High-power widely tunable Tm fibre lasers in cladding-pumped and core-pumped cavity configurations

In this paper, we report highly efficient operation of Tm-doped silica fibre lasers, pumped by a high-power cladding-pumped Er,Yb fibre laser at 1565 nm, in both cladding-pumped and core-pumped resonator configurations. In the cladding-pumped Tm fibre laser we obtained up to 19 W of output at 1991 nm with a slope efficiency of 69% with respect to absorbed pump power, and in the core-pumped laser we obtained a maximum output power of 12.1 W at 1860 nm limited by available pump power. Using tunable cavity configurations the cladding-pumped and core-pumped Tm fibre lasers could be tuned from 1861 to 2061 nm and from 1725 to 1973 nm at multi-watt power levels respectively