OPTICAL PROCESSORS FOR LIDAR APPLICATIONS

DEVELOPMENTS WHICH IMPROVE THE PERFORMANCE OF LASER-BASED DETECTION AND RANGING SYSTEMS ARE OF MORE VALUE IF THEY CAN BE APPLIED IN A WIDE VARIETY OF APPLICATIONS. LASER RADAR SYSTEMS ARE GENERALLY APPLICATION SPECIFIC DEVELOPMENTS AND HAVE LARGE POSSIBLE VARIATIONS IN DESIGN. AN APPROACH WHICH OFFERS DISTINCT PERFORMANCE IMPROVEMENTS, CAN BE EASILY IMPLEMENTED WITHIN THE DESIGN, AND SIMPLY EXTENDS A REQUIRED SYSTEM FUNCTION WILL BE ATTRACTIVE TO ALLLASER-RADAR DEVELOPERS. THIS PROPOSAL PRESENTS A NOVEL MIXING TECHNIQUE WHICH HAS SUCH ATTRIBUTES FOR COHERENT LASER RADAR APPLICATIONS. IN THE PHASE I EFFORT, THE FEASIBILITY OF USING CONTROLLED OPTICAL WAVE-FRONT MIXING TO IMPROVE NOISE REJECTION, INCREASE DYNAMIC RANGE AND REDUCE SYSTEM COMPLEXITY WILL BE INVESTIGATED. A UNIQUE OPTICAL PROCESSOR IS USED TO PRECISELY CONTROL THE PHASE RELATIONSHIPS OF THE OPTICAL WAVE FRONTS SUCH THAT THE MIXING TECHNIQUE IS INDEPENDENT OF FREE-SPACE PATHLENGTHS. THE WAVE-FRONT PROCESSOR USES A NON-LINEAR CRYSTAL WHICH ACTS AS A WAVEGUIDE AND PHASE SHIFTER.