Comparison between nonlinear and linear spectrographic techniques for the complete characterization of high bit-rate pulses used in optical communications

Two spectrographic techniques for the complete characterization (amplitude and phase) of optical pulses with durations commensurate with high bit-rate communications systems (2-30 ps) are experimentally compared. We show that a highly sensitive linear sampling technique utilizing an electroabsorption modulator gives accurate results when compared to a nonlinear sampling technique based on second-harmonic generation over a range of pulse durations from 2-33 ps.