Emission enhancement in Er3+/Pr3+ codoped germanate glasses and their use as a 2

Emission enhancement at 2.7 mm is observed in Er3+/Pr3+-codoped germanate glasses when pumped by a 980-nm laser diode. Significant reductions in 1.5-mm emission and upconversion intensity indicate efficient energy transfer between Er3+ and Pr3+; the energy transfer efficiency is as high as 77.4%. Th