High power femtosecond pulses amplified by an all-fiber system based on the model of self-similar amplification

In this paper a theoretical model of self-similar amplifications is studied experimentally in an all-fiber high power amplifier. The output vs. input characteristics of this amplifier are measured when the various femtosecond pulses at different energies and different shapes are inputted. By analyzing the data of the amplified pulses along with the data of the input pulses, it was verified that the all-fiber high power amplifier system is indeed operating in the way of self-similar amplifications. Finally, nearly transform-limited ultra-short pulses with high average power of 500 mW and time-bandwidth product of 0.342 are obtained by compressing the output pulses from the fiber amplifier to the ultra-short pulses of 113 fs at the center wavelength of 1552 nm using a segment of dispersion compensation fibers (DCFs) with large negative group velocity dispersion. The results demonstrated that the operating mode of the amplifier is consistent with the typical self-similar amplification model.