Photonic Switch Chip Segmentation for ROADM Scalability
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Solution Overview
Problem
Current Reconfigurable Optical Add/Drop Multiplexer (ROADM) designs face challenges in scalability, cost, power consumption, and size due to the need to handle a massive number of waveguides for high-degree nodes with flexible wavelength grids, which limits their ability to support a large number of add/drop wavelengths and directions efficiently.
Innovation Solution
A photonic switch chip for ROADM using silicon photonics with a three-stage architecture that partitions the add/drop Silicon Photonic Integrated Circuit (SPIC) chip, allowing it to scale with the number of directions and wavelengths, reducing waveguide interconnects, and providing a low-cost, low-power solution with pay-as-you-grow capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional ROADM designs use a massive number of waveguides to handle high-degree nodes with flexible wavelength grids, then the ability to support a large number of add/drop wavelengths and directions is improved, but the device complexity, size, cost, and power consumption increase significantly
Solution Approach 1:
The patent segments the ROADM functionality into multiple photonic integrated circuit (PIC) chips, where each PIC handles a specific subset of wavelengths and directions. This segmentation reduces the waveguide interconnect complexity on each individual chip while maintaining the overall system's ability to handle high-degree nodes with flexible wavelength grids through coordinated operation of multiple chips.
Solution Approach 2:
The patent introduces a new dimensional organization by arranging PIC chips in a multi-dimensional architecture where chips are connected through optical interconnects rather than relying solely on planar waveguide layouts. This dimensional change allows the system to scale to high-degree nodes by adding chips in multiple spatial dimensions, reducing the complexity of waveguide interconnects on each chip.
2Reliability
If traditional ROADM designs provision high bandwidth connectivity to each site to cope with unpredictable bandwidth demand, then the network reliability and service quality are improved, but the capital expenditure and network complexity increase
Solution Approach 1:
The patent implements dynamic bandwidth allocation through reconfigurable optical circuits that can adaptively provision bandwidth based on actual traffic demands. The ROADM system allows dynamic addition and dropping of wavelengths at different nodes, enabling the network to provide high bandwidth connectivity when needed while reducing complexity and resource utilization during lower demand periods.
Solution Approach 2:
The patent changes the network's operational parameters by enabling dynamic wavelength provisioning and reconfiguration. Instead of static high bandwidth provisioning to all sites, the system allows bandwidth parameters to be adjusted in real-time based on traffic patterns, maintaining reliability while reducing overall network complexity and capital expenditure.
3Adaptability or versatility
If ROADM supports pay-as-you-grow capability with dynamic wavelength provisioning, then the network flexibility and adaptability are improved, but the device complexity and initial infrastructure requirements increase
Solution Approach 1:
The patent segments the ROADM infrastructure into modular PIC chips that can be manufactured and deployed incrementally. Each PIC chip represents a manageable unit that can be produced using standard photonic integration processes, allowing the network to grow by adding chips rather than requiring complex monolithic infrastructure from the outset.
Solution Approach 2:
The patent designs universal PIC chip architectures that can perform multiple functions (add, drop, pass-through) for different wavelengths and directions. This multi-functionality allows the same basic infrastructure components to serve multiple purposes as the network grows, reducing the need for specialized infrastructure and simplifying the pay-as-you-grow deployment model.
Data Source
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AI summary
System and method embodiments are provided for a photonic switch chip for scalable reconfigurable optical add/drop multiplexer (ROADM). The embodiments enable a low-cost pay as you grow ROADM that scales as both the number of wavelengths added or dropped increases and the size of the node in terms of number of directions increase. In an embodiment, a ROADM includes an M degree optical cross-connect tandem component comprising M wavelength selective switch (WSS) coupled to M wavelength division multiplexing (WDM) node interfaces, where M is equal to a number of input or output directions; a routing stage wavelength selector switch (WSS) comprising a plurality of WSSs connected to the tandem component; and an N by M combiner/distributor for add/drop coupled to the routing stage WSS, wherein the combiner/distributor comprises one or more photonic integrated circuit (PIC) chips, and wherein N is a maximum number of add/drop wavelengths.