Characterization and modeling of ErYb co-doped waveguide amplifier in phosphate glass

Erbium-doped amplifiers are key elements not only for modern telecom systems but also for integrated narrow linewidth lasers that are used for sensing and THz generation. Ion exchange on glass is a technological platform that allows realizing very efficient erbium-doped waveguide amplifiers with low coupling losses and quite high net gains. However, integrated lasers require a shorter amplifying waveguide that is operated in a strongly saturated regime. For this reason, a co-doping with Er and Yb is used. In this paper, we present the characterizations of Er-Yb co-doped waveguide amplifiers in terms of spectroscopic and guiding properties. Then small signal and satured gains measurements are presented. Finally, all these experimental data are employed to derive and assess a theoretical model of the ion-exchanged waveguide amplifier.