Sensitivity analysis of a dispersed clad mode to surrounding refractive index

The sensitivity of a specific dispersed clad mode and a normal clad mode of a Long Period Grating (LPG) near Turn Around Point (TAP) to surrounding refractive index in the range of 1.3332 - 1.3348 has been studied experimentally. We could attain a sensitivity of ~2413 nm/RIU using LP
_{0, 11}
dispersed clad mode of a TAP-LPG with ~3dB attenuation at resonance.