Fiber optic techniques for microwaves

The recent progress in fiber optic components and technology has resulted in revived interest in applying fiber optics to microwave functions. This paper presents some of the current capabilities and limitations of fiber optics (primarily for wideband systems) as divided into four areas: sources, receivers, transmission, and signal processing (including beamforming, filtering, switching, variable delay, and microwave circuit control). Generating microwave signals on an optical carrier can be accomplished by direct or external modulation or by optical heterodyning.