Time dependent density of free carriers generated by two photon absorption in silicon waveguides

摘要

Carrier diffusion and recombination are considered in calculating the time dependent density of free carriers generated by two photon absorption in silicon waveguides. The calculations are compared to experimental results from optical pump-probe measurements of the induced loss from free carrier absorption. A generalized definition of nonlinear effective length is proposed to describe the effects of nonlinear loss. The authors experimentally demonstrate that helium-ion implantation can reduce the effective carrier lifetime and report on the observation of enhanced self-phase modulation in the helium implanted silicon waveguide.