Separate Wavelength Filter Unit for Flexible WDM Branching
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Solution Overview
Problem
In optical communication systems, the rigid wavelength allocation requirements in branching units with integrated OADM functionality increase system costs and reduce design flexibility, making it cumbersome to change wavelength allocations, especially in undersea deployments where changes can delay or require costly retrieval of units.
Innovation Solution
A separate predetermined wavelength filter unit is introduced, physically distinct from the branching unit, allowing for flexible wavelength allocation changes without modifying the branching unit, and can be retrieved independently or together with it for maintenance, reducing the risk of cable damage and improving security by blocking unallocated trunk traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wavelength allocation is determined before construction and deployment of the branching unit, then system cost increases and design flexibility is reduced, but the branching unit can be deployed with integrated OADM functionality
Solution Approach 1:
The patent divides the branching unit into two separate functional components: a wavelength-agnostic optical splitter/combiner unit and a separate wavelength-selective filter unit. This segmentation allows the main branching unit to be deployed without predetermined wavelength allocation, while wavelength-specific functions are handled by the separate filter unit that can be configured or replaced independently.
Solution Approach 2:
The wavelength-selective filtering function is extracted from the integrated OADM branching unit and placed in a separate, independently deployable filter unit. This extraction enables the main branching unit to remain flexible and adaptable to different wavelength allocations, while the filtering capability exists as a separate component that can be configured as needed.
2Adaptability or versatility
If the branching unit is customized for desired wavelength allocations, then wavelength allocation requirements are met, but customization is time consuming and cumbersome
Solution Approach 1:
By segmenting the branching functionality into a universal splitter/combiner unit and separate wavelength-specific filter units, the system eliminates the need to customize the entire branching unit for each wavelength allocation scenario. Only the filter units need to be configured or replaced, which is much faster and less cumbersome than customizing integrated OADMs.
Solution Approach 2:
The optical splitter/combiner unit is designed to be universal and wavelength-agnostic, capable of working with any wavelength allocation scheme. This universality allows the same main branching unit to serve multiple wavelength configurations by simply changing or reconfiguring the separate filter units, rather than requiring custom-built units for each scenario.
3Adaptability or versatility
If wavelength allocation requirements change after system deployment, then system adaptability is needed, but changes require retrieval of undersea BUs which delays deployment and increases cost
Solution Approach 1:
The patent segments the wavelength-selective function into a separate, independently accessible filter unit that can be modified without retrieving the entire undersea branching unit. This allows wavelength allocation changes to be made by accessing only the filter portion, significantly reducing deployment delays and retrieval costs compared to modifying integrated OADMs.
Solution Approach 2:
By extracting the wavelength-selective filtering function from the main undersea branching unit, the system enables independent modification of the filter component. This extraction allows wavelength reallocation to occur without disturbing or retrieving the main branching unit, thereby maintaining deployment productivity while achieving the needed adaptability.
4Adaptability or versatility
If a separate predetermined wavelength filter unit is used, then wavelength allocation flexibility is improved and retrieval risk is reduced, but device complexity increases
Solution Approach 1:
While segmentation does increase the number of components, it reduces the complexity of each individual component. The main branching unit becomes a simple, universal splitter/combiner without complex wavelength-selective mechanisms, and the filter units are standardized, replaceable components. This segmentation trades component count for reduced individual component complexity and improved maintainability.
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 configuration enhances system design flexibility, reduces deployment delays, and minimizes the risk of cable damage by allowing separate retrieval and replacement of the wavelength filter unit, thereby improving the reliability and security of optical communication systems.
Implementation Method 1
a wavelength division multiplexed system (hereinafter a WDM system)... with each of the multiple signals being modulated on separate wavelengths referred to as channels
Implementation Method 2
with each of the multiple signals being modulated on separate wavelengths referred to as channels
Data Source
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AI summary
In general, a branching configuration used in a wavelength division multiplexed (WDM) optical communication system includes a branching unit (BU) and a separate predetermined wavelength filter (PWF) unit. The PWF unit may include wavelength selective elements (e.g., filters) for providing a desired wavelength allocation and may also include optical connections (e.g. optical couplers) for coupling the allocated wavelengths between trunk and branch paths in the WDM system. The PWF unit is physically separate from an associated BU but coupled adjacent the BU.