Unit Cell Topology Optimization of Line Defect Photonic Crystal Waveguide

In this paper we utilize a systematic method to optimize the topology of a line defect Photonic Crystal Wave guide (PCW), a very popular and effective optical device for realizing optical buffer in room temperate operation. In order to do this, we divide the unit cell PCW to 25 squares and utilize a Binary Particle Swarm Optimization (BPSO) algorithm to find the optimum topology. During the optimization process, we apply some constraints to avoid band mixing as well. Calculation results show that Normalized Delay-Bandwidth Product (NDBP) for the structure optimized is 0.27. This structure optimized possesses a high bandwidth (20.9 nm) with group index of 21.7 as well.