Thermally-induced optical modulation in a vanadium dioxide-on-silicon waveguide

In this paper, we report phase-pure vanadium dioxide (VO2) deposition on silicon-on-insulator and demonstrate switching/modulation exploiting the phase-change property. We present electrical and optical properties of VO2 during phase transition. Exploiting the phase change property, optical modulation is achieved by thermally tuning the VO2 phase using a lateral micro-heater beside the waveguide. We achieve an optical modulation extinction of 25 dB and a low insertion loss of 1.4 dB using a ring resonator with a VO2 patch. We also demonstrate the switching performance of a symmetric Mach-Zehnder interferometer and present a detailed discussion on the optimal operating point to achieve maximum modulation, higher speed, and lower insertion loss.