Multicast Wavelength Selective Switch for CDC Add-Drop
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Solution Overview
Problem
Optical nodes in dense wavelength division multiplexed (DWDM) systems face challenges in scaling to support increased network capacity while achieving colorless, directionless, and contentionless (CDC) add/drop operations due to limitations in M×N wavelength selective switches (WSS) and multicast switches (MCS), including high insertion loss and impractical optical amplifier requirements.
Innovation Solution
A hybrid add/drop device, referred to as a multicast WSS (MC-WSS), combines elements of both M×N WSS and MCS to provide improved scalability, incorporating a first port array, dispersive elements, switching arrays, and splitting elements to enable CDC add/drop operations with reduced insertion loss and lower complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional M×N wavelength selective switches are used to achieve CDC add/drop operations, then wavelength flexibility and routing capability are improved, but insertion loss increases and scalability deteriorates
Solution Approach 1:
The WSS device is segmented into multiple independent wavelength channels, where each channel can be independently routed. This segmentation allows the system to handle multiple wavelengths simultaneously through parallel processing, reducing the insertion loss that would occur in a monolithic switching approach. Each wavelength channel is processed separately by dispersive elements and switching arrays, enabling efficient resource utilization.
Solution Approach 2:
The patent introduces a spatial dimension to wavelength switching by using dispersive elements to separate wavelengths in one dimension and switching arrays to route them in another dimension. This two-dimensional approach (wavelength separation + spatial routing) enables CDC add/drop functionality while maintaining lower insertion loss compared to traditional M×N switch architectures.
2Adaptability or versatility
If M×N wavelength selective switches are used to support increased network capacity, then routing capability is improved, but device complexity increases
Solution Approach 1:
The complex M×N switching function is segmented into multiple smaller functional blocks: dispersive elements for wavelength separation, switching arrays for spatial routing, and combining elements for recombination. This segmentation reduces the complexity of any single component while maintaining the overall routing capability through coordinated operation of multiple simpler elements.
Solution Approach 2:
Dispersive elements act as intermediaries between the input ports and switching arrays, converting wavelength multiplexed signals into spatially separated channels. This intermediary function simplifies the switching task by pre-organizing wavelengths spatially, reducing the complexity of the subsequent switching operation.
3Adaptability or versatility
If multicast switches are used to achieve CDC add/drop, then port flexibility is improved, but optical amplifier requirements become impractical
Solution Approach 1:
The patent uses optical copying through dispersive elements that replicate wavelength channels across multiple spatial paths. Instead of using optical amplifiers to boost signal strength for multicast distribution, the system creates multiple copies of the optical signal through wavelength division multiplexing and spatial routing, thereby avoiding the need for impractical optical amplifier requirements.
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
The MC-WSS achieves CDC add/drop operations with enhanced scalability, reducing the need for optical amplifiers and minimizing insertion loss, thus supporting increased network capacity with lower cost and complexity compared to traditional M×N WSS and MCS systems.
Implementation Method 1
a dispersive element to separate a beam of light, launched by one of the M input ports, into L (L>1) dispersed wavelength channel sub-beams
Implementation Method 2
a splitting element to split a wavelength channel sub-beam, of the X wavelength channel sub-beams, into K (K>1) split wavelength channel sub-beams
Data Source
AI summary
A wavelength selective switch (WSS) may include a first port array including input ports, each to launch a respective beam of light, and a dispersive element to separate, in a lateral direction, a beam of light, launched by one of the input ports, into dispersed wavelength channel sub-beams. The WSS may include a switching array to direct the dispersed wavelength channel sub-beams, at respective angles in a vertical direction. The dispersive element may converge groups of dispersed wavelength channel sub-beams in the lateral direction to form wavelength channel sub-beams. The WSS may include a splitting element to split, in the lateral direction, a wavelength channel sub-beam, of the wavelength channel sub-beams, into split wavelength channel sub-beams. The WSS may include switching elements to direct the split wavelength channel sub-beams at respective angles in the vertical direction, and output ports associated with the switching elements.