High-quality energy-scalable femtosecond pulses from a fibre-based chirped pulse amplification system via adaptive pulse shaping

In this paper, we show the versatility of adaptive pulse pre-shaping to generate a high-quality pulse train with a variable repetition rate and energy in a fibre CPA system consisting of a 1km fibre stretcher with a B-integral reaching 2.2 pirad, implying a non-negligible contribution of accumulated nonlinear phase to the degradation of the pulse quality. The adaptive shaping improved the pulse quality, thereby increasing the peak power by a factor of 3.9 and 3.6 for the pulse trains with energy 1.3 muJ and 8muJ, respectively. Thus we have demonstrated the adaptive pulse pre-shaping as a powerful technique to achieve high- quality energy-scalable femtosecond pulses in a fibre-chirped pulse amplification system, without a major system reconfiguration.