A Refractive Index Sensor Based on the Tapering Theory

Abstract

A refractive index (RI) sensor has been realized to measure RI, hardly affected by temperature. A fused biconical taper machine is used to receive two same diameter tapers, which are cascaded by a fusion splicer. This paper studies the spectral characteristics of the RI sensor with a different bending angle in tapers, and finds that with the increase of bending angle (from 0° to 100°), the extinction ratio will be improved while the spectrum moved down. When two tapers are bent to 90°, the RI sensor can serve as a sensing probe (the RI sensitivity was ~126.15 nm/RIU). The RI sensor has significant applications, and the measurement error is <;1%.