Tm³⁺-doped tellurite glasses for fiber amplifiers in broadband optical communication at 1.20 μm wavelength region

Broadband emissions at around 1.20 and 1.46 μm wavelengths from thulium (Tm³⁺)-doped tellurite glasses were observed under 465 nm wavelength excitation. The 1.20 μm emission originates from the Tm³⁺: ¹G₄→³H₄ transition, and the associated stimulated peak emission crosssection is calculated to be 0.47 × 10 ^-20 cm². Population inversion occurs between the ¹G₄ and ³H₄ levels, and a positive gain band from 1.20 to 1.28 μm is achieved at relatively low Tm ³⁺ dopant concentration. Our results suggest that this glass system is promising for optical fiber amplifiers operating at the relatively unexplored low loss 1.20 μm wavelength region. © 2010 Optical Society of America.