Reconfigurable Optical Add-Drop Multiplexer With Port-Segmented WSS
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Solution Overview
Problem
The performance of reconfigurable optical add/drop multiplexers (ROADMs) is degraded due to the increasing number of ports in wavelength selective switches (WSS) as the number of directions increases, leading to higher insertion loss, volume, and costs.
Innovation Solution
A reconfigurable optical add/drop multiplexer design that reduces the number of ports in wavelength add/drop modules by connecting them to a subset of wavelength selective switches, ensuring even allocation and reducing the overall scale and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of directions W increases in the ROADM architecture, then the routing capability and signal scheduling flexibility improve, but the number of ports in the M*N WSS increases sharply, leading to degraded performance, higher insertion loss, increased volume, and higher costs
Solution Approach 1:
The patent segments the WSS device into multiple sub-WSS units, where each sub-WSS handles a subset of directions. Specifically, the M*N WSS is divided into multiple N*K WSS units, with each unit managing a portion of the total W directions. This segmentation reduces the port count per device while maintaining overall system capability through coordinated operation of multiple smaller units.
Solution Approach 2:
The patent introduces a new dimensional organization by arranging WSS units in a grid-like structure with rows and columns, where rows correspond to input/output ports and columns correspond to wavelength channels. This spatial arrangement allows the system to handle W directions without requiring a single large M*N WSS, instead using multiple smaller N*K WSS units organized in a two-dimensional layout that scales more efficiently.
2Adaptability or versatility
If the number of ports in the M*N WSS increases to support more directions, then the signal scheduling flexibility improves, but the insertion loss increases and performance degrades
Solution Approach 1:
By segmenting the large M*N WSS into multiple smaller N*K WSS units, each unit has fewer ports and consequently lower insertion loss per connection. The patent shows that dividing the WSS into sub-units reduces the port count from M*N to N*K where K < M, thereby reducing the insertion loss associated with each wavelength switching operation while maintaining overall signal scheduling flexibility through the coordinated operation of multiple sub-units.
3Adaptability or versatility
If the number of ports in the M*N WSS increases to support more directions, then the routing capability improves, but the volume and costs of the device increase
Solution Approach 1:
The patent divides the large M*N WSS into multiple smaller N*K WSS units, each with reduced port counts. This segmentation directly reduces the volume of each individual device while the overall system achieves the required routing capability through the coordinated operation of multiple smaller units. The modular architecture allows for more compact packaging and reduces the total volume compared to a single large WSS device.
Solution Approach 2:
The patent implements dynamic configurability where the system can adaptively allocate and reconfigure the multiple N*K WSS units based on traffic demands and routing requirements. This dynamic operation allows the system to achieve high routing capability without requiring all ports to be permanently active, thereby reducing the effective volume and resource requirements compared to a static large M*N WSS design.
Data Source
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AI summary
A reconfigurable optical add/drop multiplexer includes: optical fibers, X first wavelength selective switches, and Y wavelength add/drop modules. The X first wavelength selective switches correspond to W directions, and both X and W are integers greater than 1. The W directions include a first direction and a second direction. The first direction corresponds to P first wavelength selective switches among the X first wavelength selective switches, where P is an integer greater than 1. The second direction corresponds to Q first wavelength selective switches among the X first wavelength selective switches, where P+Q is less than or equal to X. A first wavelength add/drop module is connected to A of the P first wavelength selective switches by using the optical fibers, and connected to B of the Q first wavelength selective switches by using the optical fibers, where the first wavelength add/drop module is one of the Y wavelength add/drop modules, A is a positive integer less than P, and B is a positive integer less than or equal to Q.