FULL-WAVE MULTIPLE-SCATTERING ANALYSIS OF DIFFRACTION BY SUPERPOSED GRATINGS

A recently developed multiple-scattering technique for analyzing wave diffraction by superposed gratings is extended to include backward scattering as well. This extension now permits the accurate determination of transmitted and reflected fields in the presence of both weakly and strongly modulated media. By developing algorithms based on flow graphs that track the scattering process, we show that the multiple-scattering approach can be applied to evaluate any diffracted order without requiring a large computer memory. We discuss examples relevant to optical interconnects by presenting numerical results for full-wave scattering by as many as eight superposed gratings.