Novel Er³⁺/Nd³⁺-doped borofluoride glass materials for NIR optical fiber applications with suitable thermal and mechanical properties

To advance the performance of broadband optical fiber communication systems, a novel borofluoride-based glass system with the composition 60B₂O₃-20Pb₃O₄-10MgF₂-10LiF (BPML) was synthesized and accordingly investigated. The base glass was doped with 1 mol% of Er³⁺, Nd³⁺, or their combination to produce BPML: RE³⁺ glass series. Glass structural analysis via X-ray diffraction (XRD), bulk density measurements, and Fourier transform infrared (FTIR) spectroscopy confirmed the amorphous nature of the glasses, indicating increased network compactness upon rare-earth doping, particularly with Er³⁺. The thermal properties were investigated through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), revealing enhanced thermal stability across all synthesized doped glass samples. Furthermore, the theoretical estimation of the mechanical characterization, including predicted elastic moduli and hardness using the Makishima-Mackenzie model, showed rigidity improvements with the incorporation of RE³⁺. Optical absorption spectra recorded over the 400-1600 nm range reveal characteristic transitions of Er³⁺ and Nd³⁺, with co-doped samples displaying broader absorption bands, indicative of potential for wideband signal amplification. The photoluminescence studies under 773 nm excitation have demonstrated near-infrared (NIR) emission centered at 1.55 μm ([Formula: see text]Hz). The co-doped synthesized samples have exhibited enhanced emission intensity, indicating efficient energy transfer. The present work results show that the synthesized samples, doped with Er³⁺, Nd³⁺, or their combination, exhibit an optimal balance of thermal stability, mechanical robustness, and broadband NIR emission. Evidently, the synthesized glass samples achieve a high-quality factor of ([Formula: see text]), underscoring their potential for high-performance broadband applications. These properties position the proposed samples as a promising material for the fabrication of NIR optical fibers for communication benefits.