In this paper a silica based all circular air holes photonic crystal fiber is proposed to obtain extremely high negative dispersion and large nonlinearity. By the help of finite element method (FEM) with perfectly matched boundary layer (PML), the light guiding properties of the proposed S-PCF is being studied. Four smallest air holes placed in the gap between two conjugative air holes of the vertex which is also the very first layer closing to center. The proposed highly nonlinear dispersion compensating fiber shows that it is possible to obtain an ultrahigh nonlinearity of 117.3 W ⁻¹ km ⁻¹ and ultrahigh negative dispersion of −1672 ps/(nm.km) at 1550nm wavelength by adopting a smallest number of design parameters. This S-PCF is structured with only circular holes of air which favors us with simple fabrication process. And this S-PCF is advisable for optical back propagation (OBP) pattern due to its highest values and most targetable PCF properties which is also appropriate for long transmission data link of Fiber optics.