Designing novel photonic waveguides for slow light and biosensor applications

Photonic crystals (PCs) are one of the most famous topics in recent years and many researchers all around the world are engaged in research on this topic. Thanks to control the properties like velocity, direction and phase of the light PCs can be used in the field of optical telecommunication, medical applications and electronic circuit elements. PCs have many advantages from the recent electronic components. A few of them are lack-of warm-up problem, high speed data transfer, can be working in room temperature and have small dimensions. With these advantages PCs may replace place of electronic components in the future.In this thesis, properties of square and triangular lattice PCs are investigated by finite difference time domain (FDTD) method and plane wave expansion method (PWEM). A symmetrically corrugated slab placed at the center of the square lattice PC and investigated its features. In its dispersion diagram at photonic band gap (PBG) a sharp resonance point has detected in an odd mode. Using this mode light can be localized inside the PC at the corresponding sharp resonance frequency. In real life there aren?t an odd mode source so to use the property found with the PC in real life an even to odd mode converter has to be designed. Mode converter part designed with changing air holes radii at one side of the corrugated dielectric slab. In the second part of this study a single sided corrugated dielectric slab placed at the center of square lattice PC and investigated its features. Mini-stop band (MSB) property has found in the PC?s dispersion diagram. At the edge of the MSB region we found 30dB drop in transmission in a 4nm wavelength interval. According to this property PC can split different frequencies which can propagate inside PC with different corrugation radius. From these results a DEMUX design has shown in the study. In the third part of this study using triangular lattice photonic crystal, a way to obtain large bandwidth, constant group index and low group velocity dispersion (GVD) for slow light applications has shown. After changing the radius of air holes at the sides of the waveguide and at the background, figure of merit raise up to approximately 0.30 for appropriate air hole radius values.