1.5 μm emission in Er³⁺-doped boro-germanate glasses for optical telecommunication wide-band applications

Erbium-doped boro-germanate glasses with nominal composition (55-x) B₂O₃ + 5GeO₂ + 20Na₂O + 10BaO + 10Al₂O₃ + xEr₂O₃ (where x = 0.0, 0.5, 1.0, and 1.5 mol%) were synthesized using the conventional melt-quenching technique. The optical and structural characteristics of the prepared glasses were investigated to assess their suitability for photonic and telecommunication applications. When excited at 980 nm, all glass samples exhibited a pronounced upconversion luminescence phenomenon along with strong near-infrared emission centered at about 1.5 μm. This feature was due to the transition of Er³⁺ ions from ⁴⁴I₁₅/₂ to ⁴I₁₃/₂. The emission intensity reached its maximum at 0.5 mol% Er₂O₃, beyond which concentration quenching was observed. The absorption cross-section (σ_abs(ν)) and emission cross-section (σ_emi(ν)) were evaluated based on McCumber and Judd–Ofelt analyses to elucidate radiative transition probabilities and gain parameters. Structural modifications induced by Er³⁺ incorporation were correlated with the observed optical behavior. With these changes in material composition, the glass’s photoluminescence properties are improved, making it viable for optical devices and telecommunication devices. The synthesized sodium–aluminum–barium boro-germanate glasses in comparison to other glasses have improved spectroscopic properties, making them suitable candidates for solid-state lasers, near-infrared photonic devices, solid-state lasers, erbium-doped fiber amplifiers (EDFA) along with broadband optical communication systems.