Optical Transmission System Signal Conditioning for Spectral Narrowing
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Solution Overview
Problem
In optical transmission systems, wavelength-dependent gain or loss in optical components causes signal quality variation among subchannel signals in superchannels, leading to worsened transmission quality due to spectral narrowing in the edge band portion as superchannel signals are repeatedly added and dropped.
Innovation Solution
An optical transmission system with a conditioning unit that adjusts optical intensities of channels and a managing apparatus to compute and apply a conditioning level, reducing attenuation and phase rotation differences among subchannel signals, thereby mitigating spectral narrowing and improving transmission quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wavelength-division multiplexing is used to transmit superchannel signals, then frequency utilization efficiency is improved, but signal quality variation occurs among subchannel signals due to wavelength-dependent gain or loss in optical components
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the optical characteristics (gain/loss) of different wavelength bands through the WSS. The controlling unit modifies transmission parameters based on detected signal quality, specifically compensating for wavelength-dependent variations in gain or loss to equalize signal quality across all subchannels while maintaining high frequency utilization efficiency
2Adaptability or versatility
If superchannel signals are repeatedly added and dropped on the lightpath, then network flexibility is improved, but spectral widths become narrower for subchannel signals in the edge band portion causing worsened optical transmission quality
Solution Approach 1:
The patent implements preliminary anti-action by detecting spectral narrowing in the edge band portion before it causes severe transmission quality degradation. The controlling unit proactively adjusts the optical characteristics of affected wavelength bands to counteract the narrowing effect, preventing further deterioration while allowing repeated signal addition and dropping operations to maintain network flexibility
Solution Approach 2:
The patent employs feedback mechanisms where the detecting unit continuously monitors signal quality and spectral characteristics of subchannel signals. The controlling unit uses this feedback information to dynamically adjust WSS parameters, creating a closed-loop system that maintains optimal transmission quality despite repeated network operations that would otherwise cause spectral narrowing
Data Source
AI summary
An optical transmission system includes optical transmission apparatuses configured to transmit wavelength-division multiplexed light signals via lightpaths, each of a pair of optical transmission apparatuses includes a conditioning unit configured to adjust the optical intensities of channels included in the wavelength-division multiplexed light signal, and one or more first processors configured to control, based on a conditioning level notified, the conditioning unit; and a managing apparatus configured to manage the pair of the optical transmission apparatuses, the managing apparatus including one or more second processors configured to compute a conditioning level on a basis of system information for respective the pair of optical transmission apparatuses in the optical transmission system.