Cyclic Wavelength Band Permutation for Raman Power Deviation
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Solution Overview
Problem
In multiband transmission systems using optical fibers, stimulated Raman scattering leads to power deviation among wavelength bands, causing signal quality degradation due to the inability of electrical control systems to follow dynamic power fluctuations at optical response speeds.
Innovation Solution
A cyclic wavelength band permutation device is implemented, featuring wavelength band converters that perform cyclic permutation of optical signals across wavelength bands, reallocating signals from shorter to longer bands and vice versa, connected to optical amplifiers to mitigate power deviations through optical processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrical control systems are used to manage power distribution among wavelength bands, then system complexity is reduced and ease of operation is improved, but the response speed is insufficient to follow dynamic power fluctuations at optical response speeds
Solution Approach 1:
The patent replaces electrical control systems with an all-optical control mechanism. Specifically, it uses optical amplifiers and wavelength band converters that operate purely in the optical domain to dynamically adjust power distribution among wavelength bands. This substitution eliminates the speed bottleneck of electrical-to-optical conversion, enabling real-time response to dynamic power fluctuations while maintaining operational simplicity through optical-domain processing.
Solution Approach 2:
The system implements self-service by enabling the optical transmission system to automatically compensate for power deviations caused by stimulated Raman scattering. The wavelength band converters and optical amplifiers continuously monitor and adjust power distribution among wavelength bands without external electrical control, allowing the system to self-correct dynamic power fluctuations at optical response speeds through inherent optical feedback mechanisms.
2Device complexity
If wavelength bands are fixed in sequential allocation from shorter to longer wavelengths, then system configuration is simplified, but power deviation due to stimulated Raman scattering causes signal quality degradation
Solution Approach 1:
The patent introduces dynamic wavelength band allocation by placing wavelength band converters at strategic points in the transmission system. These converters dynamically permute wavelength bands in real-time to counteract power deviations caused by stimulated Raman scattering. This dynamic approach maintains simple sequential allocation for most of the transmission path while actively adjusting band positions only where needed to compensate for Raman effects, thus preserving signal quality without significantly increasing overall system complexity.
Solution Approach 2:
The system applies local quality by implementing wavelength band permutation only at specific locations where power deviation becomes problematic, rather than uniformly across the entire transmission system. The wavelength band converters are strategically positioned to address local power imbalance issues caused by stimulated Raman scattering, allowing the majority of the transmission path to maintain simple fixed allocation while localized sections actively manage power distribution to preserve signal quality.
3Duration of action of stationary object
If optical amplifiers are used to amplify wavelength-multiplexed signals, then transmission distance is extended, but stimulated Raman scattering causes power deviation among wavelength bands
Solution Approach 1:
The patent introduces wavelength band converters as intermediary devices between optical amplifiers to mediate the power distribution among wavelength bands. These converters act as intermediaries that receive amplified signals from optical amplifiers, detect power deviations caused by stimulated Raman scattering, and actively permute wavelength bands to compensate for power imbalances. This intermediary mechanism allows the system to benefit from extended transmission distance provided by optical amplifiers while maintaining stable power distribution through active wavelength band management.
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 eliminates power deviations and maintains signal quality by reallocating power across bands, reducing OSNR degradation and transmission capacity losses, while enabling instantaneous correction of dynamic fluctuations.
Implementation Method 1
stimulated Raman scattering leads to power deviation among wavelength bands
Implementation Method 2
each wavelength band converter performs a cyclic permutation process of transitioning or converting an optical signal allocated to the shorter wavelength band side in the bands of the optical fiber to the longer wavelength band side
Data Source
AI summary
A cyclic wavelength band permutation device (31) includes as many wavelength band converters (32a to 32c) as the wavelength bands of optical signals (S1, C1, and L1), and the wavelength band converters are individually connected to the output terminals of corresponding optical amplifiers among a plurality of optical amplifiers (17a to 17c) connected to an optical fiber (16) in an inserted manner. When a wavelength-multiplexed signal beam obtained by multiplexing optical signals in different wavelength bands is multiband-transmitted through an optical fiber while being amplified by the plurality of optical amplifiers, each wavelength band converter performs a cyclic permutation process of transitioning or converting an optical signal allocated to the shorter wavelength band side in the bands of the optical fiber to the longer wavelength band side, and also transitioning or converting an optical signal allocated to the longest wavelength band to the shortest wavelength band.