Power scaling of 2 µm ytterbium-sensitised thulium-doped silica fibre laser diode-pumped at 975 nm
An ytterbium-sensitised thulium-doped silica fibre laser that generates up to 75 W of output power in the 2 µm wavelength range when cladding-pumped by a 975 nm diode stack is reported. The slope efficiency is 32% with respect to the launched pump power and the beam quality factor (M2) is 1.3.