Efficient high power operation of a Tm-doped silica fiber laser pumped at 1.319 mu m

Efficient cw and Q-switched operation of a Tm-doped silica fiber laser, pum ped with the 1.319-mu m output from a Nd:YAG laser, is described. An unsatu rated continuous wave maximum output power of 310 mW and a slope efficiency of 23% was obtained for a near optimised cavity. A relatively low measured absorption cross section in conjunction with excited state absorption (ESA ) of the pump light results in a minimum threshold pump power of 0.9 W. Q-s witching by use of a mechanical chopper resulted in 16 W/280 ns pulses at a repetition rate of 20 kHz. (C) 2000 Elsevier Science B.V. All rights reser ved.