Chromatic dispersion compensation using complex-valued all-pass filter

We propose a new optimization framework to compensate chromatic dispersion by complex-valued infinite impulse response (IIR) all-pass filter. The design of the IIR all-pass filter is based on minimizing the mean square error (MSE) in group-delay and phase cost functions. The necessary conditions are derived and incorporated into a multi-step optimization framework to ensure the stability of the resulting IIR filter. It is shown that IIR filter achieves similar or slightly better performance compared to its finite impulse response (FIR) counterpart. Moreover, IIR filtering requires significantly less number of taps to compensate the same CD channel compared to FIR filtering.