SDM Optical Add-Drop Switching With Clos Routing for Low Blocking
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Solution Overview
Problem
Optical networks face challenges in scaling capacity beyond the Shannon capacity limit of communication bands like the C and L bands, requiring manual node configurations and increased operational expenditures due to limited fiber connectivity and blocking probabilities.
Innovation Solution
Implementing an anylane add/drop capability using spatial division multiplexing (SDM) with Clos architectures, enabling flexible optical networking by allowing optical signals to be plugged into any port and routed to any fiber lane, utilizing modular spatial switches to reduce blocking probabilities and support scalable capacity growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If wavelength division multiplexing is used to multiplex multiple optical carrier signals onto a single optical fiber, then the capacity of the optical fiber is increased, but the Shannon capacity limit of communication bands is approached
Solution Approach 1:
The patent transitions from two-dimensional wavelength multiplexing to three-dimensional spatial multiplexing by utilizing multiple fiber cores within a single optical fiber. This dimensional expansion allows additional capacity growth beyond the Shannon limit of conventional WDM by adding a spatial dimension (multiple cores) to the existing wavelength dimension.
Solution Approach 2:
The invention nests multiple fiber cores within a single optical fiber structure, creating a hierarchical arrangement where multiple independent transmission paths (cores) are contained within one physical fiber. This nesting enables parallel wavelength division multiplexing across multiple cores, multiplying the total capacity while sharing the same physical infrastructure.
2Quantity of substance
If multiple fibers and multiple cores per fiber are used to support future capacity growth, then the spatial domain scaling is achieved, but the device complexity increases
Solution Approach 1:
The optical add-drop multiplexer is designed with universal functionality to handle multiple fiber cores through a single integrated device. Rather than requiring separate add-drop multiplexers for each core, the invention provides multi-core support through unified wavelength selective switches and control logic, reducing overall system complexity while maintaining spatial domain scaling capabilities.
Solution Approach 2:
The patent segments the optical signal processing into wavelength-specific channels that can be independently routed across different fiber cores. By dividing the multiplexed signal into discrete wavelength channels and assigning them to specific cores through controllable switches, the system manages complex spatial-domain routing through structured segmentation of wavelength paths.
3Adaptability or versatility
If reconfigurable optical add/drop multiplexers are used to switch traffic at the wavelength level, then the flexibility to add and drop wavelengths is improved, but the blocking probability increases in spatial division multiplexed systems
Solution Approach 1:
The invention resolves blocking issues by adding a spatial dimension (fiber core selection) to the wavelength switching capability. When a wavelength channel is blocked on one core, the system can alternatively route the same wavelength through a different core, providing spatial redundancy that eliminates blocking while maintaining wavelength-level flexibility through the combined wavelength-core switching matrix.
Solution Approach 2:
The patent introduces a spatial intermediary layer (fiber core selection mechanism) between the wavelength multiplexer and the add-drop functionality. This intermediary allows traffic to be routed through alternative spatial paths (different cores) when direct paths are blocked, mediating between the wavelength switching requirements and the physical fiber constraints to reduce blocking probability.
Data Source
AI summary
Various example embodiments for supporting optical transport systems are presented. Various example embodiments for supporting optical transport systems may be configured to support optical transport systems that support multiple fibers based on use of spatial division multiplexing (SDM) techniques. Various example embodiments for supporting optical transport systems that support multiple fibers based on use of SDM techniques may be configured to support optical transport systems that support multiple fibers based on use of an anylane add/drop capability that is based on use of a Clos architecture (e.g., a spatially-switched distributed Clos architecture with a single stage of switching for network traffic that passes through the node, a spatially-switched distributed Clos architecture with two stages of switching for network traffic that passes through the node, a spatially-switched node-contained Clos architecture with three stages of switching for network traffic that passes through the node, or the like).