Spectroscopic properties and thermal stability of Er³⁺/Yb³⁺-codoped fluorophosphate glasses

A comprehensive study on the thermal stability and spectroscopic properties of Er3+/Yb3+-codoped Al(PO3)3-based fluorophosphate glasses have been reported for 1.5-mm fiber amplifiers in this paper. From optical absorption spectra, the Judd-Ofelt parameters of Er3+ in the glasses and then several important optical properties, i.e., the radiative transition probability, the branching ratio and the spontaneous emission probability, have been calculated by Judd-Ofelt theory. The fluorophosphate glass exhibits broadband near-infrared emission at 1.53 mm with a full width at half-maximum over 63 nm, and a large calculated stimulated-emission cross-section of 6.85×10-21 cm2.