Transporting RF signals over free-space optical links

Abstract

Free space optics (FSO) is a technology that uses modulated optical beams to transmit information line-of-sight through the atmosphere. To date, the primary focus of FSO research and development has been toward the transmission of digital signals, primarily for "last mile" applications. This paper reports the use of FSO to transport modulated radio frequency (RF) analog signals, together with an investigation of key performance measures. Results indicate minimal RF signal distortion when transmitted over FSO. The advantages of using FSO include increased security and insusceptibility to electromagnetic interference (EMI).

Optimal distribution of the optical intensity within a laser beam for optical wireless communications

“…The application of these systems is advantageous for high‐speed point‐to‐point communication links in an urban area where the last mile problem arises. The OWC technology brings advantages, for example, high bandwidth, a license free band, no electromagnetic interference and quick deployment [2]. High directivity of the laser beam not only ensures more security of conveyed information but also brings a more difficult alignment procedure in comparison with the radio frequency system [3].…”

Research on Radio Frequency Assignment Mechanism of the RoFSO Network Based on Site-Specific Cognition and Utility Function

“…But there are still some defects in this system [7], such as the unfeasibility of the optical fiber deployment and the inflexibility of the network optimization. The technique of RoFSO [8] transmits RF signal through the atmosphere instead of the traditional optical fiber and gets the same performance as the optical fiber indoors or in the short distance (outdoors) [9][10]. Therefore, RoFSO network not only has advantages of the RoF network, but also effectively solves the problems in RoF network.…”

Effects of High-Order Laser Distortion Products in Radio over Free-Space Optical Links

“…This is particularly the case in large internal spaces such as atria or covered sporting venues. Such systems have been proposed for narrowband single-service cellular applications [2], and also for wideband multiservice applications [3].…”