Low loss, high contrast optical waveguides based on CMOS compatible LPCVD processing

Abstract

A new class of integrated optical waveguide structures is presented, based on low cost CMOS compatible LPCVD processing. This technology allows for medium and high index contrast waveguides with very low channel attenuation. The geometry is basically formed by a rectangular cross-section silicon nitride $(Si_{3}N_{4})$ filled with and encapsulated by silicon dioxide $(SiO_{2})$. The birefringence and minimal bend radius of the waveguide is completely controlled by the geometry of the waveguide layer structures. Experiments on typical geometries will be presented, showing excellent characteristics (channel attenuation ≤0.06 dB/cm, IL ≤0.6 dB, PDL ≤0.2 dB, Bg «1 x $10^{-3}$, bend radius ≤500 μm)