Gamma ray radiation induced absorption in Ti doped single mode optical fibres at low dose levels

Induced loss due to optical absorption of single mode optical fibres doped with TiO2 and GeO2 + TiO2 in the silica core glass matrix under 60Co gamma radiation has been studied at different dose rates in the range of 5–10 Gy/h at 1310 nm transmission wavelength for evaluation of their radiation response behaviour. The radiation sensitivity of the fibres due to induced optical absorption of Ti3+ related colour centers shows considerable variation with Ti content in SiO2 and SiO2 + GeO2 host glass matrix of the core, fibre design and operating wavelength. The maximum sensitivity in visible region was observed at 540 nm absorption wavelength. The recovery nature as well as the effect of photobleaching and thermobleaching phenomena have also been investigated. The high radiation sensitivity along with linear response behaviour, low recovery and almost dose rate independent behaviour of the material system of TiO2 doped SiO2 and TiO2 doped SiO2–GeO2 core optical fibres under gamma radiation show their capability for application as fibre optic radiation sensor.