Wavelength routing on an optical metro network subtended off an agile core optical network

• US 7,200,331 B2
• Filed: 07/15/2002
• Issued: 04/03/2007
• Est. Priority Date: 07/15/2002
• Status: Active Grant

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Solheim, Alan Glen, Roorda, Peter David
• Primary Examiner(s): Payne; David C.
• Application Number:
  US10/195,247
• Publication Number:
  US 20040208558A1
• Time in Patent Office: 1,723 Days
• Field of Search: 398/58, 398/59, 398/79
• US Class Current: 398/58
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/0209 Multi-stage arrangements, e.g. by cascading multiplexers or demultiplexers
• 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 14/0226 Fixed carrier allocation, e.g. according to service
• 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 14/0246 using one wavelength per ONU
• CPC Class Codes: H04J 14/025 using one wavelength per ONU, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
• CPC Class Codes: H04J 14/0279 WDM point-to-point architectures
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04J 14/0283 WDM ring architectures

Abstract

The is directed to extending wavelength routing on a metro network subtended off an optical agile network. Flexibility on the subtended metro network is obtained by either tuning the head-end transmitter on a metro wavelength that is the operating wavelength of the route to a specified tail-end node (tunable source, fixed wavelength-route dependency) or/and tuning a specified route to the metro wavelength (fixed source, tunable wavelength-route dependency). The routes may be tuned at one or both ends.

Claims

1. In a metro network subtended off an agile core network, a flexible metro connection for extending a flexible core connection over said metro network, comprising:

an optical laser source terminal operating at a source wavelength for transmitting a user signal over a metro channel;

a plurality of wavelength-dependent routes operating at a path wavelength, a route for directing said metro channel between an input port connected to said optical source and an output port connected to an associated optical destination terminal; and

means for assigning a metro wavelength to said metro channel and routing said metro channel to a specified destination terminal based on said metro wavelengths,

wherein any of said input port and output port is tunable to said metro wavelength.

2. A flexible metro connection as claimed in claim 1, wherein said optical source terminal is a tunable optical source, and wherein said means for assigning selects a path wavelength of a route to said specified destination terminal as said metro wavelength, and tunes said tunable optical source on said path wavelength.

3. A flexible metro connection as claimed in claim 1, wherein said wavelength-dependent routes are tunable, and wherein said means for assigning selects a source wavelength as said metro wavelength and tunes said route to said source wavelength.

4. A flexible metro connection as claimed in claim 3, wherein said route comprises a wavelength selective element for allowing said metro wavelength to pass from said optical source terminal to said specified destination terminal and to block all other wavelengths.

5. A flexible metro connection as claimed in claim 1, wherein said wavelength selective element is a wavelength selective switch.

6. In a metro network subtended of an agile core network, a method for extending an agile connection into said metro network, comprising:

generating, at a head-end transmitter [and at least one of the tail end receivers], a metro channel carrying a user signal;

connecting said head-end transmitter with a plurality of tail-end receivers along a respective plurality of wavelength-dependent routes provided over said metro network; and

selecting a route between said head-end transmitter and a specified tail-end receiver and tuning said head-end transmitter to a metro wavelength corresponding to the wavelength of said route and said specified receiver.

7. In a metro network subtended off an agile core network, a method for extending an agile connection into a metro network, comprising:

generating, at a head-end transmitter operating at a source wavelength, a metro channel for carrying a user signal;

providing a plurality of wavelength dependent routes over said metro network, a route for directing said metro channel between an input port connected to said head-end transmitter and an output port connected to an associated tail-end receiver over a path wavelength;

assigning a metro wavelength to said metro channel and routing said metro channel to a specified tail-end receiver based on said wavelength; and

tuning any of said input port and output port to said metro wavelength.

8. A method as claimed in claim 7, wherein said step of assigning comprises selecting a path wavelength of a route to said specified destination terminal as said metro wavelength, and tuning said tunable head-end transmitter on said path.

9. A method as claimed in claim 7, wherein said step of assigning comprises selecting a source wavelength as said metro wavelength and tuning said route to said source wavelength.

10. A method as claimed in claim 7, wherein said tuning step comprises providing said route with a wavelength selective element for allowing said metro wavelength to pass from said head-end transmitter to said specified tail-end receiver and to block all other wavelengths.

11. A flexible metro connection for routing a user signal on a metro network between a hub node connecting said metro network to an agile core network and an edge node, comprising:

a hub node for transferring said user signal between a metro channel of a first wavelength and a core channel of a second wavelength;

an edge node for inserting/extracting said user signal into/from said metro channel; and

a controller for tuning one of said hub node, edge node, and both said hub node and edge node to operate at said first wavelength.

12. A flexible metro connection as claimed in claim 11, wherein said edge node comprises:

an edge optical receiver for receiving said metro channel and detecting said user signal; and

a flexible metro optical add/drop multiplexer OADM for routing said metro channel from a metro WDM signal to a drop port connected to said edge optical receiver,

wherein said controller configures said flexible OADM to route said metro channel on said drop port.

13. A flexible metro connection as claimed in claim 12, wherein said OADM comprises:

means for directing a passthrough channel in said metro WDM signal from an line input port to an line output port; and

a drop and select tree for routing said metro channel from said line input port to said drop port along a drop path tuned to said first wavelength.

14. A flexible metro connection as claimed in claim 13, wherein said drop and select tree comprises a plurality of branches, each branch including a wavelength selective element.

15. A flexible metro connection as claimed in claim 12, wherein said OADM comprises a wavelength selective switch for routing said metro channel to said drop port based on said first wavelength.

16. A flexible metro connection as claimed in claim 11, wherein said edge node comprises:

an OADM for routing said metro channel from an add port into a metro WDM signal; and

a tunable edge optical transmitter for modulating said user signal over said first wavelength and providing said metro channel on said add port,

wherein said controller selects said first wavelength for connecting said edge optical transmitter to a specified hub optical receiver over said metro channel.

17. A flexible metro connection as claimed in claim 16, wherein said add port is colorless.

18. A flexible metro connection as claimed in claim 16, wherein said OADM is a wavelength selective switch.

19. A flexible metro connection as claimed in claim 11, wherein said hub node comprises:

an optical multiplexer for receiving said metro channel on an input port and routing said metro channel into a metro WDM signal; and

a tunable hub optical transmitter for modulating said user signal over said first wavelength to provide said metro channel on said input

wherein said controller selects said first wavelength for connecting said hub optical transmitter to a specified edge optical receiver over said metro channel.

20. A flexible metro connection as claimed in claim 19, wherein said input port is colorless.

21. A flexible metro connection as claimed in claim 19, wherein said optical multiplexer comprises a wavelength selective element.

22. A flexible metro connection as claimed in claim 19, wherein said optical multiplexer is a wavelength selective switch.

23. A flexible metro connection as claimed in claim 19, wherein said hub node further comprises rate adaptation means, whenever said metro network operates at an R1 rate and said core network operates at an R2.

24. A flexible metro connection as claimed in claim 23, wherein said rate adaptation means comprises a R1×

R2 mux/demux for demultiplexing said user signal from said core channel, and for multiplexing said user signal into said core channel.

25. A flexible metro connection as claimed in claim 24, wherein said rate adaptation means further comprises an OEO interface for connecting said rate adaptation means to said core network.

26. A flexible metro connection as claimed in claim 11, wherein said hub node comprises:

a flexible optical demultiplexer for routing said metro channel from an line input port to a drop port; and

a hub optical receiver connected to said drop port for detecting said user signal from said metro channel,

wherein said controller configures said flexible demultiplexer to route said metro channel on said drop port based on said first wavelength.

27. A flexible metro connection as claimed in claim 26, wherein said flexible optical demultiplexer comprises a drop and select tree for routing said metro channel from said line input port to said drop port along a drop path tuned to said first wavelength.

28. A flexible metro connection as claimed in claim 26, wherein said drop path comprises one of a wavelength selective element, a tunable filter and both.

29. A flexible metro connection as claimed in claim 26, wherein said flexible demultiplexer comprises a wavelength selective switch connected between said line input port and said drop port.