Nonlinear response of high efficient in-plane channel drop filter in Si heterostructure photonic crystal slab

High Q, small volume microcavities show a nonlinear response to low input power. Because of high Q and long resonant lifetime, two photon absorption and free carrier absorption cause deterioration of drop efficiency in a channel drop filter (CDF) for higher input power. In this paper, this drop of efficiency is compensated for by incorporating a heterostructure in the Si photonic crystal slab. Even if the vertical and in-plane quality factors are nearly equal, which is not a good condition for drop efficiency improvement of the heterostructure, the drop efficiency is 61%, almost a three times enhancement with respect to a basic four-port CDF. Nonlinear response of the high efficient Si heterostructure photonic crystal slab CDF is investigated through nonlinear coupled mode theory.