ALL OPTICAL FIBER OPTIC SWITCH USING FREE CARRIERS IN GAAS

AN ALL OPTICAL FIBER OPTIC SWITCH BASED UPON PHOTO GENERATED FREE CARRIER INDUCED OPTICAL EFFECTS IN GAAS, GAALAS, INP, AND OTHER COMPOUND SEMICONDUCTORS IS PROPOSED.A SIMPLE DEVICE STRUCTURE AND THE POSSIBILITY OF RELATIVELY EASY FABRICATION MAKES THE PROPOSED SWITCH AN ATTRACTIVE CONCEPT TO INVESTIGATE. MODULATION OF LIGHT IN FIBER OPTICS UP TO 200 MHZ USING FREE CARRIER INDUCED EFFECTS IN SILICON HAS BEEN DEMONSTRATED. GAAS AND OTHER COMPOUND SEMICONDUCTORS ARE EXPECTED TO SHOW INCREASED SENSITIVITY OVER SILICON. FREE CARRIERS IN A SEMICONDUCTOR INFLUENCE ITS OPTICAL PROPERTIES THROUGH CONDUCTIVITY CHANGES WHICH ARE INCLUDED IN THE COMPLEX DIELECTRIC CONSTANT. IN THE PROPOSED SCHEME, 850 NM PHOTONS GENERATE FREE CARRIERS THOUGH BAND TO BAND EXCITATION. THESE CARRIERS CAN INFLUENCE THE TRANSMISSION PROPERTY OF 1300 NM LIGHT, EITHER THROUGH ABSORPTION OR THROUGH FABRY-PEROT PARAMETER CHANGE. WE PROPOSE TO INVESTIGATE AND CHARACTERIZE THE MATERIALS, OPTIMIZE THE FIBER OPTIC SWITCH CONFIGURATION, MEASURE THE PROPERTIES OF CANDIDATE MATERIALS WITH REGARD TO SWITCH APPLICATION, AND GENERATE PLANS FOR THE PROTOTYPE SWITCH FABRICATION IN PHASE I.