The characteristics of dynamic gratings in ultra-narrow linewidth erbium-doped fiber ring lasers

Abstract

The characteristics of dynamic gratings greatly affect the linewidth and mode hopping properties of ultra-narrow linewidth erbium-doped fiber lasers. In this paper, we propose a novel method to estimate the temporal evolution of the reflectance spectrum of the dynamic gratings recorded in EDF based on the transient effect of the erbium ions. An experimental setup is also proposed to measure the reflectivity spectrum of the dynamic gratings utilized in lasers. The experimental data are compared with the numerical results and their differences are analyzed. The experiment results reveal some important transient characteristics of dynamic gratings in real lasers which are helpful to understand the mechanism of mode hopping.