Patent ID: 8233809

Claim:
A method for polarization independent, frequency domain equalization-based chromatic dispersion compensation of a polarization multiplexed (PolMux) optical signal comprising: applying the PolMux optical signal to an optical hybrid such that four output signals X′ I , X′ Q , Y′ I , Y′ Q are produced wherein X′ and Y′ represent two random polarizations orthogonal to one another and I and Q represent two orthogonal phases; generating four digital electrical signals from the four output signals; applying the four digital electrical signals to a digital signal processor wherein the followings are performed: performing a frequency domain equalization-based chromatic dispersion compensation of the four digital electrical signals thereby producing two complex signals; polarization demultiplexing the two complex signals; and demodulating X and Y data from the two complex signals such that two signals Pol-X data and Pol-Y data are produced, wherein said frequency domain equalization-based chromatic dispersion compensation includes: converting the digital signals to parallel digital signals in a frame-by-frame manner; forming a fast fourier transform (FFT) frame of size M from the converted frame; transforming the FFT frame into a frequency domain; multiplying the frequency domain frame with corresponding coefficients; performing an inverse FFT to transform the frame into the time domain; and adding the first N−1 output time domain signals from this frame with the last N−1 output time domain signals from the previous frame such that final output signals are produced.