Investigation on upconversion luminescence in [formula omitted] codoped tellurite glasses and fibers

Abstract

The upconversion properties of Er 3 + / Yb 3 + codoped tellurite glasses and glass fibers with D-shape cladding under 980 nm excitation were investigated. Intense emission bands centered at 531, 546 and 658 nm corresponding to the transitions Er 3 + : H 11 / 2 2 → I 15 / 2 4 , S 3 / 2 4 → I 15 / 2 4 and F 9 / 2 4 → I 15 / 2 4 , respectively, were observed at room temperature. Compared with that in Er 3 + / Yb 3 + codoped tellurite bulk glass, the upconversion luminescence becomes more efficient in the fiber geometry. The dependence of upconversion intensities on fiber geometry and possible upconversion mechanism are discussed and evaluated. The presented Er 3 + / Yb 3 + codoped tellurite fibers with intense upconversion luminescence can be used as potential host materials for upconversion fiber lasers.