Investigating nonlinear femtosecond pulse propagation with frequency-resolved optical gating

Frequency-resolved optical gating (FROG) is used to investigate nonlinear p ulse propagation in normally dispersive media. We present high-dynamic-rang e measurements of broad-bandwidth femtosecond pulses that result from nonli near propagation in fused silica and compare these measurements with a (3 1)-dimensional modified nonlinear Schrodinger equation. We also demonstrat e the ability of FROG to provide information about a noninstantaneous nonli nearity in methanol, In this case, the instantaneous nonlinear index and th e time response of the noninstantaneous nonlinearity are used as fit parame ters in a (1+1)-dimensional model.