1.9 µm Tm-doped silica fibre laser pumpedat 1.57 µm

Abstract
A 1.9 µm Tm-doped silica fibre laser pumped at 1.57 µm is described. The pump source is an Er-doped fibre laser pumped by a 0.98 µm Ti:sapphire laser. The threshold pump power is 95 mW and the slope efficiency is as high as 71%. A maximum output power of 21 mW was obtained at a launched pump power of 127 mW. The oscillation wavelength can be tuned from 1.84 to 1.90 µm by changing the length of the Tm-doped fibre.