Polarisation-insensitive Si 3 N 4 strip-loaded BaTiO 3 thin-film waveguide with low propagation losses

A low-loss and polarisation-insensitive singlemode BaTiO3 thin-film waveguide is reported. Polarisation-dependent loss as low as 0.1 dB/cm at a wavelength of 1.55 µm has been achieved by a novel Si3N4 strip-loaded BaTiO3 waveguide structure. Propagation loss of less than 0.9 dB/cm for both TE and TM polarisations was measured.