REFRACTIVE INDEX SENSOR BASED ON MACH-ZEHNDER INTERFEROMETER FORMED BY TWO CASCADED SINGLE MODE FIBER CORNERS

摘要

We reported a novel fiber sensor based on two cascaded single mode fiber corners, which has a high sensitivity for refractive index (RI) sensing and a low temperature crosstalk. RI sensing was experimentally demonstrated with an average sensitivity of 235 nm/RI unit in a RI range from 1.333 to 1.418, which is 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). The proposed RI sensor was fabricated by fiber fusion splicer, where the fiber corner was fabricated by splicing the two overlapping single mode fibers, which ensures that the proposed RI sensor is compact and strong.