Error-rate floors in differential n-level phase-shift-keying coherent receivers employing electronic dispersion equalisation

摘要

A model for the phase noise influence in differential n-level phase shift keying (nPSK) systems and 2n-level quadrature amplitude modulated (2nQAM) systems employing electronic dispersion equalization and quadruple carrier phase extraction is presented. The model includes the dispersion equalization enhanced local oscillator phase noise influence. Numerical results for phase noise error-rate floors are given for dual polarization (DQPSK, D16PSK and D64PSK) system configurations with basic baud-rate of 25 GS/s. The transmission distance in excess of 1000 km requires local oscillator lasers with sub-MHz linewidth.