Novel insights into the electronic and optical properties of the 1.53-μm emission in Er3+-doped oxide- and oxyfluoride- tellurite glasses for optical communications

There is a continuous search for novel technologies to extend the NIR emission and expand the operation range of current Er-doped silica-based glasses. In this sense, it is important to understand the different interactions between the Er3+ ions and the glass structure and how it influences the 4I13/2 -> 4I15/2 emission. The intrinsic features of tellurite glasses make them to be promising candidates. The effect of the glass composition was evaluated by comparing oxide and oxyfluoride-based tellurite glasses. These results show that the distribution of electrons in Stark levels have population dynamics obeying the Fermi-Dirac distribution against the traditional MaxwellBoltzmann function usually considered. In addition, this work explores how the Er3+ ion emissions at 1.53 mu m can be engineered. We demonstrate how the luminescence from the 4I13/2 -> 4I15/2 transition of Er3+ ions is affected by the doping concentration, showing an increase in the emission output of the oxide and oxyfluoride glasses, with up to 5.0 mol% of Er2O3, and a FWHM over 100 nm under 104 mW pumping. The variations in the emission were also assessed as related to pumping power and temperature. Under cooling, the emission intensity increased over the infrared and the emission underwent a redshift, whereas the increasing temperature led to a blueshift with a variation of FWHM ranging from 90 to 140 nm. The analysis presented in this work elucidates the different aspects involved in the emission of Er3+ ions while highlighting the versatility of these tellurite glasses as a promising glass matrix for optical communications with operations in Er3+ emission window.