Design and fabrication of SiO2/Si3N4 CVD optical waveguides

In this paper the design and fabrication of silicon-based optical waveguides are revisited. The goal was to develop a novel deposition process to minimize leakage losses, by allowing the deposition of a thick SiO2 lower cladding as an optical buffer layer, Indeed, comparison between theory and experimental data suggests that for the fabricated waveguides the dominant loss mechanism is scattering caused by side-walls surface roughness. Optical characterization yielded losses in the same range of state-of-art devices reported in the literature.