Gain and phase recovery of optically excited semiconductor optical amplifiers

An investigation of the recovery dynamics of semiconductor optical amplifiers (SOAs) explains why the ultrafast component of the gain recovery is largely absent in the phase response. The time-resolved gain and phase dynamics of a bulk GaInAs SOA are measured using a pump-probe technique and differences between the gain and phase recoveries are highlighted and explained using Kramers-Kronig analysis. These have important implications for optical signal processing.