WDM Demultiplexing by Modulation Rate Segmentation
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Solution Overview
Problem
Existing WDM optical transmission systems face challenges in multiplexing and demultiplexing signal lights with different modulation rates due to varying spectral bandwidths, leading to signal quality deterioration, crosstalk, and reduced frequency utilization efficiency.
Innovation Solution
An optical demultiplexing and multiplexing method that branches wavelength division multiplexed light into multiple routes with demultiplexers and multiplexers set on wavelength grids corresponding to specific modulation rates, using optical switches to manage optical paths and block unwanted signals, allowing flexible arrangement of signal lights at arbitrary wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common interleaver is used to multiplex/demultiplex signal lights having different modulating rates, then device complexity is reduced, but signal quality deteriorates due to spectral bandwidth mismatches
Solution Approach 1:
The invention segments the multiplexing function by providing separate interleavers for different modulating rates (10 Gbit/s interleaver and 40 Gbit/s interleaver). Each interleaver is dedicated to a specific bit rate, ensuring that signal lights are processed by devices matched to their spectral characteristics, thereby preventing signal quality deterioration while maintaining manageable system complexity through functional segmentation.
Solution Approach 2:
The invention applies local quality by making each interleaver's transmission characteristics specifically optimized for its designated modulating rate. The 10 Gbit/s interleaver has transmission bands optimized for 10 Gbit/s signals, and the 40 Gbit/s interleaver has transmission bands optimized for 40 Gbit/s signals. This localized optimization ensures that each signal light interacts with multiplexing devices having appropriate characteristics, preventing crosstalk and signal degradation.
2Productivity
If signal lights are arranged at dense wavelength intervals to increase frequency utilization efficiency, then productivity increases, but signal quality deteriorates due to crosstalk and band restriction
Solution Approach 1:
The invention introduces dynamic control through optical switches that can flexibly connect different signal lights to appropriate transmission paths based on their modulating rates. This dynamic routing capability allows the system to adapt to varying signal requirements, enabling dense wavelength packing while maintaining signal quality by directing each signal through paths optimized for its specific characteristics, thereby resolving the conflict between high frequency utilization and signal quality.
3Productivity
If the system is upgraded to support higher bit rates to increase capacity, then productivity increases, but adaptability decreases due to fixed wavelength arrangements
Solution Approach 1:
The invention enables dynamic wavelength arrangement through controllable optical switches that can reconfigure connection paths based on the modulating rates of input signals. This dynamic capability allows the system to accommodate different bit rate configurations (10 Gbit/s, 40 Gbit/s, or mixed) without being constrained by fixed wavelength assignments, thereby maintaining high system capacity while improving adaptability to various operational scenarios and future upgrades.
Solution Approach 2:
The invention achieves universality by designing a multiplexing system that can handle multiple modulating rates (10 Gbit/s and 40 Gbit/s) through a unified architecture with dedicated interleavers for each rate. This multi-functional design allows the system to process different types of signal lights appropriately, enabling flexible capacity upgrades and various wavelength arrangement patterns while maintaining a single integrated system structure.
Data Source
AI summary
According to the present invention, for example, a WDM light containing 10 Gbit/s signal lights and 40 Gbit/s signal light arranged on wavelength grids at 25 GHz intervals is branched into two by an input side optical coupler to be sent to two routes. In one route side, only the 10 Gbit/s signal lights are demultiplexed by a 10 Gbit/s demultiplexer and a plurality of 1×2 optical switches, while in the other route side, only the 40 Gbit/s signal lights are demultiplexed by a 40 Gbit/s demultiplexer and a plurality of 1×2 optical switches. Further, the respectively demultiplexed signal lights are multiplexed for each modulating rate by a 10 Gbit/s multiplexer and a 40 Gbit/s multiplexer, and thereafter, further multiplexed by an output side optical coupler to become a WDM light. Thus, it becomes possible to arrange signal lights having different modulating rates at arbitrary wavelengths on wavelength grids at predetermined intervals.