A Point-to-Multipoint Flexible Transceiver for Inherently Hub-and-Spoke IMDD Optical Access Networks

Point-to-multipoint (P2MP) transceivers offer a promising solution to transform present point-to-point optical access networks into scalable and flexible P2MP networks capable of dynamically meeting, in a cost-effective and high energy consumption efficiency manner, the requirements associated with 5G-Advance and beyond networks, including large signal transmission capacity, fast and dense connection, high network flexibility/adaptability and low latency. However, the previously reported P2MP optical transceivers based on either coherent XR optics or IMDD digital filter multiplexing (DFM) techniques are not suitable for implementing in low-latency and highly cost-sensitive IMDD-dominated optical access networks. This paper proposes, experimentally demonstrates and optimises a novel P2MP flexible transceiver incorporating a new cascaded IFFT/FFT-based multi-channel aggregation/de-aggregation technique and an orthogonal digital filtering technique. The performances of the proposed technique are extensively evaluated experimentally in an upstream 55.3 Gb/s @25 km IMDD PON. It is shown that in comparison with the conventional DFM transceivers, the proposed transceivers can reduce the transmitter DSP complexity by a factor that approximates to aggregated channel count, and simultaneously offer additional physical layer network security, without requiring long digital filter lengths and greatly compromising upstream transmission performances/spectral efficiencies as well as differential ONU launch power dynamic ranges.