Research Progress of High-Degree OXC Technologies

Authors: Y. Li, J. Lin, H. Xu, S. Han, G. Shen

Abstract: Optical Cross-Connect (OXC) nodes are key devices in backbone optical networks, enabling optical signal switching, dynamic scheduling, and failure recovery. As the core component of OXCs, the Wavelength Selective Switch (WSS) is limited by its port count, which has become the primary bottleneck restricting OXC architectures from scaling to higher dimensions. This paper presents the first systematic review of recent advances in high-dimensional OXC designs. It highlights the fabrication technologies and operating principles of WSS modules and summarizes three representative approaches to building high-dimensional OXCs using small-port-count WSSs: sparse fiber interconnection, modular OXC cascading, and multistage N×N WSS cascading. The sparse fiber interconnection approach can achieve performance close to that of conventional OXC architectures but significantly increases network operation and maintenance complexity. The modular OXC cascading approach offers good scalability and compatibility but faces challenges related to wavelength contention and insertion-loss management. The multistage N×N WSS cascading approach, with its strictly non-blocking properties and flexible structural design, provides a favorable balance between cost and performance and shows strong application potential. Finally, this paper discusses future research directions and development trends for high-dimensional OXCs, aiming to provide insights for subsequent studies.

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