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 Er 3+ 4 I 13/2 → 4 I 15/2 transition (centered at 1534 nm) as well as the emission from Tm 3+ 3 H 4 → 3 F 4 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.