Numerical simulation for photonic bandgap of cuboid structure

Detailed numerical simulations are carried out to envisage the band structure of silicon cuboid (3D) photonic crystal structure is presented in this paper. Photonic bandgap of above cuboid structure are simulated by employing plane wave expansion method. Simulation result revealed that both radius of air holes and lattice spacing of crystal play vital role to realize the photonic bandgap of the cuboid structure. Also present simulation result showed that photonic bandgaps of silicon cuboid structure exist for certain values of lattice spacing; for an example bandgap is observed, if lattice spacing along x-axis varies from 0.7 μm to 1.4 μm and lattice spacing along y and z axis is 1 μm each. Similarly photonic bandgap is found if lattice spacing along y-axis varies from 0.7 μm to 1.1 μm and lattice spacing along x and z axis is 1 μm each. Also, the photonic bandgap is found if the lattice spacing along z-axis varies from 0.8 μm to 2.1 μm and the lattice spacing of x and y axis are taken of 1 μm. Apart from this it is also seen that variation of lower and upper edges of the photonic bandgap is non-linear with respect to aforementioned lattice spacing of cuboid crystal structure.