A consideration on optimum direct detection optical communication receiver

Abstract

AbstractThis paper presents an optimum receiver for direct detection/binary intensity modulation optical communication systems. Here, the signal‐plus‐noise model assumes a signal‐dependent nonstationary Gaussian random process. Moreover, assuming white noise and an ideal low‐pass receiver, the receiver vector is generated by sampling of signals and noise. The likelihood ratio for this receive vector is derived based on the maximum likelihood test to determine the structure of optimum receiver. This paper shows that the optimum receiver has both the usual correlation detection for additive noise in the radio wave region and noise energy detection for the signal shot noise. Next, the error rate of this receiver is derived theoretically and its characteristics are evaluated. As a result, the signal shot noise can be effectively utilized for signal detection by allowing a greater bandwidth for the receiver, elucidating treatment of the shot noise from the standpoint of statistical signal detection theory.