small hardware scale and is easy to expand.
第１図は本発明の原理を説明するための図であり、ツリ
ー形光分配網の中の１つの２×２光カプラである。この
２×２光カプラ41は、双方向通信すべき複数の加入者を
少なくともカバーするものであって、４つのポートのう
ちの１つである終端ポート（第１ポート）には、全反
射膜42が付着せしめられる。第３ポートおよび第４ポ
ートは、複数の加入者のうち一群および他の群に接続
し、双方向通信すべき加入者はこれらの群の中に含まれ
る。FIG. 1 is a diagram for explaining the principle of the present invention, which is one 2 × 2 optical coupler in a tree type optical distribution network. This 2 × 2 optical coupler 41 covers at least a plurality of subscribers to be bidirectionally communicated, and a total reflection film is provided at a termination port (first port) which is one of four ports. 42 is attached. The third port and the fourth port connect to one group and another group of the plurality of subscribers, and the subscribers to be bidirectionally communicated with are included in these groups.
光CATV網であれば、第２ポートはセンター14と結ばれ
る。なお、全反射膜42としては例えば誘電体膜とかAu膜
が用いられる。この膜は、第１ポートより伸びる光フ
ァイバを直角に切断して研磨したファイバ端面に付着さ
れる。全反射膜としたのは、加入者からの光信号を無駄
なく混合するためである。If it is an optical CATV network, the second port is connected to the center 14. As the total reflection film 42, for example, a dielectric film or an Au film is used. This film is attached to the end face of the fiber which is cut by cutting the optical fiber extending from the first port at a right angle. The reason why the total reflection film is used is to mix the optical signals from the subscribers without waste.
仮に波長多重により各加入者毎の光信号（例えば波長λ
1,λ2,λ３…λ16とする）を多重化するものとすれば、
一群の加入者からの上り方向の光信号λ１〜λ８は第３
ポートに入力され、他の群の加入者からの上り方向の
光信号λ９〜λ16は第４ポートに入力される。If wavelength-multiplexing is performed, an optical signal for each subscriber (for example, wavelength λ
1 , λ 2 , λ 3 ... λ 16 ) are multiplexed,
The upstream optical signals λ 1 to λ 8 from the group of subscribers are transmitted to the third
The upstream optical signals λ 9 to λ 16 from the other groups of subscribers are input to the fourth port.
これらの光信号（λ１〜λ８とλ９〜λ16）は終端ポー
トの全反射膜42にて混合されλ１〜λ16として折り返さ
れ、下り方向の光信号として一群の加入者および他の群
の加入者に至る。なお、λ１〜λ16なる光信号は第２ポ
ートでも得られ、上り方向の光信号となるが、必要が
なければ光アイソレータでカットすれば良い。These optical signals (λ 1 to λ 8 and λ 9 to λ 16 ) are mixed by the total reflection film 42 of the termination port and are returned as λ 1 to λ 16, and as a downstream optical signal, a group of subscribers and others. To a group of subscribers. The optical signals of λ 1 to λ 16 are obtained at the second port and become upstream optical signals, but if not necessary, they may be cut by an optical isolator.
CATV網であれば第２ポートの先にはセンター（14）があ
り、このセンターからの下り方向の光信号（センター信
号）もまた第３および第４ポート，より加入者側に
至る。In the CATV network, there is a center (14) ahead of the second port, and a downstream optical signal (center signal) from this center also reaches the subscriber side from the third and fourth ports.
結局、全ての加入者がλ１〜λ16の光信号を受信できる
ことになったので、そのうち所望の１つをフィルタで抽
出すれば双方向通信が可能となる。センター信号も勿論
受信可能である。このような２×２光カプラ41は、ツリ
ー形光分配網の構築に極めて好都合であり、本発明の目
的が達成される（後述）。Eventually, all the subscribers can receive the optical signals of λ 1 to λ 16 , so that bidirectional communication becomes possible if a desired one is extracted by a filter. Of course, the center signal can also be received. Such a 2 × 2 optical coupler 41 is extremely convenient for constructing a tree type optical distribution network, and the object of the present invention is achieved (described later).
第２図は本発明に係る双方向光通信網の一構成例を示す
図であり、ツリー形光分配網21が形成され、下り方向の
末端に例えば１〜512の加入者が配置される。CATV網で
あれば上り方向の末端にセンター14が置かれる。FIG. 2 is a diagram showing an example of the configuration of the bidirectional optical communication network according to the present invention. A tree type optical distribution network 21 is formed, and 1 to 512 subscribers are arranged at the downstream ends, for example. In the case of the CATV network, the center 14 is placed at the end in the up direction.
本図において、本発明の特徴をなす２×２光カプラ（全
反射膜付）41は図示するＡの位置に置かれ、一群の加入
者と他の群の加入者との間の双方向光通信を可能にす
る。もし、１〜512の全加入者同士で双方向通信したい
ならば、全加入者をカバーすることのできる２×２光カ
プラ（全反射膜付）41を用いる。つまりＢの位置に置か
れたカプラ41を用いる（Ａの位置にはカプラ41を設けな
いで全反射膜のないカプラとする）。In this figure, a 2 × 2 optical coupler (with a total reflection film) 41, which is a feature of the present invention, is placed at the position A shown in the figure, and bidirectional light between one group of subscribers and another group of subscribers is provided. Enable communication. If bidirectional communication is required between all subscribers 1 to 512, a 2 × 2 optical coupler (with a total reflection film) 41 capable of covering all subscribers is used. That is, the coupler 41 placed at the position B is used (the coupler 41 is not provided at the position A, and the total reflection film is not provided).
複数の２×２光カプラを多段に従属接続してなるツリー
形光分配網において、２×２光カプラ（全反射膜付）41
より下流側（センター14からの光信号の流れに沿って）
には、一切同様の全反射膜付カプラを設けてはならな
い。光分配網21内に多重反射を生じさせるからである。In a tree-type optical distribution network in which a plurality of 2 × 2 optical couplers are cascade-connected, a 2 × 2 optical coupler (with a total reflection film) 41
Downstream (along the optical signal flow from the center 14)
Must not be equipped with a coupler with a total reflection film. This is because multiple reflection is generated in the light distribution network 21.
双方向光通信のためには、層方向通信を要求する加入者
において、送受光器を設ける必要がある。この送受光器
の一例を加入者11−512について示し、参照番号43を付
す。なお加入者11−512の波長はλ512であり、波長λ２
の加入者11−２と双方向光通信を行うものとする。波長
λ512の上り方向光信号は光送信器44よりハーフミラー4
5を介して光ファイバに侵入する。一方、加入者11−２
からの光信号（波長λ２）はハーフミラー45を通過して
グレーティング付の光学フィルタ46により抽出され、光
受信器47に至る。For two-way optical communication, it is necessary to provide a transmitter and a receiver at a subscriber who requests layer-direction communication. An example of this transmitter / receiver is shown for subscribers 11-512 and is designated by the reference numeral 43. The wavelength of the subscriber 11-512 is λ 512 , and the wavelength λ 2
Bidirectional optical communication with the subscriber 11-2. The upstream optical signal of wavelength λ 512 is transmitted from the optical transmitter 44 to the half mirror 4
Enter the optical fiber through 5. On the other hand, subscriber 11-2
The optical signal (wavelength λ 2 ) from the optical signal passes through the half mirror 45, is extracted by the optical filter 46 with a grating, and reaches the optical receiver 47.
以上説明したように本発明によれば、通常は無反射とさ
れる終端ポートをあえて全反射膜付きの終端ポートとす
ることにより、構成が簡単なツリー形光分配網を双方向
の光分配網として機能させることができ、ハードウェア
規模および経済性の面で実用的な双方向光通信網が実現
され、またツリー形光分配網の頂点とその末端との間の
中間段に全反射膜付きの終端ポートを備えた２×２光カ
プラを配置することにより、相互に双方向通信すべき加
入者の数を調整可能な双方向光通信網が実現される。As described above, according to the present invention, a tree-type optical distribution network having a simple structure is configured as a bidirectional optical distribution network by intentionally changing the normally non-reflecting terminal port to a terminal port with a total reflection film. It is possible to realize a two-way optical communication network that is practical in terms of hardware scale and economy, and has a total reflection film in the intermediate stage between the top and the end of the tree-type optical distribution network. By arranging the 2 × 2 optical coupler having the terminating port, a bidirectional optical communication network capable of adjusting the number of subscribers to be bidirectionally communicated with each other is realized.
第１図は本発明の原理を説明するための図、 第２図は本発明に係る双方向光通信網の一構成例を示す
図、 第３図は本発明が適用される双方向光通信網の一般的な
概要を示す図、 第４図は光分配網として一般的なツリー形光分配網を示
す図、 第５図は双方向光通信網の従来の構成例を示す図、 第6A〜6C図は光カプラの構成例を示す図である。 図において、 10……双方向光通信網、 11−1,11−２〜11−Ｎ……加入者、14……センター、 21……ツリー形光分配網、 41……２×２光カプラ、42……全反射膜。FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is a diagram showing a configuration example of a bidirectional optical communication network according to the present invention, and FIG. 3 is a bidirectional optical communication to which the present invention is applied. FIG. 4A is a diagram showing a general outline of the network, FIG. 4 is a diagram showing a tree-shaped optical distribution network as a general optical distribution network, and FIG. 5 is a diagram showing a conventional configuration example of a bidirectional optical communication network. 6C are diagrams showing a configuration example of the optical coupler. In the figure, 10 ... Bidirectional optical communication network, 11-1, 11-2 to 11-N ... Subscriber, 14 ... Center, 21 ... Tree type optical distribution network, 41 ... 2 × 2 optical coupler , 42 …… Total reflection film.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｇ０２Ｂ 6/28 Ｕ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI technical display location G02B 6/28 U
Claims (1)
てなるツリー形光分配網からなると共に、 該ツリー形光分配網の頂点とその末端との間の中間段に
配置される１つの２×２光カプラであって、該ツリー形
光分配網に収容される全加入者のうち相互に双方向通信
すべき一群の加入者と他の群の加入者とをカバーする１
つの２×２光カプラが全反射膜付きの終端ポートを備え
た２×２光カプラであることを特徴とする双方向光通信
網。1. A tree-type optical distribution network comprising a plurality of 2 × 2 optical couplers connected in cascade in multiple stages, and arranged in an intermediate stage between the apex and the end of the tree-shaped optical distribution network. One 2 × 2 optical coupler for covering a group of subscribers and another group of subscribers to be bidirectionally communicated among all the subscribers accommodated in the tree type optical distribution network 1
Two-way optical communication network, characterized in that the two 2x2 optical couplers are 2x2 optical couplers having a termination port with a total reflection film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62201914A JPH0777367B2 (en) | 1987-08-14 | 1987-08-14 | Two-way optical communication network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62201914A JPH0777367B2 (en) | 1987-08-14 | 1987-08-14 | Two-way optical communication network |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6444903A JPS6444903A (en) | 1989-02-17 |
| JPH0777367B2 true JPH0777367B2 (en) | 1995-08-16 |
Family
ID=16448897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62201914A Expired - Lifetime JPH0777367B2 (en) | 1987-08-14 | 1987-08-14 | Two-way optical communication network |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0777367B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006262381A (en) * | 2005-03-18 | 2006-09-28 | Japan Aviation Electronics Industry Ltd | Bidirectional optical communication network |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA997181A (en) * | 1973-07-05 | 1976-09-21 | Roy E. Love | Optical communication system |
| JPS59146234A (en) * | 1983-01-31 | 1984-08-22 | Fujitsu Ltd | Optical transmission system |
-
1987
- 1987-08-14 JP JP62201914A patent/JPH0777367B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006262381A (en) * | 2005-03-18 | 2006-09-28 | Japan Aviation Electronics Industry Ltd | Bidirectional optical communication network |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6444903A (en) | 1989-02-17 |
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