Stoichiometric lithium niobate (SLN) thick films were deposited on z-cut LiNbO3 using the sol-gel method from a precursor solution containing various polyvinyl alcohol (PVA) concentrations and their characteristics were investigated. The film thickness increases linearly and the roughness decreases with the increase in PVA concentration. The refractive indexes of the films prepared with PVA were n(0) = 2.28 +/- 0.02 and n(c) = 2.19 +/- 0.02 at a wavelength of 632.8 nm. The transmission loss was 0.61 +/- 0.05 dB/cm (C) 2004 Elsevier B.V. All rights reserved.