Tellurite And Fluorotellurite Glasses For Active And Passive

2. Literature review; MDO 53
Addition of GeO2 increased the intensity of the free OH band, but did not affect the
hydrogen bonded band. Addition of Y2O3 did not affect either the free or H-bonded
bands, and Na2O slightly reduced the free OH band only.
2.5.1.2. Er 3+ -doping of TZN glasses
Tellurite glasses have a lower phonon energy than silica (800 and 1000 cm -1
respectively), which is important for efficient fluorescence of rare-earth transitions, as
high phonon energy results in increased probability of non-radiative decay, with energy
lost to the host lattice as heat. The erbium (III) 1.55 µm transition has received much
attention, for use as an amplifier in that particular telecommunications window.
Wang et al. [36] showed the addition of rare-earths, including erbium (III), generally
increased the stability of TZN glasses. Table (2.4) summarises some of these results.
Table (2.4): Effect of erbium (III) on the characteristic temperatures of some tellurite
glasses [36].
Glass / mol. % (+ wt. % Er2O3)
Tg /
°C
Tx /
°C
Tx-Tg /
°C
72TeO2-28ZnO 324 420 96
" (1) 330 425 95
75TeO2-20ZnO-5Na2O 299 417 118
" (1) 304 432 128
" (3.9) 311 447 136
" (7.5) 324 443 119
It can be seen, in the ternary system 75TeO2-20ZnO-5Na2O mol. %, glass stability can be
increased up to at least 4 wt. % Er2O3. The emission width for erbium (III) was shown to