Cladless optical fiber sensor based on evanescent wave absorption for monitoring methylene blue induced water pollution

Abstract

In this paper, we present a fabricated cladless optical fiber sensor to analyze distilled water solution polluted with methylene blue (MB). The fabricated sensor is based on evanescent wave absorption by the surrounding medium at the core–liquid cladding interface. The response of the optical fiber sensor is mainly related to the MB concentration as well as its refractive index. A theoretical and experimental investigation is carried out to investigate the sensitivity of the proposed sensor. The results show that the designed sensor provides a significant response to the concentration range of 6–50 mg/L.