Barium Titanate (BaTiO3) thin films are suitable for many applications especially photonic due to its large electro-optic (EO) coefficient where the EO effect causes a change of optical refractive index in a film due presence of an electric field. The first step towards the development of thin film based EO modulators is to study its EO properties. The thin film BaTiO3 was prepared by a sol gel process and annealed at 900°C and then subjected to EO interrogation via the Sénarmont technique. It shows that the technique affected the electro-optic properties of the thin film and the electro-optic behaviour. The Sénarmont technique also utilized the EO measurement of BaTiO3 thin films from negative 20V up to positive 20V by connecting the electrical and optical domain with different angles of polarizer that are from 0° up to 180°. The results show that the power measurement is much higher between 30° to 50° with positive 20V. It is found that electric field disrupts the EO behaviour of the film.
