Parallel WSS Architecture Reducing Insertion Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Designing and constructing large wavelength selective switches (WSS) is complex and costly, and existing methods of creating larger WSS devices from smaller ones, such as daisy chaining, result in increased input-to-output insertion loss due to unused inputs and signal traversal through multiple devices.
Innovation Solution
The implementation of an optical system with reconfigurable optical add-drop multiplexers (ROADMs) and wavelength filtering devices, including multiple parallel non-cascaded WSSs and an optical coupler, which allows all inputs of smaller WSS devices to be used and reduces insertion loss by using passive optical elements in express paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple smaller WSS devices are cascaded to create a larger WSS device, then the device complexity is reduced and cost is lowered, but the insertion loss increases due to signal traversal through multiple devices and unused inputs
Solution Approach 1:
The patent divides the large WSS functionality into multiple smaller WSS devices (first WSS, second WSS, third WSS) that operate in parallel rather than cascade. Each smaller WSS handles a subset of wavelength channels, and their outputs are combined through an optical coupler to achieve the overall WSS function with reduced insertion loss since signals do not traverse multiple sequential devices
Solution Approach 2:
The patent merges the outputs of multiple parallel WSS devices through an optical coupler to create the equivalent functionality of a large WSS. This combining approach allows all inputs of smaller WSS devices to be utilized while maintaining lower insertion loss compared to cascading, as the optical coupler efficiently combines signals without requiring sequential signal traversal through multiple devices
2Ease of manufacture
If smaller WSS devices are cascaded to form a larger WSS, then cost is reduced compared to one equivalently sized large WSS, but not all inputs are available for use and insertion loss increases
Solution Approach 1:
The patent segments the WSS functionality across multiple smaller devices operating in parallel, where each device handles specific wavelength channels. This segmentation ensures that all inputs of each smaller WSS device are available for use, as each device receives its own dedicated input signals rather than sharing inputs through cascaded connections
Solution Approach 2:
The parallel architecture provides universal input availability where each WSS device can independently receive and process wavelength signals. The system achieves multi-functionality by allowing different wavelength combinations to be routed through different WSS devices simultaneously, maximizing the utilization of all available inputs across the system
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the creation of larger WSS devices with reduced insertion loss and lower costs by ensuring all inputs are utilized and optimizing signal transmission paths, resulting in a more efficient and less expensive solution compared to traditional cascading methods.
Implementation Method 1
at least two wavelength filtering devices, the at least two wavelength filtering devices configured to direct the wavelengths to the at least one dedicated express port, the at least one dedicated drop port, and the at least one express drop port
Implementation Method 2
an optical coupler optically coupled to the multiple parallel non-cascaded WSSs
Implementation Method 3
an insertion loss via passive optical elements for the express paths being lower than an insertion loss via passive optical elements of the add paths or drop paths
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Optical networks are increasingly employing optical network nodes having multiple interfaces to allow a node to direct optical signals received at any interface to any other interface connected to the node. Constructing a larger wavelength selective switching (WSS) module used in such a node can be complex and expensive. A method an apparatus for constructing a large WSS using parallelism is provided. In example embodiments, a larger WSS may include multiple parallel non-cascaded smaller WSSs and an optical coupler configured to optically couple the multiple parallel, non-cascaded smaller WSSs. This technique may be used to construct both N x 1 and 1 x N WSSs. Because the technique employs multiple parallel, non-cascaded WSSs, all inputs of a larger N x 1 WSS and all outputs of a larger 1 xN WSS are available receive or transmit external signals rather than being rather than being unavailable due to, for example, cascading smaller WSS devices together.