Tellurium oxide glass hosts have exceptionally large solubility for RE-ions. In this paper, the relationship between the host glass composition and spectroscopic properties of Er³⁺-doped and Tm³⁺-doped tellurite glasses and fibres has been examined in detail. In particular, the effect of compositional modification on the line-shapes of the transitions: ⁴I_13/2→⁴I_15/2 in Er³⁺-doped and ³H₄→³F₄ in Tm³⁺-doped tellurite glasses is analysed and discussed. The presence of co-dopants, namely Tb³⁺ and Ho³⁺ ions in Tm³⁺-doped glasses on the lifetimes of the upper (³H₄) and the lower (³F₄) levels have also been discussed for shortening the lifetime of the transition between the ³F₄ level and the ground state in thulium. The spectroscopic properties of Nd³⁺-doped glasses for designing amplifiers operating in the 1330- to 1370-nm region has also been explained for demonstrating a continuous gain spectrum from 1310- to 1610-nm. The fibre loss measurements demonstrate that the Er-doped fibres have less than 880 dB km^-1 attenuation in the 1200- to 1400-nm range. An explanation is given to determine the suitability of such RE-doped tellurite fibres for designing broadband amplifiers.

Les propriétés spectroscopiques des verres de tellurites dopés à l'erbium et au thulium ont été examinées en détail et discutées. Les fibres dopées à l'erbium présentent des pertes de fond inférieures à 800 dB km^-1 entre 1200 et 1400 nm. L'application de ces fibres aux amplificateurs optiques à large bande est discutée.