A Differential Intensity-Modulated Refractive Index Sensor Using a Droplet-Like Fiber Cascaded With FBGs.

An intensity-modulated refractive index (RI) sensor based on a bending single-mode fiber (BSF) cascaded with fiber Bragg gratings (FBGs) is designed and experimentally investigated. The BSF structure can be easily fabricated by bending a section of single-mode fiber without coating, which is immersed in the RI matching solution. The different values of RI can be measured by monitoring the variation of the intensity difference of transmission dips of two FBGs. The experimental results show that the RI sensitivity of the proposed sensor is 413.23 dB/RIU in the sensing range from 1.333 to 1.371. In addition, the designed sensing system also shows a certain resistance to temperature cross-sensitivity and the fluctuation of light source, which can make a significant directive role in the field of food safety, biochemistry and environmental science. [ABSTRACT FROM AUTHOR]