Broadband near-infrared emission in Bi-Er co-doped germanosilicate glasses

Abstract

Broadband gain materials have garnered considerable attention on account of their practical utilization in optical amplifiers. Among them, Bi-doped glasses depict tremendous potential due to their unique broadband emission. In this paper, we report a series of Bi-Er co-doped germanosilicate glasses exhibiting broadband and tunable near-infrared (NIR) emission. By the strategy of Bi-Er co-doping, the luminescence bandwidth is effectively expanded in two ways: co-excitation and energy transfer between two active centers. Importantly, broadband luminescence covering O-E-S-C-L bands with full width at half maximum (FWHM) more than 320 nm is realized via the way of energy transfer. In addition, ultrabroadband emission covering C-L-U bands with FWHM of ∼370 nm and relatively flat emission of ∼170 nm is achieved via the way of co-excitation. Furthermore, the mechanism of energy transfer is discussed. These results indicate that Bi-Er co-doped germanosilicate glasses are the promising candidates in the field of optical fiber amplifiers.