Ultrafast optical switching based on nonlinear polarization rotation in silicon waveguides

We experimentally realize ultrafast all-optical switching in the 1.5-microm spectral region using cross-phase modulation inside a 5-mm long silicon waveguide. Modulation depths of up to 90% and switching window durations approximately 1 ps are achieved using 500-fs pump pulses with energies below 10 pJ.