Research on reflective cone-cylinder-TFBG refractive index sensor

In the fields of brewing and pharmacy, the refractive index is an important reference. The reflective cone-cylinder, named fiber bragg grating (TFBG) fiber sensing system, was built in this paper. The cone-cylinder TFBG sensing structure was simulated using COMSOL and the light leakage of common cone structure was analyzed. Compared with different sizes cone-cylinder TFBG, the cone waist diameter with 45um and the gating length of 20mm were selected. The refractive index experiment of sodium chloride solution was carried out with a sensitivity of 7.4188 nm/RIU, and the linear fit reached 0.9906. The performance and feasibility of the sensor structure were verified by the refractive index experimental results of sodium chloride solution. To observe the change of reflectance spectrum, the E.coliTG1 growth state was monitored. The results show that the bacterial concentration was measured through the reflective cone-cylinder TFBG sensing system.