Sapphire-ruby single-crystal fibre for application in hightemperature optical fibre thermometers: studies at temperatures up to1500 °C

Abstract

In this work, a study of a fibre optic ruby crystal probe exposedto high temperatures has been carried out for the first time, and`annealing' effects have been considered and reported upon. The work hasenabled the device to be studied at temperatures up to 1500 °C totest its `survivability': the results show that a single-crystal probe isable to operate continuously at temperatures up to 1400 °C, and canreliably cover a wide temperature measurement range from 0 °C to1400 °C. Uncertainties in the measurement of, at worst,approximately ±7 °C result after many hundreds of hours oftemperature cycling of the probe.