Tellurite And Fluorotellurite Glasses For Active And Passive

8. Fibre drawing; MDO 369
Fig. (8.21): Fluorotellurite fibre (MOF005) pulled in this study guiding light.
Wang et al. [18] predicted a minimum loss of around 3.6×10 -3 dB.km -1 at 3.02 µm for
TeO2-Na2O-ZnO glass (see section 2.5.1.1.). This is shifted to 1.8×10 -2 dB.km -1 at 1.9 µm
with OH present. Losses are much higher in the pulled fluorotellurite fibre most likely
due to the lack of cladding, cationic impurities, crucible contamination, and other nano-
and micro-inhomogeneities. Cherbanov et al. [13] have reported around 10 5 to 10 6 cm 3
nano-inhomogeneities in a number of oxide tellurite compositions, including air bubbles,
Pt particles (52 ppm), and crystals, the size and population depending on processing.
These particles ranged in size from 70 to 170 nm. All the fibres from fig. (8.16), except
the 10 hour melt, show an increase in loss into the visible region, where these types of