Fano line shapes in transmission spectra of silicon photonic crystal resonators

Transmission measurements on symmetrically waveguide-loaded one-dimensional silicon photonic crystal microresonators are observed to exhibit Fano line shapes, which we find to be due to the interference between the resonant transmission and a leaky second-order quasi-transverse-electric mode partially guided through the photonic crystal. The line shape is tunable by varying the exciting fiber position, the material index, and via the cavity nonlinearity. This two-mode interference method applied to a one-dimensional silicon photonic crystal cavity represents a compact and tunable approach to obtaining such line shapes in integrated optical devices, with implications for efficient modulation of optical signals and nonlinear all-optical switching. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794064]