Optical Link Performance Equalization in WDM Networks
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Solution Overview
Problem
In WDM systems, unequal optical power and OSNR across different wavelengths due to stimulated Raman scattering and non-flat gain spectra of optical amplifiers lead to inconsistent transmission performance, requiring complex and time-consuming serial adjustments in ring networks.
Innovation Solution
A method and apparatus that calculate target input and output powers for each wavelength in optical multiplexing sections, determining single wave attenuation between sections, allowing concurrent calculation of target power spectra and eliminating the need for connected optical paths, enabling fast and iterative-free adjustments in complex network topologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If serial adjustment is performed at each adjusting site in a ring network, then each site can equalize its local wavelengths, but the overall adjustment process becomes time-consuming and requires multiple iterations
Solution Approach 1:
The patent pre-calculates and stores reference values for optical power and OSNR at each adjusting site before actual equalization operations. This preliminary preparation enables direct comparison and immediate adjustment without iterative calculations during the equalization process, significantly reducing adjustment time while maintaining equalization effectiveness
Solution Approach 2:
The patent creates a virtual model of the optical link performance by calculating and storing reference power and OSNR values for each wavelength at each adjusting site. This virtual reference model allows the system to determine adjustment amounts without performing time-consuming iterative measurements, achieving fast equalization by comparing actual values against the pre-established virtual model
2Reliability
If detection and adjustment are performed at each adjusting site, then local wavelength equalization can be achieved, but the optical path must be connected first, delaying the adjustment process
Solution Approach 1:
The patent performs preliminary calculation of reference optical power and OSNR values for all wavelengths at all adjusting sites before the optical path is connected. This advance preparation of reference data enables the system to immediately begin equalization operations once the optical path is established, eliminating the need to wait for connection before starting detection and adjustment
3Reliability
If optical power equalization is performed using traditional methods, then wavelength power differences can be corrected, but the process requires separate OSNR equalization and power equalization subsystems, increasing system complexity
Solution Approach 1:
The patent combines OSNR equalization and optical power equalization into a unified adjustment process. By pre-calculating reference values for both OSNR and power, and using a single adjustment mechanism that considers both parameters simultaneously, the system achieves dual equalization objectives without requiring separate subsystems, thereby reducing overall system complexity
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 allows for simultaneous calculation of target power spectra and single wave attenuation, facilitating one-off adjustments in complex networks, reducing reliance on connected optical paths and minimizing the impact of serial adjustments, thereby improving link performance efficiency.
Implementation Method 1
a gain spectrum and noise figure spectrum of an OA (Optical Amplifier, optical amplifier) in the link are not flat for all wavelengths
Implementation Method 2
Because of SRS (Stimulated Raman Scattering, stimulated Raman scattering), optical power of a short wavelength transfers to optical power of a long wavelength
Data Source
AI summary
Embodiments of the present invention provide a method and an apparatus for equalizing link performance, and relate to the field of optical wavelength division multiplexing. In the present invention, target input power spectra and target output power spectra in all OMS sections in a network and single wave attenuation at a power adjusting point may be concurrently calculated based on link information of the OMS sections, fast adjustment may also be implemented for a complex network topology, and the adjustment may be implemented in a one-off manner to avoid a problem that iteration adjustment is caused by mutual impact of power adjusting points during serial adjustment in a ring network. In addition, it is not required to connect an optical path in the calculation phase, thereby eliminating reliance on a connected optical path in a process for equalizing link performance.