Methods and apparatus for performing directionless and contentionless wavelength addition and subtraction

• US 20100272441A1
• Filed: 08/25/2009
• Published: 10/28/2010
• Est. Priority Date: 04/24/2009
• Status: Active Grant

• Current Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Original Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Inventors: Wang, Yajun, Boduch, Mark E., Papakos, Kimon
• Granted Patent: US 8,447,183 B2
• Time in Patent Office: Days
• US Class Current: 398/83
• CPC Class Codes: H04J 14/0201 Add-and-drop multiplexing
• CPC Class Codes: H04J 14/0204 Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
• CPC Class Codes: H04J 14/0205 Select and combine arrangements, e.g. with an optical combiner at the output after adding or dropping
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/021 Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/02122 Colourless, directionless or contentionless [CDC] arrangements
• CPC Class Codes: H04J 14/02126 Multicast switch arrangements
• CPC Class Codes: H04J 14/0217 Multi-degree architectures, e.g. having a connection degree greater than two
• CPC Class Codes: H04J 14/0219 Modular or upgradable architectures
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 11/0062 Network aspects
• CPC Class Codes: H04Q 2011/0013 using gating amplifiers
• CPC Class Codes: H04Q 2011/0018 using tunable transmitters or receivers
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/0039 Electrical control
• CPC Class Codes: H04Q 2011/0058 Crossbar; Matrix
• CPC Class Codes: H04Q 2011/0092 Ring

Abstract

In today'"'"'s reconfigurable optical add/drop multiplexer (ROADM) based optical node, ROADMs multiplex (and demultiplex) colored optical signals to form wavelength-division multiplexed (WDM) signals. Transponders connected to the ROADMs'"'"' add/drop ports convert noncolored optical signals to colored optical signals (and vice versa). Dedicating transponders to given ports degrades the node'"'"'s ability to route around network failures. Example embodiments of the invention include an optical node and corresponding method for routing optical signals within an optical node that compensate for this inflexibility. The optical node may include two ROADMs to transmit respective WDM signals onto at least two internode network paths and a routing module that can direct channels of the same wavelength along different internode network paths. Advantageously, a transponder may transmit (receive) different signals at the same wavelength to (from) different network node interfaces within the optical node, thereby improving the optical node'"'"'s ability to route around network failures.

Claims

1. An optical node, comprising:

at least two reconfigurable optical add/drop multiplexers (ROADMs) configured to transmit respective wavelength division multiplexed (WDM) signals, each WDM signal including multiple channels of different wavelengths, onto at least two internode network paths; and

a routing module configured to direct channels of the same wavelength to different internode network paths via the at least two ROADMs.

2. The optical node of claim 1, wherein each ROADM includes a wavelength-selective switch (WSS), and wherein channels to be added are directed to the WSSs from add/drop ports via intranode network paths.

3. The optical node of claim 1, wherein each ROADM includes a wavelength-selective switch (WSS), and wherein channels received at a ROADM via an internode network path are optically coupled to respective WSSs on the at least one other ROADM.

4. The optical node of claim 1, wherein each ROADM includes a wavelength-selective switch (WSS), wherein channels to be added are directed to the WSSs from add/drop ports via intranode network paths, and wherein channels received at a ROADM via an internode network path are optically coupled to respective WSSs on the at least one other ROADM.

5. The optical node of claim 1, further comprising:

a bank of add/drop ports optically coupled to the routing module and configured to add channels to the WDM signals or drop channels from the WDM signals.

6. The optical node of claim 5, wherein the bank of add/drop ports is optically coupled to the routing module, wherein drop ports are coupled to the routing module via respective tunable filters, and wherein add ports are optically coupled to the routing module without respective tunable filters.

7. The optical node of claim 6, wherein the bank of add/drop ports is integrated with the routing module.

8. The optical node of claim 5, wherein the bank of add/drop ports includes ports selectively coupled to the routing module via optical switches, wherein drop ports are coupled to the routing module via respective tunable filters, and wherein add ports are optically coupled to the routing module without respective tunable filters.

9. The optical node of claim 8, wherein the bank of add/drop ports is integrated with the ROADMs.

10. The optical node of claim 5, wherein the bank of add/drop ports includes colorless add/drop ports optically coupled to tunable filters, each of which is dedicated to a respective interface of the optical node.

11. The optical node of claim 1, wherein the routing module includes (i) at least one multicast switch configured to route any WDM signal to at least one drop port and (ii) at least one aggregator switch configured to route any add channel to at least one ROADM.

12. The optical node of claim 11, wherein the routing module further includes a tunable filter configured to filter the WDM signal prior to the at least one drop port.

13. The optical node of claim 12, wherein the routing module further includes an optical amplifier configured to amplify the WDM signal prior to the tunable filter.

14. The optical node of claim 11, wherein the routing module further includes an optical amplifier configured to amplify an output of the aggregator switch.

15. The optical node of claim 1, further including:

a distribution module optically coupling the ROADMs to multiple routing modules.

16. The optical node of claim 15, wherein the ROADMs are coupled to a plurality of distribution modules via a corresponding plurality of add/drop ports.

17. The optical node of claim 15, wherein the ROADMs are coupled to a plurality of distribution modules via a corresponding plurality of express ports.

18. The optical node of claim 15, wherein the multiple routing modules include colorless add/drop modules and colorless, directionless add/drop modules.

19. The optical node of claim 1, wherein the routing module includes at least one expansion port to couple the ROADMs optically to other routing modules.

20. A method of routing wavelength division multiplexed (WDM) signals, comprising:

transmitting respective WDM signals, each WDM signal including multiple channels of different wavelengths, onto at least two internode network paths using at least two reconfigurable optical add/drop multiplexers (ROADMs); and

directing channels of the same wavelength to different internode network paths via the at least two ROADMs using a routing module.

21. The method of claim 20, wherein directing channels includes directing channels to be added to a wavelength-selective switch in one of the at least two ROADMs from add/drop ports via intranode network paths.

22. The method of claim 20, wherein directing channels includes optically coupling channels received at a ROADM via an internode network path to a wavelength-selective switch on the at least one other ROADM.

23. The method of claim 20, wherein directing channels includes directing channels to be added to a wavelength-selective switch (WSS) in one of the at least two ROADMs from add/drop ports via intranode network paths and optically coupling channels received at a ROADM via an internode network path to a WSS on the at least one other ROADM.

24. The method of claim 20, further including:

adding channels to or dropping channels from the WDM signals with a bank of add/drop ports optically coupled to the routing module.

25. The method of claim 24, wherein adding channels to or dropping channels from the WDM signals includes filtering channels to be dropped with tunable filters optically coupled to the routing module and the bank of add/drop ports.

26. The method of claim 25, wherein the bank of add/drop ports is integrated with the routing module.

27. The method of claim 24, wherein filtering channels includes filtering a channel from a colorless add/drop port with a tunable filters dedicated to a particular interface of the optical node.

28. The method of claim 24, wherein adding channels to or dropping channels from the WDM signals includes selectively coupling ports in the bank of add/drop ports to the routing module via optical switches.

29. The method of claim 28, wherein the bank of add/drop ports is integrated with the ROADMs.

30. The method of claim 20, wherein adding channels to or dropping channels from the WDM signals includes (i) routing any WDM signal to a drop port using a multicast switch and (ii) routing any add channel to at least one ROADM with an aggregator switch.

31. The method of claim 30, wherein adding channels to or dropping channels from the WDM signals includes filtering the WDM signal prior to dropping channels.

32. The method of claim 31, wherein adding channels to or dropping channels from the WDM signals includes amplifying the WDM signal prior to filtering the WDM signal.

33. The method of claim 30, wherein adding channels to or dropping channels from the WDM signals includes amplifying an output of the aggregator switch.

34. The method of claim 20, further including:

distributing WDM signals among the at least two ROADMs and multiple routing modules with a distribution module.

35. The method of claim 34, wherein distributing WDM signals includes transmitting WDM signals between the ROADMs and a plurality of distribution modules coupled to the ROADMs via a corresponding plurality of add/drop ports.

36. The method of claim 34, wherein distributing WDM signals includes transmitting WDM signals between the ROADMs and a plurality of distribution modules coupled to the ROADMs via a corresponding plurality of express ports.

37. The method of claim 34, wherein the multiple routing modules include colorless routing modules and colorless, directionless routing modules.

38. The method of claim 20, wherein directing channels includes coupling WDM signals from the at least two ROADMs to multiple routing modules with an expansion port.