novel fourchannel all optical demultiplexer based on square phcrr for using wdm applications

Ring resonators have always been referred to as a highly flexible structure for designing optical devices. in this study, we have designed and simulation a four channel optical demultiplexer using square photonic crystal ring resonator. the square lattice constant for this purpose structure is used. the purposed structure has an average crosstalk, transmission coefficient, quality factor and channel spacing of -14.5 db, 90%, 858 and 1.6 nm, respectively. to obtain the photonic band gap of the structure, the plane wave expansion (pwe) method has been used and the finite-difference time-domain (fdtd) method has been also used to analyze the optical behavior of the structure. the good results obtained from designing and simulating optical demultiplexer structure such as narrower channel spacing indicate the high flexibility of this structure and ring resonator for being used in designing optical devices as well as their suitability for being used in wavelength division multiplexing (wdm) systems.