Fabrication Of Arsenic Sulfide Optical Fibre With Low Hydrogen Impurities

Arsenic sulfide glass optical fibres typically possess extrinsic absorption bands in the infrared wavelength region associated with residual hydrogen and oxygen related impurities, despite using purified precursors. This paper reports on a purification process based on the addition of tellurium tetrachloride to the glass. During melting, the chlorine from TeCl4 reacts with the hydrogen impurities to produce volatile products (e.g. HCl) that can be removed by subsequent dynamic distillation. The processing conditions have been modified accordingly to produce optical fibres with significantly reused loss due to hydrogen sulfide impurity content (1.5dB/m).