A study of optical properties and upconversion processes among Er ions in oxyfluoride glass and glass ceramic matrix has been carried out. From optical absorption spectra, the oscillator strengths have been obtained for several transitions and they have been used to
calculate the Judd–Ofelt parameters. Experimental lifetime values are compared with those obtained with the Judd–Ofelt theory. Different 31 upconversion emissions at 545, 660 and 800 nm have been obtained in Er doped glass and glass ceramics by exciting at 975 nm. A systematic investigation of the green upconversion is reported with the purpose of determining the involved upconversion mechanisms.
