Modulation instability in a fiber soliton ring laser

摘要

Modulation instability in a fiber soliton ring laser is studied by a linear stability analysis of the underlying nonlinear Schroedinger equation. Based on the modulation instability theory and the multisection fiber theory, we achieve the gain flattening in the fiber soliton ring laser. We find that the perturbation gain can be improved when the erbium doped fiber is in the normal dispersion region. When the erbium doped fiber is in the anomalous dispersion region, the perturbation gain spectrum will evolve into a supercontinuum which is similar to a parabola as the small-signal gain of the erbium doped fiber increases.