Optical fiber offers many advantages over coaxial cable for the transmission of radio frequency ͑rf͒ signals in antenna-remoting applications, as well as cellular networks and cable television ͑CATV͒ signal distribution networks. Optical fiber shows significantly less loss, can support signals demanding much higher bandwidth, is immune to electromagnetic interference ͑EMI͒, and enables considerable size and weight savings when compared to coaxial cable. Free-space optics ͑FSO͒ communications is a technology that uses modulated optical beams to transmit information line of sight through the atmosphere. FSO can be deployed faster and cheaper when compared with optical fiber. Recently, FSO has been investigated by the telecommunications industry and research centers to transport digital signals for civilian "last mile" applications and military applications. We demonstrate the successful transport of modulated rf analog signals over an FSO link and compare key performance measures against a fiber optic link configured in an identical manner. Results of measurements of optical power, transmission response, reflection response, group delay that defines phase distortion, carrier-to-noise ratio ͑CNR͒, and dynamic range that defines nonlinear distortion are presented. Results from this comparative study indicate that FSO for rf applications is a suitable replacement for fiber optic transmission links over short distances.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.