Monolayer Detection Using Etched-core Fiber Bragg Grating Sensors

In this paper, we show that the fiber Bragg grating sensor can be used to detect and differentiate the number of layers that are deposited on the fiber surface. A theory was developed for calculating the wavelength change as thin films of biological and chemical layers are immobilized on the surface of the fiber in the presence of a surrounding medium. A theory is developed and verified experimentally using immobilization of 3-aminopropyl-triethoxysilane (APTES) and 3-aminopropyl-ethoxysilane (APES) on the surface of the fiber and in-situ monitoring of the Bragg wavelength during surface functionalization