Optical Receiver Multibranch Filter-Bank Chromatic Dispersion Compensation
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Solution Overview
Problem
Existing optical receivers face challenges in reducing the complexity and power consumption of chromatic-dispersion compensation modules while maintaining effective chromatic dispersion compensation.
Innovation Solution
The implementation of an optical receiver with a dual-branch signal-processing system, utilizing finite-impulse-response filters with different group delay approximations and frequency-dependent phase-shift and amplitude-scaling profiles to compensate for chromatic dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a digital signal processor is used to compensate for chromatic dispersion, then chromatic dispersion compensation is achieved, but the complexity and power consumption of the compensation module increase
Solution Approach 1:
The patent divides the chromatic dispersion compensation function into multiple parallel signal-processing branches, each handling a specific spectral sub-band with a finite-impulse-response filter. This segmentation allows the overall compensation task to be distributed across simpler, parallel processing units rather than requiring a single complex processor, thereby reducing individual module complexity while maintaining overall compensation effectiveness.
Solution Approach 2:
The patent transitions from time-domain processing to frequency-domain processing by applying Fourier transforms to divide the signal into spectral sub-bands. This dimensional change from time to frequency domain enables the use of simpler finite-impulse-response filters in parallel branches, reducing the computational complexity required for each processing unit while achieving the same chromatic dispersion compensation goal.
2Reliability
If a digital signal processor is used to compensate for chromatic dispersion, then chromatic dispersion compensation is achieved, but the power consumption of the compensation module increases
Solution Approach 1:
By segmenting the compensation function into parallel branches with finite-impulse-response filters, each processing unit requires less computational power than a single full-featured digital signal processor. The parallel architecture allows for more energy-efficient implementation of the same compensation function.
Solution Approach 2:
The patent replaces the traditional mechanical/digital signal processor approach with an optical-domain solution using optical filters and Fourier transform optics. This substitution leverages physical optical processes to perform chromatic dispersion compensation, significantly reducing the electronic power consumption associated with digital signal processing while maintaining compensation effectiveness.
3Use of energy by moving object
If the complexity of the compensation module is reduced, then power consumption decreases, but the range of dispersion compensation is limited
Solution Approach 1:
The patent designs the parallel signal-processing branches with tunable parameters that allow each branch to be configured for different dispersion conditions. The system can adaptively adjust the filtering and processing parameters across the parallel branches to handle a wide range of chromatic dispersion scenarios, making the simplified architecture universally applicable to various compensation needs without requiring a complex fixed design.
Solution Approach 2:
The compensation module incorporates dynamic parameter adjustment capabilities that allow the system to adapt its processing characteristics in real-time based on the input signal conditions. This dynamic behavior enables the simplified parallel filter architecture to effectively handle varying ranges of chromatic dispersion by adjusting filter coefficients and processing parameters, maintaining versatility without increasing structural complexity.
Data Source
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AI summary
An optical receiver having an electronic dispersion-compensation module with two parallel signal-processing branches configured to provide a greater range of dispersion compensation than that provided by a prior-art device of comparable implementation complexity. In an example embodiment, each of the signal-processing branches includes a respective bank of finite-impulse-response filters that are configured in accordance with a différent respective approximation of the group delay that needs to be compensated. The two group-delay approximations used by the filter banks rely on différent respective step functions, each having a respective plurality of quantized steps, with the transitions between adjacent steps in one step function being spectrally aligned with the flat portions of the corresponding steps in the other step function. The filter banks may be further configured to apply différent respective frequency-dependent phase-shift and/or amplitude-scaling profiles designed to reduce signal distortions associated with the transitions between adjacent steps in the step functions.