Sol-Gel derived SiO2-SnO2 glass-ceramics planar waveguides

SnO2 is a wide-band gap semiconductor (Eg = 3.6 eV), with a maximum phonon energy less than 630 cm-1. This communication reports on low-loss SiO2 - SnO2 glass-ceramic waveguides with high SnO2 content, doped with Eu3+, grown by a suitable top-down thermal process. The optical and spectroscopic properties of the waveguiding system are discussed as a function of SnO2 content. (100-x) SiO2 - x SnO2 (x = 8, 16 and 25 mol %) glass-ceramic waveguides doped with 1 mol% Eu3+ were fabricated by the sol-gel technique and dip coating process. A suitable top-down thermal process leads to the formation of SnO2 nanocrystals of ~ 4 nm embedding Eu3+ ions. Significant enhancement of the 5D0 -> 7F2 emission of Eu3+ due to SnO2 nanocrystals has been demonstrated, as a function of both SnO2 content and annealing protocol. The glass-ceramic waveguides exhibited an attenuation coefficient as low as 0.8 ± 0.2 dB/cm at 632.8 nm making this nanostructured material suitable for integrated optics.