FDTD analysis of photonic crystals with square symmetry and defects

Photonic crystals (PhCs), due to their special property of forbidding the light propagation in a certain direction and in a specific frequency range, offer the possibility of creating many efficient applications in electronics and optoelectronics. In this paper we investigate the properties of 2D PhCs related with their potential application in active and passive electronic device design using numerical simulations. Calculation of the properties for several devices and circuits based on 2D PhCs were performed using FDTD algorithms. We focused on point defects states and defects inserted in waveguides. Being known that the light can easily propagate in bent waveguides, we generated optical guides with enhanced transmission by cleverly tuning the defect profile. As basic element was used air and for building periodical structures with square symmetry different designs were used. The efficiency of these devices and circuits was studied for a propagating radiation of 1.55µm wavelength, which lies in the frequency range of a forbidden photonic band gap. The network period was chosen to be 1 µm and the radius of all elements was r = 0,3*a