The 2.0 μm emission originating from Ho^3＋：^5I7→^5I8 were investigated upon excitation with 808 nm laser diode （LD） transition in Ho^3＋/Tm^3＋-codoped gallate-bismuth-germanium-lead glasses Energy transfer （ET） process between Tm^3＋： ^3F4 level and Ho^3＋： ^5I7 level was also discussed. It was noted that the measured peak wavelength and stimulated emission cross-section of Ho^3＋-doped bismuth-germanium-lead glasses were -2.02 μm and 5.1×10^-21 cm^2, respectively. Intense emission of Ho^3＋ in Tm^3＋/Ho^3＋-codoped GBPG glass were observed, which resulted from the ET between Tm^3＋： ^3F4 and Ho^3＋： ^5I7 level upon excitation with 808 nm LD.
We investigated the thermal stability and spectroscopic properties of the 1.53 μm emission from ^4I13/2→^4I15/2 transition of Er^3＋ ions in Er^3＋/Yb^3＋-codoped Ga-Bi-Pb-Ge heavy metal oxide glass for use in broadband fiber amplifiers. It was noted that the addition of GeO2 effectively enhanced the thermal stability of the heavy metal oxide glass studied. The emission peak located at approximately 1530 nm with a full width at haft-maximum of approximately 58 nm. The measured lifetime and the calculated emission cross-section of this transition were -3.2 ms and -10.3×10^-21 cm^2, respectively. As a result, Ga-Bi-Pb-Ge heavy metal oxide glasses were assumed to be potential host material for the 1.53 μm broadband optical fiber amplifiers.
