A new optical add–drop filter based on two-dimensional photonic crystal ring resonator

In this paper, a new optical add–drop filter (OADF) based on two-dimensional photonic crystal ring resonator (2D PCRR) is proposed. The filter is designed in two-dimensional photonic crystals (2D PCs) with triangular lattice of silicon rods in air. Using the finite-difference time-domain (FDTD) technique, 100% forward dropping efficiency can be achieved at maximum transfer efficiency while the operating wavelength is 1550 nm. Moreover, the effects of changing the dielectric constant of whole rods and coupling rods of the structure as well as radius of whole rods and coupling rods are discussed. The overall size of the structure is 10.9 μm × 10.3 μm. The proposed device could be used as an optical add–drop filter (OADF) and has the ability to be highly suitable for integration.