The demand of advanced aircraft propulsion systems on sensor technologies to operate at extended temperature ranges has to date been primarily focused on redesigning existing measurement system techniques. This proposed program will show the feasibility of a new remote fly-by-light technology made possible by the availability of high temperature air-clad sapphire optical fibers. The LEL concept for applying this technology to pressure and related measurements is electrically passive-optically active. No electrically active parts reside in the sensor, minimizing temperature effect on the sensor output. The sensor's input and output optical fibers can be integrated in the engine's composite structure or passed through traditional wire ways to traditional electronic components which are located remotely from the sensor. A primary feature of this new sensor design concept is to measure differential motion as opposed to absolute motion, typical of diaphragm designs. A properly designed differential motion sensor measures only the input parameter not the side effects caused by temperature and induced stresses, both static and dynamic. This fiber optic miniaturized ceramic transducer is "Thermally Hardened" by material modifications allowing it to operate in a high temperature (1000 degrees C) environment. It does not require active temperature compensation or linearization to achieve specified accuracy.
