Highly efficient 1.064 µm upconversion pumped 1.47 µm thulium doped fluoride fibre laser

Abstract
Results are presented on a 1064 nm upconversion pumped thulium doped fluoride fibre laser operating on the 3F4 – 3H4 transition around 1.47 µm. A minimum threshold of 8.7mW (3.6mW absorbed), and a maximum slope efficiency of 58% (80% photon conversion efficiency), with respect to launched pump power has been observed. In addition a maximum gain efficiency of 0.22 dB/mW has been demonstrated.