Novel Scheme for Remote LO Delivery and Wavelength Reuse for Bidirectional Radio-over-Fiber Architecture

Abstract

RoF is a promising technology to fulfill future broadband access requirements with reliability and flexibility. We present a bi-directional RoF system with high RF carrier support. An all-optical frequency up-conversion technique is employed in downlink. The technique up-converts optical IF downlink signal to optical RF signal by photonic mm-wave mixing in a photonic mixer. The LO signal for the up-conversion is optically generated in the CS and sent to RN via optical fiber. During the mixing process at RN, LO gets modulated over optical channel carrying up-converted downlink signal. This LO component is extracted and employed for remote down-conversion of uplink data to IF in BS. Hence this novel scheme requires sending single LO signal from CS that is used both in optical up-conversion (in downlink) and electrical down-conversion (in uplink). Downlink optical signal was generated in DSB format allowing for optical carrier to be re-used at BS for uplink. Bi-directional 155 Mbps data was successfully transmitted over 41 Km single mode fiber for both downstream and upstream with less than 0.2 dB power penalties.