On the Benefits of Programmable FON for Low-Cost OTN-Over-WDM Metro Networks

Paper in proceeding, 2025

Network operators are constantly investigating cost-efficient technologies and solutions to deploy a low-cost and scalable optical metro network that can accommodate never-ceasing traffic growth. Filterless optical networks (FONs) have previously been introduced as a low-cost technology that leverages passive equipment, e.g., splitters, and combiners, but they result in a significant penalty in flexibility due to their pre-fixed fiber interconnection within the nodes. On the other hand, today's optical metro networks must support a wide range of data rates as well as varying traffic patterns, even within a short time frame, e.g., throughout the day. Accordingly, to achieve a low-cost metro network architecture that can support time-varying traffic patterns, a reconfigurable interconnection within the nodes would be highly beneficial. Recently, Programmable FONs (PFONs) have been presented as a network architecture that can benefit from the low-cost FON nodal structure, while providing more reconfigurability and flexibility in terms of node interconnection. Here, we observe that the programmability enabled by PFONs has a significant impact not only on the deployment of equipment (e.g., such as splitters/couplers, and optical amplifiers) at the Wavelength Division Multiplexing (WDM) layer, but it also has an impact on the deployment of equipment at the Optical Transport Network (OTN) layer, by enabling less restricted OTN deployments compared to FON. In this paper, we quantitatively analyze the effect of different network architectures (FON, PFON, and Wavelegth-Switched Optical Networks (WSON)) on the deployment cost of a multilayer OTN-and-WDM metro network. Our results on a realistic metro network topology demonstrate that PFON can provide up to 29% cost savings in a scenario where network reconfigurability is required to serve a time-varying daily traffic profile.