Homogeneous broadening effect on temperature dependence of green upconversion luminescence in erbium doped fibers

► We study green upconversion luminescence of Er3+ ions in a fiber excited at 787 nm. ► Upconversion luminescence variation from room to cryogenic temperature is analyzed. ► Upconversion emission consists in a sequential two-photon absorption process. ► A semiclassical model considering inhomogeneous broadening explains the results. ► Homogeneous broadening is responsible for the upconversion temperature dependence.