Comparison between polyimide coated fiber grating and hydrogel coated long period grating for measuring sugar and salt concentration

In this paper, we compared the sensitivity and response time of polyimide (PI-2525) coated fiber Bragg grating and hydrogel (agarose) coated long period grating in respect to sugar and salt concentration measurement. This hydrogel coated long period grating is used for the first time for measuring sugar and salt concentration and it shows high sensitivity and good response time as compared to fiber Bragg grating based sensor.