Polarization-Mode Dispersion Impairment in Return-to-Zero and Nonreturn-to-Zero Systems

Using 10 Gb/s signals, amplitude modulated with either a return-to-zero (RZ) or a nonreturn-to-zero format (NRZ),we measured optically-preamplified receiver sensitivity after distortion by polarization mode dispersion (PMD). RZ modulation was found to be more resilient to PMD than NRZ modulation.