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A Random-displacement Measurement by Combining a Magnetic Scale and Two Fiber Bragg Gratings
Published on: September 30, 2019
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Evaluation of fiber Bragg grating sensor interrogation using InGaAs linear detector arrays and Gaussian approximation
Saurabh Kumar1, Bharadwaj Amrutur2, Sundarrajan Asokan1
1Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012, India.
The Review of Scientific Instruments
|March 3, 2018
Summary
Interrogation systems using InGaAs linear detector arrays offer a cost-effective solution for Fiber Bragg Grating (FBG) sensing. This study optimizes curve-fitting algorithms for improved accuracy in FBG wavelength shift detection.
Area of Science:
- Optical Engineering
- Sensor Technology
- Signal Processing
Background:
- Fiber Bragg Grating (FBG) sensors are crucial for structural health monitoring, biomedical engineering, and robotics.
- Effective FBG interrogation systems are vital for widespread adoption, influencing sensor count per fiber and distance.
- InGaAs linear detector array systems are suitable for applications requiring few sensors and short distances, but their resolution depends on curve-fitting algorithms.
Purpose of the Study:
- To analyze the impact of algorithm choice and pixel count on curve-fitting errors in FBG spectrum analysis.
- To identify conditions leading to maximum errors in wavelength shift detection.
- To evaluate a computationally efficient algorithm for FBG interrogation.
Main Methods:
- Detailed analysis of algorithm choice using Gaussian approximation for FBG spectra.
- Investigation of the effect of pixel count on curve-fitting accuracy.
- Comparison of wavelength shift detection errors against a tunable swept laser interrogation system.
Main Results:
- Maximum errors in wavelength shift detection occur when the shift causes one new pixel to be included in curve fitting.
- A computationally less expensive algorithm achieves comparable accuracy to iterative non-linear least squares estimation.
- Implementation on embedded hardware resulted in an approximate six-fold speed-up.
Conclusions:
- Optimized curve-fitting algorithms can enhance the accuracy and efficiency of InGaAs linear detector array-based FBG interrogation systems.
- The identified error-prone conditions provide insights for system design and algorithm selection.
- A faster, accurate algorithm suitable for embedded applications has been demonstrated.
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