DEVELOPMENT OF A FIBER-OPTIC CHAMBER PRESSURE TRANSDUCER

A FIBER-OPTIC PRESSURE TRANSDUCER (FOPT) BASED ON PATENTED FIBER-OPTIC SENSING METHODS WILL BE DEVELOPED FOR USE IN PRESSURE CHAMBERS AT PRESSURES FROM 50,000 TO 120,000 POUNDS PER SQUARE INCH. THE FOPT, OPERATING IN EITHER THE AMPLITUDEOR PHASE-MODULATION MODE, WILL DETECT THE DISPLACEMENT OF A DIAPHRAGM AS A MEASURE OF THE EXTERNAL PRESSURE. THE FOPT WOULD HAVE VERY HIGH RESONANT FREQUENCY TO ACHIEVE A FREQUENCY RESPONSE OF BETTER THAN 150 KHZ. UNLIKE THE PIEZOELECTRIC TRANSDUCER, THE FOPT WILL MEASURE THE STATIC RATHER THAN THE DYNAMIC PRESSURE. OPTICAL SENSING VIA A FIBER-OPTIC LINK WILL ISOLATE THE ELECTRONICS FROM THE HOSTILE ENVIRONMENT AND ALLEVIATE ELECTRONIC DRIFT DUE TO INTERFERENCE FROM STRONG ELECTROMAGNETIC AND RADIO FREQUENCY FIELDS AND/OR TEMPERATURE VARIATIONS. THE PROPOSED DEVELOPMENT EFFORT WILL BE AN EXTENSION OF AN ONGOING ARMY-SPONSORED SBIR PHASE II PROGRAM TO DEVELOP AN FOPT FOR PRESSURE MEASUREMENTS UP TO 100,000 PSI IN GUN-BARREL ENVIRONMENTS. FOR THAT APPLICATION, SPECIAL SENSOR CONFIGURATIONS WERE DESIGNED EMPLOYING A FINITE ELEMENT ALGORITHM IN ORDER TO AVOID CONCENTRATION OF LOCAL STRESS POTENTIALLY EXCEEDING THE YIELD STRENGTH OF AVAILABLE ALLOYS. THE PROPOSED EXTENSION 120,000 PSI IS BY NO MEANS TRIVIAL. THE KEYS TO THE SUCCESS OF THE PROPOSED DEVELOPMENT WILL BE INNOVATIVE DESIGN OF THE SENSOR CONFIGURATION USING A HIGH-STRENGTH/LOW-MODULUS MATERIALS AS WELL AS STABILIZATION OF THE LIGHT SOURCE.