HIGH DYNAMIC RANGE ACOUSTO-OPTIC BRAGG CELL TRANSDUCER DESIGN

OPTICAL TECHNOLOGY IS CAPABLE OF PERFORMING COMPUTATIONALLY INTENSIVE SIGNAL PROCESSING FUNCTIONS SUCH AS FOURIER TRANSORMATION, CORRELATION, AND AMBIGUITY FUNCTION CALCULATION, IN REAL-TIME AT SPEEDS MUCH FASTER THAN THAT OFFERED BY DIGITAL OR OTHER ANALOG PROCESSING TECHNOLOGIES. DESPITE RECENT DEMONSTRATIONS OF HIGH SPEED, COMPACT, RUGGED, ACOUSTO-OPTIC CHANNELIZERS AND CORRELATORS, THEIR RESTRICTED DYNAMIC RANGE PERFORMANCE MAY ULTIMATELY LIMIT THEIR USEFULLNESS IN MANY SIGNAL PROCESSING APPLICATIONS. THIS PROPOSAL ADDRESSES THE NEED FOR SIGNIFICANT DYNAMIC RANGE IMPROVEMENT IN ACOUSTO-OPTIC BRAGG CELLS. OUR APPROACH IS TO DEVELOP AN APODIZED PHASED ARRAY TRANSDUCE DESIGN METHODOLOGY THAT EXPLICITLY USES DYNAMIC RANGE AS A DESIGN CRITERIA. WE PROPOSE TO MINIMIZE THE ELASTIC TWO-TONE THIRD ORDER INTERMODULATION PRODUCTS BY LIMITING THE POWER IN THE UPPER HARMONIC ACOUSTIC WAVES. THIS WILL BE ACCOMPLISHED WITH A TRANSDUCER DESING UTILIZING ACOUSTIC BEAM STEERING AND APPROPRIATE MANAGEMENT OF ACOUSTIC DIFFRACTION AND ATTENUATION. THIS NEW DESIGN METHODOLOGY WILL BE APPLICABLE TO ALL CURRENT ACOUSTO-OPTIC DESIGNS. A SLOW SHEAR TEO(2) BRAGG CELL, A DEVICE WITH PARTICULARLY POOR DYNAMIC RANGE PERFORMANCE, WILL BE FABRICATED AND CHARACTERIZED USING THIS TECHNIQUE.