Precise regulation of bismuth active centres in alkaline earth ion-doped Ga2O3–GeO2 glasses by Bi–Al pre-combination

Abstract

Bismuth (Bi)-doped glasses and optical fibers have been widely applied in the research of tunable lasers and amplifiers due to their ultra-broadband near-infrared (NIR) luminescence, which originates from the bismuth active centres (BACs). Traditional methods for regulating BACs typically involve pre-treatment strategies, such as altering glass composition and adjusting the structure units of glass, as well as post-treatment methods, including thermal activation. However, these approaches struggle to precisely regulate the surrounding environment of the BACs, as they mainly depend on structure changes in the glass network induced by network modifiers or post-treatments. In this study, we break through traditional methods and propose a strategy for the precise regulation of BACs by Bi–Al pre-combination in the form of Bi₂(Al₂O₄)₃ doping. The effectiveness of this strategy is further validated by modifying the alkaline earth ion species. The results demonstrate that this method significantly raises the Bi concentration quenching threshold, helping to overcome the limitations of low BAC concentrations in Bi-doped fibers. Furthermore, it improves the photostability of BACs under continuous 830 nm pumping and reduces the differences in photostability across different alkaline earth ion glasses, thus facilitating further application research on Bi-doped optical amplifiers.