Red upconversion Yb-sensitised Pr fluoride fibre laser pumped in 0.8 μm region

Abstract

Room temperature upconversion lasing has been obtained at 635 nm in Yb : Pr codoped fluoride fibre pumped in the 0.8μm region. Yb3+ is excited by ground state absorption and transfers energy to the 1G4 level of Pr3+, which is then brought into the 3P0 level by excited state absorption. Extracted powers in excess of 20 mW at 635 nm and a slope efficiency of 10% were observed for 840–850 nm.