Dispersion Compensation Signal Generation via Multi-Channel Pre-Warping
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Solution Overview
Problem
The existing electrical dispersion compensation techniques for optical fiber transmission systems over 10Gbit/s face challenges in suppressing non-linear effects due to high peak power, which requires a broad bandwidth for digit-analog converters, exceeding current device capabilities.
Innovation Solution
The proposed method involves splitting data signals into multiple channels, adjusting their phases and amplitudes using pre-processing modules, generating coherent optical carriers, and modulating them to produce pre-warped optical signals that are coupled for dispersion compensation, allowing for the use of existing devices and reducing the bandwidth requirement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Return-to-Zero symbols are introduced to suppress non-linear effects, then signal transmission quality is improved, but the bandwidth requirement for digit-analog converter increases beyond current device capabilities
Solution Approach 1:
The patent divides the data signal into multiple wavelength channels, processing each channel separately through its own pre-processing module. This segmentation allows the system to handle Return-to-Zero symbols with reduced bandwidth requirements per channel, making the overall system feasible with current device capabilities while maintaining signal transmission quality.
Solution Approach 2:
The patent transitions from single-channel time-domain processing to multi-wavelength channel processing in the frequency domain. By distributing the signal across multiple wavelength channels with different pulse widths, the system achieves non-linear effect suppression without requiring excessive bandwidth from individual digit-analog converters.
2Reliability
If dispersion pre-compensation is performed to compensate dispersion effect, then transmission function is improved, but peak power to average power ratio increases causing severer non-linear effects
Solution Approach 1:
The patent applies different pulse widths to different wavelength channels, creating local variations in signal characteristics. This allows each channel to contribute differently to dispersion compensation while the combined effect suppresses non-linearities, resolving the contradiction between achieving transmission function and avoiding non-linear effects.
Solution Approach 2:
The patent combines multiple wavelength channels with different pulse width characteristics to create a composite signal structure. This composite approach enables simultaneous dispersion compensation and non-linear effect suppression, as the diverse channel characteristics work together to mitigate both issues.
3Reliability
If Carrier-Suppressed Return-to-Zero electrical signals are generated with various pulse widths, then dispersion compensation capability is improved, but the main lobe width increases requiring broader bandwidth
Solution Approach 1:
The patent segments the dispersion compensation task across multiple wavelength channels, each with optimized pulse widths. This segmentation reduces the bandwidth requirement for individual digit-analog converters while maintaining overall dispersion compensation capability through the combined effect of all channels.
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 enhances signal transmission quality by effectively counteracting non-linear effects in optical fiber systems while utilizing existing devices, thus overcoming the limitations of prior art in introducing Return-to-Zero symbols for electrical dispersion pre-compensation.
Implementation Method 1
N electro-optic modulators configured to modulate the N channels of coherent optical carriers based on the N channels of pre-warped electrical signals and generate N channels of pre-warped optical signals
Implementation Method 2
an optical fiber transmission system over 10Gbit/s requires a dispersion compensation to guarantee the transmission function of the system
Implementation Method 3
The non-linear effect herein mainly refers to self-phase modulation effect, cross-phase modulation effect, four-wave mixing effect and the like in optical fibers
Data Source
Figure 1~3
Figure 4~5(a)
Figure 5(b)~5(c)
AI summary
An apparatus for generating a dispersion compensation signal includes a splitting module for splitting a data signal to be transmitted into N channels of data signals; N pre-processing modules for adjusting in frequency domain the phases and amplitudes of the N channels of data signals and outputting N channels of pre-warped electrical signals; an optical carrier generating module for generating N channels of coherent optical carriers; N electro-optic modulators for modulating the N channels of coherent optical carriers based on the N channels of pre-warped electrical signals and generating N channels of pre-warped optical signals; an optical coupling module for coupling the N channels of pre-warped optical signals into a dispersion compensation optical signal. A method for generating a dispersion compensation signal is also provided. By pre-processing the data signals, the present disclosure may allow the use of existing devices to generate a dispersion compensation signal so that the bandwidth requirement set by prior art on the electrical device is reduced.