New design of an optical diplexer based on Core-shell rods defect in photonic-crystal

This work investigates a novel design of an optical Y and T-junctions diplexer based on photonic crystal appropriate for an optical communication network. We used two core/shell (C/S) rods to select two communication wavelengths, 1.49μm, and 1.55 μm. The C/S rod is formed by etching a circular hole in the center of the silicon particle. A cubic lattice of Si rods immersed in the air is used for Y- and T-shaped platforms. The Finite Difference Time Domain (FDTD) method is chosen to simulate the properties of the suggested device. We demonstrated that selecting two wavelength channels may be achieved by adjusting the values for the inner and outer radius of the C/S rods. The results show that Y and T-shaped diplexer’s average transmission efficiency is 99.65% and 99%, respectively. Moreover, the total footprints of the Y and T-branch diplexers are 124.85 μm
²
and 134.59 μm
²
, accordingly. Photonic integrated devices with small sizes and simple designs can profit from their use in fiber-to-the-home (FTTH) transmission systems and network applications.