Chemical and Biological Sensing using Nano-Structured Single-Mode Fiber Bragg Grating

In this paper, we report a specified refractive index based sensor which is used to identify different types of chemical and biological materials using a fiber Bragg grating (FBG) structure. In nano- and micro-grating optical fibers, the wavelength of the transmitted and reflected wave would be changed by altering the chemical and biological materials around or inside the fiber Bragg grating, thus the optical property helps to detect the mentioned materials [1,2]. The functionality of this type of label-free optical sensor can be improved by optimizing structures containing a cavity in the middle of Bragg mirrors. Moreover, at the desired position the evanescent wave can be introduced and controlled to interact with these materials and consequently affect the wavelength of the photonic modes. In this paper, design and simulations for the fiber Bragg grating sensor are done by finite element method based Comsol Multiphysics commercial software. Some design strategies have been proposed to measure the reflection wavelength to improve the performance of the sensing system