Design of a salinity sensor based on long-period fiber grating for aquatic environment

This study proposes a simulation-based methodology for the design and analysis of a salinity sensor utilizing Long Period Fiber Grating (LPFG) technology. LPFGs offer a promising platform for sensing applications due to their sensitivity to changes in refractive index. We focus on designing and evaluating the performance of an LPFG-based salinity sensor for measuring seawater concentration. By employing the Transfer Matrix Method for sensor design and leveraging the Coupled Mode Theory (CMT), which underpins LPFG modeling, we investigate the sensor’s response to varying salinity levels. Thesensitivity of the designed sensor is reported as $1776 \mathrm{~nm} /$ RIU ($0.3189 \mathrm{~nm} / \%$).