Radiation Spectral Integral for Tapered Structure in Optical Communication

The study here is mainly adapted to the implementation of a radiation spectral integral, involved to describe modal field behaviour outside a non uniform structure for optical communication purposes. This is achieved by simply associating with each individual spectral plane wave incident on any boundary of the structure, a refracted wave with appropriate transmission coefficient. This spectral integral describes rigorously and systematically a source-free field behaviour not only before and after a branch point singularity (transition region), but also outside a tapered structure too. In this sense, the implementation of the resulting spectral formulation, for the case of homogenous media, contains all informations pertinent to the modal propagation mechanism, not only outside the structure, but also inside it, before and after the singularity caused by cut off of the propagating mode.