Wavefront control of a multicore ytterbium-doped pulse fiber amplifier by digital holography

We demonstrate the active wavefront control of a 19-core ytterbium-doped fiber amplifier by the digital holography technique. The output wavefront is corrected even in the presence of large externally induced perturbations, with a measured output Strehl ratio of 0.6 in all cases. The wavefront-controlled multicore fiber is used to amplify 800 ps pulses at 1064 nm at a repetition rate of 40 kHz, and a gain of 23 dB is obtained. (C) 2010 Optical Society of America