Optical Communication System Raman Scattering Compensation
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Solution Overview
Problem
In optical communication systems using wavelength division multiplexing, the intensity of C-band optical signals is reduced more than L-band signals due to inter-signal stimulated Raman scattering, leading to unbalanced signal intensities and degraded signal quality at the reception side.
Innovation Solution
The system includes a first optical transmitter for outputting a C-band optical signal at a specific transmission intensity and a second optical transmitter for outputting an L-band optical signal at a lower transmission intensity. A multiplexer combines these signals and transmits them through an optical transmission line, where the L-band signal is amplified by inter-signal stimulated Raman scattering, while the C-band signal intensity is reduced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If C-band and L-band optical signals are multiplexed and transmitted through the same optical transmission line, then transmission capacity is increased, but the intensity of C-band signals is reduced more than L-band signals due to inter-signal stimulated Raman scattering, leading to unbalanced signal intensities and degraded signal quality
Solution Approach 1:
The patent applies parameter changes by adjusting the transmission intensity of optical signals based on their wavelength bands. Specifically, it sets the transmission intensity of C-band signals lower than that of L-band signals to compensate for the stronger Raman scattering loss experienced by C-band signals. This differential intensity setting balances the received signal intensities and maintains signal quality across both bands while preserving high transmission capacity through wavelength division multiplexing.
2Productivity
If the number of multiplexed wavelengths is increased to improve transmission capacity, then more wavelengths can be transmitted, but the inter-signal stimulated Raman scattering effect becomes more significant, causing greater intensity imbalance and signal quality degradation
Solution Approach 1:
The patent addresses the harmful Raman scattering effect by changing the transmission intensity parameter for different wavelength bands. When multiple wavelengths are multiplexed, the system dynamically adjusts the transmission intensities of C-band and L-band signals to compensate for the nonlinear scattering interactions. This allows the system to maintain high transmission capacity with numerous multiplexed wavelengths while mitigating the detrimental effects of inter-signal Raman scattering through intelligent parameter optimization.
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 configuration adjusts the signal intensities to achieve balanced reception intensities for both C-band and L-band signals, thereby improving signal quality and reducing OSNR degradation.
Implementation Method 1
an optical signal in the C-band acts as a Raman excitation light due to stimulated Raman scattering, and thereby an optical signal in the L-band is amplified (Inter-signal stimulated Raman scattering)
Data Source
AI summary
An aim is to provide an optical communication system and an optical communication method for transmitting a wavelength-multiplexed signal whose signal quality on a reception side is adjusted to desired quality. A first optical transmitter outputs a first optical signal of a first wavelength at a first transmission intensity. A second optical transmitter outputs a second optical signal of a second wavelength longer than the first wavelength at a second transmission intensity lower than the first transmission intensity. A multiplexer outputs a third optical signal obtained by multiplexing the first optical signal and the second optical signal to an optical transmission line. The intensity of the first optical signal transmitted through the optical transmission line is reduced by inter-signal stimulated Raman scattering. The second optical signal transmitted through the optical transmission line is amplified by the inter-signal stimulated Raman scattering of the first optical signal.