Fundamental limits on optical pulse detection and digital communication

In this paper, the techniques of statistical decision theory are applied to direct detection of optical pulses. A realistic and general model of a classical photodetector/amplifier receiver is considered. Optimum decision strategies and corresponding receiver sensitivities are derived both for single-pulse detection and for continuous digital communication in which the intersymbol interference is constrained to be zero. A comparison is made to the classic work of Personick and Smith. Their results are shown to be remarkably close to the fundamental limits at high bit rates. At low bit rates, the optimal filter for small duty-cycle pulses gives much better performance than the filters analyzed by Personick and Smith. Optimum values for the Personick integrals are also given. Results are given for a number of cases of practical importance including a photodiode/FET receiver