An Optical Fiber Probe for the Measurement of High Temperatures

72255S03-I In the materials processing industry, melting raw materials and forming them into products involve high-temperature operations in which large amounts of energy are consumed. Sensors that work in these high-temperature industrial processing environments (which also have harsh chemicals, physical restrictions, and electromagnetic interference) will contribute significantly to minimizing waste energy and products. This project will develop a sensitive, high-temperature fiber optic probe that can withstand ultra-high processing temperatures, hostile environments, and is not subject to electromagnetic interference. In Phase I, 1/4 wave stacks (with alternating refractive indices) of high temperature oxides will be deposited on a sapphire or zirconia fiber coupled to a silica fiber. Light sent into the fiber from some large distance away will be reflected from this dielectric stack, and the shift in wavelength will be a direct measure of temperature. The probe will be tested at elevated temperatures and packaged so that a 40 cm length of sapphire fiber can be easily connected to a silica fiber. Algorithms for interpreting the optical signal and converting this into temperature have already been prepared. Commercial Applications and Other Benefits as described awardee: The new temperature measuring technique should be applicable to various industrial processes including glass melting and metal forming, as well as gas turbine temperature measurements.