Sensitivity Enhanced Refractive Index Sensor With In-Line Fiber Mach-Zehnder Interferometer Based on Double-Peanut and Er-Doped Fiber Taper Structure

• DOI: 10.1109/jlt.2021.3118285
• Publication Date: 2021-10-07T02:49:29Z
• Authors: Fang Zhao; Dongrui Xiao; Weihao Lin; Yun Chen; Guoqing Wang; Jie Hu; Shuaiqi Liu; Feihong Yu; Weijie Xu; Xiaolu Yang; Liu Yibin; Li-Yang Shao; Perry Ping Shum; Weizhi Wang
• Keywords: Cladding (metalworking); Fusion splicing; Normalized frequency (unit); Cladding mode

A fiber-optic Mach Zehnder interferometer (MZI) refractive index (RI) sensor based on a double peanut-shaped structure in Er-doped fiber with section of tapered was fabricated using fusion splicer and experimentally demonstrated. The structures placed at both ends the function as beam splitting/combining. Besides, region works sensing area. With RI changes, optical path difference between core mode cladding modes will change correspondingly, resulting interference spectrum shifting. By monitoring shift, measured can be obtained. experimental results show that sensitivity significantly improved compared other types sensors. comparing different taper diameters, it is found finer fiber, higher measuring RI.High 441.56 nm/RIU obtained experiments. Compared similar-structure consisted single-mode (SMF), proposed 115.22 than former. has characteristics compact structure. In addition, potential environmental, medical, aerospace applications.