Binary Detection in an Optical Twin Channel Receiver

In this concise paper we sketch the derivation of a rigorous (and tight) upper bound on the probability of error in a binary pulse-code modulation (PCM) twin channel optical receiver in the absence of thermal noise. This result is valid for any binary system, described by Poisson statistics in each of its states, in which the binary decision is based on which state has the larger count. Examples of such systems include polarization modulation, binary pulse position modulation, frequency-shift keying with separate detectors, and differentially-coherent phase-shift keying.