Optimisation of photonic crystal weveguide based optical filter

Abstract

Photonic integrated circuits (PIC) based on Photonic Crystals are becoming increasingly favoured in emerging signal processing and optical communication technologies. Photonic crystals (PhCs) are periodic dielectric micro/nano structures that inhibit propagation of electromagnetic wave of a certain range of frequencies, therefore introducing a frequency band gap, popularly known as photonic band gap. In this thesis, numerical simulation of a photonic crystal based optical filter or demultiplexer is carried out by the introduction of defect rods in a perfectly periodic photonic crystal, whose parameters are chosen using the band gap map. The dimensions of the defect rods are exclusively tailored for the wavelength to be extracted via that channel. Optimisation of the proposed design by changing the number of rods in the defects is also discussed based on the results of the calculations of the Finite Difference Time Domain (FDTD) method.