High Sensitivity Tapered LPFG Fiber Refractive Index Sensor Based on Dispersion Turning Point

A tapered LPFG sensor with high sensitivity to environmental changes has been designed utilizing the dispersion turning point (DTP). The sensitivity of the conical LPFG sensor with different periods is simulated, and it is found that the sensitivity of the sensor increases when the grating period is close to the DTP. In the experiment, a tapered LPFG was fabricated using a carbon dioxide laser, and the sensitivity of the sensor reached 539.7 nm/RIU in the SRI range of 1.3-1.34, which is consistent with the simulation results.