Multi-Plane Scalable ROADM Architecture with Cross-Plane Switching
Solution Overview
Problem
Conventional ROADM designs face scalability challenges and increased complexity as network capacity grows, especially with the transition to Space Division Multiplexing (SDM) architectures, leading to higher interconnect requirements and costs, while existing solutions either reduce functionality or result in complex, expensive large-scale integrated systems.
Innovation Solution
A scalable ROADM architecture is introduced that organizes nodes into multiple planes with cross-plane switching, reducing interconnect complexity and port requirements by using a space switch that only operates on cross-plane traffic, allowing for smaller, denser, and more reliable systems with enhanced connectivity and resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional ROADM designs are scaled to increase network capacity, then network capacity increases, but interconnect complexity and port requirements increase significantly
Solution Approach 1:
The patent divides the ROADM node into multiple independent planes, where each plane handles a subset of fiber connections. This segmentation reduces the interconnect complexity from O(W²) in conventional designs to O(P×N²) where P is the number of planes and N is the number of degrees per plane, making scaling to high-capacity networks feasible without exponential growth in interconnect complexity
Solution Approach 2:
The patent introduces a new dimensional organization by creating multiple parallel planes instead of scaling within a single plane. This dimensional change allows the system to handle more degrees by distributing them across planes, transforming the scaling challenge from a single-dimension problem to a multi-dimensional solution space
2Adaptability or versatility
If the number of WSS ports is increased to support more degrees, then more fibers can be interconnected, but device size and cost increase
Solution Approach 1:
The patent segments the WSS port requirements by assigning different port subsets to different planes. Each WSS device within a plane only needs to handle ports for that plane's degrees, reducing individual device size from O(W) ports to O(N) ports per plane, while the aggregate system maintains full connectivity through the multi-plane structure
3Device complexity
If planes are separated to reduce interconnect complexity, then fewer ports are required, but switching between planes is prevented
Solution Approach 1:
The patent introduces a cross-plane switching mechanism that acts as an intermediary between separated planes. This mediator enables traffic to be routed between planes when needed for resilience or spectral efficiency, while allowing planes to remain independently organized for the majority of operations, thus maintaining both reduced interconnect complexity and full switching capability
Data Source
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AI summary
An optical node (20) includes P switching planes (40) interconnected by an S x S cross-plane switch (50), P > 1; and N, degrees (22) per switching plane P, where i = 1 to P, each degree (22) formed by corresponding degree components having R ports, wherein a first set of ports of the R ports is for intra-plane switching, a second set of ports of the R ports is for inter-plane switching, and a third set of ports of the R ports is for in-plane add/drop. S is greater than or equal to a sum of a number of degrees (22) across all of the P switching planes (40). R is greater than or equal to a sum of the first set of ports, the second set of ports, and the third set of ports.