Optical Fiber Filling Channels Stabilize Spectral Center of Gravity
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Solution Overview
Problem
In optical fiber communication networks, sudden changes in carrier wave power due to failures or protection mechanisms can lead to abrupt gain changes, causing signal-noise ratio perturbations and potential network failures, especially when combined with Raman tilt effects that shift spectral energies, compromising the quality of high-frequency signals.
Innovation Solution
The introduction of filling channels with adjustable power distribution across the spectrum to maintain a stable center of gravity, using orthogonal radiation sources and unpolarized light to minimize non-linear effects, and strategically placing filling channels within the information carrier frequency band to match amplifier gains, while employing redundant radiation sources and sensors to manage power adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filling channels are used to compensate power variations when carrier channels fail, then the total optical power remains constant and abrupt gain changes are avoided, but the Raman tilt causes signal-noise ratio deterioration at high frequencies
Solution Approach 1:
The patent changes the physical parameters of the filling channels by using unpolarized light instead of polarized light. This parameter change reduces non-linear optical effects and minimizes Raman tilt, thereby improving signal-noise ratio while maintaining the power compensation function that ensures network reliability.
Solution Approach 2:
The patent employs a composite approach by combining multiple filling channels with different polarization states (unpolarized light from orthogonal radiation sources) to create a filling channel system that simultaneously maintains total optical power and minimizes Raman tilt effects on high-frequency signals.
2Length of moving object
If optical power is increased to extend distance between amplifiers, then transmission distance is improved, but non-linear optical effects corrupt the spectrum and impulse shape
Solution Approach 1:
The patent changes the polarization parameter of the filling channels to unpolarized light, which reduces the impact of non-linear optical effects such as stimulated Raman scattering and four-wave mixing. This allows higher optical powers to be transmitted over longer distances without spectrum corruption or impulse shape distortion.
3Quantity of substance
If filling channels use wavelengths outside the information carrier band, then the bandwidth for information carriers is preserved, but amplifier gain variations affect the filling channels
Solution Approach 1:
The patent makes the filling channels universal by allowing them to serve dual purposes: maintaining total optical power for network reliability while simultaneously experiencing the same amplifier gain variations as information carrier channels. This universality is achieved by placing filling channels within the same frequency band as information carriers, ensuring they share the same amplifier gain characteristics.
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 minimizes signal-noise ratio perturbations by stabilizing the spectral center of gravity, reducing the risk of network failures and non-linear effects, ensuring consistent signal quality and network reliability even with carrier wave failures.
Implementation Method 1
One of these effects is stimulated Raman scattering, which may be understood as inelastic scattering of light by lattice vibrations of the fibre material. This effect mainly causes a spectral shift of the optical signals to lower frequencies
Data Source
AI summary
For transmitting information on an optical fiber, a plurality of information carrier channels at different carrier frequencies and a plurality of filling channels are used. The filling channels are transmitted together with the information carrier channels along the fiber. The total optical power of the information carrier channels and the filling channels transmitted on the fiber is maintained constant by compensating every change of the optical power of the information carrier channels by an inverse change of the optical power of the filling channels. The change of the optical power of the filling channels is distributed to the individual filling channels such that a minimum displacement of the center of gravity of the common spectrum of information carrier channels and filling channels results.