2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/80355We present an analytical study of four-wave mixing instabilities in tapered fibers and photonic crystal fibers. Our approach avoids the use of Taylor expansion for the linear susceptibility and the slowly-varying envelope approximation. This allows us to describe the generation of sidebands strongly detuned from the pump wave with simultaneous account for the entire dispersion characteristic of a fiber, which is found to be important for describing properly the key role of the parametric instabilities in the supercontinuum generation in these kind of fibers.15 pages, 3 figures, misprints correctedPattern Formation and Solitonstext