Sidewall roughness and deformations in high index-contrast waveguides and photonic crystals

Design rules for low-loss waveguides with random perturbations are presented. For strip waveguides, the width should be chosen larger than 1/4 of the coherence length of the sidewall roughness. For an ensemble of perturbed 2D photonic crystal line defect waveguide bends, we give the statistics of the relative transmission.