WDM Passive Optical Networks and Beyond: the Road Ahead [Invited]

After discussing point-to-point fiber-to-the-home, WDM passive optical networks (PONs), and multistage WDM PON networks and elaborating on their respective advantages and limitations, I attempt to lift the veil of next-generation WDM PON topologies and optical network unit architectures while paying close attention to their smooth evolutionary migration path from current TDM PONs. I introduce optical coding enhanced WDM PONs that allow for enhanced real-time dynamic bandwidth allocation and outline future research avenues.