Experiment of cladding pumped femtosecond fiber amplifier

Experiment of the double-clad erbium-ytterbium co-doped fiber amplifiers were discussed. This fiber with hexagonal inner clad is utilized as gain medium to amplify femtosecond pulse, which is pumped by LD with pigtail fiber. The signal with 10.8 mW average power at 20.84 MHz repetition rate is amplified to 176 mW by using 50 cm long fiber when launched pumping power is 2.5 W. The gain is 12.2 dB and the single pulse energy is 8.1 nJ. The amplified pulse width is 480 fs, corresponding to a peak power of 16 kW.