High repetition rate femtosecond Yb-doped fiber amplifier

The optimum fiber length of the single mode Yb-doped fiber amplifier is simulated. Experiments of the single-mode Yb-doped fiber amplifier and gratings compressor are discussed. The seed pulses come from a mode-locking Yb-doped fiber ring laser. The maximum output average power of the fiber laser is 7 mW at 25.4 MHz repetition rate with a pulse width of 56 ps. The seed pulses are amplified by using three different length single mode Yb-doped fibers respectively which are pumped by a 976 nm semiconductor laser with a maximum output power about 250 mW. The amplified pulses are compressed by using the traditional gratings compressor. When the length of the single mode Yb-doped fiber is 1.2 m, the fiber amplifier generates a maximum power of 140 mW corresponding to a gain about 13 dB. The ampl