Experimental and theoretical studies on NIR luminescence of titanate-germanate glasses doped with Pr3+ and Tm3+ ions

Near-infrared (NIR) luminescence of Pr3+ and Tm3+ ions in titanate-germanate glasses has been studied for laser and fiber amplifier applications. The effect of the molar ratio GeO2:TiO2 (from 5:1 to 1:5) on spectroscopic properties of glass systems was studied by absorption, luminescence measurements, and theoretical calculations using the Judd-Ofelt theory. It was found that independent of the TiO2 concentration, intense NIR emissions at 1.5 and 1.8 & mu;m were observed for glasses doped with Pr3+ and Tm3+ ions, respectively. Moreover, several spectroscopic and NIR laser parameters for Pr3+ and Tm3+ ions, such as emission bandwidth, stimulated emission cross-section, quantum efficiency, gain bandwidth, and figure of merit, were determined. The results were discussed in detail and compared to the different laser glasses. Systematic investigations indicate that Pr3+-doped system with GeO2:TiO2 = 2:1 and Tm3+-doped glass with GeO2:TiO2 = 1:2 present profit laser parameters and could be successfully applied to NIR lasers and broadband optical amplifiers.

Automated summary

The NIR luminescence of Pr3+ and Tm3+ ions in titanate-germanate glasses was studied for laser and fiber amplifier applications. The effect of the GeO2:TiO2 molar ratio on the spectroscopic properties of the glasses was investigated using absorption, luminescence measurements, and theoretical calculations. Strong NIR emissions were observed at 1.5 and 1.8 μm for glasses doped with Pr3+ and Tm3+ ions, respectively, regardless of the TiO2 concentration. The spectroscopic and laser parameters of the Pr3+ and Tm3+ ions were determined and compared to other laser glasses, and it was found that the Pr3+-doped glass with a GeO2:TiO2 ratio of 2:1 and the Tm3+-doped glass with a GeO2:TiO2 ratio of 1:2 exhibited favorable laser characteristics for use in NIR lasers and broadband optical amplifiers.