Switches and frequency converters based on cross-gain modulation in semiconductor optical amplifiers

The large-signal theory of frequency converters based on cross-gain and cross-phase modulations in a semiconductor optical amplifier is developed, for the case in which pump and probe are injected from the same facet (co-propagating case). Simple expressions for the bandwidth of cross-gain modulation are derived for single and cascaded SOA´s, and large-signal simulations are carried out for cascaded SOA´s, pointing out some important system issues. In the cascaded case, the effect of the loss between the SOA´s is highlighted.