Emission of 1.38 μm and gain properties from Ho³⁺-doped low-phonon-energy gallate bismuth lead oxide glasses for fiber-optic amplifiers

Efficient emission at 1.38 μm wavelength from holmium (Ho ³⁺)-doped low-phonon-energy gallate bismuth lead (GBL) oxide glasses, owing to the Ho³⁺: (⁵S₂,⁵F ₄)→⁵I₅ transition, was observed, and the stimulated emission cross section was calculated to be 2.4 × 10 ^-21 cm². Population inversions between the ( ⁵S₂,⁵F₄) and ⁵I ₅ levels have been achieved, and a broad gain bandwidth from 1350 to 1450 nm was obtained. The large product of emission cross section and measured lifetime also support this characteristic. The results indicate that a Ho ³⁺-doped GBL glass system is a promising candidate for the development of E-band (1360-1460 nm) fiber-optic amplifiers.