Efficient Generation of Watt-Level Output From Short-Length Nd-Doped Phosphate Fiber Lasers

We report experimental results on high-power heavily Nd-doped phosphate continuous-wave (CW) fiber lasers of very short length. The optimum fiber laser with a length of 26 cm exhibited a maximum output power of as much as 2.87 W and a slope efficiency of 44.7% with respect to absorbed pump power at 795 nm. Up to 1-W laser was also obtained from a 6-cm-short active fiber. The fiber lasers were demonstrated at 1053 nm with a linewidth of 1.6 nm, and showed no evidence of roll-over even at highest output power. The output powers were stable and limited only by available pump power.