High-power diode-cladding-pumped Tm-doped silica fiber laser

The operation of a diode-pumped Tm-doped silica fiber laser that uses the cladding-pumping arrangement to produce high-power cw output at wavelengths near 2 microm is reported. We obtained a maximum output power of 5.4 W at a slope efficiency of 31% with respect to the launched pump power at a total optical-to-optical efficiency of 22%. The fiber-laser output wavelength was tuned between 1.880 and 2.033 microm by adjustment of the fiber length, with >4W of power obtainable from 1.94 to 2.01 microm. Self-pulsations detected in the output from the double-clad fiber laser may indicate the presence of ion-clustering effects.