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 Er 3+ -doped and Tm 3+ -doped tellurite glasses and fibres has been examined in detail. In particular, the effect of compositional modification on the line-shapes of the transitions: 4 I 13/2 → 4 I 15/2 in Er 3+ -doped and 3 H 4 → 3 F 4 in Tm 3+ -doped tellurite glasses is analysed and discussed. The presence of co-dopants, namely Tb 3+ and Ho 3+ ions in Tm 3+ -doped glasses on the lifetimes of the upper ( 3 H 4 ) and the lower ( 3 F 4 ) levels have also been discussed for shortening the lifetime of the transition between the 3 F 4 level and the ground state in thulium. The spectroscopic properties of Nd 3+ -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.