Broadband near-infrared emission from Bi–Er–Tm Co-doped germanate glasses

Bi–Er–Tm co-doped germanate glasses and Bi, Er, Tm singly doped glasses were prepared and characterized through absorption spectra, NIR emission spectra and decay lifetime. A super broadband near-infrared emission from 1000 nm to 1600 nm, covering the whole O, E, S, C, and L bands, was observed in the Bi–Er–Tm co-doped samples due to the result of the overlapping of the Bi related emission band (centered at 1300 nm), the emission from Er3+ 4I13/2 → 4I15/2 transition (centered at 1534 nm) as well as the emission from Tm3+ 3H4 → 3F4 transition (centered at 1440 nm), which is essential for broadly tunable laser sources and broadband optical amplifiers. The energy transfer process was also discussed at the end of the paper.