The propagation of intense femtosecond pulses in a nonlinear, dispersive bulk medium is investigated numerically in the regime where the combined effects of diffraction, normal dispersion, and cubic nonlinearity lead to pulse splitting. We present numerical solutions of a modified $\mathrm{}(3+1)\mathrm{}$-dimensional nonlinear Schrödinger equation, accounting for the Raman effect, linear and nonlinear shock terms, third-order dispersion, and initial temporal third-order phase modulation. The calculated results are found to be in good agreement with experimental measurements.

• Received 20 January 1998

DOI:https://doi.org/10.1103/PhysRevA.58.3303