Effects of Yb3+ and Er3+ concentrations and doping procedure on excitation transfer efficiency in Er-Yb doped phosphosilicate fibers

Abstract

We have studied the effects of preform fabrication procedure and ytterbium and erbium concentrations on the efficiency of excitation transfer from Yb 3+ to Er 3+ and lasing on erbium transitions in the range 1.53–1.61 μm in phosphosilicate glass fibers. The results indicate that the fabrication of fiber preforms by different MCVD-based processes has no effect on the excitation transfer efficiency. In the ranges 0.07–0.4wt % Er 3+ and ∼ 0.4–8 wt % Yb 3+ (Yb/Er ratio from ∼ 5 to 40), the excitation transfer efficiency is determined by the ytterbium concentration and is essentially independent of erbium concentration.