Broadband infrared fluorescence in Er-doped BaO–SiO2 glasses

Er³⁺-doped SiO₂ glasses with or without BaO were fabricated by containerless processing. Scanning electron microscope observations and the scan profiles of electron-probe microanalysis demonstrated that the Ba-silicate glass was homogeneous and no aggregation of Er³⁺ ions occurred. The infrared fluorescence at around 1.55 μm from Er³⁺ in the Ba-silicate glass excited by a 980-nm laser was broader and its lifetime was longer than that of the silica glass, indicating the difference in the local structures around Er³⁺ ions between the Ba-silicate and silica glasses; this was supported by Raman scattering measurements. These results demonstrated that the Ba-silicate-glass system might be a new candidate for a host glass for Er³⁺-doped fiber amplifiers.