Review and Analysis of Peak Tracking Techniques for Fiber Bragg Grating Sensors

Abstract

Fiber Bragg Grating (FBG) sensors are among the most popular elements for fiber optic sensor networks used for the direct measurement of temperature and strain. Modern FBG interrogation setups measure the FBG spectrum in real-time, and determine the shift of the Bragg wavelength of the FBG in order to estimate the physical parameters. The problem of determining the peak wavelength of the FBG from a spectral measurement limited in resolution and noise, is referred as the peak-tracking problem. In this work, the several peak-tracking approaches are reviewed and classified, outlining their algorithmic implementations: the methods based on direct estimation, interpolation, correlation, resampling, transforms, and optimization are discussed in all their proposed implementations. Then, a simulation based on coupled-mode theory compares the performance of the main peak-tracking methods, in terms of accuracy and signal to noise ratio resilience.

Machine Learning Assisted Fiber Bragg Grating-Based Temperature Sensing

“…In order to realize a practical sensing system using this technology, the small shift in Bragg wavelength caused by the measurand has to be detected. Most of the conventional ways of doing this uses peak tracking methods [4]. These methods can be categorized into the [4]:…”

“…Most of the conventional ways of doing this uses peak tracking methods [4]. These methods can be categorized into the [4]:…”

“…• Optimization-based technique, where a model is optimized to the data. Some interesting properties of these methods are that the direct and curve fitting methods work well for fast interrogation, and the correlation-based methods are very robust to noise [4]. However, the detection accuracy of these methods is limited especially where the FBG spectrum has few sample points.…”

“…This regime is useful to make faster interrogation as the measurement takes less time. Other signal processing methods, e.g., Karhunen-Loeve transform based algorithms [5], have been proposed to improve the detection accuracy in this regime, but these methods are intrinsically limited to a small spectral range, computational intensive and have low tolerance to spectral deformations of the FBG [4].…”

Novel Fiber Grating for Sensing Applications

“…Additionally, the FBG could also be used as a tool of the peak tracking method because of its narrow‐band spectrum. Tosi summarized several peak tracking methods based on FBGs.…”