Dynamics and self-pulsing effects in Tm3+-doped silica fibre lasers

Observations are presented on the self-pulsing behaviour of the Tm3+-doped silica fibre laser operating near 2 mum. Various self-pulsing regimes are observed for a range of pumping rates when the fibre is end-pumped with a high power Nd:YAG laser operating at 1.319 mum in a linear bidirectional cavity. A rich variety of nonlinear phenomena, ranging from self-pulsing to self-Q-switching and to a modulated quasi-CW wave. are observed. The phenomenon of pair-induced quenching (PIQ) is considered, compatible with excited-state absorption (ESA). The influence of thulium concentration on ion-pair production is described. The model developed based on the rate equations for a three-level system describes the experimental observations. (C) 2002 Elsevier Science B,V. All rights reserved.