Enhanced fluorescence from Eu3+ in low-loss silica glass-ceramic waveguides with high SnO2 content

We report on the sol-gel fabrication and characterization of (100-x)SiO2-xSnO2 (x=8, 16 and 25 mol%) glass-ceramic waveguides, doped with 1 mol% Eu3+. A suitable top-down thermal process led to the formation of SnO2 nanocrystals ~ 4 nm embedding Eu3+ ions. The excitation spectra evidence the role of interband electronic transition of SnO2 nanocrystals on the luminescence of Eu3+. Monitoring the 5D0->7F2 Eu3+ emission, we observe about 15 times increase in the intensity of SnO2 absorption band, moving from x=8 to 25 mol%. These waveguides also exhibit low-losses making them quite promising for development of high-gain integrated optical amplifiers.