AIRCRAFT ENGINE TURBINE INSTRUMENTATION

WITH THE RECENT, RAPID ACCELERATION IN THE GROWTH OF FIBER OPTIC TRANSMISSION SYSTEMS, IT SEEMS LOGICAL THAT ALL-OPTICAL SENSORS WILL BE THE NEXT GENERATION OF SENSORS--NOT JUST FOR TEMPERATURE AND PRESSURE BUT FOR A VARIETY OF PARAMETERS, INCLUDING STRESS, DISPLACEMENT, LIQUID LEVEL, ETC. TO DEMONSTRATE THE OPTICAL SENSOR CONCEPT, A PRESURE SENSOR WILL BE DESIGNED AND FABRICATED FOR APPLICATION IN THE EMP/EMI, HIGH-TEMPERATURE CONDITIONS OF TURBINE ENGINE TEST INSTRUMENTATION. THE SENSOR CONSISTS OF A BROADBAND LIGHT SOURCE COUPLED INTO AN OPTICAL FIBER WHICH TRANSMITS THIS BROADBAND SPECTRUM TO THE REMOTE SENSOR ELEMENT. THE SENSOR ELEMENT IS A VARIABLE GAP FABRYPEROT CAVITY WHICH MODULATES THE REFLECTED SPECTRUM ACCORDING TO GAP DIMENSION. THE REFLECTED SPECTRUM IS FIBER-TRANSMITTED BACK TO A MICROPROCESSOR BASED, COLOR DEMODULATION SYSTEM. THIS COLOR DEMODULA-TION IS ACCOMPLISHED BY PRISM DISPERSION OVER A CHARGE-COUPLED-DEVICE (CCD). THE MICROPROCESSOR USES KALMAN FILTERING TO ANALYZE AND CONVERT THE SPECTRAL DATA TO PRESSURE.