Abstract

Several theories have been put forward to explain the self-pulsing regime that occurs in heavily erbium-doped fiber lasers (EDFL's) operating at 1.55 µm The ion-pair model [1] is very useful because it allows to explain qualitatively a variety of experimental observations. Beyond the fact that the ion-pair model gives a good description of previously observed experimental results, the two-mode model predicts the existence of a bistable region between 2T and 3T periodic orbits versus the pump power, where T represents the fundamental periodicity of the pulses We present an experimental confirmation of this prediction. The experimental setup is shown in Fig. 1 The two modes involve in our experiment correspond to the two wavelengths centered at the peak reflectivity of the Bragg gratings which can be independently tuned. This situation ensures optimized competing effect in order to observe the bistability. The experimental results are in good agreement with the theoretical prediction : we have observed bistability between the 2T and the 3T regimes in a narrow range of pumping rates.

© 1998 IEEE