Multisoliton supercontinuum from a photonic-crystal fibre as a source of frequency-tunable megawatt femtosecond pulses in the infrared

We demonstrate a new method of generation of frequency-tunable megawatt femtosecond pulses in the infrared based on multisoliton supercontinuum generation in a large-mode-area photonic-crystal fibre (PCF) followed by the temporal compression of the PCF output. Photonic-crystal fibres with a core area of about 710 μm² are employed to convert microjoule femtosecond laser pulses with a spectrum centreed at 1.39 μm into pulses with a central wavelength of 1520 nm, a pulse width of 210 fs, and a peak power of about 1 MW.