Design of an integrated optical demultiplexer based on photonic crystals using ring resonators and resonant cavities

In this paper, a novel optical demultiplexer based on two-dimensional photonic crystals is proposed. At first, we design a 1⨯4 demultiplexer then we try to increase the number of channels to 6 using line defects and resonant cavities. The final part of our work is increasing the number of channels to 8 by employing photonic crystal ring resonators. After each part we calculate the crosstalk values of channels, it has been showed that crosstalk value of the proposed device is fine enough. Basic structure of our proposed demultiplexer is hexagonal and made from 676 Gallium(III) phosphide rods immersed in the air in x and z directions. The cross-section of our demultiplexer is 248.2μm2 (14.6μm*17μm) which is suitable for integrated optical circuits. It has to be mentioned that our proposed device is totally suitable for WDM (wavelength division multiplexing) and DWDM (dense wavelength division multiplexing) communication.