Optical properties of Er3+-doped alkali fluorophosphate glasses

A systematic study of the optical absorption and luminescence spectra of Er3+-doped alkali fluorophosphate glasses (RTFP) 50(NaPO3)–10TeO2–20AlF3–19RF–1Er2O3 (R = Li, Na and K) has been performed. The phenomenological Judd–Ofelt intensity parameters have been determined from the spectral intensities of the absorption bands in order to calculate the radiative transition probabilities, radiative lifetimes and branching ratios for various excited luminescent states. Using the visible and near infrared emission spectra, full width at half maximum (FWHM), emission cross-sections (σe) and figure of merit (FOM) were evaluated and compared with other hosts. Especially, the numerical values of these parameters indicate that the emission transition 4I13/2 → 4I15/2 transition at 1.534 μm in Er3+-doped fluorophosphate glasses may be highly useful in optical communication. The decay characteristic of 4S3/2 excited level has also been recorded and analyzed. The calculated and experimental lifetimes were compared in terms of quantum efficiencies and multiphonon relaxation rates.