Granted Patent B1

US 7,558,478 · App. 11/362,912 · Granted Jul 7, 2009

Abstract

Claims (41)

1. A method of controlling an optical network including a transmitter including a processor for electronically compensating optical impairments based on at least one optical parameter, the method comprising steps of:

the network preliminarily:

identifying a respective optical path between the transmitter and each one of a plurality of receivers; and

determining a respective optical parameter for each path; and

during run-time, the network:

selecting a path between the transmitter and a receiver for receiving an optical signal from the transmitter; and

providing the respective optical parameter of the selected path to the processor of the transmitter, such that the transmitter generates an optical signal that is pre-compensated for optical impairments of the selected path.

2. The method as claimed in claim 1 wherein the optical parameter comprises either one of a magnitude of an optical impairment of the path, and a compensation function that compensates the optical impairment.

3. The method as claimed in claim 1 wherein the optical parameter comprises any one or more of: total path dispersion; a dispersion slope of the path; a linear transfer function of the path; and a nonlinear characteristic of the path.

4. The method as claimed in claim 1 wherein the step of determining a respective optical parameter for each path comprises a step of measuring a respective optical characteristic of each path.

5. The method as claimed in claim 4 wherein the step of measuring the optical characteristic comprises a step of transmitting a probe signal through the path.

6. The method as claimed in claim 4 wherein the optical characteristic comprises any one or more of: dispersion, polarization dependent loss (PDL); polarization mode dispersion (PMD); four wave mixing, cross-phase modulation (XPM); and self-phase modulation (SPM).

7. The method as claimed in claim 1 wherein the step of determining a respective optical parameter for each path comprises a step of computing an estimate of the parameter.

8. The method as claimed in claim 7 wherein the optical parameter estimate is computed based on known physical properties of the path.

9. The method as claimed in claim 7 wherein the step of computing an estimate of the parameter comprises steps of:

preliminarily determining a respective parameter value for each link in the network; and

during run-time:

identifying each link traversed by the path; and

computing the parameter value using the respective parameter values of each identified link.

10. The method as claimed in claim 1 wherein the step of determining a respective optical parameter for each path comprises a step of periodically updating the parameter based on a feedback signal from at least the selected receiver.

11. The method as claimed in claim 10 wherein the step of periodically updating the parameter comprises a step of computing a running average of the parameter.

12. The method as claimed in claim 1 wherein the step of enabling the transmitter to generate the optical signal comprises a step of providing a path identifier to the transmitter to enable the transmitter to download the respective optical parameter of the selected path from a storage medium.

13. The method as claimed in claim 1 wherein the selected receiver receives the optical signal via a wavelength selective network element.

14. The method as claimed in claim 13 wherein the wavelength selective network element comprises any one of:

an optical switch;

an optical add/drop multiplexer (OADM); and

an optical drop and continue.

15. The method as claimed in claim 1 , wherein respective paths between the transmitter and two or more receivers are selected, and wherein the step of providing the optical parameter to the processor of the transmitter comprises steps of:

computing an average of the respective parameter values of each selected path; and

providing the computed average parameter value to the processor of the transmitter, such that the transmitter generates an optical signal that is at least partially pre-compensated for optical impairments of each selected path.

16. An agile all-optical network comprising:

an optical transmitter at a first edge node of the network, the transmitter including a processor for electronically compensating optical impairments based on at least one optical parameter;

means preliminarily identifying a respective optical path between the transmitter and each one of a plurality of receivers; and determining a respective optical parameter for each path; and

during run-time, means:

selecting a path between the transmitter and a receiver for receiving an optical signal from the transmitter; and

providing the respective optical parameter of the selected path to the processor of the transmitter, such that the transmitter generates an optical signal that is pre-compensated for optical impairments of the selected path;

such that routing of optical signal traffic within the network can be performed independently of dispersion differences between respective different paths through the network.

17. The network as claimed in claim 16 further comprising at least one optical add-drop multiplexer (OADM), and wherein the path between the transmitter and a receiver traverses either one of:

a drop-path of the OADM; and

a node subtending a path that traverses a glass-through of the OADM.

18. The network as claimed in claim 16 further comprising at least one optical switch traversed by the path between the transmitter and the receiver.

Assignments (8)