Highly sensitive and wide-dynamic-range side-polished fiber-optic taste sensor

In this study, we have developed a highly sensitive, side-polished optical fiber sensor, which is widely used as the primary sensing device in many applications, to detect low concentrations of taste substances. The working principle of the proposed sensor is based on the intensity modulation principle. In our experiment, a sensing membrane was coated on the surface of a single-mode side-polished optical fiber by incorporating six different solvatochromic dyes, polyvinyl chloride, and N,N-dimethylacetamide. When the sensing membrane of the sensor contacts the taste substances, the refractive index of the planar waveguide changes owing to the change in the transfer band of the dye. Therefore, the intensity of the received light changes. The performance of the sensor was assessed by testing six types of taste substances. The sensor exhibited a linear response over concentrations ranging from 1 α/4M to 1 M. Superior response was observed in various contexts. The results indicated that the best sensitivity and linearity averages were observed for R-dye and auramine O, respectively. Furthermore, a fast response time of 90 s and a recovery time of 100 s were obtained at room temperature.