Photonic Crystal Three-Port Channel Drop Filter Based on One-Way Waveguide

We design a highly efficient three-port channel drop filter (CDF) with only one channel drop micro-cavity based on photonic crystal (PC) one-way waveguide. According to the coupled mode theory in time, the conditions to achieve 100% drop efficiency are derived thoroughly. The numerical results are all calculated by using the finite element method, and accord well with the theoretical analysis. Compared with previous three-port CDF based on general dielectric PC, the CDF based on PC one-way waveguide first shows almost complete channel drop tunneling at resonance via only one channel drop micro-cavity without the need for any reflection feedback.