Post Engineering the Efficiency in a Three-Port Add/Drop Filter Based on a Triangular Lattice Air-Hole PhC Platform

In this paper we study the resonant state and transmission characteristics in an infiltrated silicon triangular lattice photonic crystal channel drop filter. The structure is composed of two cavities that are created by increasing the radii and infiltrating with a fluid of specific refractive indices of two holes surrounding the bus waveguide. According to the theoretical analysis, in order to have maximum efficiency, radii of both cavities must be equal. Unavoidable deviation from the desired radius, in creating each cavity in practice, causes the wavelength to deviate from the desired. This, in turn, causes a decrease in the filter efficiency. In this paper, we show that the hole size deviation can be compensated by replacing the liquid into the infiltrated cavities by another liquid with appropriate refractive index. In this manner, efficiency can be maximized.