Optical Signal Quality Measurement Using Wavelength Selective Switches
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Solution Overview
Problem
Current methods for measuring optical signal-to-noise ratio (OSNR) in optical networks are inaccurate due to reliance on predetermined parameters, and existing solutions either fail to measure OSNR within transmission paths or increase costs through the use of monitoring devices.
Innovation Solution
A signal quality measurement device that sets passbands for wavelength selective switches and calculates OSNR by detecting powers of optical signals and amplified spontaneous emissions across multiple amplifiers, allowing for precise OSNR measurement at various points in the transmission path without the need for monitoring devices at each site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If monitoring devices are installed at different sites in the transmission path to measure OSNR, then measurement capability is improved, but cost increases
Solution Approach 1:
The existing wavelength selective switches and optical amplifiers in the transmission path are made to serve the measurement function. The wavelength selective switches perform both signal routing and spectral filtering for measurement, while optical amplifiers provide both signal amplification and generate the ASE noise spectrum that is measured. This eliminates the need for separate monitoring devices at multiple sites.
Solution Approach 2:
Existing network components (wavelength selective switches and optical amplifiers) are utilized for dual purposes: their primary functions (signal routing and amplification) plus the additional function of enabling OSNR measurement. The wavelength selective switches filter signals for power measurement, and optical amplifiers provide both signal boosting and noise generation for comprehensive OSNR assessment throughout the transmission path.
2Productivity
If predetermined parameters are used for network design, then design process is simplified, but accuracy decreases
Solution Approach 1:
The patent replaces the manual/measured approach of obtaining OSNR values (which would require physical measurements at multiple points) with an automated calculation system. The calculating unit automatically computes OSNR values by processing power measurements from wavelength selective switches and noise spectrum measurements from optical amplifiers, eliminating the need for predetermined parameters while maintaining high productivity.
3Device complexity
If OSNR is measured only at transmitter and receiver, then measurement simplicity is maintained, but measurement completeness is reduced
Solution Approach 1:
The transmission path is divided into multiple measurement segments corresponding to different wavelength selective switches and optical amplifiers. Each segment's OSNR is measured and calculated separately, providing comprehensive coverage of the entire transmission path. This segmentation enables detection of quality degradation at specific points without requiring complex monitoring infrastructure throughout.
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 enhances the accuracy of network design by enabling precise OSNR measurement along transmission paths, reducing costs by eliminating the need for extensive monitoring infrastructure and improving the reliability of network performance assessments.
Implementation Method 1
a first power of an optical component in a first wavelength band including a center wavelength of the optical signal received by the receiver, and a second power of an optical component in a second wavelength band adjacent to the first wavelength band
Implementation Method 2
the quality of an optical signal that is transmitted from a transmitter, passes through wavelength selective switches and optical amplifiers
Implementation Method 3
the calculating unit detects a combined power of various amplified spontaneous emissions of the optical amplifiers from the second power
Data Source
AI summary
A signal quality measurement device includes: a setting processing unit that sets respective passbands of WSSs; and a calculating unit that calculates quality of an optical signal by acquiring a first power of an optical component in a first wavelength band, and a second power of an optical component in a second wavelength band adjacent to the first wavelength band. When the setting processing unit sets each of the passbands of the WWSs, the calculating unit detects a combined power of various ASEs of the optical amplifiers from the second power, and detects the power of the optical signal from the first power and the second power. When the setting processing unit sets the passband of one of the WSSs, the calculating unit detects, from the second power, the ASE of an optical amplifier existing between one of the wavelength selective switches and the receiver.