Investigation of Long Period Grating as refractive index sensor

In this paper, we have theoretically and experimentally investigated the response of Long Period Grating (LPG) as refractive index sensor. The response has been checked for the refractive index ranging from 1 to 1.458. It was found that the experimental results are very close to the theoretically simulated results. The ambient refractive index response of an LPG over a much wider index range has been modeled for values both less and more than the cladding refractive index