Here, we propose an optical filter and an optical power splitter based on two-dimensional
photonic crystal all circular ring resonators. These structures are made of a square lattice of
silicon rods with the refractive index n1=3.464 surrounded by air (with refractive index
n2=1). First, we have designed the filter and by using that, we designed a power splitter. The
transmission efficiency and Quality factor for both, an optical filter and an optical power
splitter, respectively, are more than 90% and 1000. Resonant modes of the all-circular ring
resonator with their corresponding degenerated poles and the transmission spectra are
calculated using the PWE, and 2D-FDTD methods respectively.