All-fiber Q-switched holmium laser

For the first time we have suggested and realized all-fiber Q-switched Ho-doped laser with the fiber saturable absorber based on the heavily Ho-doped fiber. Two oscillation modes were observed. One of them allows one to obtain pulses with the duration of 20 ns and the peak power as high as 2 kW. Second mode is similar to the self-pulsing providing by an interaction of ions within the clusters. Type of Q-switching is determined by the length of the absorber. [GRAPHICS] The output power versus the pump power for Ho-doped fiber laser, 1 - without absorber, 2 - with 1.5-m-length absorber, and 3 - with 1-m-length absorber (C) 2011 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA