Highly photorefractive Eu3+ activated sol-gel SiO2-SnO2 thin film waveguides

We report on the photorefractive properties of tin-silica slab waveguides, deposited on vitreous-SiO2 by means of sol-gel dip-coating technique. The basic composition of these amorphous binary systems is 75 SiO2 - 25 SnO2 mol% with 1 mol% of Eu3+ ions. Europium was chosen as an optical probe of the glass structure. These guiding structures exhibit low propagation losses (around 0.5 dB/cm at 633 nm) and a high refractive index modulation, as large as - 1.5 × 10-3 under the UV irradiation of a KrF excimer laser source at ? = 248 nm, suitable for writing waveguide gratings. © 2010 Copyright SPIE - The International Society for Optical Engineering.