Optical device including dynamic channel equalization

• US 20040228602A1
• Filed: 06/15/2004
• Published: 11/18/2004
• Est. Priority Date: 01/28/2000
• Status: Active Grant

• Current Assignee: Ciena Corporation
• Original Assignee: Ciena Corporation
• Inventors: Brenner, Tomas, Livas, Jeffrey C.
• Granted Patent: US 6,931,196 B2
• Time in Patent Office: Days
• US Class Current: 385/140
• CPC Class Codes: H04B 10/077 using a supervisory or additional signal
• CPC Class Codes: H04B 10/07955 Monitoring or measuring power
• CPC Class Codes: H04B 10/296 Transient power control, e.g. due to channel add/drop or rapid fluctuations in the input power
• CPC Class Codes: H04L 2025/03477 not time-recursive
• CPC Class Codes: H04L 2025/03611 Iterative algorithms

Abstract

An optical device including dynamic channel equalization is provided. In an exemplary multiplexer or line amplifier configuration the device includes a plurality of separate optical paths, each of which receiving a separate group of optical signals. Each group of optical signals is provided to an associated variable optical attenuator. Separate inputs of an optical combiner are each coupled to an output of an associated one of the variable optical attenuators. The optical combiner has an output providing the separate groups of optical signals in an aggregated form on an aggregate optical signal path. An optical performance monitor is coupled to the aggregate optical signal path, and is configured to detect an optical signal to noise ratio of each of the separate groups. The monitor supplied a feedback signal to corresponding ones of the variable optical attenuators for adjusting a respective attenuation associated with each of the attenuators in dependence of the detected optical signal to noise ratios. The device may also be provided in a demultiplexer configuration.

Claims

1. An optical apparatus comprising:

a plurality of separate optical paths, each of which receiving a separate group of optical signals;

a plurality of variable optical attenuators, each of which having an input coupled to an associated one of said separate optical paths;

an optical combiner having separate inputs, each of which coupled to an output of an associated one of said variable optical attenuators, said optical combiner having an output providing said separate groups of optical signals in an aggregated form on an aggregate optical signal path; and

an optical performance monitor coupled to said aggregate optical signal path, said optical performance monitor being configured to detect a plurality of optical signal to noise ratios, each of which being associated with a respective one of said separate groups and to supply a feedback signal to corresponding ones of said variable optical attenuators for adjusting a respective attenuation associated with each of said attenuators in response to the detected plurality of optical signal to noise ratios.

2. An optical apparatus according to claim 1, wherein said device further comprises a plurality of first optical combiners, each of which being coupled to an associated one of said optical paths for supplying a respective one of said separate groups of optical signals.

3. An optical apparatus according to claim 1, wherein said device further comprises an optical demultiplexer, said optical demultiplexer having a plurality of outputs, each of which being coupled to an associated one of said optical paths for supplying a respective one of said separate groups of optical signals.

4. An optical apparatus according to claim 1, wherein said device further comprises an optical amplifier coupled to an output of said optical combiner.

5. An optical apparatus according to claim 1, wherein said device further comprises a filter coupled to said aggregate optical signal path, said filter having an output coupled to an input of said optical performance monitor.

6. An optical apparatus according to claim 1, wherein said combiner comprises a plurality of cascaded optical filters, each of said optical filters having an input coupled to an output of an associated one of said variable optical attenuators.

7. An optical apparatus according to claim 1, wherein said optical performance monitor circuit comprises an optical spectrum analyzer for detecting said plurality of optical signal to noise ratios and a processor circuit for supplying said feedback signals.

8. An optical apparatus according to claim 1,

said optical performance monitor being configured to detect a plurality of optical signal to noise ratios and optical powers, each of which being associated with a respective one of said separate groups and to supply a feedback signal to corresponding ones of said variable optical attenuators for adjusting a respective attenuation associated with each of said variable optical attenuators in response to said detected plurality of optical signal to noise ratios and optical powers.

9. The optical apparatus according to claim 1, wherein at least one of the groups of optical signals includes only one wavelength division multiplexed channel.

10. An optical apparatus comprising:

an optical communication path receiving an optical signal including a plurality of separate wavelengths;

an optical performance monitor coupled to said optical communication path, said optical performance monitor circuit being configured to detect a plurality of optical signal to noise ratios, each of which being associated with a respective one of a plurality of separate groups of said separate wavelengths and to supply separate feedback signals in response to said detected plurality of optical signal to noise ratios;

an optical demultiplexer configured to receive an output of said optical performance monitor circuit, said demultiplexer supplying each of said plurality of groups of said separate wavelengths on a separate associated output; and

a plurality of variable optical attenuators, each of which receiving a separate one of said separate associated outputs, each of said plurality of optical attenuators receiving an associated one of said separate feedback signals for adjusting an associated attenuation level.

11. An optical device apparatus according to claim 10, wherein said device further comprises an optical amplifier coupled to said optical communication path.

12. An optical apparatus according to claim 10 wherein said device further comprises a filter coupled to said optical communication path, said filter having an output coupled to an input of said optical performance monitor.

13. An optical apparatus according to claim 10, wherein said optical performance monitor circuit comprises an optical spectrum analyzer for detecting said optical signal and a processor circuit for supplying said feedback signals.

14. A method for processing optical signals, comprising:

providing each of a plurality groups of said optical signals on a respective one of a plurality of separate optical signal paths;

combining each of said groups of optical signals on an aggregate optical signal path;

detecting a plurality of optical signal to noise ratios, each of said plurality of optical signal to noise ratios being associated with a corresponding one of said plurality of groups of optical signals; and

attenuating each group of said plurality of optical signals on said separate optical signal paths in response to a corresponding one of said detected plurality of optical signal to noise ratios.

15. A method for processing optical signals according to claim 14,

said detecting step detecting a plurality of optical signal powers and optical signal to noise ratios, each of said optical signal powers and said optical signal to noise ratios being associated with a corresponding one of said plurality of groups of optical signals,

said attenuating step attenuating each group of said plurality of optical signals on said separate optical paths in response to corresponding ones of the optical signal powers and optical signal to noise ratios.

16. A method for processing optical signals according to claim 14, wherein at least one of the groups of optical signals includes only one wavelength division multiplexed channel.

17. A method for processing optical signals, comprising:

providing each of a plurality of groups of said optical signals in an aggregated form on an optical signal path;

detecting plurality of optical signal to noise ratios, each of said plurality of optical signal to noise ratios being associated with a corresponding one of said plurality of groups of optical signals;

separating said groups of optical signals onto associated separate optical signal paths; and

attenuating each group of said plurality of optical signals on said separate optical signal paths in response to a corresponding one of said detected plurality of optical signal to noise ratios.

18. A method for processing optical signals according to claim 17,

said detecting step detecting a plurality of optical signal powers and optical signal to noise ratios, each of said optical signal powers and said optical signal to noise ratios being associated with a corresponding one of said plurality of groups of optical signals,

said attenuating step attenuating each group of said plurality of optical signals on said separate optical paths in response to corresponding ones of said optical signal powers and optical signal to noise ratios.

19. A method for processing optical signals according to claim 17, wherein at least one of the groups of optical signals includes only one wavelength division multiplexed channel.