Er3+/Yb3+-codoped silica–germania sputtered films: structural and spectroscopic characterization

We report on the fabrication and spectroscopic characterization of highly photo-refractive Er3+/Yb3+ coactivated silica–germania slab waveguides, single mode at 1550 nm, deposited by radio-frequency-magnetron-sputtering technique. Details of the sputtering procedure are reported. The structural properties of the films were investigated by Raman spectroscopy. Propagation losses of guided modes were measured at 633 nm and 1320 nm. The emission of the 4I13/2 → 4I15/2 transition of the Er3+ ion was analyzed upon excitation of the TE0 mode at 514 and 981 nm. Back energy transfer from Er3+ to Yb3+ was observed by measurement of Yb3+ emission upon Er3+ excitation at 514.5 nm. Photoluminescence excitation spectroscopy was used to obtain information about the Yb3+ to Er3+ energy transfer process.