Universal nonlinear stage of the locally induced modulational instability in fiber optics

TL;DR

This paper experimentally investigates the nonlinear evolution of modulational instability in optical fibers, revealing universal oscillatory structures consistent with integrable theory despite real-world imperfections.

Contribution

It demonstrates the universal nonlinear stage of modulational instability in fiber optics through experiments, confirming theoretical predictions in a non-ideal, dissipative environment.

Findings

Universal oscillatory structures observed experimentally

Agreement with integrable nonlinear Schrödinger equation predictions

Persistence of universal behavior despite dissipation and noise

Abstract

We report an optical fiber experiment in which we study nonlinear stage of modulational instability of a plane wave in the presence of a localized perturbation. Using a recirculating fiber loop as experimental platform, we show that the initial perturbation evolves into expanding nonlinear oscillatory structure exhibiting some universal characteristics that agree with theoretical predictions based on integrability properties of the focusing nonlinear Schr\"odinger equation. Our experimental results demonstrate persistence of the universal evolution scenario, even in the presence of small dissipation and noise in an experimental system that is not rigorously of an integrable nature.