  We combine soliton dynamics in gas-filled hollow-core photonic crystal fibers
with a state-of-the-art fiber laser to realize a turn-key system producing
few-fs pulses at 8 MHz repetition rate at pump energies as low as 220 nJ.
Furthermore, by exploiting the soliton self-frequency shift in a second
hydrogen-filled hollow-core fiber, we efficiently generate pulses as short as
22 fs, continuously tunable from 1100 nm to 1474 nm.
