A new design of an optical fiber coupler constituted by two and three cores based on Step Index Holey Fiber (SIHF) is proposed and analyzed by an efficient Vectorial Beam Propagation Method (VBPM) in conjunction with Genetic Algorithm ( GA). The fiber is made from pure silica and germanium doped silica and contains two or three identical cores with index holey separated by a distance ℓ. The proposed structures exhibit a very simple geometry, easy of fabrication, and each fiber that composes the coupler is obtained through the inclusion of a very small air hole at the core of one conventional step index fiber. Firstly, we consider the coupler constituted by two cores and the signal power launched in the left core is completely transferred to neighbor core with 100 % of the coupling ratio. Next, we consider the coupler constituted from three cores and the signal power launched in the central core is transferred to neighboring cores with 50 % of the coupling ratio.