Development of high-quality TiO₂ photonics with E-gun evaporation

In this work, we demonstrate the fabrication of high-quality (Q) TiO₂ waveguide resonators by E-gun evaporation. The deposited titanium dioxide (TiO₂) films exhibit superior roughness below 1 nm, demonstrating high-Q TiO₂ integrated photonics. By employing the low-temperature, high-deposition-rate evaporation process, both low-confined and high-confined TiO₂ waveguides are investigated, highlighting their potential for applications in nonlinear and quantum photonics. Meanwhile, the Q factor of waveguide resonators can reach approximately 1.1 × 10⁵. With an optimized pulley coupling design, high extinction ratios (ER) above 27.1 dB for the silicon substrate and 68.7 dB for the glass substrate are achieved, respectively. This work shows the potential in fabricating both high-Q, high-ER waveguide resonators, and highly confined TiO₂ photonic waveguides with E-gun evaporation for applications in co-packaged optics.