Highly doped and highly efficient Tm doped fiber laser (Conference Presentation)

We report on a very highly doped and very highly efficient cladding pumped single mode Tm3+ silica fiber laser operating at 1.985 microns. The preform was fabricated using a proprietary all halide vapor phase modification of the MCVD process. The preform core has a maximum Tm2O3 doping concentration of greater than 8.5 wt%. A laser based on the resulting double clad fiber was pumped at 793 nm and demonstrated a record slope efficiency of 74.5 % wrt absorbed pump power.