Optical path cross-connect and optical wavelength multiplexing diversity communication system using the same

• US 20020126350A1
• Filed: 07/19/2001
• Published: 09/12/2002
• Est. Priority Date: 03/06/2001
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Sato, Kazuyuki, Dokai, Masami, Konno, Hiroki
• Granted Patent: US 7,242,861 B2
• Time in Patent Office: Days
• US Class Current: 398/7
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/022 For interconnection of WDM optical networks
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04J 14/0241 Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0286 WDM hierarchical architectures
• CPC Class Codes: H04J 14/0295 Shared protection at the optical channel (1:1, n:m)
• CPC Class Codes: H04J 14/0297 Optical equipment protection

Abstract

A protection system protects paths of internetwork communication between WDM ring networks, and includes a plurality of optical wavelength multiplexing networks having a plurality of nodes and a network management system for monitoring conditions of the plurality of nodes. The nodes include a first node having add/drop functions of adding/dropping wavelength-multiplexed optical signals; a second node having a signal transfer function as well as the add/drop functions; and a third node having an internetwork connection function between the networks. Each first, second and third nodes further includes optical path cross-connect switches and a table for indicating conditions of the optical path cross-connect switches and a detected node fault condition. The network management system controls to set the optical path cross-connect switches in the first, second and third nodes so that the optimal optical path connection may be obtained according to the detected node fault condition indicated in the node tables.

Claims

1. An optical wavelength multiplexing diversity communication system comprising:

a plurality of optical wavelength multiplexing networks each having a plurality of nodes; and

a network management system for monitoring conditions of the plurality of nodes,

wherein the plurality of nodes have,

a first node having functions of adding and dropping optical wavelength-multiplexed signals to/from the network;

a second node having a signal transferring function as well as the adding and dropping functions; and

a third node having an internetworking function for interconnecting the networks, and

the first, second and third nodes further respectively include,

an optical path cross-connect switches, and

a table for indicating status of the optical path cross-connect switches and a node fault detection condition, and

wherein the network management system controls to set the optical path cross-connect switches according to fault detection condition of the first, second and third nodes indicated in each of the tables so that the optimal optical path connection may be obtained.

2. The optical wavelength multiplexing diversity communication system according to claim 1,

wherein the network management system retains in advance the shortest path information related to the interconnection of the plurality of nodes, to determine the optimal path based on the node fault detection condition to control to set the optical path cross-connect switches in the each node.

3. The optical wavelength multiplexing diversity communication system according to claim 1,

wherein the optical wavelength multiplexing network includes a first ring network and a second ring network, and at least two pairs of nodes functioning as the third nodes are provided for interconnecting the first ring network and the second ring network.

4. The optical wavelength multiplexing diversity communication system according to claim 3,

wherein optical transmission lines for interconnecting nodes in the first and second ring networks are constituted by a pair of optical transmission lines to transmit optical signals in mutually opposite directions, and at least two pairs of nodes for interconnecting the first ring network and the second ring network are respectively connected with a pair of optical transmission lines to transmit optical signals in mutually opposite directions.

5. Optical path cross-connect equipment comprising:

a first to third optical branching devices for branching each first to third optical path into two optical paths; and

a first to third optical path cross-connect switches for selecting one input out of the two optical path inputs to output respectively to connect to a fourth to sixth optical paths,

wherein the first optical path cross-connect switch selects one of the first and second optical paths respectively branched by the first and second optical branching devices, to connect to the fourth optical path,

the second optical path cross-connect switch selects one of the second and third optical paths respectively branched by the second and third optical branching devices, to connect to the fifth optical path, and

the third optical path cross-connect switch selects one of the first and third optical paths respectively branched by the first and third optical branching devices to connect to the sixth optical path.

6. The optical path cross-connect equipment according to claim 5,

wherein the second and sixth optical paths, and the third and fourth optical paths, are respectively connected to the networks through optical wavelength conversion equipment provided for converting each input optical wavelength into a desired optical wavelength.

7. In an optical wavelength multiplexing diversity communication system having at least one set of optical path cross-connect equipment, a network management system connected to the optical path cross-connect equipment, and a plurality of optical wavelength multiplexing networks connected through optical path cross-connect equipment, said optical path cross-connect equipment comprising:

a first to third optical branching devices for branching each first to third optical path into two optical paths; and

a first to third optical path cross-connect switches for selecting one input out of two optical path inputs to output respectively to connect to a fourth to sixth optical paths,

wherein the first optical path cross-connect switch selects one of the first and second optical paths respectively branched by the first and second optical branching devices, to connect to the fourth optical path,

the second optical path cross-connect switch selects one of the second and third optical paths respectively branched by the second and third optical branching devices, to connect to the fifth optical path,

the third optical path cross-connect switch selects one of the first and third optical paths respectively branched by the first and third optical branching devices to connect to the sixth optical path, and

the first to third optical path cross-connect switches perform switch connection to each desired optical path according to an indication from the network management system.

8. The optical path cross-connect equipment according to claim 7,

wherein the second and sixth optical paths, and the third and fourth optical paths, are respectively connected to networks through optical wavelength conversion equipment provided for converting each input optical wavelength into a desired optical wavelength.

9. Optical path cross-connect equipment comprising:

a first to third optical cross-connect switches having a function of either branching each first to third optical path into two optical paths, or switching either of two input optical paths out of a first to third optical paths; and

a fourth to sixth optical path cross-connect switches for selecting one optical path input out of two inputs to output respectively to connect to a fourth to sixth optical paths,

wherein the fourth optical path cross-connect switch selects one of the first and second optical paths respectively branched by the first and second optical path cross-connect switches, or one optical path switched out of the two optical paths, to connect to the fourth optical path,

the fifth optical path cross-connect switch selects one of the second and third optical paths respectively branched by the second and third optical path cross-connect switches, or one optical path switched out of the two optical paths, to connect to the fifth optical path, and

the sixth optical path cross-connect switch selects one of the first and third optical paths respectively branched by the first and third optical path cross-connect switches, or one optical path switched out of the two optical paths, to connect to the sixth optical path.

10. The optical path cross-connect equipment according to claim 9, wherein at least one of the first to third optical path cross-connect switches is constituted by an optical branching device for branching an optical path into two optical paths.

11. In an optical wavelength multiplexing diversity communication system having at least one set of optical path cross-connect equipment, a network management system connected to the optical path cross-connect equipment, and a plurality of optical wavelength multiplexing networks connected through optical path cross-connect equipment, said optical path cross-connect equipment comprising:

a first to third optical cross-connect switches having a function of either branching each first to third optical path into two optical paths, or switching either of two input optical paths out of a first to third optical paths; and

a fourth to sixth optical path cross-connect switches for selecting one optical path input out of two inputs to output respectively to connect to a fourth to sixth optical paths,

wherein the fourth optical path cross-connect switch selects one of the first and second optical paths respectively branched by the first and second optical path cross-connect switches, or one optical path switched out of the two optical paths, to connect to the fourth optical path,

the fifth optical path cross-connect switch selects one of the second and third optical paths respectively branched by the second and third optical path cross-connect switches, or one optical path switched out of the two optical paths, to connect to the fifth optical path,

the sixth optical path cross-connect switch selects one of the first and third optical paths respectively branched by the first and third optical path cross-connect switches, or one optical path switched out of the two optical paths, to connect to the sixth optical path, and

the fourth to sixth optical path cross-connect switches perform switch connection to each desired optical path according to an indication from the network management system.

12. The optical path cross-connect equipment according to claim 11, wherein at least one optical path cross-connect switch of the first to third optical path cross-connect switches is constituted by an optical branching device for branching an optical path into two optical paths.