2 research outputs found
Chromatic Dispersion Compensation Using Filter Bank Based Complex-Valued All-Pass Filter
A long-haul transmission of 100 Gb/s without optical chromatic-dispersion
(CD) compensation provides a range of benefits regarding cost effectiveness,
power budget, and nonlinearity tolerance. The channel memory is largely
dominated by CD in this case with an intersymbol-interference spread of more
than 100 symbol durations. In this paper, we propose CD equalization technique
based on nonmaximally decimated discrete Fourier transform (NMDFT) filter bank
(FB) with non-trivial prototype filter and complex-valued infinite impulse
response (IIR) all-pass filter per sub-band. The design of the sub-band IIR
all-pass filter is based on minimizing the mean square error (MSE) in group
delay and phase cost functions in an optimization framework. Necessary
conditions are derived and incorporated in a multi-step and multi-band
optimization framework to ensure the stability of the resulting IIR filter. It
is shown that the complexity of the proposed method grows logarithmically with
the channel memory, therefore, larger CD values can be tolerated with our
approach