Abstract

For efficiently transferring radio-frequency (RF) signals to remote places using Radio-over-Fiber (RoF) techniques, it is important to increase optical power of RoF signals launched to optical fiber links. Fiber nonlinearity is going to be a critical obstacle against such high-power operation. To cope with this problem, we have proposed a transfer system of digitally data-modulated RF signals over fiber links, called conjugated-paired RoF (C-RoF) [1]. In the approach, phase conjugated twin signal transmission [2] is naturally achieved through photonic up-conversion and down-conversion, by which the RoF system obtains higher tolerance against optical fiber nonlinearity. In this report, focusing on direct down-conversion of 15-Gb/s 8PSK C-RoF signals, we numerically demonstrate that the homodyne direct down-conversion in the C-RoF system can cancel the nonlinear distortion even if the higher-order phase-shift keying (PSK) signaling is applied.

© 2017 IEEE