New class of fibre laser based on lead-germanate glass

Abstract
The first fibre laser based on rare-earth doped lead-germanate glass is reported. The thulium-doped fibre had a background loss of 2dBm−1 and a maximum phonon energy of ̃920cm−1. Lasing was achieved on the Tm3+3H43H6 transition at 1.905μm with a 3.6 mW threshold, when diode-pumped at 790 nm. A quantum efficiency of 30% was obtained.