In this research TiO 2 , SnO 2 and TiO 2 :SnO 2 nanocomposite thin films were fabricated by the sol-gel dip coating technique. The mixture was prepared by varying the molar ratio of SnO 2 to TiO 2 , i.e. TiO 2 :SnO 2 (9:1), TiO 2 :SnO 2 (8:2) and TiO 2 :SnO 2 (6:4)). The obtained samples were characterized by means of the Raman microscopy, Scanning Electron Microscopy (SEM), UV-Vis spectrophotometry and m-lines spectroscopy (Prism coupler). Raman analysis shows that pure TiO 2 and SnO 2 thin films are characterized by the vibrational modes of anatase and rutile cassiterite, respectively. Furthermore, the Raman spectra of the TiO 2 :SnO 2 nanocomposites show the presence of a mixture of anatase and rutile TiO 2 phases. The SEM images reveal that the morphology is clearly modified with SnO 2 content. The ripples in the transmittance spectra decreased with increasing SnO 2 content. Also, the evolution of the optical band gap seems to be consistent with the Raman analysis. A great attention has been paid to the refractive index measurements by the prism coupler technique. In this way, variable-refractive index systems have been successfully obtained using TiO 2 :SnO 2 nanocomposite thin films.