Semiconductor devices for all-optical signal processing: just how fast can they go?

Several different semiconductor device structures for accomplishing all-optical signal processing have been proposed, but they nearly all employ the semiconductor optical amplifier (SOA) as a central element. In this talk we will discuss the physical processes in SOA´s that are important in determining the speed of SOA based switches. We shall consider both devices based on incoherent processes, such as optically induced cross-gain and cross-phase modulation as well as devices employing coherent four-wave mixing