Yang G, Shen Y R
Opt Lett. 1984 Nov 1;9(11):510-2. doi: 10.1364/ol.9.000510.
Spectral superbroadening of ultrashort-pulse propagation in a nonlinear medium is calculated by solving the nonlinear-wave equation more exactly. The effects of four-wave mixing and pulse deformation on phase modulation are included. The results yield an asymmetric Stokes-anti-Stokes broadening in fair agreement with the experimental observation.