Analog free-space optical links.

Abstract

Free-space optics (FSO) communications is a technology that uses modulated infrared optical beams to transmit information line-of-sight through the atmosphere. There has been a substantial increase in the use of FSO technology over the last few years, mainly for "last mile" applications, because FSO links provide the transmission capacity to overcome bandwidth bottlenecks between backbone optical fiber links and metropolitan concentrations of end users. Optical fiber has been traditionally deployed for the transmission of both digital and analog signals. While transmission techniques for analog radio frequency (RF) intensity-modulated signals over optical fibers is well-established, prior to the investigations presented in this dissertation, there is no report of research on the efficiency of FSO for transmission of analog signals in the technical literature. This dissertation research investigated the effectiveness of FSO to transport modulated RF analog signals and compares key performance measures against those of fiber optic links. In addition, a new method to setup temporary IS-95 CDMA microcells or permanent IS-95 CDMA macrocells using FSO was proposed and its viability investigated. Finally, a new transmission technique for transmitting multiple RF signals (channels) over a single FSO link using wavelength division multiplexing (WDM) technology for potential CATV applications was demonstrated.