Networking assessment of ROADM architecture based on a photonics integrated WSS for 800G multi-band optical transport

The capacity of the optical transport network must be expanded to support the increasing demand due to bandwidth-intensive applications. Multi-band transmission solutions can achieve this goal by exploiting the low-loss optical spectrum windows while maintaining the same existing fiber infrastructure, increasing the network's capacity, and minimizing the operator capital expenditure (CAPEX) by limiting the need for a new fiber deployment. In the context of multi-band transmission, this work proposes a novel reconfigurable optical add-drop multiplexer (ROADM) architecture using a modular photonic integrated multi-band wavelength selective switch (WSS) that operates over multi-bands (S + C + L). This study focuses on conducting a comprehensive network performance analysis of different settings, enabling operation from 400G up to 800G using the proposed multi-band WSS on two real network topologies: German and Italian. The results provide the potential benefits of transitioning from traditional C-band transmission to multi-band transmission based on overall network performance.