Ferroelectric (FE) films constitute an important component of electro-optic devices; such films have been used for second harmonic generation, spatial light modulators and optical switches. FE films typically yield large values of linear and quadratic electro-optic coefficients. Most electric field induced birefringence measurements have been made with transverse electrodes, i. e. with light beam between poled electrodes. In the present study, an Ultimate Ellipsometer was used; a HeNe laser was directed perpendicularly through FE capacitors with applied voltages and the phase change monitored. The layout of this device is discussed in details.