In this paper, using annular resonator we have designed an adding and dropping filter light based on
two-dimensional photonic crystals. The shape of ring resonator filter adding and dropping that we
have proposed is Race Track. This filter has a hexagonal lattice structure of silicon bars with
refractive index 3/46 that is located in the context of air with refractive index 1. Transmission
efficiency and quality coefficient of our proposed filter are respectively 94% and 310. Finite difference
method in two-dimensional time domain (2-D FDTD) used for normalized transmission spectra of
photonic crystal ring resonator and to calculate the photonic band, plane wave expansion method
(PWE) has been used.