Effect of temperature and irradiation on fused silica optical fiber for temperature measurement

The thermal radiation and luminescence of fused silica-core optical fibers with cores that are pure or doped with moderate and large amounts of fluorine was measured at elevated temperature with and without Co-60 γ-ray irradiation to study the effect of temperature and irradiation on the optical fibers. In the temperature range up to 1000 °C, peaks from OH were observed in all fibers and the intensity was temperature dependent. When the temperature of F-doped fibers was kept at 1000 °C, unexpected peaks appeared and grew. As a result, the peaks from OH could not be observed either with or without irradiation. In the case of pure fiber, thermal radiation increased as the elapsed time increased and the intensity with irradiation was much larger than that without irradiation. However, peaks from OH could be identified clearly and discriminated from the thermal radiation. The pure fiber is a promising temperature sensor.