Athermal High-Index-Contrast Waveguide Design

Abstract

We present generalized design rules for athermal performance and materials compatibility in high-index-contrast (HIC) waveguides. Thermal stability of integrated photonic devices is one critical limitation in the development of commercially viable integrated optoelectronic circuits. Thermooptically neutral designs are achieved by choosing a cladding material whose thermooptic coefficient is opposite to that of the waveguide core. We derive analytical expressions of athermal conditions for both symmetric and asymmetric channel waveguide structures. The equations apply to general HIC systems such as silicon-on-insulator and SiN-based structures.