ROADM Slice-Switched Architecture for Wide-Spectrum Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ROADM architectures are constrained by WSS technology limitations, leading to high costs and operational complexity, and the shift to space division multiplexing results in stranded capacity and static connectivity, failing to meet growing bandwidth requirements.
Innovation Solution
A ROADM architecture that views spectral slices as media channels, using optical switches between degrees instead of fixed fiber connectivity, allowing high-degree nodes with existing components, and employing fiber/space switches for dynamic interconnectivity without dedicated switching planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If WSS technology is scaled to support higher fan-out (1×32, 1×64) to increase ROADM degrees, then the number of supported degrees increases, but the cost of all ROADM degrees increases significantly
Solution Approach 1:
The patent divides the optical spectrum into multiple spectral slices (e.g., 8 slices of 1.2 THz each within the 9.6 THz C+L band). Each WSS handles only one spectral slice instead of the entire spectrum, allowing standard 1×9 WSS components to be used. This segmentation enables high-degree ROADMs using affordable components rather than expensive high-fan-out WSSs.
Solution Approach 2:
The patent introduces a new dimension for scalability by switching from scaling WSS fan-out (horizontal scaling) to scaling the number of spectral slices (vertical scaling). Instead of requiring WSSs with higher port counts, the system achieves high-degree connectivity by multiplying the number of spectral slices that can be switched through the same physical ports.
2Productivity
If Space Division Multiplexing (SDM) is used to overlay new ROADM planes to support growth, then capacity increases, but the system becomes costly, complex to manage, and results in stranded capacity on individual planes
Solution Approach 1:
The patent makes each ROADM degree universal by enabling it to handle multiple spectral slices through the same physical ports. Instead of requiring separate dedicated planes for different capacity levels, a single degree can dynamically accommodate any number of spectral slices by reconfiguring the WSS assignments, eliminating stranded capacity and reducing management complexity.
Solution Approach 2:
The patent introduces dynamic reconfigurability where the assignment of spectral slices to WSS ports can be changed on-demand. This dynamic allocation allows the system to adapt to varying traffic requirements without physical reconfiguration or dedicated planes, enabling efficient capacity utilization and eliminating the static limitations of SDM approaches.
3Productivity
If coherent modem technology is scaled to push transmission closer to the Shannon Limit, then electro-optic bandwidth increases, but spectral occupancy increases, shifting focus from wavelength division multiplexing to space division multiplexing
Solution Approach 1:
The patent segments the increasingly occupied spectrum into multiple manageable spectral slices. As coherent modems consume more spectrum, the system divides this spectrum into slices (e.g., 1.2 THz each) that can be independently switched and managed through standard WSS components, maintaining WDM efficiency even at high bandwidth utilization.
Data Source
AI summary
A Reconfigurable Optical Add/Drop Multiplexer (ROADM) node architecture is disclosed that supports wide-spectrum channel operation. The ROADM includes a plurality of degrees, each degree comprising a Wavelength Selective Switch (WSS) configured to define variable-width spectral slices and perform spectral shaping or equalization. A central fiber/space switch interconnects slice ports of the WSSs and provides programmable partial-mesh connectivity. Local add/drop is achieved through direct connection of optical modems, including Full-Spectrum-Transponders (FSTs) that integrate multiple modems and internal multiplexing to provide wide-spectrum outputs spanning all or part of an amplified band. The fiber/space switch treats the FST as an add/drop degree, simplifying operations by eliminating intervening multiplexers and reducing external fiber connections. This architecture enables efficient end-to-end transport of wide spectral slices, reduces insertion loss, and allows scalable, cost-effective deployment of high-capacity ROADM nodes using existing optical components.