Tb3+/Yb3+ co-activated Silica-Hafnia glass ceramic waveguides

70SiO2-30HfO2 glass ceramic planar waveguides co-activated by Tb3+/Yb3+ ions were fabricated by sol gel route using a top-down approach. The energy transfer from Tb3+ to Yb3+ ions was investigated as a function of the Tb3+/Yb3+ molar ratio as well as of the total amount of rare earth ions. In particular, the conversion of absorbed photons at 476 nm into photons at 980 nm is considered, looking for potential application in photovoltaic systems.