AbstractIn this article, a 2D photonic crystal (PC)-based optical filter has been designed using a PC ring resonator. The resonator used is of square type with a square lattice constant, which has been designed by increasing the radius of the inner rods of the resonator. The filter designed can separate the light of the wavelength of 1545.3 nm with a transmission coefficient of 98 %. The bandwidth of the above wavelength is equal to 0.5 nm and hence the quality factor of the device at this wavelength is equal to 3091. The effects of the structural parameters, such as the refractive index, the lattice constant, the radius of the dielectric rods, the radius of the inner rods of the resonator on the behavior of the proposed device, are fully investigated. To obtain the photonic band gap, the plane wave expansion method is used. In addition, the finite difference time domain method is used to examine, simulate, and to obtain the output spectrum of the structure. The designed structure has both high transmission coefficient and quality factor. Comparatively speaking, it is also simple to design which justifies its use in other photonic crystal-based optical devices.
Theory of ultra-narrow bandwidth optical filter consisting of anomalous dispersion photonic crystal
