Multidirectional Add Drop Devices for Optical Networks
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Solution Overview
Problem
Current optical add and drop devices in WDM networks face challenges in achieving flexible, high-capacity, and cost-effective operations with minimal signal quality impact, particularly in supporting high data rates and scalability, while also addressing contention and redundancy issues.
Innovation Solution
The development of multidirectional optical drop and add devices with programmable wavelength demultiplexers and spatial switching matrices allows for flexible configuration, contentionless operations, and scalable designs, enabling the same receiver or transmitter to handle signals from multiple directions and paths, with reconfigurable optical paths and amplifiers to manage traffic efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If discrete components are used to construct ROADMs or OXCs, then the system can achieve basic wavelength switching functionality, but the structure becomes complex and the size increases
Solution Approach 1:
The patent combines multiple discrete wavelength selective switches and switching matrices into an integrated ROADM device architecture. The first and second WSSs are merged with recirculation means and add/drop modules to create a unified system that reduces structural complexity while maintaining high reliability through the integrated design.
Solution Approach 2:
The recirculation means enable the same receiver to handle signals from multiple directions and the same transmitter to serve multiple output directions. This multi-functionality reduces the number of discrete components needed while enhancing system reliability and flexibility.
2Device complexity
If the same receiver handles signals from multiple directions, then the device complexity is reduced, but signal quality degradation may occur
Solution Approach 1:
The system segments optical signals by wavelength using WDM technology, directing different wavelength channels to different receivers through the recirculation means. This segmentation allows the same receiver to handle multiple directions without signal quality degradation by ensuring wavelength-specific signal routing.
Solution Approach 2:
The recirculation means act as intermediary components that condition and route optical signals between the WSSs and receivers. They ensure signal quality is maintained while enabling the same receiver to process signals from multiple input directions through proper signal conditioning and wavelength selection.
3Productivity
If traditional add and drop devices are used, then basic WDM functionality is provided, but contention occurs among client signals for given receivers
Solution Approach 1:
The system dynamically configures wavelength routing through the recirculation means and WSSs, allowing flexible assignment of wavelength channels to different receivers based on current network conditions. This dynamic capability eliminates signal contention by providing multiple possible routing paths and enabling real-time optimization of signal distribution.
Solution Approach 2:
The system changes wavelength parameters and routing configurations to avoid signal contention. By adjusting which wavelength channels are directed to which receivers through the recirculation means, the system can dynamically resolve contention situations and maintain high productivity without conflicts among client signals.
4Adaptability or versatility
If optical-electrical-optical conversions are performed at network routing nodes, then signal processing flexibility is improved, but the cost of network equipment increases
Solution Approach 1:
The system replaces optical-electrical-optical conversion mechanisms with all-optical wavelength switching using WSSs and recirculation means. This substitution maintains signal processing flexibility through optical domain manipulation while eliminating the need for expensive transducers and electronic processing equipment, thereby reducing overall system cost.
Solution Approach 2:
The recirculation means and WSSs provide multi-functional optical signal processing capabilities including wavelength selection, routing, and switching without requiring conversion to the electrical domain. This universal optical processing approach maintains adaptability while reducing equipment complexity and cost compared to systems requiring optical-electrical-optical conversions.
Data Source
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AI summary
An optical drop device comprises first and second wavelength demultiplexers (33, 43) connected to first and second WDM input lines (21), first and second groups of optical receivers (36, 37; 46, 47) respectively connected to the first and second wavelength demultiplexers, and an optical spatial switching matrix (50) comprising demultiplexer-side ports and receiver-side ports, a first subset of the demultiplexer-side ports being respectively connected (51) to a second subset (38) of the outputs of the first wavelength demultiplexer, a second subset of the demultiplexer-side ports being respectively connected (52) to a second subset (48) of the outputs of the second wavelength demultiplexer, a first subset of the receiver-side ports being respectively connected (53) to the optical receivers (36) of the first group, a second subset of the receiver-side ports being respectively connected (54) to the optical receivers (46) of the second group. An optical add device is symmetrical. Another embodiment provides recirculation lines between the first and second wavelength demultiplexers.