Wide-band low cross-talk photonic crystal waveguide intersections using self-collimation phenomenon

In this paper, wide-bandwidth low cross-talk W1 photonic crystal waveguide intersections are proposed based on self-collimation effect. The waveguides are realized using a 2D square lattice of GaAs rods in an air background. A second photonic crystal lattice is inserted in the intersection region which provides the self-collimation effect and eliminates the cross-talk. The region between the two lattices is optimized in this paper to produce the highest transmittance and widest bandwidth. Consequently, several waveguide intersections are designed based on the proposed method. Each has a different bandwidth and central wavelength. Due to their unique features such as the wide bandwidth, the low cross-talk value and having high transmittances, such structures have a variety of applications in highly integrated optical circuits which are realized based on photonic crystals. Plane wave expansion and finite difference time domain methods are used to analyze the structures. Simulation results show that a bandwidth of 124 nm and a maximum transmission value of 99% can be obtained using the proposed method.