Analysis and optimisation of high-density photonic crystal devices in a subsystem by use of finite difference time domain

Finite-difference time-domain (FDTD) simulation is employed to study Y- and T-junction photonic crystal (PC) components which incorporate defects along the waveguides. In particular, such components designed in silicon with hexagonal lattices of air cylinders are studied, and the FDTD method is used to optimise key design parameters. It is shown that the defects can allow control over power-splitting ratios in these compact structures. Further, the coupling efficiency between the PC T-junction structures and single mode fibre is investigated. Finally, simulations of a PC Mach-Zehnder Interferometer are presented.