Dynamically reconfigurable optical smart node

• US 7,123,833 B2
• Filed: 08/08/2002
• Issued: 10/17/2006
• Est. Priority Date: 08/09/2001
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Cidra Sarl (Nordic Cultural & Educational Foundation)
• Inventors: Davis, Michael A., Moon, John A., Dawson, Jay W., Szczepanek, Paul
• Primary Examiner(s): Payne, David C.
• Application Number:
  US10/216,000
• Publication Number:
  US 20030053175A1
• Time in Patent Office: 1,531 Days
• Field of Search: 398/33, 398 81- 83, 398/177
• US Class Current: 398/33
• CPC Class Codes: H04B 10/0797 Monitoring line amplifier or line repeater equipment
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant

Abstract

A smart node is provided for use in an optical communications network wherein the smart node comprising dynamically reconfigurable optical signal manipulation devices in combination with sensing devices and processors to provide real time closed and open loop control of various channels of the network.

Claims

1. A smart node for use in an optical communications network having optical signals, the smart node providing continuous, real time, autonomous feedback and correction with closed and/or open loop control of the optical signals in the optical communications network, the smart node comprises:

an equalization filter for filtering the optical signals in response to a feedback processor signal;

a coupler for coupling filtered optical signals;

a channel monitor for monitoring a feedback portion of the filtered optical signals; and

a processor for processing a channel monitor signal from the channel monitor, and providing the feedback processor signal to the equalization filter.

2. A smart node according to claim 1, wherein the smart node further comprises:

an input/output user interface for receiving input signals from a user and providing user input interface signals to the processor, and for receiving user output signals from the processor and providing user output interface signals to the user.

3. A smart node according to claim 1, wherein the optical signals include different wavelengths, bands or channels.

4. A smart node according to claim 1, wherein the optical signals include wavelength division multiplexed signals having various levels of power.

5. A smart node according to claim 1, wherein the equalization filter is a dynamic gain equalization filter that selectively attenuates one or more wavelengths, bands or channels to provide a dynamic gain equalization filter signal.

6. A smart node according to claim 5, wherein the dynamic gain equalization filter is either a pixelated optical filter, a Mach Zender/Fourier interference filter, acoustic filter, array waveguide or variable optical attenuator.

7. A smart node according to claim 1, wherein the channel monitor signal is indicative of a profile of the power levels of the various wavelengths, channels or bands of the optical signals.

8. A smart node according to claim 1, wherein the channel monitor is a micromirror device, an optical channel monitor (OCM), an optical channel analyzer (OCA), or optical power meter capable of accurately monitoring power levels.

9. A smart node according to claim 1, wherein the processor includes software and hardware capable of dynamically controlling the equalization filter to equalize the power spectrum of wavelengths, channels or bands entering the equalization filter.

10. A smart node according to claim 1, wherein the processor, upon receiving information from the channel monitor, provides commands to the equalization filter to selectively attenuate preselected wavelengths, channels or bands to provide a preselected spectrum output.

11. A smart node according to claim 1, wherein the processor attenuates each of the optical signals by substantially the same amount and controllably attenuates the optical signals so that the output amplifier is provided with a preselected gain profile for each of the optical signals.

12. A smart node according to claim 1, wherein the processor corrects the gain tilt of the output amplifier.

13. A smart node according to claim 1, wherein the output amplifier provides a second stage of amplification.

14. A smart node according to claim 1, wherein the coupler is an optical tap or splitter.

15. A smart node according to claim 1, wherein the channel monitor has either a band attenuation mode or a channel-by-channel mode.

16. A smart node according to claim 2, wherein the channel monitor has either a band attenuation mode or a channel-by-channel mode.

17. A smart node according to claim 16, wherein the equalization filter and the channel monitor share a common digital micro-mirror device.

18. A smart node according to claim 2, wherein the input/output user interface includes an input user interface for receiving inputs from an outside user for dynamically changing the configuration of the smart node, including timing, traffic or other distinct attribute basis.

19. A smart node according to claim 2, wherein the input/output user interface includes an output user interface for providing outputs containing information that may cause an outside user to dynamically change the configuration of the smart node.

20. A smart node according to claim 2, wherein the outputs include the power levels of various bands or channels, the band or channel spacing, channel drift, the degree of attenuation taking place, and along with other sensors or devices, the amount of dispersion/correction, empty channels, or a combination thereof.

21. A smart node according to claim 1, wherein the smart node includes a reconfigurable optical add/drop multiplexer for adding and dropping one or more of the optical signals to and from the smart node.

22. A smart node according to claim 21, wherein the processor either through programmed software, firmware, or by other means, commands the reconfigurable optical add/drop multiplexer to add certain channels and/or drop other certain channels.

23. A smart node according to claim 1, wherein the smart node comprises:

an input amplifier for amplifying the optical signals; and

an output amplifier for amplifying the filtered optical signals and providing a dynamically reconfigurable filtered and amplified output signal.

24. A smart node according to claim 1, wherein the smart node comprises:

an input amplifier for amplifying the optical signals.

25. A smart node according to claim 1, wherein the smart node comprises:

an output amplifier for amplifying the filtered optical signals and providing a dynamically reconfigurable filtered and amplified output signal.

26. A smart node according to claim 23, wherein the input amplifier, output amplifier or a combination thereof is an erbium doped fiber amplifier.

27. A smart node according to claim 23, wherein the output amplifier is arranged between the equalization filter and the coupler.

28. A smart node according to claim 27, wherein the smart node includes a reconfigurable optical add/drop multiplexer for adding and dropping one or more of the optical signals to and from the smart node.

29. A smart node according to claim 28, wherein the reconfigurable optical add/drop multiplexer is arranged between the input amplifier and the equalization filter and controlled by the processor.

30. A smart node according to claim 29, wherein the reconfigurable optical add/drop multiplexer provides subsequent equalization and other manipulation of an added channel.

31. A smart node according to claim 27, wherein the reconfigurable optical add/drop multiplexer is arranged after the coupler and controlled by the processor.

32. A smart node according to claim 27, wherein the reconfigurable optical add/drop multiplexer is arranged before the input amplifier and controlled by the processor.

33. A smart node according to claim 29, wherein the smart node includes a dispersion sensor and a dispersion compensator that combine to provide the ability to dynamically compensate for dispersion within the various bands or channels.

34. A smart node according to claim 33, wherein

the smart node includes a second coupler arranged after the coupler connected to the output amplifier;

the dispersion sensor is arranged between the second coupler and the processor, receives a small portion of the filter optical signals from the coupler, and determines the dispersion among the various channels or bands; and

the dispersion compensator is arranged between the reconfigurable optical add/drop multiplexer and the equalization filter and compensates for the dispersion of the various channels.

35. A smart node according to claim 34, wherein the dispersion sensor and the dispersion compensator are controlled by the processor.

36. A smart node according to claim 34, wherein the dispersion sensor comprises a bit error rate detector, an open eye diagram or other devices suitable for detecting chromatic dispersion, polarization mode dispersion or dispersion slope.

37. A smart node according to claim 34, wherein the dispersion compensation device comprises a chromatic dispersion compensator (CDC), a polarization mode dispersion compensator (PMDC) or a dispersion slope compensator.

38. A smart node according to claim 33, wherein

the smart node includes a second coupler arranged after the coupler connected to the output amplifier;

the dispersion sensor is arranged between the second coupler and the processor, receives a small portion of the filter optical signals from the coupler, and determines the dispersion among the various channels or bands; and

the dispersion compensator is arranged between the equalization filter and the output amplifier and compensates for the dispersion of the various channels.

39. A smart node according to claim 28, wherein the smart node includes a wavelength conversion device optically coupled to the reconfigurable optical add/drop multiplexer.

40. A smart node according to claim 39, wherein the wavelength conversion device provides for the ability to dynamically add a channel regardless of its wavelength.

41. A smart node according to claim 39, wherein the wavelength conversion device comprises a tunable laser controlled by the processor.

42. A smart node according to claim 39, wherein the reconfigurable optical add/drop comprises a device for providing a single channel to be selected that will be wavelength converted and dropped from a full dense wavelength division multiplexed data stream.