Compensation for chromatic dispersion

• US 20040184730A1
• Filed: 03/21/2003
• Published: 09/23/2004
• Est. Priority Date: 03/21/2003
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Grunnet-Jepsen, Anders, Nikonov, Dmitri E., Willis, Thomas G., Tambe, Atul A.
• Granted Patent: US 7,072,546 B2
• Time in Patent Office: Days
• US Class Current: 385/37
• CPC Class Codes: G02B 2006/12107 Grating
• CPC Class Codes: G02B 6/02085 characterised by the grating profile, e.g. chirped, apodised, tilted, helical
• CPC Class Codes: G02B 6/02204 using thermal effects, e.g. heating or cooling of a temperature sensitive mounting body optical modulation using thermo-optic effect G02F1/0147
• CPC Class Codes: G02B 6/12019 characterised by the optical interconnection to or from the AWG devices, e.g. integration or coupling with lasers or photodiodes coupling integrated waveguide to fibre G02B6/30, to optoelectronic element G02B6/42; monolithic integration of integrated waveguides with other optical elements G02B6/12004
• CPC Class Codes: G02B 6/12033 characterised by means for configuring the device, e.g. moveable element for wavelength tuning switching G02B6/35; thermo-optic devices G02F1/0147
• CPC Class Codes: G02B 6/29361 Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
• CPC Class Codes: G02B 6/29394 Compensating wavelength dispersion G02B6/29376 takes precedence; dispersion compensated optical transmission systems H04B10/2507

Abstract

A plurality of channels of a wavelength division multiplexing system may be subjected to dispersion compensation in a fashion which enables tuning of the compensation for each individual wavelength channel. Moreover, the tuning may be done in a space-efficient fashion. The chirped Bragg gratings may be formed, for example, on a planar light circuit. Each grating may be heated to controllably adjust its dispersion compensation, in one embodiment of the present invention.

Claims

1. A method comprising:

demultiplexing two channels; and

providing different dispersion compensation to each channel.

2. The method of claim 1 including multiplexing said channels after providing different dispersion compensation to each of said channels.

3. The method of claim 1 including demultiplexing using a planar waveguide demultiplexer.

4. The method of claim 1 including using Bragg gratings to compensate said channels for dispersion.

5. The method of claim 4 including heating one of said gratings to control the compensation applied to at least one of said channels.

6. The method of claim 5 where the heating profile is variable.

7. The method of claim 1 including providing a planar waveguide to dispersion compensate and demultiplex the two channels.

8. The method of claim 1 including demultiplexing the channels in a demultiplexer and reflecting the dispersion compensated signals back through the demultiplexer.

9. The method of claim 8 including extracting the compensated signals, after being multiplexed, from a circulator.

10. The method of claim 1 including transmitting light of a dispersion compensated wavelength through the Bragg grating.

11. A device comprising:

a demultiplexer having at least two channels; and

a Bragg grating coupled to each of said two channels to provide separate dispersion compensation to each channel.

12. The device of claim 11 including a Bragg grating to provide different dispersion compensation to each channel.

13. The device of claim 11 wherein said demultiplexer is a planar waveguide demultiplexer.

14. The device of claim 12 wherein said element includes a heater to control the compensation applied to at least one of said channels.

15. The device of claim 11 including a circulator coupled to the input of said demultiplexer.

16. The device of claim 11 including a Bragg grating that reflects a dispersion compensated wavelength.

17. The device of claim 11 including a Bragg grating that passes a dispersion compensated wavelength.

18. The device of claim 11 where both demultiplexer and Bragg grating are in the form of a planar waveguide.

19. The device of claim 11 wherein said demultiplexer demultiplexes signals traveling in one direction and multiplexes signals traveling in the opposite direction.

20. The device of claim 11 including a heater on each of said gratings.

21. An optical device comprising:

a demultiplexer to demultiplex a multiple channel signal into at least two channels, said demultiplexer being a planar light circuit; and

a planar Bragg grating optically coupled to each of said channels to provide different dispersion compensation to each of said channels.

22. The device of claim 21 including a heater to control the average index of refraction of at least one of said Bragg gratings.

23. The device of claim 22 including a heater with a variable profile on each of said Bragg gratings.

24. The device of claim 21 including a circulator attached to the input to said demultiplexer.

25. The device of claim 21 wherein said planar light circuit includes an arrayed waveguide grating.

26. The device of claim 21 wherein at least one of said Bragg gratings reflects a dispersion compensated wavelength.

27. The device of claim 21 wherein at least one of said Bragg gratings passes a dispersion compensated wavelength.

28. The device of claim 21 wherein said planar light circuit is an arrayed waveguide which demultiplexes said signal passing in one direction and re-multiplexes signals reflected from said Bragg gratings.

29. The device of claim 26 where the light from said Bragg grating is directed to separate outputs.

30. The device of claim 29 wherein Bragg gratings are formed in each arm of an interferometer.