Multidimensional Optical Network Spatial Mode Switching
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Solution Overview
Problem
Current optical networks face limitations in flexibility and bandwidth efficiency due to per-wavelength or per-fiber granularity switching, leading to unnecessary re-direction of wavelengths and reduced spectral utilization, especially with dynamic traffic demands and the introduction of novel frequency-domain degrees of freedom from optical orthogonal frequency division multiplexing (OFDM).
Innovation Solution
The implementation of a multidimensional optical network utilizing spatial mode multiplexers, spatial-spectral routing nodes, and multidimensional coders/modulators to enable switching and routing at a higher granularity by exploiting spatial and spectral domains, including multicore and multimode fibers, and employing OFDM super/subcarriers with advanced modulation formats and forward error correction schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switching is performed at per-wavelength or per-fiber granularity using traditional ROADM and PXC devices, then optical switching and routing can be implemented, but flexibility is significantly limited and bandwidth efficiency is reduced
Solution Approach 1:
The patent transitions from traditional per-wavelength or per-fiber switching dimensions to a new spatial dimension by utilizing multiple fiber cores and spatial modes. This dimensional expansion enables finer granularity switching (spatial-mode level) while maintaining bandwidth efficiency, as switches can redirect specific spatial modes or core-mode combinations without affecting entire fibers or wavelengths.
Solution Approach 2:
The patent segments the optical fiber transmission capacity into multiple independent spatial modes and fiber cores, treating each as a separate switching unit. This segmentation allows granular control at the spatial-mode level, enabling precise routing decisions that improve both flexibility and bandwidth utilization by switching only the necessary spatial-mode components rather than entire fibers.
2Ease of operation
If switching is performed at fiber-level granularity, then optical switching can be implemented, but unnecessary re-direction of certain wavelengths occurs resulting in substantial bandwidth waste
Solution Approach 1:
By introducing spatial mode as an additional switching dimension beyond fiber level, the patent enables selective routing of specific spatial modes within a fiber. This allows wavelengths to be redirected only when necessary and only for specific spatial-mode components, preventing unnecessary re-direction and reducing bandwidth waste while maintaining operational simplicity.
Solution Approach 2:
The patent applies local quality by enabling different switching behaviors for different spatial modes within the same fiber. Each spatial mode can be independently routed, allowing optimal path selection for each mode-wavelength combination, thereby minimizing bandwidth waste by avoiding unnecessary re-direction of wavelengths that are already on optimal paths.
3Adaptability or versatility
If switching is performed at wavelength level, then finer granularity is enabled, but unnecessary complexity is inserted to the overall ROADM design
Solution Approach 1:
The patent introduces spatial mode as a new switching dimension that provides fine granularity without the complexity of wavelength-level switching. By switching at the spatial-mode level rather than wavelength level, the system achieves comparable granularity benefits while avoiding the complexity of wavelength-selective components, as spatial-mode switching can be implemented at the fiber level using mode-selective couplers and filters.
Data Source
AI summary
An optical network includes a multidimensional coder and modulator for handling multiple-in-multiple-out MIMO spatial lightpath properties and content of any specific supercarrier, a spatial mode multiplexer responsive to orthogonal frequency division multiplexing OFDM transmissions and the multidimensional coder, a spatial-spectral routing node coupled over a fiber link to the spatial mode multiplexer for performing switching granularity by a spatial mode reconnection, a multidimensional decoder and demodulator; and a spatial mode demultiplexer coupled over a fiber link to the spatial-spectral routing node and responsive to the multidimensional decoder and demodulator.