Effect of third-order dispersion on the phases of solitonlike Cr4+: YAG-laser pulses characterized by the second-harmonic generation frequency-resolved optical gating method

The effect of third-order dispersion on solitonlike operation of the L-fold cavity Cr4+:YAG laser is studied. Dispersion equations are derived to the fourth order for an L-fold cavity, and dispersion values for a Cr4+:YAG las er are calculated. Third-order dispersion is found to be comparable with th e second-order dispersion in a 60-fs-class Cr4+:YAG laser, and fourth-order dispersion is negligible. The temporal and spectral phases of a 60-fs puls e are calculated from the dispersion properties of the cavity. The spectral phase is constant, despite considerable third-order dispersion. A second-h armonic generation (SHG) frequency-resolved optical gating (FROG) trace is calculated for the simulated pulse. The SHG spectrum has a tail to the shor t-wavelength side at zero delay, consistent with experimental results. The calculated phase and the FROG trace should be recognized as characteristic of the third-order-dispersion effect on solitonlike lasers. (C) 2001 Optica l Society of America.