Chromatic Dispersion Equalization FIR Digital Filter for Coherent Receiver

Abstract

Chromatic dispersion equalization (CDE) in coherent optical communication systems is extremely critical for subsequent digital signal processing (such as frequency offset estimation and carrier phase recovery). Various methods mentioned in the published literature are not satisfactory when the signal bandwidth is limited. This paper proposes a way of using singular value decomposition least square (SVDLS) to obtain the optimal tap weight of the CDE filter and a method to introduce the adaptive mutation particle swarm optimizer (AMPSO) algorithm into the CDE. We show that the two proposed approaches are based on the best approximation of the frequency domain response of the designed and ideal CDE filter. Compared with the traditional CDE method, which needs to be implemented in the full frequency band, the two methods can be implemented in the narrow frequency band. The simulation shows that the effective bandwidth of the baseband signal is limited by squared-root-raised-cosine (SRRC) pulse shaping with a roll-off factor of 0.25 in different modulation formats (DP-QPSK, DP-16 QAM, DP-64 QAM) when the number of taps of the filter is 131, which is 37.5% less than the full frequency band. The designed filter is superior to the existing filter in terms of filtering effect and implementation complexity.

Design and Development of GUI for the Mitigation of Chromatic Dispersion: A New Approach

“…By further solving for z = 0 at instantaneous value for frequency will generate the transfer function as in (7):…”

“…After that signal having transfer function of chromatic dispersion in (7), the inverse FFT is taken in order to show the signal in time domain via (8):…”

“…The author Wu in [7] has focused the equalization of Chromatic dispersion equalization for optical communication using PSO algorithm the proposed system was designed using the programming no simulator or GUI was created in order to facilitate the design for future perspective. The system was tested for QAM modulation and reduction of chromatic dispersion with 25% was attained using the proposed system.…”