Modelling and Simulation for the Electro-optic Characteristics of BaTiO₃ Crystal Film Waveguide with Complementary Push-pull Polarization Modulations

Abstract BaTiO3 crystal films, possessing the advanced electro-optic (EO) properties, have been activating a broad interest in research and development of EO modulators for optic-fibre communications. However, the accurate measurements for the key physical parameter, the EO coefficient, is still at unoriented state. In this work, a BaTiO3 crystal film is grown on a magnesium oxide (MgO) crystal substrate and a device structure having an ultrahigh two-dimensional (2D) optic-electric field interaction is designed to conduct the synchronous measurements for the EO coefficient r 51 and the birefringence b eo of the BaTiO3 crystal film with an intra-guide push-pull modulation of linear polarization. As a result, the average values of 570±2pm/V and -0.0135±0.0007 of r 51 and b eo are obtained, respectively. Furthermore, a theoretical model for analysing the measurement accuracies of r 51 and b eo, and the accuracy dependences on the drive voltage and optic-electric interaction efficiency are studied, leading to an efficient way to developing the high-speed BaTiO3 crystal film EO modulators.