Polycrystalline Anatase Titanium Dioxide Micro-ring Resonators with Negative Thermo-optic Coefficient

Abstract:

We fabricate polycrystalline anatase TiO2 micro-ring resonators with loaded quality factors as high as 25,000 and average losses of 0.58 dB/mm in the telecommunications band. Additionally, we measure a negative thermo-optic coefficient dn/dT of −4.9 ± 0.5 × 10−5 K−1. The presented fabrication uses CMOS- compatible lithographic techniques that take advantage of substrate-independent, non-epitaxial growth. These properties make polycrystalline anatase a promising candidate for the implementation of athermal, vertically-integrated, CMOS- compatible nanophotonic devices for nonlinear applications.