Theoretical analysis of tuning property of the graphene integrated excessively tilted fiber grating for sensitivity enhancement

Abstract

The graphene integrated optical fiber devices show many excellent characteristics, especially their tunable optical properties. Here we investigate thoroughly the influence of the tuning property of the graphene on the resonance and sensing performance of the excessively tilted fiber grating (Ex-TFG) operating around the dispersion tuning point. An improved piecewise discretization method for the finite-difference mode solver combined with coupling mode theory is presented to explore the general variation rule of mode characteristics and polarization-dependent resonances corresponding to polarized TE/TM0,m and HE/EHv,m modes of the graphene integrated Ex-TFG. The results reveal that both p-polarized and s-polarized modes and their resonances are greatly influenced by the tunable graphene. On this basis, the sensitivity enhancement of the graphene coated Ex-TFG is explored in detail. It is shown that the sensing performance of both polarized cases can be greatly improved by tuning the chemical potential. In particular, the graphene induces a greater influence on both resonance wavelength and resonance strength of the s-polarized mode, but the p-polarized one has a higher sensitivity. We believe that these unique tuning properties make the graphene integrated Ex-TFG devices ideal for the telecommunication and sensing applications, such as tunable fiber modulators and biochemical sensors.