Tapered Optical Fiber Coated with ZnO Nanorods for Detection of Ethanol Concentration in Water

This work presents ZnO nanorods coated multimode optical fiber sensing behavior in response to ethanol solution. The sensor operates based on modulation of light intensity which arises from manipulation of light interaction with the ambient environment in sensing region. For this purpose, two steps are experimentally applied here; etching and then coating fiber with ZnO nanorods to provide stronger evanescent waves causing an enhanced interaction. Long length of fiber (15 mm) was etched uniformly and then well-ordered ZnO nanorods were grown hydrothermally on the core of optical fiber. Fiber coated with ZnO demonstrated an enhanced sensing performances such that response time decreased to 0.6s, linearity increased to 97% and sensitivity improved. Applicable features of the proposed device such as fast response time and high linearity make it favorable candidate for fiber optic sensing applications.