Optical Properties of Er3+-doped K2O ? Nb2O5 ? SiO2 Glasses for Fiber Amplifiers

The optical properties of Er3+- doped K2O ? Nb2O5 ? SiO2 glasses obtained from the absorption and emission measurements. The visible and NIR emission spectra revealed one intense band green band at around 526 nm, corresponding to 2H11/2 → 4 I15/2 transition and another weak green band at 550 nm corresponding 4 S3/2 → 4 I15/2 transition. By the increase of Er3+ ions concentration, the intensities of emission bands in the visible and NIR regions increased up to 0.5 mol % and then decreased at higher concentrations (> 0.5 mol %) due to the concentration quenching. The decay profiles of the 4 I13/2 excited state for all Er3+ ions concentrations were fitted to a single exponential function and quantum efficiency of the 4I13/2 excited state is found to be 87%. From these results, it is suggested that, the KNbSiEr10 glasses could be more suitable for amplifiers in the near infrared region.