The effect of grating period on refractive index sensitivity of long period gratings written in hydrogen loaded SMF-28 fiber

摘要

In this paper, the influence of grating period of Long Period Grating (LPG) on refractive index sensitivity is experimentally investigated. Two LPGs with grating periods 415 μm and 550 μm are used to carry out the experimental study. The fundamental principle of analysis is the sensitive dependence of the resonance peaks of an LPG on the changes in the refractive index of the medium surrounding the cladding surface of the grating. The response of the LPG to refractive indices greater than and less than that of cladding is studied by monitoring the wave length shift and amplitude changes of the attenuation bands.