A new refractive index sensor based on Mach-Zehnder interferometer fabricated by two cascaded single-mode fiber corners

Abstract

We reported two kinds of fiber sensor based on double cascaded single mode fiber corners, which has a high sensitivity for refractive index (RI) sensing. RI sensing was experimentally demonstrated with average sensitivity of 95.5nm/RI unit (RIU) in a RI range from 1.333 to 1.421 and the other is 235nm/RI unit (RIU) from 1.333 to 1.418, which are relatively high among the previously reported similar fiber sensors (e.g., it is about 10 times higher than that of the normal two or three-cascaded-taper based Mach–Zehnder interferometer). Besides, The proposed RI sensors were fabricated only by a fiber fusion splicer. So , the fiber sensor is quite easy to made.