Fused Silica Capillary Interferometer with a layer-by-layer Functional Coating for the Analysis of Chemicals Content in Aqueous Solutions

Arun Kumar Mallik, Technological University Dublin
Gerald Farrell, Technological University Dublin
Qiang wu, Technological University Dublin
Yuliya Semenova, Technological University Dublin

European Workshop on Optical Fibre Sensors, EWOFS'2019


A simple fused silica capillary interferometric (FSCI) sensor has been proposed and investigated for the detection and analysis of multiple chemical compounds content in aqueous solutions. The sensor was fabricated by splicing a commercially available fused silica capillary (FSC) with two single mode fibers to create a 0.7 cm long air cavity. The fiber surface was functionalized with two different polymers: poly (allylamine hydrochloride) (PAH) and sol-gel silica in sequence using a layer-by-layer deposition method. The operating principle of the sensor relies on light interference in the fused silica capillary cavity due to adhesion of the different chemical compounds on the functional coating surface. Studies of the sensors response to the presence of five different compounds in water solutions at different concentrations have been carried out and the results have been analyzed using the principal component analysis (PCA). This work is a preliminary investigation towards the development of a novel method for assessment of content and quality of alcoholic beverages in real time using functionalized FSCIs