A rigorous method for modeling received power coupling efficiency (η<sub><i>F/R</i></sub>) and transmitted power coupling efficiency (η<sub><i>F/T</i></sub>) in a general-target-illumination ladar system is presented. For our analysis we concentrate on incorporating a single-mode optical fiber into the ladar return signal path. By developing expressions for both η<sub><i>F/R</i></sub> and η<sub><i>F/T</i></sub> for a simple, diffuse target, our model allows for varying range, beam size on target, target diameter, and coupling optics. Through numerical analysis η<sub><i>F/R</i></sub> is shown to increase as the range to target increases and decrease as target diameter increases, and η<sub><i>F/T</i></sub> is shown to decrease with target range. A baseline signal-to-noise ratio analysis of the system is also provided for varying illumination schemes.
© 1998 Optical Society of America
Christopher D. Brewer, Bradley D. Duncan, Kenneth J. Barnard, and Edward A. Watson, "Coupling efficiencies for general-target-illumination ladar systems incorporating single-mode optical fiber receivers," J. Opt. Soc. Am. A 15, 736-747 (1998)