High-power widely tunable Tm:fibre lasers pumped by an Er,Yb co-doped fibre laser at 1.6 μm

High-power and widely tunable Tm-doped silica fibre lasers cladding-pumped and core-pumped by a 1565 nm Er,Yb fibre laser are reported. Output power up to 19.2W was generated from the cladding-pumped cavity configuration for ~38.2W of launched pump power and with slope efficiency up to ~72% with respect to absorbed pump power. Wavelength tuning was realized by use of an external cavity containing a diffraction grating. A maximum output power of 17.4 W at 1941 nm was generated for 38.2 W of launched pump power and the operating wavelength could be tuned over 202 nm from 1859 to 2061 nm. In the core-pumped configuration, a maximum output power of 12.1 W was generated at 1851 nm for 23.1 W absorbed pump power using a simple free-running cavity configuration with only ~24 cm of Tm-doped fibre. By employing a tunable cavity configuration, the operating wavelength of the core-pumped Tm:fibre laser could be tuned over 250 nm from 1723-1973 nm at multiwatt power levels.