Spectroscopy of Dy 3+ in Ge–Ga–S glass and its suitability for 1.3-μm fiber-optical amplifier applications

Absorption and emission spectra, along with lifetime measurements, of Dy3+ in Ge–Ga–S glasses are reported. Fluorescence is observed at 1.3, 1.8, and 2.9 μm. A Judd–Ofelt analysis is performed to determine branching ratios and quantum efficiencies. The hypersensitive transition 6F11/2 → 6H15/2 at 1.3 μm has a quantum efficiency of 17%. Its suitability for an optical amplifier at 1.3 μm depends on the excited-state absorption from the 6H11/2 and 6H13/2 states, which has not yet been measured.