Free-Carrier-Induced Nonlinear Relaxation in a Silicon Waveguide

This letter reports our study on the effects of free carrier lifetimes due to surface/interface recombination and Auger recombination on the nonlinear dynamics of light propagation in a silicon waveguide at moderate to high power levels. It is shown that due to the coupling dynamics between the optical intensity and the free carrier density, the effective decay time of the optical intensity in the waveguide is not constant but becomes significantly reduced at high input powers, a result which may have important implications to nonlinear optics applications of silicon waveguides such as all-optical switching and modulation.