Realization and characterization of a low intensity noise ultrafast Yb-doped fiber amplifier

We report on the design and whole characterization of low-noise and affordable-cost Yb-doped double-clad fiber amplifiers operating at room temperature in the near-infrared spectral region at pulse repetition rate of 160MHz. Two different experimental configurations are discussed. In the first one, a broadband seed radiation with a transform limited pulse duration of 71 fs, an optical spectrum of 20 nm wide at around 1040 nm, and ∼20mW average power is adopted. In the second configuration, the seed radiation is constituted by stretched pulses with a time duration as long as 170 ps, with a 5 nm narrow pulse spectrum centered at 1029 nm and ∼2mW average input power. In both cases we obtained transform limited pulse trains with an amplified output power exceeding 2 W. Furthermore, relative intensity noise measurements show that no significant noise degradation occurs during the amplification process.