Optical access network interfaces for 5G and beyond [Invited]

Point to point (PtP), wavelength division multiplexing (WDM) and time division multiplexing (TDM) optical interfaces are discussed as solutions for backhaul, midhaul, and fronthaul networks. The evolution of radio access networks (RANs) for 5G and beyond is introduced and PtP is identified as the most deployed solution, with many transceiver technologies available to cover the different needs for each RAN configuration. WDM and TDM interfaces remain of interest when a lack of fiber occurs. WDM technologies are being adapted to answer to this RAN market with the appearance of medium-WDM (MWDM) and autotunable dense-WDM (DWDM) transceivers. TDM technologies are trying to evolve towards higher bit rates and lower latency to cope with RAN backhaul specifications. A gap in the transceiver technologies is identified for each of those interface types and also for bit rates above 25 Gbit/s that will impose more complex optics, electronics, and integration.