Estimation and Suppression of Dispersion-Induced Phase Noise in W-band Direct-Detection OFDM Radio-Over-Fiber Systems

This study experimentally investigated the impact of dispersion-induced phase noise (DPN) on the transmission performance of a 100-GHz DD OFDM-RoF system. We sought to extend the transmission distance through the reduction of DPN using two digital phase noise suppression (PNS) schemes, based on the assumption that all subcarriers suffer from common DPN. The decision-aided PNS (DA-PNS) scheme treats the OFDM signal as feedback to aid in the calculation of DPN without incurring additional overhead. Pilot-aided PNS (PA-PNS) estimates the common DPN by inserting an additional optical pilot tone with guard band. Although both schemes are able to extend fiber transmission distance to beyond 150 km, the PA-PNS scheme tends to be outperformed by the DA-PNS scheme due to additional power required for the pilot tone. Nonetheless, in the DA-PNS scheme, the bandwidth of the estimated DPN must be truncated to avoid error propagation, which can result in the relatively faster increment in the transmission penalty. In contrast, the PA-PNS scheme maintains the variation in penalty to <;1 dB, thereby achieving the performance that is insensitive to transmission distance.