Four-wave mixing in semiconductor optical amplifiers for frequency conversion and fast optical switching

Four-wave mixing (FWM) in semiconductor optical amplifiers (SOA's) is an important tool for frequency conversion and fast optical switching in all-optical communication networks, We review the main applications of SOA's as nonlinear optical components, Concentrating on FWM, we define general parameters that are of relevance for signal processing applications, We show, how basic experiments and general simulation procedures can be used to determine optimum operating conditions for the intended applications, Besides a comprehensive investigation of FWM among continuous waves, we present new experimental results on FWM with picosecond optical pulses, A comparison of both reveals a different behavior and demonstrates that new optimization criteria and advanced theoretical models have to be applied for the case of short optical pulses. Moreover, we discuss the possibility to extract the dynamical SOA parameters from our experiments.