BER performance of bandwidth-limited QPSK optical coherent receiver with carrier phase estimation

In this paper, the bit error-rate (BER) performance considering the impact of bandwidth limitation of electronic devices is investigated in QPSK coherent receiver with carrier phase estimation. Before signal sampling, we introduce a low-pass filter to model this bandwidth limitation which induces inter-symbol interference (ISI). Two phase estimation (PE) schemes, decision-aided maximum likelihood (DAML) and M-th power, are considered. Monte-Carlo (MC) simulation results show that, for different optical signal to noise ratios (OSNRs) and PE schemes, 0.7-0.9 times the symbol rate is always a reasonable bandwidth range which includes the optimal bandwidth. It is also found that the advantage of DAML receiver compared to M-th power would be destroyed when ISI is determinant of BER performance.