Supercontinuum generation by the modulation instability

We report on a numerical study of supercontinuum generation in a single-mode optical fiber. We show that the modulation instability is responsible for the generation of ultrabroadband octave-spanning continua for pico- and subpicosecond pulses in the anomalous- as well as in the normal dispersion region. The MI turns out to dominate higher-order effects such as third- and fourth-order dispersion, self-steepening and stimulated Raman scattering. In particular we point out the role of fourth-order dispersion for the MI in the case of normal dispersion.