Dynamics of erbium-doped fibre ring laser under cavity-loss modulation

Abstract

The time-domain response of an erbium doped fibre laser constructed with a uni-directional ring cavity is studied when the cavity loss is sinusoidally modulated in the frequency range of the relaxation oscillation frequency of the laser. Fourier transformed data are used to analyse the spectral features. The experimental demonstration of different periodic states and chaos thus reached under the period-doubling route at kHz frequencies are substantiated with numerical calculations using parameters appropriate to the experimental conditions. Bifurcation diagrams and reconstructed attractors are calculated to show the change of different dynamical regimes while varying the modulation frequency. The modulation of intra-cavity losses in a fibre laser enables the study of its nonlinear dynamical response in a highly controlled manner.