Broadband 1.45-2.1 Μm Luminescence in Er3+/Tm3+/Yb3+ Tri-Doped Bismuth-Germanate Glasses

Optical properties of novel Er3+-doped, Er3+/Yb3+ and Er3+/Tm3+ co-doped and Er3+/Tm3+/Yb3+ tri-doped bismuth-germanate glasses were fabricated. Thermal characterization by differential scanning calorimetry showed the suitability of the glass for fiber drawing. Tri-doped sample presented a broadband luminescence spectrum ranging from 1450 to 2100 nm when it was excited by 980 and 1480 nm laser diodes. Energy transfer mechanisms from the donor (Yb3+, Er3+) to acceptor (Er3+, Tm3+) ions were found out to be the cause of the intense luminescence with broad bandwidth which can be tailored through doping content and concentration. It was observed that the Tm3+ addition helps broadening the luminescence spectrum, while the Yb3+ incorporation enhances the emission intensity. This study provides insightful contributions to the possibility of signal amplification in L +U-bands and beyond, up to 2100 nm.