This paper presents detailed numerical and experimental study of SPM in semiconductor optical amplifiers (SOAs) with
ultrafast gain-recovery times. These SOAs have a range of gain-recovery speed which is a function of drive current. At
increased drive current, the amount of internal ASE in the SOA increases, which causes the small signal gain to saturate
and reduces the gain-recovery time. Understanding pulse amplification in these SOAs is important for optimizing the
performance of SOA-based optical regenerators and wavelength converters. Our study addresses the full range of gain-recovery
times in commercial SOAs extending from less than 10 ps to >100 ps.