Efficient distortion-free amplification of 1.3 mu m femtosecond pulses in a Pr3+-doped fluoride fiber amplifier

Amplification of ultrashort pulses in rare earth doped fiber amplifiers is governed by the combined effects of gain, dispersion and the intrinsic fiber nonlinearities (mainly the optical Kerr effect). This may lead to a serious degradation of the pulse quality, especially if the influence of the nonlinear effects becomes strong. In this work we demonstrate that the use of an amplifying fiber with a large group velocity dispersion effectively suppresses the deleterious influence of the fiber nonlinearities through Chirped Pulse Amplification in the active fiber. Efficient (up to similar to 20 dB), distortion-free amplification of 340 fs pulses in a Pr3+-doped fluoride fiber amplifier at 1.3 mu m is reported for the first time. This result is important in view of many short pulse applications in the fields of ultrafast spectroscopy, optical signal processing and optical communications.