Low-noise amplification of high-power pulses in multimode fibers

Low-noise amplification of high-power pulses in multimode erbium/ytterbium-doped fibers is demonstrated. The use of multimode fiber amplifiers allows to overcome the peak power limitations of single-mode amplifiers. As a result femtosecond pulses can be efficiently amplified to peak powers >50 kW in a high-power chirped pulse amplification system using chirped PPLN for frequency-doubling. With an average power level of 1.2 W at the fundamental wavelength of 1.55-μm average powers up to 420 mW are generated at 775 mm.