I have a planar dielectric waveguide with a thickness on the length scale of a wavelength. But the width is on the length scale of mm's. The lensing effect is obtained by changing the thickness of the waveguide such that the boundary at which the thickness changes, forms a semicircle. Does anyone have any ideas?"
Synopsis
Doug Sinclair answers waveguide question in a newsgroup
Solution
Yes. OSLO includes the ability to model (and design) waveguide lenses of the type you describe. This is a feature developed By Prof. Szarvas and his student G. Erdei at the Technical University of Budapest some time ago. It is only included in OSLO Premium, not OSLO LT. It's not necessary to use BPM for this purpose; that would be too slow. The dimensions of interest are large compared to a wavelength, so the usual types of optical analysis are valid. -Doug Sinclair