Rare frustration of optical supercontinuum generation

Recent work has shown that optical rogue waves, large bandwidth fluctuations following heavy-tailed statistics, can arise during spectral broadening by stochastic enhancement of nonlinearity. Here, we report the observation of a different form of extreme fluctuations in supercontinuum pulse trains: Pulses of unusually small spectral bandwidth following left-skewed heavy-tailed statistics. Displaying a pulse evolution strongly varying from that of large extremes in supercontinuum, these rogue events appear when spectral broadening is frustrated by competition between presolitonic features within the modulation-instability band. This suppression effect can also be externally induced with a weak control pulse.