Binary optical communication in single-mode and entangled quantum noisy channels

Abstract

We address binary optical communication in single-mode and entangled quantum noisy channels. For single-mode we present a systematic comparison between direct photodetection and homodyne detection in realistic conditions, i.e. taking into account the noise that occurs both during the propagation and the detection of the signals. We then consider entangled channels based on twin-beam state of radiation, and show that with realistic heterodyne detection the error probability at fixed channel energy is reduced in comparison to the single-mode cases for a large range of values of quantum efficiency and noise parameters.