Highly efficient and tunable operation of two colour Tm-doped fluoride fibre laser

Abstract

A near theoretical maximum slope efficiency of 37% (90% photon conversion) has been demonstrated at 1.925 μm by forcing simultaneous operation of the 1.82 and 2.31 μm transitions in a thulium-doped ZBLAN fibre. In addition significant amounts of tunable output powe, >30 mW, have been observed over a range of 40 nm from 1.818 to 1.858 μm for a launched pump power of 183mW.