Lithium niobate (LiNbO<sub>3</sub>) thin films for optical waveguide purpose have been grown on (0001) sapphire substrates using the pulsed laser deposition technique at the wavelength of 355 nm. To improve surface smoothness of the films, an off-axis deposition geometry with substrates parallel to the plasma plume has been used. Optical properties have been studied based on excitation of guided modes in the film with a prism coupler. M-lines observations associated to extraction of guided light in the films have shown that planar LiNbO<sub>3</sub> optical waveguide have been elaborated. The
propagation losses at 633 nm have been estimated by measurement of light streak intensity along the propagation direction with a CCD camera. Values of 4.8 and 5.8 dB cm<sup>-1</sup> have been attained for TM<sub>0</sub> and TE<sub>0</sub> guided modes, respectively. The light scattering is mainly due to the presence of residual droplets on the film surface.