Broadband near-infrared emission covering S+C+L in Er³⁺-doped nanocrystal modified PbO-PbF₂-Bi₂O₃-Ga₂O₃ glasses

This paper reports a broadband near-infrared emission ranging from 1400 to 1660 nm in Er³⁺-doped nanocrystal-modified PbO-PbF₂-Bi₂O₃-Ga₂O₃ glasses. After heat treatment, X-ray diffraction measurements were performed and confirmed that PbBiO₂F nanocrystals were precipitated in the precursor glasses. As nanocrystals alter the local environment around Er³⁺ ions, the emission spectrum of the transition ⁴I_13/2→⁴I_15/2 is broadened and enhanced, resulting in a broadband emission and an FWHM wavelength range of 143.4 nm from 1470.1 to 1613.5 nm, which overlaps the S+C+L optical communications windows. In addition, the emission intensity of the ⁴I_11/2→⁴I_13/2 transition is also found to be increased after heat treatment, thus enhancing the λ∼2750 nm emission intensity. Our results indicate that an Er³⁺-doped nanocrystal-modified PbO-PbF₂-Bi₂O₃-Ga₂O₃ glass could be a competitive candidate material that can offer improved bandwidths for S+C+L broadband amplifiers used in very high-capacity optical communications systems.