COUPLING EFFICIENCIES FOR GENERAL-TARGET-ILLUMINATION LADAR SYSTEMS INCORPORATING SINGLE-MODE OPTICAL-FIBER RECEIVERS

A rigorous method for modeling received power coupling efficiency (eta (F/R)) and transmitted power coupling efficiency (eta(F/T)) in a gener al-target-illumination ladar system is presented. For our analysis we concentrate on incorporating a single-mode optical fiber into the lada r return signal path. By developing expressions for both eta(F/R) and eta(F/T) for a simple, diffuse target, our model allows for varying ra nge, beam size on target, target diameter, and coupling optics. Throug h numerical analysis eta(F/R) is shown to increase as the range to tar get increases and decrease as target diameter increases, and eta(F/T) is shown to decrease with target range. A baseline signal-to-noise rat io analysis of the system is also provided for varying illumination sc hemes. (C) 1998 Optical Society of America.