Optically Powered and Controlled Beam Steering System for Radio-Over-Fiber Networks

Abstract

This study presents an optically powered and controlled beam steering system for radio-over-fiber networks. The beam steering technique is based on optical multicasting and true-time delay among the multicast signals for a remote antenna unit. The power required for driving the entire remote antenna unit is delivered from a central office to the remote antenna unit by power-over-fiber technique using double-clad fibers, which consist of a single-mode core and an inner-cladding that surrounds the single-mode core. In the fiber link, an optical data signal is transmitted into the single-mode core without limiting the signal bandwidth because of modal dispersion, whereas high-power feed light for optical powering is transmitted into the inner-cladding with a core effective area that is much larger than the single-mode core. To show the feasibility of the beam steering system, we have experimentally evaluated the signal performance of beam steering for a 60-W power-over-fiber feed using a 300-m double-clad fiber link in terms of error-vector magnitude measurements. We have successfully achieved good signal performances for various beam angles estimated using true-time delay settings for multicast signals.