Improved performance and flexibility of P2MP IMDD PON transceivers with reduced complexity and latency by parallel multi-channel aggregation

Point-to-multipoint (P2MP) optical transceivers are promising for meeting the diversified requirements of emerging applications in the 6G era. However, for intensity modulation and direct detection (IMDD) passive optical networks (PONs), the previously reported P2MP optical transceivers cannot effectively accommodate a large number of diversified applications due to their limited flexibility, high digital signal processing (DSP) complexity and latency, as well as relatively high sensitivity to transmission system impairments. To cost-effectively address the challenges, this paper proposes a novel P2MP flexible optical transceiver based on a new parallel multi-channel aggregation/de-aggregation operation and an advanced extended Gaussian function (EGF)-based orthogonal digital filter bank. In comparison with the previously reported transceivers in a >50Gbit/s@25 km IMDD upstream PON with two optical network units (ONUs), our experimental measurements show that for channel counts of 8 (>10), the proposed transceivers can enhance the maximum achievable upstream transmission capacities by >52% (>290%). The new design can also reduce the overall transmitter DSP complexity (transmitter maximum DSP latency) by >70% (>24%) and decrease the receiver multi-channel de-aggregation DSP complexity by >40%. In addition, for the proposed transceivers, the network operation flexibility and scalability are also experimentally explored in a 25 km, >52Gbit/s IMDD upstream PON with five ONUs supporting 70 independent channels of different bandwidths and latencies. It is shown that the proposed transceivers fully support flexible sleep-awake ONU operation, and for a specific ONU, doubling the activated ONU count can only increase its required minimum received optical powers by ∼1.7 dB. Furthermore, the proposed transceivers can also support the ONU count growth without considerably compromising the maximum achievable upstream transmission capacities.