OSNR Detection Using Wavelength Label Modulation Depth
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Solution Overview
Problem
Current methods for detecting the optical signal-to-noise ratio (OSNR) in high-rate optical signals, such as 40G or 100G, particularly for polarization multiplexed signals, are complex and not suitable for wide-range flexible use in Reconfigurable Optical Add-Drop Multiplexer (ROADM) systems, as they require complicated calibration and algorithms.
Innovation Solution
A method and system that load a wavelength label signal into an optical signal, allowing an OSNR detector to analyze the modulation depth of the wavelength label signal to calculate the OSNR, eliminating the need for modulation code type consideration and simplifying the detection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional OSNR detection methods are used for high-rate optical signals, then OSNR measurement can be performed, but the detection process becomes complex requiring calibration and interpolation
Solution Approach 1:
The patent extracts the wavelength label signal from the high-rate optical signal by filtering out the specific wavelength label wavelength component. This separated wavelength label signal contains the modulation depth information needed for OSNR calculation, allowing the measurement to proceed without complex calibration or interpolation algorithms while maintaining accuracy.
2Measurement precision
If polarization extinction or interpolation methods are applied, then OSNR detection can be performed on polarization multiplexed signals, but the method becomes unsuitable for wide-range flexible use in ROADMs
Solution Approach 1:
The patent implements a universal OSNR detection method that works for high-rate optical signals including polarization multiplexed signals without requiring signal-specific processing. By using wavelength label signal modulation depth analysis, the method achieves broad adaptability across different signal types and ROADM configurations, eliminating the need for polarization extinction or interpolation techniques.
3Measurement precision
If narrowband optical tunable filters are used to filter center-passband and offset-passband signals, then OSNR can be calculated from pilot tone and signal strength, but complicated calibration is required
Solution Approach 1:
The patent utilizes the wavelength label signal that is already present in the optical signal, which carries inherent modulation depth information. By analyzing this existing signal component rather than introducing separate pilot tones or requiring external calibration references, the method achieves accurate OSNR calculation without complicated calibration procedures or additional hardware complexity.
Data Source
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AI summary
A method for detecting an optical signal-to-noise ratio (OSNR). A wavelength label loading end (11) loads a wavelength label signal in an optical signal, and sends a loading modulation depth of the wavelength label signal to an OSNR detection end (12) through a wavelength label channel or an optical monitoring channel. The OSNR detection end (12) obtains a loading modulation depth of a wavelength label signal loaded in each wavelength optical signal, parses the wavelength label signal to obtain a current modulation depth of the wavelength label signal, and obtains an OSNR value of each wavelength optical signal according to the loading modulation depth and the current modulation depth of the wavelength label signal. A system and device for detecting an OSNR applicable to OSNR tests of present optical signals with high rates of 40G, 100G, etc., and in particular to OSNR tests of polarization multiplexing optical signals.