REFRACTIVE-INDEX PROFILE RECONSTRUCTIONS IN PLANAR WAVE-GUIDES BY THEWKB INVERSE METHOD AND REFLECTIVITY CALCULATIONS

Two formalisms used in index profile reconstructions are compared. We develop a novel formulation of the WKB inverse method and show that th is method is not sufficient to recover the entire index profile in ion -implanted waveguides. A reflectivity calculation involving a matrix f ormalism solves the problem. The index profile parameters are adjusted to fit experimental mode indices. With this formalism, the reconstruc tion of the entire index profile is achieved. An application is shown in a BaTiO3 sample.