Wavelength Selective Switch Design Configurations for Mesh Light-Trails

• US 20070274724A1
• Filed: 05/25/2006
• Published: 11/29/2007
• Est. Priority Date: 05/25/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Gumaste, Ashwin A.
• Granted Patent: US 7,715,711 B2
• Time in Patent Office: Days
• US Class Current: 398/83
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements
• CPC Class Codes: H04J 14/0217 Multi-degree architectures, e.g. having a connection degree greater than two
• 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 14/0238 Wavelength allocation for communications one-to-many, e.g. multicasting wavelengths
• CPC Class Codes: H04J 14/0241 Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
• CPC Class Codes: H04J 14/0284 WDM mesh architectures
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 11/0067 Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0052 Interconnection of switches
• CPC Class Codes: H04Q 2011/006 Full mesh
• CPC Class Codes: H04Q 2011/0098 Mesh

Abstract

In accordance with the teachings of the present invention, wavelength selective switch (WSS) design configurations for mesh light-trails are provided. In a particular embodiment, a node included in an optical network comprises a first light access unit operable to add or drop local traffic and a first WSS assembly communicatively coupled to the first light access unit and comprising at least four WSSs, at least two input ports, and at least four output ports, the four WSSs configured to direct any input traffic in any wavelength received at one of the input ports to the first light access unit and/or to any of the output ports.

Claims

1. A node included in one or more light-trails in a mesh network, each light-trail enabling a plurality of nodes included in the light-trail to share the use of an optical wavelength to transmit traffic between the nodes included in the light-trail, the node comprising:

a plurality of wavelength selective switch (WSS) assemblies each configured to receive traffic in one or more light-trails via an associated input port of the node; and

a plurality of light-trail access units (LAUs), each LAU associated with a WSS assembly, where;

each WSS assembly comprises four WSSs, two input ports, and more than two output ports, where each light trail is associated with an output port, the associated output port corresponding to the next node in the particular light-trail;

each WSS assembly is configured to send traffic in one or more of the light-trails via one of the output ports to the associated LAU;

each LAU is configured to;

receive traffic in one or more of the light-trails from the associated WSS assembly;

demultiplex traffic of different wavelengths;

drop traffic in one or more of the light-trails;

add traffic to one or more of the light-trails;

multiplex traffic of different wavelengths;

forward the multiplexed traffic to the associated WSS assembly; and

each WSS assembly is further configured to receive the traffic from the associated LAU at the second input port and send the traffic in a particular light-trail through the output port that corresponds to the next node in the particular light-trail.

2. The node of claim 1, further comprising a plurality of output switches, each output switch configured to receive traffic from two or more of the WSS assemblies, to combine the received traffic, and to forward the combined traffic as an output of the node.

3. The node of claim 1, wherein each LAU is configured to drop the traffic and add the traffic passively.

4. A node included in one or more light-trails in a mesh network, each light-trail enabling a plurality of nodes included in the light-trail to share the use of an optical wavelength to transmit traffic between the nodes included in the light-trail, the node comprising:

a plurality of wavelength selective switch (WSS) assemblies each configured to receive traffic in one or more light-trails via an associated input port of the node; and

a plurality of light-trail access units (LAUs), each LAU associated with a WSS assembly, where;

each WSS assembly comprises a plurality of output ports, where each light trail is associated with an output port, the associated output port corresponding to the next node in the particular light-trail;

each WSS assembly is configured to send traffic in one or more of the light-trails via one of the output ports to the associated LAU;

each LAU is configured to;

receive traffic in one or more of the light-trails from the associated WSS assembly;

drop traffic in one or more of the light-trails;

add traffic to one or more of the light-trails; and

forward any added or passed-through traffic to the associated WSS assembly; and

each WSS assembly is further configured to receive the traffic from the associated LAU and send the traffic in a particular light-trail through the output port that corresponds to the next node in the particular light-trail.

5. The node of claim 4, further comprising a plurality of output switches, each output switch configured to receive traffic from two or more of the WSS assemblies, to combine the received traffic, and to forward the combined traffic as an output of the node.

6. The node of claim 4, wherein each LAU comprises:

a demultiplexer configured to demultiplex the traffic that the LAU receives from the associated WSS assembly into the traffic'"'"'s constituent wavelengths;

a plurality of drop couplers, each drop coupler configured to receive traffic in one of the wavelengths and configured to split the received traffic into two copies, drop a first copy of the traffic, and forward a second copy along the LAU;

a plurality of add couplers, each add coupler associated with a particular drop coupler and configured to either pass traffic or add traffic;

a plurality of switches, each switch associated with a particular add coupler and a particular drop coupler and configurable to terminate traffic or pass traffic, each switch positioned downstream of a corresponding drop coupler and upstream of a corresponding add coupler; and

a multiplexer configured to multiplex any added and passed-through traffic and forward the traffic to the associated assembly.

7. The node of claim 4, wherein the at least one WSS assembly comprises two input ports and more than two output ports.

8. The node of claim 4, wherein each LAU is configured to drop the traffic and add the traffic passively.

9. A method for channeling traffic at a node included in one or more light-trails in a mesh network, each light-trail enabling a plurality of nodes included in the light-trail to share the use of an optical wavelength to transmit traffic between the nodes included in the light-trail, the method comprising:

receiving traffic in one or more light-trails at one or more wavelength selective switch (WSS) assemblies;

sending traffic in one or more of the light-trails received at one of the WSS assemblies to a light-trail access unit (LAU) associated with the WSS assembly;

dropping traffic in one or more of the light-trails at the LAU;

adding local traffic to one or more of the light-trails at the LAU;

forwarding any added or passed-through traffic to the associated WSS assembly;

receiving the traffic from the associated LAU; and

sending the traffic in a particular light-trail through an output port of the WSS assembly that corresponds to the next node in the particular light-trail.

10. The method of claim 9, further comprising:

receiving traffic from two or more of the WSS assemblies at an output switch;

combining the received traffic at the output switch; and

forwarding the combined traffic as an output of the node.

11. The method of claim 9, further comprising:

after sending traffic to the LAU, demultiplexing the traffic at the LAU into the traffic'"'"'s constituent wavelengths; and

multiplexing any added and passed-through traffic at the LAU;

12. The method of claim 9, wherein the WSS assemblies comprise two input ports and more than two output ports.

13. The method of claim 9, wherein the traffic is dropped and added passively at the LAU.

14. A node included in an optical network, comprising:

a first light access unit operable to add or drop local traffic; and

a first wavelength selective switch (WSS) assembly communicatively coupled to the first light access unit and comprising at least four WSSs, at least two input ports, and at least four output ports, the four WSSs configured to direct any input traffic in any wavelength received at one of the input ports to the first light access unit and/or to any of the output ports.

15. The node of claim 14, further comprising:

a second light access unit operable to add or drop local traffic;

a second WSS assembly communicatively coupled to the second light access unit and comprising at least four WSSs, at least two input ports, and at least four output ports, the four WSSs configured to direct any input traffic in any wavelength received at one of the input ports to the second light access unit and/or to any of the output ports; and

at least one output switch configured to receive traffic from at least the first WSS assembly and the second WSS assembly, to combine the received traffic, and to forward the combined traffic as an output of the node.

16. The node of claim 14, wherein the first light access unit is configured to add or drop the traffic passively.