Balancing gain narrowing with self phase modulation: 100-fs, 800-nJ from an all-fiber-integrated Yb amplifier

This paper presents a novel scheme for multi-stage fiber amplification of ultrashort pulses, where each stage is designed to mimic pulse amplification and shaping as closely as possible a scaled-version of intra-cavity pulse amplification and scaling, thereby balancing gain narrowing with self-phase modulation (SPM). While additional work is necessary for full optimisation, as a first experimental demonstration of this approach, a highly integrated Yb-doped oscillator-amplifier system, which generates 1.15-μJ, 20-ps pulses at 1030 nm, which are dechirped in a grating compressor, yielding 0.8-μJ, 100-fs pulses at 1-MHz repetition rate, was constructed.