240 W narrow-linewidth Yb-doped double-cladding fiber amplifier operated in the 100-ps pulse regime

摘要

High average power picosecond (similar to 100 ps) lasers with narrow-linewidth are in great demand for some specific applications. In this paper, a 240 W Yb-doped double-cladding fiber amplifier system at 1064 nm delivering 112 ps pulses at 40 MHz repetition rate was demonstrated. To prevent possible double-cladding fiber damage, a bandwidth-limited (0.1 nm) fiber Bragg grating (FBG) was used to force a stretched pulse-width of 72 ps and a narrow-linewidth of 23 pm. The laser pulses were then stretched to similar to 100 ps after dispersion management and amplified without notable spectral distortion by nonlinear management. The output of the amplifier produces a pulsed energy of 6 mu J, which corresponds to a peak power of 54 kW. The M-2 factor was measured to be about 1.2 at the maximum power of 240 W. The spectral width was 0.45 nm after the power amplification. Further power-scaling was only limited by available pump power.