Optical Receiving Apparatus for Waveform Distortion Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The digital backpropagation method for compensating waveform distortion in optical communications requires multiple FFT and IFFT circuits, leading to a large circuit scale, which is inefficient for high-accuracy compensation.
Innovation Solution
An optical receiving device that divides received signals into frequency bands, matches timing, and performs compensation using wavelength dispersion and nonlinear compensation units before and after combining, reducing the need for additional Fourier transform units and allowing high-accuracy distortion compensation with a smaller circuit scale.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the digital backpropagation method is used to compensate for waveform distortion with high accuracy, then the compensation accuracy is improved, but the circuit scale increases due to the need for multiple FFT and IFFT circuits
Solution Approach 1:
The patent divides the frequency band into multiple sub-bands and processes each sub-band separately through parallel compensation paths. This segmentation allows the system to achieve high-accuracy compensation by treating different frequency components independently, reducing the computational burden on a single large FFT/IFFT circuit while maintaining overall compensation accuracy.
Solution Approach 2:
The patent transitions from time-domain processing to frequency-domain processing by applying FFT to divide the signal into frequency sub-bands. This dimensional change from time to frequency domain enables parallel processing of multiple frequency components simultaneously, reducing the need for sequential time-domain iterations and thereby reducing the overall circuit scale while maintaining compensation accuracy.
2Reliability
If multiple FFT and IFFT circuits are used for repeated compensation, then the compensation accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent segments the wavelength dispersion compensation into multiple frequency sub-bands, where each sub-band is processed through its own compensation path. This segmentation allows the system to achieve reliable high-accuracy compensation by independently optimizing each frequency component, reducing the need for multiple full-bandwidth FFT/IFFT circuits.
Solution Approach 2:
The patent merges multiple sub-band compensation results in the frequency domain and then applies inverse FFT to convert back to time domain. This merging approach consolidates the compensation function into a unified process that achieves the same reliability as multiple separate compensation iterations but with reduced circuit complexity.
Data Source
AI summary
An optical receiving device that divides receive signals obtained by receiving an optical signal using a coherent detection scheme into a plurality of frequency bands, matches timing of the receive signals along a time axis between the frequency bands resulting from the division, performs a combining process of combining the receive signals contained in the plurality of frequency bands, and compensates the receive signals for waveform distortion either before or after the combining process, includes: a first wavelength dispersion compensation unit adapted to compensate the receive signals for waveform distortion in each of the frequency bands resulting from the division; a first nonlinear compensation unit adapted to compensate the receive signals belonging to each of the frequency bands and timed with each other in a time domain for a nonlinear optical effect; and a second wavelength dispersion compensation unit adapted to compensate the receive signals belonging to each of the frequency bands and compensated for the nonlinear optical effect for wavelength dispersion in each of the frequency bands.