HIGH DYNAMIC RANGE EXTERNAL MODULATOR

MILITARY AND SPACE SYSTEMS DEMAND HIGH DYNAMIC RANGE (DR), LOW DISTORTION 60 GHZ ELECTRO-OPTIC MODULATOR (EOM). TO IMPROVE EOM LINEARITY AND DR, E-TEK PROPOSES THE USE OF COMBINED TECHNIQUES OF THIRD-HARMONIC COMPENSATING FUNDAMENTAL NONLINEARLITY, AUTOMATIC GAIN CONTROL OF THE EOM DRIVER, MINIMIZATIONS OF PHASE ERROR/OPTICAL DAMAGE/LASER NOISES, OPTIMIZATIONS OF EOM GAP AND VOLTAGE/MODULATION DEPTH, IMPROVEMENT OF VELOCITY MATCHING, ETC. THE HEMT OR MESFET IS ALSO PROPOSED AS AN EFFICIENT 60 GHZ PHOTODETECTOR WITH AMPLIFICATION GAIN TO IMPROVE DR. FURTHERMORE, IN PHASE I RD&D, E-TEK SUGGESTS FINDING A TEST METHOD OR EQUIPMENT WHICH IS CAPABLE OF MEASURING WIDE DR AT 60 GHZ. THE POSSIBLE ACHIEVABLE SINGLE-TONE DR OF EOM IS 122 DB/HZ, AND TWO-TONE DR IS 105 TO 118 DB/HZ.