PHOTOREFRACTIVE AND ELECTROREFRACTIVE NONLINEAR OPTICAL WAVEGUIDES

PHOTOREFRACTIVE BULK CRYSTALS HAVE BEEN THE BASIS FOR DEMONSTRATING MANY STRIKING PHENOMENA OF NONLINEAR OPTICS BUT TEND TO BE SLOW IN RESPONSE SPEED AND SUITABLE ONLY FOR LABORATORY RESEARCH. SPEED OF RESPONSE, DEVICE UNIFORMITY AND PRACTICAL APPLICATIONS WOULD BE GREATLY ENHANCED IF PHOTOREFRACTIVE MECHANISMS WERE TO BE AVAILABLE IN THIN FILM WAVEGUIDE STRUCTURES. THE PROPOSED PHASE I RESEARCH WILL EXPLORE A NUMBER OF ALTERNATIVE MATERIALS AND FABRICATION TECHNIQUES TO IDENTIFY THE OPTIMUM PATH FOR PHOTOREFRACTIVE WAVEGUIDES. MATERIALS TO BE USED INCLUDE POLYCRYSTALLINE FILMS OF BARIUM TITANATE AND PLZT GROWN USING SOL-GEL WAVEGUIDE PROCESSING, AND FILMS OF SEMICONDUCTORS EMPLOYING LIFT-OFF FILM TECHNIQUES. FABRICATION AND CHARACTERIZATION OF A NUMBER OF ALTERNATIVE WAVEGUIDE STRUCTURES WILL LAY THE FOUNDATION OF PHASE II PRODUCTION OF EFFICIENT DEVICES WITH RESPECT TO SUCH PERFORMANCE MEASURES AS PHASE CONJUGATE REFLECTIVITY, TWO-BEAM COUPLING COEFFICIENT AND RESPONSE SPEED. PHOTOREFRACTIVE NONLINEAR OPTICAL WAVEGUIDES MAY PROVIDE A NEW LOW-COST, HIGH-PERFORMANCE DEVICE TECHNOLOGY FOR APPLICATIONS IN DIRECTED ENERGY WEAPONS, OPTICAL PHASE CONJUGATION, AMPLIFIERS AND SWITCHES COMPATIBLE WITH FIBER OPTICS TECHNOLOGY, OPTICAL COMPUTING, AND NEURAL NETWORKS.