Intra-Transceiver Optical Superchannel Switching via RF Sub-Band Multiplexing
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Solution Overview
Problem
Conventional optical wavelength selective switches (WSS) have limited switching resolution, making it difficult to handle subcarrier switching in optical superchannels, especially with reduced subcarrier/channel spacing, which limits flexibility and increases cost and complexity in ROADM design, and existing digital sub-banding schemes require significant investment and are limited by WSS resolution.
Innovation Solution
The use of RF sub-band multiplexing and demultiplexing via cascaded RF mixing modules and optical dual-polarized QPSK modulators for hybrid RF/optical IQ modulation, allowing intra-transceiver optical superchannel switching without new DSP design, and utilizing sharp electronic filtering for higher resolution sub-band switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical WSS with fixed channel spacing is used, then system implementation is simple, but switching resolution is insufficient for subcarrier-level switching in optical superchannel
Solution Approach 1:
The patent segments the optical superchannel into multiple subcarriers with finer granularity than conventional WSS can handle. By dividing the superchannel spectrum into discrete subcarrier slots, the system enables switching at the subcarrier level rather than at the conventional channel level, achieving the required switching resolution through spectral segmentation
Solution Approach 2:
The patent changes the operating parameters by using variable subcarrier spacing that adapts to different superchannel configurations. Instead of fixed channel spacing, the system dynamically adjusts subcarrier spacing to optimize switching performance while maintaining compatibility with existing WSS capabilities, thereby resolving the resolution versus complexity contradiction
2Adaptability or versatility
If inter-transceiver switching with coarse granularity is used, then transceiver cost per bit is reduced, but network flexibility and grooming capability are limited
Solution Approach 1:
The patent segments the transceiver output into multiple subcarriers within the superchannel, enabling fine-grained switching at the subcarrier level. This segmentation allows the system to achieve both low cost per bit (by sharing transceiver resources) and high network flexibility (by enabling precise subcarrier grooming), resolving the contradiction between adaptability and complexity
Solution Approach 2:
The patent implements dynamic subcarrier switching capability that allows the system to adapt to varying network traffic patterns. By dynamically allocating and switching subcarriers rather than being fixed to coarse transceiver-level switching, the system gains network flexibility while maintaining cost efficiency through shared transceiver infrastructure
3Measurement precision
If digital sub-banding scheme is adopted, then sub-band granularity is improved, but DSP design complexity and investment requirement increase significantly
Solution Approach 1:
The patent substitutes complex digital signal processing with optical-domain techniques. Instead of using DSP to achieve sub-banding (which requires significant investment in new DSP designs), the system uses optical superchannel multiplexing and WSS in the optical domain to achieve the same sub-band granularity, thereby reducing DSP design complexity while maintaining measurement precision
Solution Approach 2:
The patent introduces an optical intermediary layer (optical superchannel with WSS) that mediates between the digital sub-band requirements and the physical implementation. This optical intermediary enables sub-band granularity without requiring direct digital processing, thus reducing DSP investment while achieving the desired measurement precision
4Measurement precision
If WSS bandwidth is reduced to achieve higher spectral resolution, then subcarrier guard-band is reduced, but system cost and complexity increase significantly
Solution Approach 1:
The patent segments the superchannel into multiple subcarriers with optimized spacing that balances spectral resolution requirements with WSS capability. By segmenting the spectrum appropriately, the system achieves the necessary guard-bands without requiring excessively high-resolution WSS, thus reducing overall system complexity while maintaining measurement precision
Solution Approach 2:
The patent optimizes the parameter of subcarrier spacing to achieve the minimum necessary spectral resolution. By carefully selecting subcarrier spacing parameters, the system achieves adequate guard-bands for isolation while avoiding the need for ultra-high-resolution WSS, thereby reducing device complexity and cost
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 enables flexible intra-transceiver superchannel generation and detection with lower transceiver costs, improved system capacity, and reduced complexity by allowing sub-band switching without DSP, compatible with standard 32 Gbaud rate and modulation formats, and supports smaller sub-band spacing and higher spectral efficiency.
Implementation Method 1
performing RF sub-band multiplexing and demultiplexing by cascading a radio-frequency (RF) mixing module and optical dual-polarized (DP) QPSK modulator for hybrid RF/optical IQ modulation
Implementation Method 2
optical dual-polarized (DP) QPSK modulator for hybrid RF/optical IQ modulation
Data Source
AI summary
Systems and methods are disclosed for data communication by performing RF sub-band multiplexing and demultiplexing by cascading a radio-frequency (RF) mixing module and optical dual-polarized (DP) QPSK modulator forhybrid RF/optical IQ modulation; and performing intra-transceiver optical superchannel switching through the RF sub-band multiplexing.