Optimizing energy transfer in Er3+/Yb3+ Co-doped heavy metal oxide bismuth borate glasses for C-band optical amplifiers

Abstract

This study investigates the photoluminescence properties of heavy metal oxide glasses composed of B₂O₃, Bi₂O₃, Gd₂O₃, K₂O, and Li₂O, doped with Ytterbium (Yb³⁺) and Erbium (Er³⁺) ions, referred to as BBGKLEr³⁺/Yb³⁺. These glasses were made by melt-quenching procedure with varying concentrations of the Yb³⁺ dopant to assess their luminescence characteristics. Highpersensitive band in the visible spectrum was appeared at 521 nm for the transition (²H, ⁴G)_11/2 for Er³⁺ ions in BBGKLEr³⁺/Yb³⁺ glasses. A 980 nm diode laser was employed to excite the Er³⁺/Yb³⁺ ions, facilitating the investigation of up-conversion (UC) and down-conversion processes. The BBGKLEr³⁺/Yb³⁺ glasses exhibited significant UC emission alongside a strong emission band at 1530 nm. Notably, the gain cross-section for BBGKLglasses doped with 0.5 mol% Er³⁺ and 5 mol% Yb³⁺ ions increased to 2.39 × 10⁻²¹ cm², as determined by Mc Cumber theory. With an estimated lifetime of 0.885 ± 0.05 ms, the 1530 nm near infra-red emission demonstrated remarkable efficiency in promoting rare earth ion emission, further enhanced by the extended lifetime of the BBGKLEr³⁺/Yb³⁺ glasses. Spectroscopic analyses, including emission spectra, emission decay profiles, and gain cross-sections, suggest that BBGKLEr³⁺/Yb³⁺ glasses hold promise for use in C-band amplifiers or as laser gain media.