Optimization and Performance Evaluation of Apodization Function for Fiber Bragg Grating as Vital Sign Sensor

Abstract

AbstractSensing is the recent and most widely executed implementation of Fiber Bragg Grating (FBG). In this paper, a comprehensive investigation of various apodization functions based on Reflectivity, Maximum side lobe (MSL), Side lobe suppression ratio (SLSR), Full width Half maximum (FWHM), Sensitivity, Detection Accuracy and Quality parameter are evaluated and a novel apodization function was proposed which can be implemented in FBG to use it as vital sign sensor for measuring temperature and heart rate. The simulations were carried out for the grating parameters of L = 10 mm and ∆n = 0.0001. From the results, peak reflectivity of −0.564754 dB was achieved in Uniform apodization function but it also has larger side lobe level and less sensitivity. The highest side lobe suppression ratio was achieved by Gaussian function which is −32.58601 dB. Based on the sensing characteristics, the proposed apodization function has lower FWHM of 0.06 nm and the highest sensitivity of 5.9698AU/RIU, thus having a better detection accuracy of 26,114. Higher sensitivity and narrow FWHM, leads to greater quality parameter of 99.49667 AU/nm-RIU which is a desirable characteristics of sensor. Also the proposed function proved to have better wavelength shift for the measurement of heart rate and temperature compared to other apodizations with 1.3 pm/µε and 13 pm/°C.KeywordsApodizationFiber Bragg gratingOptical sensorSensitivityStrainTemperature