Femtosecond pulse amplification in cladding-pumped fibers

Abstract
Femtosecond pulse amplification in a cladding-pumped fiber amplifier is demonstrated for the first time to our knowledge. Using a cladding-pumped erbium-doped fiber power amplifier and a passively mode-locked fiber seed oscillator in conjunction with an all-fiber chirped-pulse amplification system, we obtain 380-fs near-bandwidth-limited pulses with an average power of 260 mW. The pulse repetition rate is varied between 5 and 50 MHz, and pulse energies as high as 20 nJ are generated.