Abstract

Erbium-doped fiber lasers are of particular interest because of their large variety of dynamical behaviors: CW or self-pulsing regime when operating around 1.55μm [1], nT-periodic orbits and chaotic motion when operating simultaneously at 1.55 μm and 1.536 μm [2]. A simple modeling of the dynamics has been developed in [1] in the case of single-mode oscillation. The model assumed the existence of isolated erbium-ions (concentration 1-2x) and ions pairs (concentration x) which act as a saturable absorber (via a quenching effect between two excited neighboring ions). In this communication, we present a general analysis of erbium-doped fiber lasers dynamics [3]. The model is based on the well-known two-mode laser model where we have added two equations for the population dynamics of ion pairs. The different routes to chaos are investigated. Figure 1 gives an example of a bifurcation diagram which represents the evolution of the extrema of the intensity versus the pumping ratio r. Note the bistability domain occurring between the 2T- and 3T-periodic orbits.

© 1996 IEEE