etical approach is developed to evaluate pressure detection sensitivity and its temperature dependence for diaphragm-type fiber optic combustion pressure sensors. Temperature-induced mechanical response variations and diaphragm optical reflectivity degradation, particularly at high temperatures, are identified as the two major factors that produce errors in sensitivity, and hence in pressure measurement. Experimental results using hermetically sealed sensor construction prove the feasibility of maintaining diaphragm optical reflectivity under high temperatures. This analysis predicts that simple temperature compensation could reduce temperature-induced errors in sensor output, and obtain desired pressure measurement accuracies. Engine tests performed with the present fiber optic sensors demonstrate good signal-to-noise performance and temperature stability.
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