Optical Fiber Sensor Length Compensation for Sensitivity Uniformity
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Solution Overview
Problem
Distributed optical fiber sensors face challenges in comparing measurement results from multiple locations due to differences in reception sensitivities caused by varying light transmission loss along the optical fiber, which are affected by the distance from the light source.
Innovation Solution
An optical fiber sensor system with a control section that computes and averages physical quantities based on the intensity of scattered light, compensating for differences in optical fiber length at each measurement location to ensure consistent reception sensitivity across all locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If distributed optical fiber sensing is used to measure multiple locations, then measurement coverage is improved, but reception sensitivity varies across locations due to different light transmission loss
Solution Approach 1:
The patent applies local quality by installing different lengths of optical fiber at different measurement locations. Specifically, locations farther from the light source have longer optical fiber installed, while closer locations have shorter optical fiber. This local variation in optical fiber length compensates for the distance-dependent transmission loss, ensuring that each measurement location receives approximately the same amount of scattered light and achieves uniform reception sensitivity across all measurement points.
2Measurement precision
If optical fiber length is increased for distant measurement locations, then reception sensitivity is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by varying the length parameter of the optical fiber installation at different measurement locations. The control section calculates the appropriate optical fiber length for each location based on its distance from the light source, and the system installs optical fiber with these calculated lengths. This parameter adjustment compensates for transmission loss differences without requiring complex additional components or systems.
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
Facilitates easy comparison of measurement results by making reception sensitivities substantially the same at multiple measurement locations, enabling accurate and consistent data analysis.
Implementation Method 1
The optical fiber is installed at plural measurement locations and is configured to scatter the input light to generate scattered light
Implementation Method 2
The control section may employ Brillouin optical time domain reflectometry (BOTDR) to compute the physical quantity in the optical fiber and to compute the average of the physical quantity
Data Source
AI summary
An optical fiber sensor device includes a control section configured to compute a physical quantity in an optical fiber installed at plural measurement locations based on intensity of scattered light received, and to compute an average of the computed physical quantity for the optical fiber. The control section is configured to compute the average of the physical quantity based on the computed physical quantity and on a length of the optical fiber. A length of the optical fiber installed at the measurement location is increased as a distance between a light source and the respective measurement location increases.