Compositional effects and spectroscopy of rare earths (Er3+, Tm3+, and Nd3+) in tellurite glasses

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: I-4(13/2)-->I-4(15/2) in Er3+-doped and H-3(4)-->F-3(4) 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 (H-3(4)) and the lower (F-3(4)) levels have also been discussed for shortening the lifetime of the transition between the F-3(4) 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. (C) 2002 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.