Second-harmonic generation-frequency-resolved optical gating analysis of low-intensity shaped femtosecond pulses at 1.55 μm

We illustrate observation and characterization of medium- and low-intensity shaped ultrashort pulses at λ = 1.55 μm through single-shot geometry (multishot-average) second-harmonic generation-frequency-resolved optical gating. The pulses are shaped by amplitude filters in the Fourier plane of a compact folded shaper. Sensitivity to pulses with energies of less than 20 pJ and high dynamic range is reported for this configuration. Application of this method to the propagation of ∼170-fs pulses through a 50-m fiber link is also illustrated.