Scaling of average power in sub-MW peak power Yb-doped tapered fiber picosecond pulse amplifiers
Konstantin K. Bobkov, Andrey E. Levchenko, T.A. Kashaykina, Svetlana S. Aleshkina, Mikhail M. Bubnov, Denis S. Lipatov, Aleksandr Laptev, Alexey Guryanov, Yann Leventoux, G. Granger, Vincent Couderc, Sébastien Février, Mikhail E. Likhachev
Abstract
Prospects for average power scaling of sub-MW output peak power picosecond fiber lasers by utilization of a Yb-doped tapered fiber at the final amplification stage were studied. In this paper, it was shown experimentally that a tapered fiber allows the achievement of an average power level of 150 W (limited by the available pump power) with a peak power of 0.74 MW for 22 ps pulses with no signs of transverse mode instability. Measurements of the mode content using the S 2 technique showed a negligible level of high order modes (less than 0.3%) in the output radiation even for the maximum output power level. Our reliability tests predict no thermal issues during long-term operation (10 5 hours) of the developed tapered fiber laser up to kilowatt output average power levels.