Dual-Ganged Optical Switch Geometry for Hitless Channel Routing
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Solution Overview
Problem
Current optical switching technologies face challenges in scalability, cost-effectiveness, and efficiency, particularly in achieving low loss, high directivity, and high isolation, especially as switch fabric density increases, leading to issues with insertion loss and cross-talk in multicast optical switches.
Innovation Solution
The implementation of a dual-ganged optical switch geometry that allows simultaneous switching of transmit and receive fibers using a signal redirection element, such as a MEMS mirror and lens, with a specific waveguide topology that breaks symmetry between network and device signal paths, reducing the number of individual switches required and incorporating inter-fiber gaps for improved isolation and directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PLC technology is used for M×N multicast optical switches, then batch processing cost reduction is achieved, but polarization dispersion loss increases and manufacturing flexibility decreases
Solution Approach 1:
The invention segments the M×N switching function into multiple 1×N PLC switches combined with optical couplers. Each 1×N PLC switch handles a subset of ports, and the optical couplers combine the outputs. This segmentation allows batch processing benefits of PLC while reducing the polarization dispersion loss that would occur in a single large-scale PLC switch, as each smaller PLC unit has lower accumulated PDL.
2Ease of manufacture
If PLC switches are used, then wafer-based fabrication cost is reduced, but device complexity and packaging requirements increase
Solution Approach 1:
The system divides the complex M×N switching function into multiple simpler 1×N PLC switch modules. Each module can be fabricated using standard wafer-based processes and packaged independently. The overall system complexity is managed by combining these standardized modules with optical couplers, rather than requiring a single complex custom-packaged PLC switch.
Solution Approach 2:
The invention uses universal 1×N PLC switch modules that can be configured in different arrangements to achieve various M×N switching configurations. These standardized modules with consistent interfaces and packaging requirements can be mass-produced using wafer-based fabrication, reducing both manufacturing cost and packaging complexity compared to custom-designed large-scale PLC switches.
3Adaptability or versatility
If MEMS switches are used for M×N configuration, then modular scalability is improved, but the number of required switching elements increases
Solution Approach 1:
The invention combines multiple 1×N PLC switches with optical couplers to achieve M×N switching functionality. By merging the functions of multiple smaller switches through optical combining, the system achieves the scalability and adaptability of modular designs while reducing the total number of active switching elements compared to a fully modular MEMS-based M×N switch array.
4Productivity
If switch fabric density is increased, then routing capacity is improved, but insertion loss and cross-talk increase
Solution Approach 1:
The invention segments the high-density switching fabric into multiple lower-density 1×N PLC switch modules. Each module operates at a manageable density with controlled insertion loss and cross-talk performance. The optical couplers combine signals from multiple modules, distributing the routing capacity across several lower-loss paths rather than forcing all traffic through a single high-density fabric, thereby maintaining low insertion loss and cross-talk while achieving high overall routing capacity.
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 reduces the number of switching elements by 50%, lowers costs, and enhances reliability by providing high directivity and hitless switching with reduced cross-talk and insertion loss, making the system more scalable and efficient.
Implementation Method 1
an optical signal redirection element (in some embodiments, a biaxially-symmetric redirection element) disposed to couple optical signals between a selected optical channel and the device common port
Implementation Method 2
a collimating lens disposed in an optical signal path between the optical waveguiding structure and the optical signal redirection element
Data Source
AI summary
An optical switch is configured in a “dual-ganged” switch geometry to provide for the simultaneous switching of a selected transmit/receive pair of optical signal paths between a specific optical communication device and an optical communication network. A biaxially-symmetric signal redirection component may be used to direct the signals between the selected channel and the optical communication device. A specific waveguide (e.g., fiber) array topology within the dual-ganged switch (DGS) breaks the symmetry between the network transmit/receive arrays and a pair of transmit and receive signal paths associated with the communication device to improve isolation and minimize the possibility of cross-talk between non-selected waveguides in the transmit and receive arrays. The possibility of “hits” during switching between channels can be eliminated, and is controlled by dictating the process or switching steps used to rotate the biaxially-symmetric signal redirection element.