Influence of the localization of process-induced disorder on planar photonic crystal waveguide properties

Abstract

The influence on photonic crystal waveguide properties of the fabrication-induced disorder was numerically studied. By comparing the transmission spectra obtained using 3D-FDTD for four kinds of fabrication disorders, it was shown that disorder modifies the waveguide mode properties, especially in the slow light regime. Emphasis was put on the influence of the disorder localization. Results have shown the major role played by technological fluctuations of the size, shape, and position of the two first rows of holes along PhC waveguide axis. Results have revealed that bandgap properties remain almost unaffected even for huge disorder levels provided that the two first rows of holes remain unchanged. Interestingly, 3D-simulation have also shown that sharp transmission spectrum cutoffs that characteristize slow wave modes in the two-dimensional PhC bandgap are then not suppressed by the introduction of disorder but are only blue-shifted. This point constitutes an interesting result for optical integrated devices relying on low group velocity phenomena.