▎ 摘　　要

An optical sensor composed of a circular cylindrical fiber surrounded by graphene layer is investigated. The thin layer of graphene is located at the core-cladding interface. The cladding is an aqueous material. The conductivity (sigma) of the graphene layer is taken as sigma = sigma' + j sigma '', where sigma' and sigma '' is the real and imaginary parts of the conductivity. We consider TE waves to propagate in the structure. Using Maxwell's equations, the dispersion relation is derived. Also, the sensitivity of the effective refractive index to any changes in the aqueous cladding refractive index is deduced. It is found that the sensitivity of the proposed optical fiber can be dramatically improved with the variation of graphene layer conductivity.