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OPTICAL CROSS-CONNECT DEVICE

Foreign code F180009344
File No. S2016-0448-C0
Posted date Apr 17, 2018
Country WIPO
International application number 2017JP009333
International publication number WO 2017155001
Date of international filing Mar 8, 2017
Date of international publication Sep 14, 2017
Priority data
  • P2016-044823 (Mar 8, 2016) JP
Title OPTICAL CROSS-CONNECT DEVICE
Abstract An OXC device of route-and-select architecture in the prior art requires 120 1×9 WSSs in the entire device when the number of ports is 20. An OXC device of route-and-select type exceeding 20 ports requires a large quantity of expensive WSSs and lacks feasibility in terms of cost. Expansion matched to the extent of increase in traffic of a node is impossible, there is a lack of flexible scalability, and reasonable network operation including economy is difficult. An OXC device of the present disclosure uses smaller-scale WSSs than in prior art and internally connects the WSSs from a different viewpoint than in prior art, irrespective of the number of input ports and the number of output ports of the device, thereby making it possible to greatly reduce the cost of the device. Furthermore, this OXC device can be expanded flexibly, economically, stepwise only as necessary, and without limits in accordance with the initial state of traffic and subsequent increases thereto.
Outline of related art and contending technology BACKGROUND ART
And the optical fiber as a transmission medium is optical communication technology, uncompressed result in a signal transmission distance, a large-scale optical network has been constructed. In recent years, ADSL(Asymmetric Digital Subscriber Line: asymmetric digital subscriber line) via the communication line or Internet line FTTH(Fiber To The Home) is widely used, a portable wireless through the communication line and a wireless terminal reaches the situation of the commodity. As a result, in both wired and wireless networks, and communication traffic is explosively increasing, the capacity of the communication network, high-speed, high function and low power consumption are increasingly required. In recent years, the amount of the streaming music service or using a high definition movie distribution service is popular, the world's future IP traffic continues to increase at a rate of 1.3 times per year is predicted.
In optical communication, a plurality of different wavelengths of the optical fiber transmission path 1 optical signals transmitted at the same time by the introduction of wavelength division multiplexing communication techniques, it is possible to increase the transmission capacity between the point 2 becomes possible. Further collects a plurality of transmission paths in a communication network in the node, the optical signal into an electrical signal of the optical signal without converting the signal path remains set and the switching processing method is used, the so-called photonic network has been realized. By using a photonic network, and dramatically increase the throughput of the node, significantly reducing the power consumption of the node device can be expected.
Using the optical node system includes a photonic network, a plurality of nodes connected in a bus ring or a reconfigurable optical add drop multiplexing (ROADM: Reconfigurable Optical Add Drop Multiplexing) system, a plurality of nodes connected to a mesh optical cross-connect (OXC: Optical Cross-Connect) system is well known. OXC system, each node and a plurality of input side optical fiber transmission path, a plurality of output side is connected to the optical fiber transmission path, the optical fiber transmission line on the input side inputted from the wavelength division multiplexed optical signal (hereinafter, referred to as a wavelength multiplexed light) with respect to, the connection path for each wavelength (path) switching the optical switch is provided. With this configuration, the input side of the optical fiber transmission path from any input wavelength-multiplexed optical signal of any wavelength of light, any of the output side can be output to the optical fiber transmission path.
Fig. 1 is, in the OXC system diagram illustrating an outline of switching traffic path of the optical node to the invention. OXC system in the optical network, the mesh node 1 to a plurality of adjacent nodes are connected, the other adjacent node as a plurality of optical fibers 10 connected to an input node 1. A specific traffic node 1 after the path switching is performed, the traffic is again one of the plurality of optical fibers 11 through 1 is transferred to the other nodes. Specifically, in one of the 1 input optical fiber 10-1, in the plurality of adjacent nodes of the two nodes of 1, λ1 from λx a plurality of wavelength multiplexed optical signal of wavelength multiplexed light 12 propagates. In the node 1, any of the wavelength multiplexed light 12 1 the signal light of one wavelength, the wavelength of the optical signal λ k 14-1 is selected. The selected optical signal, a plurality of output optical fiber 11 the output of any of the one optical fiber 1, for example an output optical fiber 11-n wavelength multiplexed light 13 propagates in the light of the wavelength λ k as the 14-2 signal, is transmitted to the other adjacent node. Therefore, node 1 is, the number m of the m input optical fiber is connected to the input to the input ports of the optical signal of any wavelength, one of n output optical fiber is connected to any output port is switched to the operation. In this manner, m and n input ports has two output ports, each port of the wavelength-multiplexed light propagated through the optical fiber is connected and light, having a particular wavelength remains in the optical signal to any node which performs the path switching, the optical cross connect (OXC: Optical Cross-Connect) called. Incidentally, this node may be referred to as a ROADM is, in the description herein below, this node (Patent Document 1) is referred to as OXC device.
Fig. 2A and Fig. 2B is, one of the OXC 2 a diagram schematically showing an example of the configuration of the present invention. Fig. 2A is, the configuration of the OXC device of the broadcast and select type & and 20-1, m of the m input ports to the optical fiber is connected, to the n output ports n is connected to the optical fiber. M on an input side optical coupler 21 of the 1xn configuration and are arranged, each optical coupler of the input wavelength-multiplexed light branched into n pieces so as to operate. The optical coupler 21, a substantially constant level because the simple branching, the branch of the optical signal after a lower level. N mx1 is the output side of the configuration of the wavelength selective switch (WSS: Wavelength Selective Switch) 22 and arranged, each of the WSS is one from the optical coupler in the respective m included in the light of light in the wavelength-multiplexed optical signal of any wavelength can be selected in any combination.
WSS is, the same wavelength from different wavelength multiplexed light are simultaneously selected at the output side of the optical signal cannot be distinguished from each other, light from different wavelength multiplexed optical signals of different wavelengths is selected. WSS is, the optical signal having wavelength selectivity and can be selected, for example an arrayed waveguide grating (AWG) and an optical switch or a combination are available and, further, instead of the AWG of the other of the diffraction grating can be utilized for the bulky. Fig. 2A is a configuration of a 20-1 OXC apparatus, light wavelength-multiplexed by the optical coupler 21 (branching) and distributed, and then selects an optical signal of an arbitrary wavelength by WSS22 since, referred to as broadcast and select type &.
Fig. 2B is, the root OXC device of the combined configuration of the & 20-2 and, in the configuration of the broadcast and select type & reverse the direction of the optical signal and the configuration. That is, an input side of the configuration of m 1xn and WSS23 are arranged, the output side optical coupler 24 is configured of n mx1 are arranged. For selecting a wavelength and the order is different from the broadcast and select type &, any input port of the wavelength multiplexed optical signal of any wavelength of any output port from the viewpoint of operation, Fig. 2A and Fig. 2B there is a difference between each of the components. Incidentally, generally the number of input ports of the OXC device n and m the number of output ports may be different from each other, may be the same.
As described above, the optical coupler 21, in 24, the insertion loss increases in accordance with the number of branches. Specifically, when n number of branches (n) 10log (dB) is generated due to the loss, for example the number of branches is increased to 13dB to 20 and loss. On the other hand, the input 1 (1xL) configuration of the WSS output L, the same number of branches can be configured with a less loss than an optical coupler (output port number 7dB in the case of at most about 20). OXC device increases the number of the ports of the optical coupler 21, 24 increases the loss, Fig. 2A and Fig. 2B may be any configuration, a reduction in the level of the optical signal introduced into the optical amplifier such as is required. Loss caused by the optical coupler in order to avoid the problem, without the use of an optical coupler may be composed only of WSS OXC apparatus, as an optical switch for a large-scale node is promising.
Fig. 3 is, the root OXC & showing the configuration of a select type of the present invention. Fig. 2A and in the same manner as the configurations shown in Fig. 2B, m input ports of the optical fiber is connected to the m, n of n to output ports connected to the optical fiber. Route referred to as OXC & select type in the present configuration of the device, without the use of an optical coupler so as to switch the path by the WSS, described in Fig. 2A and Fig. 2B & & route and combine the broadcast and select type such as a combination type according to the embodiment. Fig. 2A and Fig. 2B each of the compared with the configuration, the number of input ports and output ports of the OXC device increase even if the increase in the insertion loss is suppressed, the number of the ports in the case of more than about 8, typically the root OXC & select type are used as a device.
Fig. 4A and Fig. 4B is, in the actual network which the device operates as the OXC in accordance with this embodiment. Fig. 4A is, shown as squares and a plurality of nodes which are connected to each other in a mesh network that indicates the physical locations of the. For example, four square 1 corresponds to the city, the city (node) between the plurality of optical fiber transmission path are connected by a link corresponds. A white square with regard to the node 40, node 40 as the center, directly connected to the 40 node 6 surrounded by two adjacent nodes are shown by dotted-line circles. In the nodes, transmission links are directly connected to the node number of the adjacent nodes (Node Degree) called order. Therefore, in the case of the node arrangement of Fig. 4A, and 6 is the node degree. To each node connected to the mesh, the neighbor node for processing traffic between the OXC apparatus is arranged.
Fig. 4B is, central node 40 of the OXC device arranged in the configuration shown in Fig. 41. OXC apparatus 41 in the root & select type, the input port side and the output port side of the WSS are both provided. Fig. 4A in the case of a network layout, when viewed from the center node 40 connected to the central node 40 since only one 6 is the number of neighbor nodes, each node 1 is connected between the optical fiber in the case of a pair (uplink and downlink), the input optical fiber and output optical fiber and the number of m 6 respectively. In the drawing, an optical fiber and the input of the OXC device 41 from the input port and #1-6, output optical fiber and output port number 1-6 and from the top. A first input 1 of the optical fiber 1 of the optical fiber and output port number, 6 in two adjacent node 1 and connected to the first node. Similarly, the same number of input optical fibers and output optical fiber is, the numbers corresponding to adjacent and connected to the node. In the OXC apparatus 41, the adjacent node connected to the same input optical fiber and the output optical fiber is generally between the note is not necessary to connect to. And the input-side WSS WSS connection between the output side, the same number of input ports and output ports 44 shown in dotted line connecting between the internal connection is generally not necessary. In the same node and to route optical signals no meaning, such a switching path for which are prepared in advance is wasteful in some cases. That is, in one of the adjacent node of the optical signal from 1, via the central node 40, except the neighbor node of the path switching to the adjacent node 5 suffices. Therefore, the input side and output side of each of the N number of ports of the WSSWSS may be a (m-1) =5.
As shown in Fig. 4B, a central node and the OXC apparatus is installed between the two neighbor nodes is 1, the input (upstream) optical fiber and the output 2 of the optical fiber of the fiber (the downlink) may be provided as a pair. Therefore, the amount of traffic through the node increases with time in order to perform the extension of the OXC as a result, a new additional optical fiber as the fiber optic link at the time of an additional, dedicated downlink and uplink optical fiber is usually a dedicated pair of optical fiber 2 is added as this. This is because, in the wide area network, typically 1 optical fibers for two-way communication is not used in some cases. In addition, Fig. 2A and Fig. 2B and Fig. 3 is a configuration example of, the number of input ports and m n is the number of output ports is described as being different, and the number of input ports of the OXC apparatus is usually the number of output ports will be the same. The uplink and downlink traffic amount is very different from, one transmission path in the optical fiber link 1 is the number of uplink and downlink may differ between, usually be regarded as m=n.
As the first-mentioned, the more traffic between optical nodes, OXC device also increases the amount of traffic handled by, one of the transmission path 1 on the link increases the number of the optical fiber. The number of the optical fiber when an attempt to, connecting optical fiber to the OXC device according to the present embodiment also increases the number of ports required.
Scope of claims (In Japanese)[請求項1]
複数の入力光ファイバが接続される複数の入力ポートおよび複数の出力光ファイバが接続される複数の出力ポートを有し、前記複数の入力光ファイバおよび前記複数の出力光ファイバによってN個(Nは自然数)の隣接ノードと相互接続され、前記複数の入力ポートの1つに入力された波長多重された光信号を前記複数の出力ポートのいずれかへ波長ルーティングする光クロスコネクト(OXC)装置において、
前記OXC装置の前記複数の入力ポート側に、各々が、前記複数の入力光ファイバの1つに接続された入力ポート、および、NWSS個の出力ポートを有する、1×NWSS構成の複数の波長選択スイッチ(WSS)を備え、
前記N個の隣接ノードの内の1つの隣接ノードj(j=1、2・・、N)において、前記OXC装置と接続された1つの前記入力光ファイバおよび1つの前記出力光ファイバからなるファイバペアの数をNPair,j(j=1、2・・、N)とし、当該1つの隣接ノードjを除いた(N-1)個の隣接ノードと前記OXC装置との間の前記ファイバペアの数の合計をNTotal, jとするとき、前記N個の隣接ノードの各々についての前記NTotal, jの最大値NMaxが、
NMax> NWSS の関係を満たすこと
を特徴とする光クロスコネクト装置。
[請求項2]
前記複数のWSSは、1つの隣接ノードに接続された1つのWSSの前記NWSS個の前記出力ポートが、前記複数の出力光ファイバの中で、前記1つの隣接ノードを除いた(N-1)個の隣接ノードに接続された光ファイバの内の一部の光ファイバだけに、内部経路を経由して接続されているWSSを含む、ことを特徴とする請求項1に記載の光クロスコネクト装置。
[請求項3]
複数の入力光ファイバが接続される複数の入力ポートおよび複数の出力光ファイバが接続される複数の出力ポートを有し、前記複数の入力光ファイバおよび前記複数の出力光ファイバによってN個(Nは自然数)の隣接ノードと相互接続され、前記複数の入力ポートの1つに入力された波長多重された光信号を前記複数の出力ポートのいずれかへ波長ルーティングする光クロスコネクト(OXC)装置において、
前記OXC装置の前記複数の入力ポート側に、各々が、前記複数の入力光ファイバの1つに接続された入力ポート、および、NWSS個の出力ポートを有する、1×NWSS構成の複数の波長選択スイッチ(WSS)を備え、
前記複数のWSSは、1つの隣接ノードに接続された1つのWSSの前記NWSS個の前記出力ポートが、前記複数の出力光ファイバの中で、前記1つの隣接ノードを除いた(N-1)個の隣接ノードに接続された光ファイバの内の一部の光ファイバだけに、内部経路を経由して接続されているWSSを含むこと
を特徴とする光クロスコネクト装置。
[請求項4]
複数の入力光ファイバが接続される複数の入力ポートおよび複数の出力光ファイバが接続される複数の出力ポートを有し、前記複数の入力光ファイバおよび前記複数の出力光ファイバによってN個(Nは自然数)の隣接ノードと相互接続され、前記複数の入力ポートの1つに入力された波長多重された光信号を前記複数の出力ポートのいずれかへ波長ルーティングする光クロスコネクト(OXC)装置において、
前記OXC装置の前記複数の出力ポート側に、各々が、前記複数の出力光ファイバの1つに接続された入力ポート、および、NWSS個の出力ポートを有する、1×NWSS構成の複数の波長選択スイッチ(WSS)を備え、
前記N個の隣接ノードの内の1つの隣接ノードj(j=1、2・・、N)において、前記OXC装置と接続された1つの前記入力光ファイバおよび1つの前記出力光ファイバからなるファイバペアの数をNPair,j(j=1、2・・、N)とし、当該1つの隣接ノードjを除いた(N-1)個の隣接ノードと前記OXC装置との間の前記ファイバペアの数の合計をNTotal, jとするとき、前記N個の隣接ノードの各々についての前記NTotal, jの最大値NMaxが、
NMax> NWSS の関係を満たすこと
を特徴とする光クロスコネクト装置。
[請求項5]
前記複数のWSSは、1つの隣接ノードに接続された1つのWSSの前記NWSS個の前記出力ポートが、前記複数の入力光ファイバの中で、前記1つの隣接ノードを除いた(N-1)個の隣接ノードに接続された光ファイバの内の一部の光ファイバだけに、内部経路を経由して接続されているWSSを含む、ことを特徴とする請求項4に記載の光クロスコネクト装置。
[請求項6]
複数の入力光ファイバが接続される複数の入力ポートおよび複数の出力光ファイバが接続される複数の出力ポートを有し、前記複数の入力光ファイバおよび前記複数の出力光ファイバによってN個(Nは自然数)の隣接ノードと相互接続され、前記複数の入力ポートの1つに入力された波長多重された光信号を前記複数の出力ポートのいずれかへ波長ルーティングする光クロスコネクト(OXC)装置において、
前記OXC装置の前記複数の出力ポート側に、各々が、前記複数の出力光ファイバの1つに接続された入力ポート、および、NWSS個の出力ポートを有する、1×NWSS構成の複数の波長選択スイッチ(WSS)を備え、
前記複数のWSSは、1つの隣接ノードに接続された1つのWSSの前記NWSS個の前記出力ポートが、前記複数の入力光ファイバの中で、前記1つの隣接ノードを除いた(N-1)個の隣接ノードに接続された光ファイバの内の一部の光ファイバだけに、内部経路を経由して接続されているWSSを含むこと
を特徴とする光クロスコネクト装置。
[請求項7]
前記OXC装置の前記複数の出力ポート側に、前記複数のWSSの前記出力ポートが内部経路によって接続された複数のカプラを備えたルート&コンバイン型の構成、または、
前記OXC装置の前記複数の出力ポート側に、1×NWSS構成の複数のWSSをさらに備え、それぞれの側のWSSの前記出力ポートが内部経路によって相互に接続されたルート&セレクト型の構成
を有することを特徴とする請求項1乃至3いずれかに記載の光クロスコネクト装置。
[請求項8]
前記OXC装置の前記複数の入力ポート側に、前記複数のWSSの前記出力ポートが内部経路によって接続された複数のカプラを備えたブロードキャスト&セレクト型の構成、または、
前記OXC装置の前記複数の入力ポート側に、1×NWSS構成の複数のWSSをさらに備え、それぞれの側のWSSの前記出力ポートが内部経路によって相互に接続されたルート&セレクト型の構成
を有することを特徴とする請求項4乃至6いずれかに記載の光クロスコネクト装置。
[請求項9]
前記複数の出力ポート側または前記複数の入力ポート側に備えた前記複数のWSSの各々は、
NWSSよりも少ない数の出力ポートを有する複数のWSSを従属接続した構成、または
カプラと、当該カプラの分岐出力に、NWSSよりも少ない数の出力ポートを有する複数のWSSとを従属接続した構成
を有することを特徴とする請求項1乃至8いずれかに記載の光クロスコネクト装置。
[請求項10]
前記入力光ファイバの使用状況に応じた信号を出力する制御部
をさらに備えたことを特徴とする請求項2に記載の光クロスコネクト装置。
[請求項11]
前記信号に応じて、前記入力光ファイバの使用状況を表示する表示部をさらに備えたことを特徴とする請求項10に記載の光クロスコネクト装置。
[請求項12]
前記出力光ファイバの使用状況に応じた信号を出力する制御部
をさらに備えたことを特徴とする請求項5に記載の光クロスコネクト装置。
[請求項13]
前記信号に応じて、前記入力光ファイバの使用状況を表示する表示部をさらに備えたことを特徴とする請求項12に記載の光クロスコネクト装置。
[請求項14]
前記入力光ファイバの使用状況が閾値を超えたことを表示する表示部
をさらに備えたことを特徴とする請求項2に記載の光クロスコネクト装置。
[請求項15]
前記出力光ファイバの使用状況が閾値を超えたことを表示する表示部
をさらに備えたことを特徴とする請求項5に記載の光クロスコネクト装置。
[請求項16]
前記信号は、前記使用状況として、
対象とする光ファイバに割り当て可能な最大の周波数帯域と現在使用されている光パスの帯域の総和との比率、または、
前記対象とする光ファイバに収容可能な光パスの本数と現在使用されている光パスの本数との比率
のいずれかに基づいて出力されることを特徴とする請求項11乃至13いずれかに記載の光クロスコネクト装置。
[請求項17]
前記信号は、前記比率が予め定められた閾値以下であること、または、予め定められた範囲の閾値内にあることによって出力されることを特徴とする請求項16に記載の光クロスコネクト装置。
[請求項18]
前記複数のWSSの出力ポート数NWSSは、N-1(前記隣接ノード数N-1)以上であることを特徴とする請求項1乃至17いずれかに記載の光クロスコネクト装置。
  • Applicant
  • ※All designated countries except for US in the data before July 2012
  • NAGOYA UNIVERSITY
  • Inventor
  • Kenichi Sato
  • HASEGAWA HIROSHI
  • Yojiro Mori
  • Kosuke Sato
IPC(International Patent Classification)
Specified countries National States: AE AG AL AM AO AT AU AZ BA BB BG BH BN BR BW BY BZ CA CH CL CN CO CR CU CZ DE DJ DK DM DO DZ EC EE EG ES FI GB GD GE GH GM GT HN HR HU ID IL IN IR IS JP KE KG KH KN KP KR KW KZ LA LC LK LR LS LU LY MA MD ME MG MK MN MW MX MY MZ NA NG NI NO NZ OM PA PE PG PH PL PT QA RO RS RU RW SA SC SD SE SG SK SL SM ST SV SY TH TJ TM TN TR TT TZ UA UG US UZ VC VN ZA ZM ZW
ARIPO: BW GH GM KE LR LS MW MZ NA RW SD SL SZ TZ UG ZM ZW
EAPO: AM AZ BY KG KZ RU TJ TM
EPO: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
OAPI: BF BJ CF CG CI CM GA GN GQ GW KM ML MR NE SN ST TD TG
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