Optical Channel Monitor Filter FWHM Optimization
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Solution Overview
Problem
Conventional optical channel monitors (OCMs) of the polychromator system require a large number of photo detectors to improve resolving power, leading to increased manufacturing costs and reduced dynamic range due to noise interference.
Innovation Solution
An OCM design that includes a demultiplexer with a filter having a Full Width at Half Maximum (FWHM) within a predetermined range, optimized signal band detection, and power correction calculations to enhance resolving power without increasing costs, using a processing section to calculate correction values for optical powers based on demultiplexer characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of photo detectors are used to improve resolving power in a polychromator system, then the resolving power is improved, but the manufacturing cost increases and the dynamic range decreases due to noise interference
Solution Approach 1:
The patent changes the parameter of filter FWHM (Full Width at Half Maximum) to an optimized value within a predetermined range. This parameter optimization allows the system to achieve high resolving power without requiring a large number of photo detectors, thereby reducing device complexity and manufacturing cost while maintaining measurement precision.
Solution Approach 2:
The patent replaces the mechanical approach of using multiple photo detectors with an optimized filter design and signal processing approach. By carefully selecting the filter FWHM parameter and using correction value calculations, the system achieves the same resolving power with fewer photo detectors, substituting a complex mechanical arrangement with a more efficient parameter-optimized system.
2Measurement precision
If a large number of photo detectors are used to improve resolving power, then the resolving power is improved, but the dynamic range decreases due to noise interference
Solution Approach 1:
The patent optimizes the filter FWHM parameter to a specific range that balances resolving power and dynamic range. This parameter change reduces noise interference and improves the dynamic range while maintaining high resolving power, eliminating the trade-off between these two performance metrics.
Solution Approach 2:
The patent implements a feedback mechanism through correction value calculations. The processing section calculates correction values based on the optical signal characteristics and uses these to compensate for noise and improve measurement accuracy. This feedback approach enhances the dynamic range by continuously adjusting for noise interference.
3Measurement precision
If the filter FWHM is reduced to improve resolving power, then the resolving power is improved, but the signal-to-noise ratio deteriorates
Solution Approach 1:
The patent sets the filter FWHM within a predetermined range that optimizes the balance between resolving power and signal-to-noise ratio. This parameter optimization ensures that the filter is narrow enough to provide high resolving power while wide enough to maintain adequate signal strength and reject noise effectively.
Solution Approach 2:
The patent uses correction value calculations as a feedback mechanism to compensate for noise interference. The processing section continuously adjusts and corrects the measured optical power values based on the actual signal characteristics, thereby maintaining high signal-to-noise ratio even with optimized filter settings.
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 improves the dynamic range and accuracy of power detection in the OCM, even in poor signal-to-noise environments, by optimizing signal band detection and reducing noise components, thus enhancing the system's resolving power without increasing manufacturing costs.
Implementation Method 1
a demultiplexer, a plurality of paths, and a processing section. The demultiplexer demultiplexes an input optical signal, which is wavelength-multiplexed, for respective multiplexed wavelengths
Implementation Method 2
receives outputs of the optical filter by a photo detector
Data Source
AI summary
An optical channel monitor includes a demultiplexer, a plurality of paths and a processing section. The demultiplexer demultiplexes an input optical signal, which is wavelength-multiplexed, for respective multiplexed wavelengths to generate a plurality of optical signals. The plurality of paths respectively generate a plurality of digital signals indicating optical powers of the plurality of optical signals. The processing section inputs the plurality of digital signals to calculate correction values of the optical powers, which correspond to characteristics of the demultiplexer. The demultiplexer includes a filter having FMHM (Full With at Half Maximum) within a predetermined range. The predetermined range is set based on a pass center wavelength accuracy of the filter and an oscillation wavelength accuracy of a transponder which generates the input optical signal.