Self-pulsing dynamics of ytterbium-doped fiber laser with pump-bypassed cavity

Abstract

The pump-bypassed laser cavity is suggested as a suitable configuration for investigating the self-pulsing instability in fibre laser. Such arrangement allows access to the residual pump light, which acts as a probe of the intra-cavity dynamics and reflects the inversion variation along the whole gain fibre. We check this method with ytterbium-doped fibre (YDF) laser. The experimental results in original cavity and modified cavity are offered in detail respectively. The analyses of both the temporal traces of the residual pump and laser signal manifest that the various instabilities in YDF laser are associated with the interactions among stimulated emission, pump and/or reabsorption, dependently on the inversion level and also the intensities of the pump and laser intra-cavity signal.