Demonstration of optical fiber probes for high bandwidth thermal measurements in turbomachinery

Interferometric temperature sensors comprising a zinc selenide film on the end of a single-mode optical fiber have been incorporated into rugged probes for measurement of gas temperature fluctuations in aerospace turbomachinery test rigs. Two-wavelength illumination provides signals in quadrature for determination of optical phase change of the signal reflected from the film which is exposed to the gas flow. We present ensemble-averaged results showing 15 K amplitude gas temperature fluctuations up to 70 kHz with a resolution of 1 K. >