Spectral-slicing noise in polarization-modulated optical links

Polarization-shift keying offers multi-dimensional signaling for optical links to achieve high data rates using low-coherence sources. In binary systems with spectrally sliced broadband sources, on–off keying with a finite extinction ratio causes non-Gaussian noise distributions that lead to bit-error-rate floors. We show theoretically and experimentally that binary polarization-shift keying eliminates these error floors as well as improves sensitivity under all tested conditions.