LASER DETECTION AND RANGING ARRAYS FOR REENTRY AND OUTGOING TARGET TRACKING AT THE KWAJALEIN ATOLL FACILITY

WE PROPOSE TO DEVELOP A LASER DETECTION AND RANGING (LADAR) TECHNIQUE FOR AIRBORNE TARGET DETECTION AND TRACKING AT RANGES OF 10 KM OR GREATER. WE WILL DEVELOP THE SEL ARRAY USING INGAAS/GAAS MULTIPLE QUANTUM WELLS (MQWS) SANDWICHED BETWEEN TWO DISTRIBUTED BRAGG REFLECTORS (DBR) OF GAAS/ALAS. THE MQWS AND DBR WILL BE FABRIATED ON GAAS SUBSTRATE IN TANDEM BY MOLECULAR BEAM EPITAXY (MBE). THE TWO-DIMENSIONAL ARRAY OF THE MQW LASERS WILL LASE PERPENDICULAR TO THE SURFACE OF THE SUBSTRATE AND THE EMITTED POWER FROM EACH LASER CAN BE CONTROLLED INDEPENDENTLY AND COHERENTLY. IN ADDITION, WE WILL DEVELOP A PHOTODETECTOR PLACED NEXT TO EACH LASER PIXEL, RESULTING IN A 2-DIMENSIONAL ARRAY OF RADAR ELEMENTS, WHICH WILL TAKE IMAGES OF THE LASER RETURNS FROM TARGETS. THE MAJOR PHASE I TASK IS TO CONCEIVE AND DESIGN THE ARRAY LAYOUT, THE ON-CHIP BIAS/ADDRESS CIRCUIT AND THE CONTROL PROCESSOR NEEDED FOR THE ARRY OPERATION AND IMAGE GENERATION AND RANGE COMPUTATION. THIS IS FOLLOWED BY A DELINEATION OF AN MBE PROCESS TO FABRICATE THE MULTIPLE LAYERS FOR THE SEL AND DETECTORS ALL ON A SINGLE GAAS WAFER. THE RESULTANT SEL "RADAR" ARRAY WILL BE USED FOR GENERATING MODULATED IMAGES WITH HIGH RESOLUTION AND HIGH DYNAMIC RANGE, WITH CORRESPONDING RANGE VALUES, THUS MAKING IT IDEAL FOR DETECTING AND TRACKING OF AIRBORNE TARGETS.