The transmitted energy required for an airborne laser radar system to be able to image a target at 20 km is investigated. Because direct detection is being considered, two methods of enhancing the received signal are discussed: (1) using an avalanche photodiode (APD) as the detector and (2) using a commercial fiber amplifier as a preamplifier before a photodetector. For this analysis a specified signal-to-noise ratio was used in conjunction with the radar range equation, which includes the effects of atmospheric transmission and turbulence. Theoretical analysis reveals that a system with a fiber amplifier performs nearly the same as a system incorporating an APD.
© 1995 Optical Society of America
Jay A. Overbeck, Michael S. Salisbury, Martin B. Mark, and Edward A. Watson, "Required energy for a laser radar system incorporating a fiber amplifier or an avalanche photodiode," Appl. Opt. 34, 7724-7730 (1995)