Photoelectron Counter Dead Time Effects on Direct Detection Optical Communication Systems

The effects of photon counter dead time on a direct detection binary pulse position modulation optical communication system are computed for both a free space optical channel and an atmospheric channel subject to clear air turbulence. The degradation in the performance of an optimum receiver structure due to dead time losses was found to be typically 1 dB for the free space channel and less than 1 dB for the atmospheric fading channel, even at the large value of the ratio of counter dead time to counting interval length of ten percent.