Optical Transmission Device Nonlinear Pre-equalization
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Solution Overview
Problem
In polarization multiplexing systems, existing nonlinear pre-equalization methods require significant computational resources, leading to increased power consumption and reduced transmission efficiency due to nonlinear effects in optical fibers.
Innovation Solution
An optical transmission device that maps transmission data to signal points within a defined signal space, calculates perturbation quantities based on signal electric field vectors, and selects symbols with lower perturbation to generate a transmission signal, thereby reducing computational load and enhancing transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonlinear pre-equalization methods are used to compensate for nonlinear effects in optical fibers, then transmission quality is improved, but computational resources increase leading to higher power consumption
Solution Approach 1:
The patent changes the parameter representation from continuous complex-valued signal processing to discrete symbol-level perturbation quantities. By representing nonlinear effects as discrete perturbation symbols that can be selected from a finite set, the system achieves nonlinear compensation with reduced computational complexity and lower power consumption while maintaining transmission quality.
Solution Approach 2:
The patent replaces the conventional mechanical/computational approach of continuous nonlinear equalization with a simplified symbolic perturbation method. Instead of performing heavy mathematical operations on continuous signals, the system uses discrete symbol manipulation and selection, significantly reducing the computational burden and energy consumption.
2Reliability
If conventional nonlinear compensation methods are applied, then transmission errors are reduced, but calculation amount increases reducing transmission efficiency
Solution Approach 1:
The patent segments the continuous nonlinear compensation problem into discrete symbol-level perturbation components. By dividing the compensation task into individual symbol perturbations that can be independently calculated and selected, the system reduces the overall computational load while maintaining effective nonlinear compensation, thereby improving transmission efficiency.
Solution Approach 2:
The patent applies partial action by focusing compensation efforts only on the dominant perturbation components rather than attempting to compensate for all nonlinear effects with full precision. This selective approach achieves sufficient error reduction without the excessive computational requirements of complete nonlinear equalization.
3Ease of manufacture
If signal points are mapped without considering perturbation quantities, then mapping simplicity is maintained, but nonlinear degradation increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing perturbation quantities for each signal point before transmission. This allows the transmitter to select optimal signal points that account for expected nonlinear degradation, and enables the receiver to apply appropriate compensation without complex real-time calculations, thus reducing nonlinear degradation while maintaining mapping simplicity.
Data Source
AI summary
An optical transmission device includes: a memory; and a processor coupled to the memory; the processor: generate a first symbol by mapping a transmission data series to a first signal point which belongs to a first group within a signal space defined with regard to characteristics of an optical carrier wave of the transmission data series; generate a second symbol by mapping the transmission data series to a second signal point belonging to a second group; calculate a perturbation quantity of a signal electric field for each of the first and second symbols based on signal electric field vector information of a symbol which is generated before the first symbol and the second symbol; and determine, as a transmission signal, a symbol having a smaller perturbation quantity between the first symbol and the second symbol.