Low-loss electrooptic BaTiO₃ thin film waveguide modulator

A strip-loaded electrooptic waveguide modulator based on an epitaxial BaTiO₃ thin film was fabricated and characterized for the first time. The strip-loaded waveguide structure greatly improves waveguide propagation and polarization-dependent loss performance. A propagation loss of 1.1 dB/cm and polarization dependent loss of 0.1 dB/cm were measured. The electrooptic waveguide modulator exhibited a half-wave voltage-interaction length product of 4.5 V · cm at a wavelength of 1542 nm. The measured effective electrooptic coefficient of the as-grown BaTiO₃ waveguide modulator was 38 pm/V. The experimental results indicate that a strip-loaded thin film waveguide modulator is suitable for photonic applications.