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

Efficient cw and Q-switched operation of a Tm-doped silica fiber laser, pumped with the 1.319-μm output from a Nd:YAG laser, is described. An unsaturated continuous wave maximum output power of 310 mW and a slope efficiency of 23% was obtained for a near optimized 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-switching by use of a mechanical chopper resulted in 16 W/280 ns pulses at a repetition rate of 20 kHz.