Broadband near-infrared emission in Bi-Tm co-doped germanium silicate glasses

Broadband gain materials are of considerable interest for the next generation telecommunication system because of their potential for realization of the optical amplification in the whole telecommunication low-loss window. One of the major challenges is to extend the operation waveband of the gain materials. Here, we report the synthesis and spectral analysis on the Bi-Tm co-doped germanium silicate glasses. Various characteristic emission bands at 952 nm, 1156 nm, 1428 nm and 1800 nm are analyzed and their origins are identified. By tuning the excitation wavelength, the broadband near-infrared emission in the 1000–2000 nm with smooth shape and full width at half maximum of ∼450 nm is achieved. The physical mechanism based on the energy transfer between Bi n m + and Tm ³⁺ is proposed for explain the interesting luminescence phenomenon. The results provide valuable reference for exploration of the novel broadband gain materials for fiber amplifier.