2.31 μm laser under up-conversion pumping at 1.064 μm in Tm3+:ZBLAN fibre lasers

A 150 mW output power continuous-wave laser (2-3 mu m) in a 1000 ppm. wt thulium (Tm+3)-doped ZBLAN fibre laser is presented. The fibre is pumped by a wavelength of 1064 nm (up-conversion pumping) generated from a diode-pumped Nd: YAG laser. A threshold of 700 mW and slope efficiency of 7.8% with respect to the launched pump power has been obtained.