Optical Spectrum Analyzer Resolution Correction for OSNR Precision
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Solution Overview
Problem
The existing optical signal-to-noise ratio (OSNR) measurement methods using optical spectrum analyzers (OSA) suffer from low precision due to differences between setting and actual spectral resolutions, caused by mechanical adjustments and environmental changes.
Innovation Solution
A method that corrects spectral resolution by obtaining actual power of broad spectrum signals, measuring their spectra, fitting corrected resolutions using the least squares method, and replacing setting resolutions with corrected ones to enhance OSNR measurement precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If setting resolution of OSA is used for OSNR measurement, then measurement process is simple, but measurement precision deteriorates due to difference between setting and actual resolution
Solution Approach 1:
The patent applies preliminary action by pre-calibrating the relationship between setting resolution and actual resolution through measuring known test signals with precise power values. This calibration data is stored and used to correct subsequent OSNR measurements, eliminating the need for real-time complex corrections while maintaining high precision.
Solution Approach 2:
The patent replaces the mechanical/physical resolution limitation of the OSA with a computational correction system. By using software algorithms to calculate and apply resolution correction factors based on calibration data, the system substitutes the physical measurement limitation with an information-processing solution.
2Measurement precision
If corrected resolution method is used to improve OSNR measurement precision, then measurement precision is improved, but device complexity increases due to additional calibration and calculation steps
Solution Approach 1:
The calibration process is performed once in advance to establish the correction relationship, and the results are stored for repeated use. This preliminary action separates the complex calibration work from routine measurements, making the operational system simple despite the sophisticated correction methodology.
Solution Approach 2:
The system performs self-calibration using internal test signals with known characteristics. The OSA measures these reference signals and automatically generates correction factors without requiring external calibration equipment or manual intervention, making the system self-sufficient and reducing operational complexity.
3Adaptability or versatility
If out-of-band monitoring method is used for OSNR measurement, then service interruption is avoided, but measurement precision deteriorates due to interchannel noise
Solution Approach 1:
The patent replaces the physical limitation of out-of-band noise measurement with a computational approach. By using calibration data to correct the measured power values and calculate actual resolution effects, the system compensates for interchannel noise interference through information processing rather than physical isolation.
Solution Approach 2:
The patent changes the measurement parameters by using corrected resolution values and calibrated power relationships to recalculate OSNR from the raw measurement data. This parameter transformation allows the system to extract accurate OSNR information even when the raw measurements are contaminated by interchannel noise.
Data Source
AI summary
A method for enhancing optical signal-to-noise ratio measuring precision by correcting spectral resolution is provided, which can obtain optical signal-to-noise ratio with enhanced measuring precision, by measuring actual power of broad spectrum signals in a certain bandwidth, determining the sum of the power of the sampling points for the broad spectrum signals in the bandwidth by using an optical spectrum analyzer, obtaining the corrected resolution of the optical spectrum analyzer, and replacing the setting resolution of the optical spectrum analyzer with the corrected resolution. The method can effectively solve the problem of large OSNR measuring error resulted from the difference between the setting resolution and the actual resolution of optical spectrum analyzer. The method is applicable to correct resolution for all optical spectrum analyzers, and also applicable to enhance the measuring precision for all OSNR measuring methods based on spectrum analysis, and has the advantages of easiness to handle and implement.