A new design of a directional coupling based on Photonic Quasi-Crystals Fiber with extended core

A new design of an optical fiber constituted from photonic quasi-crystals is applied in the development of a dual-core coupler. The structure is composed of pure silica, and is obtained from twelve-fold distributions of air holes arranged symmetrically with defects caused by drawing of air holes to form two identical cores equidistant from the air hole localized in the center of the fiber. The power launched into the core located on the left side of the fiber is completely transferred to the right core for the propagation distance around of 7.60 cm. The validation of the design is ensured with an accurate Photonic Quasi-Crystal Fiber analysis based on finite element and the vectorial beam propagation method.