Beyond 100G three-dimensional flexible coherent PON with time, frequency, and power resource-allocation capabilities

Abstract

Emerging services such as 8K/16K high-quality video streaming, virtual reality/augmented reality, beyond-5G mobile Internet, and edge computing are driving the need for even higher speed, capacity, and flexibility in optical access networks. Coherent passive optical networks (CPONs) have garnered significant attention in recent years due to their superior receiver sensitivity and high flexibility for 100G speeds and beyond. Research interest has surged in flexible, multi-dimensional multiplexing schemes that go beyond traditional time-division multiplexing (TDM). To further leverage the flexibility offered by CPONs, this paper proposes and experimentally demonstrates what we believe to be a novel three-dimensional flexible coherent PON (3D FLCS-CPON) for downstream applications. This system offers resource-allocation capabilities in the time, frequency, and power domains. By utilizing digital subcarrier multiplexing and power allocation in both the time and frequency domains, we achieve more flexible and adaptable access rates compared to traditional TDM and frequency-division multiplexing (FDM). We present in detail the operating principles of 3D FLCS-CPON in the downstream, along with steps for power calibration between subcarriers. As a proof of concept, we demonstrate the feasibility of 3D FLCS-CPON in the downstream using four subcarriers, achieving a peak data rate of ${250}\;{\rm Gb/s/}\lambda$ over a 20-km fiber.