Title :
Mitigation of Imperfect Carver-Induced Phase Distortions in a Coherent PM-RZ-QPSK Receiver
Author :
Chung, Hwan Seok ; Chang, Sun Hyok ; Kim, Kwangjoon
Author_Institution :
Opt. Internet Res. Dept., Electron. & Telecommun. Res. Inst., Daejeon, South Korea
Abstract :
The impact of phase distortions caused by imperfect return-to-zero (RZ) pulse carving on 112 Gb/s polarization-multiplexed (PM)-RZ-quadrature-phase-shift-keying (QPSK) is investigated, and mitigation of the phase distortion is demonstrated by using digital signal processing technique. We show that carver-induced phase distortion causes an error in frequency offset estimation as well as sensitivity degradation. Based on the periodicity of distortion pattern, the phase distortion is compensated by estimating mean phase distortions for even and odd symbols after block phase estimation and subtracting these values from original symbols. The optical SNR penalty measured at 112 Gb/s PM-RZ-DQPSK signal is reduced from 3.8 to 1.1 dB with the help of correction algorithm.
Keywords :
distortion; phase shift keying; receivers; signal processing; block phase estimation; coherent PM-RZ-QPSK receiver; digital signal processing; distortion pattern; frequency offset estimation; imperfect carver-induced phase distortions; imperfect return-to-zero pulse carving; mean phase distortion; polarization multiplexed-RZ-quadrature-phase-shift-keying; sensitivity degradation; Estimation; Frequency estimation; Optical distortion; Optical noise; Optical transmitters; Phase distortion; Signal to noise ratio; 100 Gb/s; coherent; pulse carver; return-to-zero quadrature- phase-shift-keying (RZ-QPSK);
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2010.2090131
