Intense infrared emissions at 1.20μm (Ho 3+ : 5 I 6 → 5 I 8 transition) and 2.0μm (Ho 3+ : 5 I 7 → 5 I 8 transition) wavelengths from holmium–ytterbium (Ho 3+ –Yb 3+ ) codoped low-phonon-energy germanotellurite glasses and fibers were observed. In comparison to Ho 3+ -singly doped glass, the incorporation of Yb 3+ as sensitizer increases the quantum efficiency of the 1.20μm wavelength emission from 2.4% to 7.9% through efficient energy transfer from Yb 3+ ( 2 F 5/2 ) to Ho 3+ ( 5 I 6 ). Emission of 1.38μm originating from the Ho 3+ : ( 5 F 4 , 5 S 2 )→ 5 I 5 transition was also recorded under 488nm excitation. The observation of both 1.20 and 1.38μm wavelength emissions is primarily due to the low phonon energy of the germanotellurite glasses and is 770cm −1 in accordance to the Raman spectrum. Excellent gain performance is predicted by the long lifetime and the large stimulated emission cross-section. The results suggest that low-phonon-energy germanotellurite glass is a promising candidate for optical amplification at relatively unexplored 1.20 and 1.38μm wavelength regions, and lasing operation at the eye-safe 2.0μm wavelength region.