Optical and spectroscopic properties erbium-activated modified silica glass with 1.54 µm high quantum efficiency

Several modified silicate glass samples activated with erbium ions at two different doping rates, namely 0.2 and 0.5 mol%, exhibit at room temperature a fine-structured emission band around 1.5 ?m. The decay of luminescence from the Er 3+ 4I 13/2 metastable level is found to evolve according to a single-exponential law and a lifetime as long as 14.2 ms is measured from the glass with the lower erbium concentration. An estimation of the corresponding radiative lifetime, ? rad, is achieved on the basis of various theoretical models. Internal gain curves resulting from absorption and stimulated emission cross sections are also shown. A 75% quantum efficiency is deduced for the less Er 3+ concentrated glass, which is nearly the highest one obtained from silica based doped-glasses.