Title
Wavelet-Based Demodulation of Multimode Etched Fiber Bragg Grating Refractive Index Sensor.
Abstract
Etched fiber Bragg grating (EFBG)-based sensors are used as evanescent field sensors for refractive index detection. When the fiber thickness is thin and the refractive index sensitivity increases, the number of propagating modes increases, resulting in a spectral enlargement that complicates the interrogation of the sensor. In this work, we present a method to analyze the spectrum of a multimode etched fiber Bragg grating (MMEFBG) in the wavelet domain, which analyzes the amount of spectral density independently from the peak reflectivity value. The proposed interrogation method permits defining the integral of the spectral density as a novel and unconventional estimator. With respect to the conventional estimators based on wavelength shift, this estimator can better exploit the larger amount of information given by the spectral enlargement typical of multimode behavior. Results were obtained by etching an MMEFBG in hydrofluoric acid and using water/sucrose mixtures to evaluate the refractive index sensitivity, validating the interrogation method.
Year
DOI
Venue
2019
10.3390/s19010039
SENSORS
Keywords
Field
DocType
Evanescent field sensors,fiber Bragg grating (FBG),optical fiber sensor (OFS),refractive index sensors,wavelet density estimation
Demodulation,Analytical chemistry,Fiber Bragg grating,Fiber,Spectral density,Multi-mode optical fiber,Engineering,Wavelet,Estimator,Refractive index
Journal
Volume
Issue
ISSN
19
1.0
1424-8220
Citations 
PageRank 
References 
0
0.34
0
Authors
7