Relay Amplification With Spectrum Inversion to Reduce Inter-Core Crosstalk
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Solution Overview
Problem
In optical transmission systems using multi-core fibers, inter-core crosstalk (XT) increases, limiting the capacity and efficiency of data transmission, particularly in long wavelength bands, and managing wavelength-dependent signal parameters complicates the system and increases costs.
Innovation Solution
An optical transmission system utilizing a relay amplification device that branches optical signals into single-core fibers, performs optical parametric amplification with pump lights to generate phase conjugate lights, and multiplexes these lights back into multi-core fibers, reducing XT through spectrum inversion and strategic core usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-core fiber is used to expand transmission capacity, then transmission capacity is improved, but inter-core crosstalk increases
Solution Approach 1:
The patent segments the multi-core fiber transmission into multiple single-core fiber segments by branching the optical signals at relay amplification devices. Each core's signal is separated and amplified individually, preventing crosstalk accumulation across the entire transmission distance. This segmentation approach maintains the high capacity benefit of multi-core fibers while eliminating the crosstalk penalty.
Solution Approach 2:
The relay amplification device acts as an intermediary between transmission spans. It branches signals from multiple cores into separate single-core fibers, amplifies them through optical parametric amplification with pump lights, and then multiplexes them back. This intermediary process resets the crosstalk accumulation for each segment, allowing long-distance high-capacity transmission.
2Productivity
If wavelength division multiplexing is used to increase channel number, then transmission capacity is improved, but system complexity increases
Solution Approach 1:
The patent combines spatial multiplexing (multi-core fibers) with wavelength division multiplexing in a unified transmission system. Each core can carry multiple wavelength channels, and the relay amplification devices handle both spatial and spectral dimensions simultaneously through optical parametric amplification, which amplifies all wavelengths in a core together rather than requiring separate processing for each wavelength.
3Reliability
If optical parametric amplification is used to reduce crosstalk, then signal quality is improved, but device complexity increases
Solution Approach 1:
The patent replaces conventional electronic signal processing and multiple discrete amplifiers with optical parametric amplification. Instead of converting optical signals to electrical, processing them, and converting back, the system uses nonlinear optical effects in a single device to amplify signals directly in the optical domain, reducing crosstalk and simplifying the overall device architecture.
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 effectively reduces wavelength-dependent XT accumulation and inter-core crosstalk, enhancing transmission capacity and efficiency while maintaining bandwidth utilization.
Implementation Method 1
a spectrum inversion unit for performing optical parametric amplification on the respective optical signals branched into the respective single fibers with pump lights to output phase conjugate lights of the respective optical signals generated by the optical parametric amplification
Data Source
AI summary
An optical transmission system comprising: an optical transmitter; an optical receiver; and a relay amplification device for amplifying and relaying an optical signal, in which the optical transmitter and the relay amplification device are connected by a first multi-core fiber, the optical receiver and the relay amplification device are connected by a second multi-core fiber, in which the relay amplification device includes a branch unit for branching optical signals transmitted by respective cores of the first multi-core fiber into a plurality of single-core fibers, a spectrum inversion unit for performing optical parametric amplification on the respective optical signals with pump lights to output phase conjugate lights of respective optical signals generated by the optical parametric amplification; and a multiplex unit for multiplexing the phase conjugate lights of the respective optical signals output from the spectrum inversion unit to output the multiplexed lights to the second multi-core fiber.