Dispersive-wave self-frequency shift unveiled through length scales propagation

Nonlinear propagation of light pulses can excite dispersive waves anchored at frequencies determined by the chromatic dispersion curve. In this work, conditions enabling dispersive-wave self-frequency shift over distance are analytically derived in normal regime. Importantly, novel, to best our knowledge, scenario is not found solving complex dynamics pulse, but studying evolution nonlinear and length scales. This approach allows a simpler, yet consistent insightful, analysis that may also be very useful other regimes.