Ultrafast all-optical modulation in silicon-based nanoplasmonic devices

A five-layer silicon-based nanoplasmonic waveguiding structure is proposed for ultrafast all-optical modulation and switching applications. Ultrafast nonlinear phase and amplitude modulation is achieved via photo-generated free carrier dynamics in ion-implanted silicon using above-bandgap femtosecond pump pulses. Both an analytical model and rigorous numerical simulations of the structures have shown that a switching time of 5 ps and an on-off contrast of 35 dB can be achieved in these devices.