Amplitude noise reduction in Yb-doped fiber amplifiers

We experimentally observe attenuation of low-frequency amplitude noise in the amplifier chain of a high-power ultrafast fiber laser system due to amplifier saturation. Simulations are carried out evaluating the impact of pump and signal noise, showing that the upper frequency bound of the damping mechanism is proportional to the reciprocal effective excited state lifetime. Design guidelines for low-noise ultrafast fiber laser sources are derived.