Model and Characteristics of Self-Pulsing in ${rm Tm}^{3+}$-Doped Silica Fiber Lasers

摘要

In this paper, a theoretical model, taking into account the phonon-assisted excited-state absorption process $left({{^{3}H_{5}}rightarrow{^{3}H_{4}}}right)$, has been constructed to explain the self-pulsing (SP) phenomenon in the ${rm Tm}^{3+}$ -doped fiber lasers. Both numerical simulation and experimental investigation on the SP characteristics of ${sim}{2}hbox{-}mu{rm m}~{rm Tm}^{3+}$-doped fiber lasers have been carried out. The numerical simulation shows agreement with the experimental results. Furthermore, the impacts of output coupling, pump intensity, and ${rm Tm}^{3+}$-ion doping concentration on the SP characteristics of the ${rm Tm}^{3+}$-doped fiber lasers have been studied explicitly, and optimization of the SP features has been discussed. In addition, the potential applications of SP in fiber lasers or solid-state lasers have also been proposed.