Improved modeling of an InP-based spot-size converter

Integrated Spot-Size Converters (SSCs) are crucial for reducing the coupling loss between InP-based Photonic Integrated Circuits and optical fibers. Previously we reported a novel 2D simulation tool for SSCs based on the continuos limit of the Coupled-Mode Theory. In this paper we present the 3D extension of this model. This model is illustrated with a SSC structure in which the vertically etched taper is replaced by a laterally tapered layer in the upper part of the converter, which is easier from a fabrication point of view