FIBER OPTIC MAGNETIC GRADIOMETER FOR DETECTING DEEPLY BURIED ORDNANCE

A MAGNETIC GRADIOMETER BASED ON THE PROVEN CONCEPT OF A FIBER OPTIC INTERFEROMETRIC MAGNETIC TRANSDUCER IS PROPOSED FOR THE DETECTION OF DEEPLY BURIED ORDNANCE. THE LOCAL MAGNETIC GRADIENT CAN BE MEASURED WITH HIGH SENSITIVITY WITH A MACH-ZEHNDER OPTICL INTERFEROMETER; THE TWO SENSING ARMS ARE COMPOSED OF A SINGLE MODE OPTICAL FIBER COATED WITH, OR OTHERWISE ATTACHED TO, A MAGNETOSTRICTIVE MATERIAL. A FIBER OPTIC SENSOR OFFERS UNIQUE ADVANTAGES OVER OTHER SENSORS IN SENSITIVITY, LOW POWER CONSUMPTION, LOW MAGNETIC SIGNATURE AND PORTABILITY. DURING PHASE I, DYNAMICS TECHNOLOGY WILL CALCULATE THE PRINCIPAL PERFORMANCE REQUIREMENTS AND ANTICIPATED NOISE LEVELS FOR A FIBER GRADIOMETER USING OUR EXISTING MAGNETIC FIELD SIGNATURE MODELS, AND WILL TEST THE MOST PROMISING CANDIDATE CONFIGURATIONS IN OUR OPTICS LABORATORY USING CONTROLLED MAGNETIC FIELD SOURCES. SENSITIVITY MEASUREMENTS WILL BE MADE FROM WHICH EXTRAPOLATIONS TO A PROTOTYPE SENSOR PERFORMANCE CAN BE CALCULATED. A PRELIMINARY DESIGN FOR A PHASE II PROTOTYPE SENSOR WILL BE DEVELOPED