Single-mode criterion for rib waveguides with small cross sections

摘要

We modify the Soref single-mode criterion such that it can be applied also to waveguides with small cross sections. This is verified for highly sensitive silicon on insulator (SOI) rib waveguides with core thicknesses of 60 nm for TE- and 220 nm for TM-polarization, respectively, at a wavelength of 1550 nm by a fully vectorial finite element method (FEM) eigenmode analysis. The semi-analytical criterion enables an efficient design of rib waveguides for evanescent wave sensing devices.