Point-to-Multipoint Optical Networks Using Coherent Digital Subcarriers

Abstract

A paradigm shift in optical communication networks is proposed, with the introduction of a new ecosystem of devices and components with the capability of transforming current point-to-point optical networks (with their entailed, limiting, electrical aggregation) into flexible, scalable and cost-effective pointto-multipoint networks. In the new architecture, which better aligns with the hub-and-spoke traffic patterns observed in today's metro and access network segments, interoperability across a variety of transceivers operating at different speeds is achieved using individually routed, digitally generated subcarriers. The first comprehensive demonstration of the technical feasibility of the proposed point-to-multipoint architecture based on digital subcarrier multiplexing is presented, along with the remarkable cost savings and simplification of the network it enables.

Digital Subcarrier Multiplexing: Enabling Software-Configurable Optical Networks

“…P2MP is not a new concept, having been used in wireless systems [16] and in commercial deployments in fiber optics, in Passive Optical Network (PON) [17], which enabled the successful wide deployment of the broadband internet at home. However, future innovation, for example, 5G / 6G, will require capacity that cannot be provided by existing Intensity Modulation Direct-Detection (IM-DD) solutions [18] and it will be necessary to move towards a coherent solution in access/metro [7], [19].…”

“…To solve the above issues, we propose to realize P2MP DWDM with coherent technology. Among the options available for the design of the transceiver, the following are the most relevant: Sliceable Bandwidth Variable Transponder (S-BVT) [20], Orthogonal Frequency-Division Multiplexing (OFDM) [21], and Digital Subcarrier Multiplexing (DSCM) [7]. Among them, we select DSCM-based transceivers, which represent a sweet spot in terms of hardware and enabled applications.…”

“…The use of DSCM was initially pursued for its propagation advantages [4], [22]- [27], particularly for long-haul transmission. Here, however, we are proposing it to efficiently realize P2MP coherent transceivers that can enable softwareconfigurable P2MP optical networks [7]. For instance, this type of transceivers can be advantageously used in aggregation networks, characterized by a H&S traffic pattern between smaller leaf nodes and larger hub nodes.…”

“…These challenges are being mitigated through advances in photonic technology and by Complementary Metal-oxide-semiconductor (CMOS) technology with 7 nm and beyond to support higher density and lower power consumption. The application of DSCM-based P2MP networks has already been evaluated in several techno-economic studies [29], [33], and has been experimentally validated in laboratory experiments [7] and trials [34]. These investigations have shown the potential for 400G transmission over existing PONs.…”

“…These investigations have shown the potential for 400G transmission over existing PONs. In these scenarios, significant cost reduction has been reported in [33], by eliminating the need for routing [29] or reducing Opto-Electro-Optical (OEO) conversions [7]. In this paper, for the first time, we present experimental results with passive optical aggregation and with signals transmitted and received by a real-time DSCM-based P2MP system operating at 100G/200G/400G.…”