Optical Wavelength Shifter Placement in Auxiliary Graphs
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Solution Overview
Problem
Optical communication networks face challenges in determining efficient optical paths that minimize the use of optical-electrical-optical (O-E-O) regenerators, which are costly and less effective, and in optimizing wavelength utilization due to spectral slot fragmentation, especially when direct reachability between nodes is absent.
Innovation Solution
The method involves generating an auxiliary graph for optical networks to evaluate the placement of wavelength shifters, including virtual nodes and links, and associating cost values to determine a lowest cost optical path that optimally utilizes wavelength channels and minimizes the use of O-E-O regenerators by strategically placing optical wavelength shifters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If O-E-O regenerators are used for wavelength recoloring, then wavelength shifting can be achieved, but network cost and complexity increase
Solution Approach 1:
The patent replaces O-E-O regenerators (electrical processing) with all-optical wavelength shifters (optical processing) for wavelength recoloring. The auxiliary graph methodology models different recoloring options including no-recolor links, O-E-O regeneration links, and optical wavelength shifter links, enabling the system to select optimal optical paths that avoid electrical regeneration when possible, thereby reducing network complexity while maintaining wavelength adaptability
Solution Approach 2:
The patent introduces an auxiliary graph as an intermediary computational model that evaluates multiple recoloring strategies. This graph includes virtual nodes representing wavelength shifters and recoloring nodes, allowing the system to indirectly assess and compare different wavelength path options without directly implementing each option, thus simplifying the decision-making process for wavelength management
2Reliability
If O-E-O regenerators are used for path routing, then end-end reachability can be achieved, but network resource utilization decreases
Solution Approach 1:
The patent implements dynamic path computation that evaluates multiple possible optical paths and recoloring strategies using the auxiliary graph model. The system can adaptively select paths that minimize regenerator usage based on current network conditions, wavelength availability, and cost assignments, thereby improving resource utilization while maintaining reachability. The cost values assigned to different link types dynamically guide the selection toward more efficient paths
Solution Approach 2:
The patent changes the optimization parameters from simple reachability to multi-criteria optimization including cost, regenerator count, and wavelength utilization. By assigning cost values to different link types (source links, destination links, passthrough links, recoloring links) and using these costs to determine the lowest cost optical path, the system transforms the problem from binary reachability to nuanced resource-efficient routing
3Reliability
If wavelength channels are strictly maintained without shifting, then signal integrity is preserved, but network flexibility and resource utilization decrease
Solution Approach 1:
The patent performs preliminary evaluation of wavelength shifting options by pre-building the auxiliary graph that includes all possible recoloring paths and wavelength shifter locations. This allows the system to plan wavelength shifts in advance along the entire optical path before signal transmission, ensuring that integrity is maintained while flexibility is enabled. The graph pre-computation identifies optimal recoloring points without requiring real-time decisions during signal transmission
Data Source
AI summary
Methods and systems enable optimized placement of wavelength shifters in optical networks. The wavelength shifters may include O-E-O regenerators for a single wavelength and all optical wavelength shifters for one or more wavelengths. An auxiliary graph is used to represent various links in a provisioned optical path. By applying cost values to each of the links, different types of optimizations for network resource utilization may be realized.