Thickness matching in planar multilayer waveguides.

A theoretical method is described from which the thickness of an arbitrary layer in a dielectric multilayer stack is determined if all other thicknesses and all refractive indices are given, such that a prescribed effective index for a given mode of the stack is obtained. The same theory can determine the optimal cover thickness of such a stack for prism coupling. Experimental verification shows effective indices that are in agreement with the designed values.