  We revisit the problem of modulation instability (MI) in optical fibers,
including higher-order dispersion terms, self-steepening, and Raman response.
We derive expressions for the MI gain and use them to explore the role of
self-steepening towards a high-power limit. We show that, contrary to common
wisdom, there is a pump power level that maximizes the MI gain. Further
increasing the power not only diminishes the gain, but eventually makes it
disappear. We believe these findings to be of special relevance, for instance,
when applied to the generation of supercontinuum in the mid and far infrared
bands. Finally, numerical simulations confirming our analytical results are
presented.
