Improved Ultra-Dense Connection Provision Capability of Concurrent Upstream and Direct Inter-ONU Communication IMDD PONs by P2MP Flexible Optical Transceivers

To cost-effectively meet 6G latency requirements, concurrent upstream and direct inter-optical network unit (ONU) communication passive optical networks (PONs) based on flexible point-to-multipoint (P2MP) optical transceivers and intensity modulation and direct detection (IMDD) have been reported to enable direct communications among different ONUs within the same PON without passing data to the optical line terminal (OLT). However, the previously reported P2MP transceivers suffer from high DSP complexity for establishing ultra-dense connections. For such application scenarios, the PON’s remote nodes also have high inter-ONU signal power losses. To effectively solve these technical challenges, this paper experimentally showcases (a) new P2MP transceivers by utilizing parallel multi-channel aggregation/de-aggregation and advanced extended Gaussian function (EGF)-based orthogonal digital filter banks, along with (b) low inter-ONU signal power loss-remote nodes. By introducing these two techniques into a 27 km, >54.31 Gbit/s concurrent upstream and direct inter-ONU communication IMDD PON, comprehensive experimental explorations of the PON’s performances were undertaken for the first time. The remote node is capable of supporting 128 ONUs. The results show that the new P2MP transceivers lead to >75% (>40%) reductions in overall transmitter (receiver multi-channel de-aggregation) DSP complexity, and they can also equip the PONs with an enhanced capability of providing ultra-dense connections. The experimental results also show that the PON allows each ONU to flexibly change its upstream and inter-ONU communication channel count without considerably compromising its performance. Therefore, the PON outperforms those of previously reported works in terms of ensuring low DSP complexity, highly robust transmission performance, and enhanced capabilities of flexibly accommodating numerous applications with diverse requirements regarding traffic characteristics, thus making it suitable for ultra-dense connection application scenarios.