Control of channel power excursions at sudden reconfiguration or faults in a ROADM-based WDM network

This paper addresses the problem of reducing power excursions in amplified WDM communication networks with Reconfigurable Optical Add-Drop Multiplexers (ROADM). We consider a basic WDM network topology, namely, a ROADM-based optically amplified chain network, where each ROADM node is equipped with Wavelength Selective Switch (WSS) for channel power adjustment. In dynamic network loading scenarios or at sudden failures, conventional WSS control strategies lead to transient power excursions across the chain. We propose a new WSS coordination control strategy that effectively decouples nodes in the chain network and reduces WSS transient power excursions across the chain in the event of failures or reconfigurations.We provide analytical bounds on these reductions as well as experimental results implemented on a Transparent Optical Mesh Simulator (ATOM) for two realistic scenarios.