OSNR Measurement Using Multi-Wavelength Signal Power Analysis
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Solution Overview
Problem
Existing methods for determining the quality parameters of polarization-multiplexed optical communication signals fail to accurately assess signal quality due to Non-Linear Effects (NLE)-induced spectral deformations, which are not accounted for in conventional OSNR measurements.
Innovation Solution
The method involves measuring signal powers at three or more wavelengths to calculate an extended signal-to-noise ratio (eOSNR) and a signal deformation factor (SDF), allowing for the characterization of OSNR in the presence of NLE-induced spectral deformations, using a device with recording, optical filter, opto-electrical conversion, and data processing units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional OSNR measurement methods are used, then measurement simplicity is maintained, but measurement precision deteriorates due to unaccounted NLE-induced spectral deformations
Solution Approach 1:
The patent segments the optical spectrum into multiple wavelength regions (first, second, and third wavelength regions) and performs separate measurements in each region. This segmentation allows the system to capture spectral deformations caused by NLEs at different locations, enabling accurate OSNR calculation while maintaining manageable measurement complexity through structured multi-point observation.
Solution Approach 2:
The patent transitions from conventional two-point measurement to a three-dimensional measurement approach by adding a third wavelength region. This dimensional expansion enables the system to characterize both OSNR and spectral deformation independently, improving measurement precision without proportionally increasing complexity.
2Reliability
If signal power is increased to improve BER performance, then communication quality improves, but NLE-induced spectral deformations worsen
Solution Approach 1:
The patent implements a feedback mechanism where the measured spectral deformation information is fed back into the OSNR calculation process. By continuously monitoring the actual spectrum shape at multiple wavelengths and adjusting the OSNR calculation accordingly, the system can accurately assess signal quality even when NLEs are present, allowing optimal power settings without compromising measurement accuracy.
Solution Approach 2:
The patent changes the measurement parameters by introducing additional wavelength regions and measuring both signal power and spectral shape characteristics. This parameter expansion allows the system to distinguish between signal degradation due to NLEs and actual OSNR degradation, enabling reliable quality assessment at high power levels where NLEs are significant.
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 enables accurate determination of OSNR and characterization of signal deformations, improving the assessment of signal quality in optical communication systems by accounting for NLE-induced effects, thereby enhancing Bit Error Rate (BER) performance.
Implementation Method 1
an optical filter unit, configured to filter a channel to be detected and obtain a signal power P1 of a first optical signal at a detection point
Implementation Method 2
an opto-electrical conversion unit, configured to convert the signal power P1, the signal power P2 and the signal power P3 to respective electrical signals
Data Source
AI summary
There are provided methods and devices for determining a quality parameter characterizing an optical communication signal, the methods being performed by signal detection devices. At the transmitting end, there are obtained a signal power P1 of a first optical signal, a signal power P2 of a second optical signal, a signal power P3 of a third optical signal, optionally a signal power P4 of a fourth optical signal, and a total signal power Ps of a channel where the first, second, third and optional fourth optical signals are located. At a detection point, there are further obtained a signal power P1′ of the first optical signal, a signal power P2′ of the second optical signal, a signal power P3′ of the third optical signal and optionally a signal power P4′ of the fourth optical signal. There are then determined a signal deformation factor SDF and/or an optical signal to ASE noise ratio OSNR from the obtained signal powers.