Contentionless Wavelength Cross Connect Using Transmissive Interferometric Switching
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Solution Overview
Problem
Existing optical switching devices for wavelength connections in optical fibers face issues such as high insertion loss, high cost, and reliability problems due to broadcasting functions, complex component failures, and crosstalk, especially in multi-degree network topologies.
Innovation Solution
A contentionless N×M Wavelength Cross Connect (WXC) module with a transmissive switching core using active liquid crystal cells and polarization diverse elements, allowing independent handling of wavelengths across multiple ports with reduced insertion loss and cost, and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Multicast Switch (MCS) is used to add or drop channels, then channel routing flexibility is improved, but insertion loss increases and device cost increases
Solution Approach 1:
The patent replaces the mechanical/broadcasting-based MCS switching mechanism with an optical field-based interference mechanism. The Mach-Zehnder interferometer uses optical path difference and constructive/destructive interference to achieve wavelength-selective routing without broadcasting, thereby reducing insertion loss while maintaining routing flexibility.
Solution Approach 2:
The patent introduces wavelength-specific interferometric paths as intermediaries between input and output ports. Each wavelength channel has its own dedicated interference-based routing path, allowing selective addition/dropping without affecting other channels, thus reducing overall insertion loss compared to broadcast-based MCS.
2Adaptability or versatility
If Multicast Switch (MCS) and Wavelength Selective Switch (WSS) are used together, then channel routing capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the routing function and wavelength selection function into a single interferometric structure. The Mach-Zehnder interferometer simultaneously performs both wavelength filtering and routing operations that were previously separated into MCS and WSS components, thereby reducing device complexity while maintaining full channel routing capability.
Solution Approach 2:
The interferometric wavelength cross-connect structure serves multiple functions: wavelength selection, routing, addition, and dropping all within a single device architecture. This multi-functional design eliminates the need for separate MCS and WSS components, reducing overall device complexity.
3Adaptability or versatility
If reflective MEMS mirror arrays are used to switch optical signals, then routing flexibility is improved, but device size increases and reliability decreases
Solution Approach 1:
The patent replaces the mechanical MEMS mirror system with a static optical field-based interferometric system. The Mach-Zehnder interferometer uses optical path manipulation rather than mechanical mirror movement, eliminating moving parts and thereby improving reliability while maintaining routing flexibility through optical phase control.
4Adaptability or versatility
If LCoS chips are used for phase modulation and signal routing, then wavelength routing capability is improved, but crosstalk increases and insertion loss increases
Solution Approach 1:
The patent replaces the LCoS liquid crystal phase modulation system with an interferometric optical path-based system. The Mach-Zehnder interferometer achieves wavelength routing through optical path difference and interference patterns rather than liquid crystal phase modulation, eliminating the crosstalk and insertion loss issues associated with LCoS pixelation and limited diffraction efficiency.
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 solution enables efficient, flexible, and cost-effective wavelength routing with reduced power consumption and physical size, supporting multi-degree network operations and dynamic node architectures, while eliminating wavelength blocking and contention.
Implementation Method 1
LCoS chips' phase modulation functions are used to control the routing of the optical signals with respective wavelengths
Implementation Method 2
transmissive switching core using active liquid crystal cells
Implementation Method 3
polarization diverse elements
Implementation Method 4
transmissive switching core using active liquid crystal cells
Data Source
AI summary
Technology for a contentionless N×M wavelength cross connect (WXC) device is disclosed herein. The WXC device includes multiple input and output wavelength dispersive elements and a cross connect assembly. The cross connect assembly includes multiple rows of incoming ports. For each individual wavelength of different wavelengths, split optical beams of the individual wavelength from the input wavelength dispersive elements reach a row of incoming ports corresponding to the individual wavelength. The cross connect assembly further includes transmissive active switching elements and multiple rows of outgoing ports. The transmissive active switching elements configured to dynamically establish at least one optical path between an incoming port within the row of incoming ports corresponding to the individual wavelength and an outgoing port within a row of output ports corresponding to the individual wavelength.