Ultrafast all-optical switching in AlGaAs photonic crystal waveguide interferometers

We have demonstrated ultrafast all-optical switching with photonic crystals integrated into AlGaAs Mach-Zehnder interferometers. The nonlinearity is induced by optical excitation of carriers into one arm of the interferometer, and switching times as short as 3 ps are achieved by surface recombination at the air holes in the photonic crystal. The fast recombination times and high nonlinearities of the AlGaAs material make this design suitable for high speed all-optical switching applications. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3236542]