High-Sensitivity Salinity Sensor Based on Helical Long-Period Fiber Grating in Thin-Cladding Fiber

• DOI: 10.1109/jlt.2024.3396572
• Publication Date: 2024-05-03T18:44:19Z
• Authors: Yunhe Zhao; Ziyang Hua; Mengying Hu; Siyu Chen; Chengbo Mou; Yunqi Liu; Zuyuan He
• Keywords: Cladding mode; Cladding (metalworking); Long-period fiber grating; Fiber Bragg Grating

In this paper, we demonstrate a detailed investigation of the high-performance helical long-period fiber grating (HLPFG) near dispersion turning point (DTP) based on thin-cladding (TCF). The LP17 mode DTP can be generated by CO2-laser-inscribed TCF-HLPFG, whose transmissive properties have been studied theoretically and experimentally. With period 140 μm, TCF-HLPFG could obtained at presents high-sensitivity refractive index (RI) sensing ability that maximum RI sensitivity −14962.4 nm/RIU achieved. Furthermore, temperature characteristics proposed are investigated. changing from 20 to 80°C, demonstrates highest −1.14 nm/°C for 137.5 μm ultra-low wavelength shifts respectively. insensitive property makes it useful eliminating cross-sensitivity temperature. Meanwhile, experimental results salinity 0.87 nm/‰ achieved when increases 5‰ 50‰. potential environmental monitoring.