The blue-shift of the resonant wavelength with displacement increasing is indeed induced by the increase of fiber curvature. As indicated by TY Wang[6], the refractive index for the core mode and the cladding mode , of the curved special fiber become larger relative to a straight one. However, for the proposed special fiber,the thickness of the outer cladding is much larger than the radius of fiber core, thus the increment of effective index for the cladding modes is much larger than that for the core mode. As a result, the phase-matching resonant wavelength shifts to shorter wavelength.