Colorless Differential Phase Shift Keyed and Low Crosstalk Demodulators
AssigneeNEC Laboratories America, Inc.
InventorsLei Xu, Ting Wang, Philip Ji, Lei Zong, Milorad Cvijetic
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Abstract
A new differential phase-shift-keyed demodulator is disclosed which can achieve signal demodulation at different wavelengths on ITU grids without requiring active thermal tuning. In accordance with another aspect of the invention, a low-crosstalk demodulator is disclosed which reduces channel leakage by placing neighboring channels at non-optimal interference positions. A demodulator in accordance with the invention may be deployed in a WDM optical system.
Claims22
A differential phase shift keyed demodulator comprising:
- an input receiving at least two different wavelength channels of differential phase shift keyed communication signals;
- a delay element which is tuned to simultaneously delay the different wavelength channels so that, when delayed signals are recombined with undelayed signals, the differential phase shift keyed communication signals are converted in parallel to intensity modulated signals for the different wavelength channels.
In a wavelength division multiplexing (WDM) optical system having a plurality of differential phase-shift keyed (DPSK) transmitters for outputting a plurality of different wavelength channels of DPSK communication signals and a wavelength multiplexer for multiplexing the different wavelength channels of DPSK communication signals:
- a demodulator coupled to the wavelength multiplexer and comprising an input receiving the multiplexed wavelength channels of DPSK communication signals and a delay element which is tuned to simultaneously delay the different wavelength channels so that, when delayed signals are recombined with undelayed signals, the DPSK communication signals are converted in parallel to intensity modulated signals for the different wavelength channels;
- a wavelength demultiplexer coupled to an output of the DPSK demodulator for demultiplexing the intensity modulated signals into a plurality of demultiplexed intensity modulated signals.
A differential phase shift keyed demodulator comprising:
- an input receiving at least two different wavelength channels of differential phase shift keyed communication signals;
- a delay element which is tuned to simultaneously delay the different wavelength channels so that, when delayed signals are recombined with undelayed signals, the differential phase shift keyed communication signals are placed at non-optimal interference positions for the different wavelength channels.
Dependencies are inferred from the claim text.