Athermal and low loss ridge silicon waveguides

In this paper, we investigate athermal and low propagation loss silicon-on-insulator (SOI) rib waveguides. Propagation losses have been modeled for different dimensions of ridge waveguides achieving good agreement with experimental measurements. At certain waveguide widths, it is possible to obtain low propagation losses for both TE (transverse electric) and TM (transverse magnetic) modes. Racetrack ring resonator structures based on ridge waveguides covered by a polymer have been fabricated, aiming for an athermal design and therefore, a very small temperature dependent wavelength shift. Design guidelines for temperature insensitive and small propagation loss ridge waveguides are presented in this paper together with experimental data.