Configurable Frequency Domain Equalizer for Dispersion Compensation
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Solution Overview
Problem
Wavelength division multiplexed (WDM) optical communication systems face challenges in efficiently compensating for chromatic dispersion and polarization mode dispersion, which affect signal quality and require large, complex filters when using a single carrier, leading to increased computational complexity and performance penalties.
Innovation Solution
The implementation of multiple sub-carriers allows for the breakdown of dispersion compensation into smaller, more manageable components, using digital signal processors to generate and process frequency domain sample vectors, enabling smaller filters and reduced computational complexity while maintaining signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single carrier is used for dispersion compensation, then signal quality can be maintained, but filter size and computational complexity increase significantly
Solution Approach 1:
The patent divides the single carrier signal into multiple sub-carriers (e.g., 4 sub-carriers). Each sub-carrier is processed independently with its own smaller filter, breaking down the complex single-carrier dispersion compensation into manageable segments. This segmentation reduces the filter size and computational complexity while maintaining overall signal quality through coherent combination of the processed sub-carriers.
2Reliability
If a single carrier is used for dispersion compensation, then signal quality can be maintained, but computational complexity increases
Solution Approach 1:
By segmenting the signal into multiple sub-carriers, the computational load is distributed across parallel processing paths. Each sub-carrier requires less computational resources individually, and the overall complexity is reduced because smaller filters operate in parallel rather than one large filter operating sequentially on the entire signal.
Solution Approach 2:
The patent applies dispersion compensation partially to each sub-carrier rather than fully to the entire signal at once. Each sub-carrier receives a portion of the total computational effort, making the processing more efficient while achieving complete dispersion compensation when all sub-carriers are combined.
3Reliability
If larger filters are used for dispersion compensation, then signal quality improves, but device complexity increases
Solution Approach 1:
Instead of using one large filter for the entire signal, the patent segments the signal into multiple sub-carriers and applies smaller filters to each. The sum of the sizes of these smaller filters is less than the size of the single large filter that would be needed to process the entire signal with equivalent dispersion compensation performance.
Data Source
AI summary
A system may include an optical transmitter and an optical receiver. The optical transmitter may generate optical signals associated with sub-carriers, and may provide the optical signals via an optical link. The optical receiver may receive the optical signals via the optical link, and may generate samples based on the optical signals. The samples may be associated with the sub-carriers. The optical receiver may combine the samples to form a time domain sample vector having a particular size, and may generate a frequency domain sample vector, having the particular size, based on the time domain sample vector. The optical receiver may demultiplex the frequency domain sample vector to generate domain sample vectors corresponding to the sub-carriers. The optical receiver may process the frequency domain sample vectors to generate equalized frequency domain sample vectors, and may output the equalized frequency domain sample vectors.