Heterogeneous Transmission of Analog Radio and Digital Coherent Signals Over Multi-Span Metro and PON for Bandwidth-Efficient Fronthaul in mmWave Centralized RAN Networks [Invited]

Abstract

We experimentally investigate the transparent coexistence of heterogeneous Analog Radio-over-Fiber (ARoF) and Digital Coherent Optical (DCO) signals in a converged metro/PON network. Our streamlined setup employs RF generation via optical heterodyning, so that both carrier and modulated signals can be generated centrally and transmitted to the antenna site, across a metro network and Passive Optical Network (PON). The experiment includes the transmission of 8.8 Gbps mmWave signals and 400 Gbps coherent optical signals within a 68.75 GHz ROADM channel bandwidth and a 1:32 to 1:128 split PON. We also analyze the impact of varying ROADM channel bandwidth, PON split ratios, metro network distance and number of ROADMs traversed, on the performance of DCO and ARoF signals. The results reveal that the error vector magnitude (EVM) of the ARoF signal is significantly influenced by the allocated bandwidth, the number of ROADMs, and the overall network loss, providing insights into optimizations necessary to achieve target EVM levels.