Abstract

Quantum Communication employing coherent state encoding and quadrature detection is an interesting alternative to the commonly used single-photon strategy. As an example, information can be encoded into binary coherent states (e.g. |α〉 and |−α〉 and measured using either homodyne or heterodyne detectors. Any communication link is however inflicted by noise. Therefore, in order to remove noise from the signal, a filter protocol is needed. Note that filtering differs from distillation. While distillation means the preservation of a single resource state, filtering is the process of preserving a set of states. It has been shown that a distillation protocol is rather difficult to implement when considering Gaussian noise [1], but for non-Gaussian noise, distillation can be performed using only linear optics and homodyne detection as recently demonstrated in [2,3]. In this paper, we consider the process of filtering non-Gaussian noise from binary coherent states using two different measurement methods: homodyne detection and on/off detection.

© 2007 IEEE