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 resu lt femtosecond pulses can be efficiently amplified to peak powers >50 kW in a high-power chirped pulse amplification system using chirped PPLN for fre quency-doubling. With an average power level of 1.2 W at the fundamental wa velength of 1.55-mu m average powers up to 420 mW are generated at 775 nm.