OFDR Spectrogram Filtering for Laser Phase Noise Reduction
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Solution Overview
Problem
Existing optical frequency domain reflectometry (OFDR) systems face issues with phase noise from lasers affecting reproducibility and spectrum structure variation, complicating reception systems and prolonging analysis time.
Innovation Solution
An optical spectrogram is generated, representing a temporal change in frequency characteristics, using a plurality of spectral data measured by an OFDR measurement instrument at different times, and filtering the optical spectrogram in both a time and a frequency direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase noise monitoring is added to compensate for laser phase noise, then measurement precision is improved, but device complexity increases and analysis time is prolonged
Solution Approach 1:
The patent extracts and removes the harmful phase noise component from the spectral data through filtering operations. By identifying and eliminating the phase noise contribution, the system achieves accurate temperature and strain sensing without requiring additional monitoring channels, thus avoiding increased device complexity while maintaining measurement precision.
Solution Approach 2:
The patent introduces a filtering operation as an intermediary step between the raw spectral data and the final measurement results. This intermediary filtering process removes phase noise effects without requiring additional sensing channels or complex reception system modifications, effectively mediating between the noisy measurements and the accurate results.
2Measurement precision
If phase noise monitoring is added to compensate for laser phase noise, then measurement precision is improved, but analysis time is prolonged
Solution Approach 1:
The patent performs preliminary filtering operations on the spectral data to remove phase noise effects before the actual temperature and strain analysis. By preparing the data in advance through filtering, the system avoids time-consuming phase noise compensation calculations during the measurement analysis, thus reducing overall analysis time while maintaining precision.
Solution Approach 2:
The patent extracts and removes the harmful phase noise component from the spectral data through filtering operations. By identifying and eliminating the phase noise contribution, the system achieves accurate temperature and strain sensing without requiring additional monitoring channels, thus avoiding increased device complexity while maintaining measurement precision.
3Measurement precision
If spectral data is processed to remove phase noise, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent changes the parameters of the spectral data through filtering operations, transforming the raw spectral measurements into processed data with reduced phase noise. By adjusting and optimizing filtering parameters, the system achieves precise spectral shift analysis while keeping the processing algorithm simple and manageable, avoiding excessive device complexity.
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
The optical spectrogram, representing a temporal change in frequency characteristics, using a plurality of spectral data measured by an OFDR measurement instrument at different times, and filtering the optical spectrogram in both a time and a frequency direction.
Implementation Method 1
measuring time-series data (spectrogram) of a spectrum of Rayleigh backscattered light in an optical fiber
Implementation Method 2
using optical frequency domain reflectometry (OFDR), and by analyzing a spectral shift
Implementation Method 3
filters the optical spectrogram in both a time direction and a frequency direction
Data Source
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AI summary
An object of the present disclosure is to reduce measurement instrument noise without complicating a reception system nor prolonging an analysis time. The present disclosure generates an optical spectrogram, representing a temporal change in frequency characteristics, using a plurality of spectral data measured by an OFDR measurement instrument at different times, and filters the optical spectrogram in both a time direction and a frequency direction.