Impact of the cell geometry on the spectral properties of photonic crystal structures

Photonic-crystal-based devices are expected to perform many of the functionalities of standard integrated optics devices used in optical communication systems. Their reliability and the reliability of fabrication technologies in achieving acceptable geometrical tolerance are still to be demonstrated. In this work an analysis of the effects of the cell geometry is presented, showing how small variations can cause hundreds of GHz shifts in the spectral response. A wide-band, finite-element time-domain approach and a frequency-domain formulation have been used for this kind of analysis. The ability of the finite-element method in coping with any kind of geometry has been successfully exploited to investigate the effect of the cell shape.