Gain-managed nonlinear amplification and noise performance of an Yb-doped fiber amplifier seeded at different wavelengths

The performance of a low-noise, Yb-doped nonlinear fiber amplifier seeded by a spectrally-filtered ∼8-MHz ultrafast fiber Mamyshev oscillator was investigated across input wavelengths from ∼1040 to 1064 nm. Using a simple and efficient setup, pulses as short as 31 fs with a small pedestal and energy up to 120 nJ were achieved from <1 nJ input pulses at shorter wavelengths. A detailed characterization of the noise performance of the master oscillator and the gain-managed nonlinear amplifier showed a relative intensity noise at a level of 0.2 % in the integration bandwidth from 2 Hz up to half of the repetition rate, highlighting the exceptional stability of the system.