  We present the generation and characterization of the class of bracket
states, namely phase-sensitive mixtures of coherent states exhibiting symmetry
properties in the phase-space description. A bracket state can be seen as the
statistical ensemble arriving at a receiver in a typical coherent-state-based
communication channel. We show that when a bracket state is mixed at a beam
splitter with a local oscillator, both the emerging beams exhibit a Fano factor
larger than 1 and dependent on the relative phase between the input state and
the local oscillator. We discuss the possibility to exploit this dependence to
monitor the phase difference for the enhancement of the performances of a
simple communication scheme based on direct detection. Our experimental setup
involves linear optical elements and a pair of photon-number-resolving
detectors operated in the mesoscopic photon-number domain.
