Abstract
A new D-type fiber optic sensor based on silicon/graphene hybrid structure is proposed. The refractive index variations are detected with phase difference changes instead of the conventional intensity and spectral variations. An ultrahigh phase sensitivity of 1:3716 x 10(6) deg=RIU (RIU: refractive index unit) was achieved, which is 3447fold and 380-fold higher than that of fiber optic sensor without silicon/graphene coating, and with only silicon coating, respectively. This phase sensitivity enhancement factor is depending on the incident angle. The phase sensitivity decreases with the incident angle, height of fiber core, while increases with the length of sensing region.