All-normal-dispersion femtosecond fiber laser

We demonstrate a modelocked ytterbium (Yb)-doped fiber laser that is designed to have strong pulse-shaping based on spectral filtering of a highly-chirped pulse in the cavity. This laser generates femtosecond pulses without a dispersive delay line or anomalous dispersion in the cavity. Pulses as short as 170 fs, with pulse energy up to 3 nJ, are produced.