Milliwatt-peak-power pulse characterization at 155 µm by wavelength-conversion frequency-resolved optical gating

Abstract
A novel wavelength-conversion configuration based on four-wave mixing in an optical fiber has been used to generate a frequency-resolved optical gating (FROG) trace identical to that obtained from second-harmonic generation (SHG). The use of an optical fiber waveguide permits enhanced measurement sensitivity compared with that of conventional SHG–FROG and has been used for complete characterization of 1-mW peak-power picosecond pulses at 1.55 µm from an unamplified semiconductor laser diode gain switched at 10 GHz.