Effects of gamma radiation on optical fibre sensors

Consideration of thermo-optic coefficients is essential in the applications of optical fibre sensors and high-speed fibre communication systems. The Fabry-Perot interference method is applied to study these coefficients of four types of commercial fibres. The results are in agreement with the values calculated from the Sellmeier equation for fused silica fibre, with a difference of only about 0.2% for the Corning single-mode fibre SMF-28. In order to apply fibre sensors to a highradiation environment, the thermo-optic coefficients for these fibres have been investigated after exposure to heavy doses of gamma radiation, and their radiation resistance has been studied.