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US 6,603,890 B2Granted
Compensation for polarization-mode dispersion in multiple wavelength-division multiplexed channels without separate composition for each individual channel
AssigneeUniversity of Southern California
InventorsReza Khosravani, Steven A. Havstad, Yong-Won Song, Paniz Ebrahimi, Alan E. Willner
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Abstract
Techniques for compensating for PMD in multiple WDM channels by processing all WDM channels in the same manner without demultpliexing the channels. A feedback control is provided to decrease the worst-case power penalty and the channel fading probability by optimizing over the entire group of WDM channels.
Claims18
A system, comprising:
- a polarization-mode dispersion (PMD) compensator operable to guide a plurality of wavelength-division multiplexed (WDM) optical channels through a common optical path to modify a differential group delay (DGD) in each channel, said PMD compensator operable to adjust said DGD in response to a control signal;
- and
- a feedback control coupled to measure an AC electrical power proportional to the total optical power of said channels, and wherein the feedback control is further operable to generate said control signal to increase said AC electrical power.
A method, comprising:
- directing each of a plurality of wavelength-division multiplexed (WDM) optical channels through a common optical path to modify a differential group delay (DGD) in each channel so as to produce an output with modified WDM channels;
- measuring power of an AC portion of said output;
- and
- modifying the DGD to increase said power.
1 more element
A system, comprising:
- a polarization-mode dispersion (PMD) compensator operable to guide a plurality of wavelength-division multiplexed (WDM) optical channels through a common optical path to modify a differential group delay (DGD) in each channel, said common optical path comprising a plurality of adjustable units connected in series respectively operable to adjust the DGD in response to a plurality of control signals, respectively;
- and
- a feedback control coupled to measure an AC electrical power proportional to the total optical power of said channels after transmitting through said common optical path, and wherein the feedback control is further operable to generate said control signals to increase said AC electrical power.
A method, comprising:
- directing each of a plurality of wavelength-division multiplexed (WDM) optical channels through a common optical path to modify a differential group delay (DGD) in each channel so as to produce an output with modified WDM channels;
- and
- controlling said DGD to reduce an overall signal fading in said output caused by polarization-mode dispersion (PMD) on all of said channels without separately compensating PMD in each channel.
Dependencies are inferred from the claim text.