Supercontinuum generation in photonic crystal fibers made from highly nonlinear glasses

The nonlinear propagation of femtosecond pulses and supercontinuum generation in photonic crystal fibers made from glasses with high nonlinear refractive indices are theoretically investigated without the use of the slowly varying envelope approximation. For specifically designed photonic crystal fibers with two zero-dispersion wavelengths, we predict supercontinuum generation due to nonsolitonic radiation emitted by the solitons on the shorter- and on the longer-wavelength sides. The physical mechanism and the peculiarities of such radiation on both spectral sides are studied and explained by the specific phase-matching relations between the solitons and their associated radiation.