Broadband 1.45–2.1 μm luminescence in Er3+/Tm3+/Yb3+ tri-doped bismuth-germanate glasses

Optical properties of novel Er 3+ -doped, Er 3+ /Yb 3+ and Er 3+ /Tm 3+ co-doped and Er 3+ /Tm 3+ /Yb 3+ 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 (Yb 3+ , Er 3+ ) to acceptor (Er 3+ , Tm 3+ ) 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 Tm 3+ addition helps broadening the luminescence spectrum, while the Yb 3+ 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. • A broadband emission spectrum from 1450 to 2100 nm was obtained by Er 3+ /Tm 3+ /Yb 3+ tri-doping of bismuth-germanate glass. • Thermal, optical and spectroscopic properties were examined under different doping approaches. • The addition of Tm 3+ broadened the emission spectrum while the Yb 3+ increased the luminescence intensity of Er 3+ and Tm 3+ . • The effects of 980 and 1480 nm excitation on the luminescence intensity and decay times of Er 3+ and Tm 3+ ions were studied.