A polarization-maintaining pedestal-free femtosecond pulse compressor incorporating an ultrafast dispersion-imbalanced nonlinear optical loop mirror

We report a polarization-maintaining and dispersion-flattened pulse compres sor based on a dispersion decreasing fiber (DDF) for compression and a disp ersion-imbalanced nonlinear optical loop mirror (DI-NOLM) for pedestal remo val. A dispersion management scheme was used in the DI-NOLM to reduce dispe rsive spreading, which allows efficient switching fur ultrashort pulses, In put pulses of 3 ps duration at 10 GHz were compressed to as short as 140 fs with a spectral width of 56 nm, time-bandwidth product of 0.96, and averag e power of 8.5 mW, This pulsewidth was limited by the higher order dispersi on in the DI-NOLM. Using a post filter and a post amplifier, we obtained tr ansform-limited 170 fs pulses at an average power of 100 mW with peak-to-pe destal ratios exceeding 35 dB, The compressor was adjustment-free, which is critical for practical use.