Study Of Two-dimensional Photonic Crystal Waveguides Based On SOI

Photonic crystals (PhC) are optical structures with wavelength-scale periodic variations of the refractive index. There are frequency bands, which called photonic bandgap (PBG), in the periodic dielectric materials. Light with frequency in the PBG can't propagate through the photonic crystals. If there are defects (dot or line) in the periodic dielectric it will appear frequency bands in which light can propagate. With PhC some waveguides of micrometer-scale can be made which has more advantages than conventional waveguides.In this work PBG structures and PhC waveguides based on SOI (silicon on insulator) are studied from the perspectives of theory and fabrication.A method, which incorporates Plane Wave Expansion (PWE) method with Finite-Difference Time-Domain (FDTD) method, is presented to design and simulate PBG structures and PhC waveguides. This enlarges the scale of simulation and improves the precision and speed of simulation. PWE will present a band structure and according to the band structure, FDTD with a perfectly matched layer (PML) boundary condition gives a light propagation simulation. Some waveguides are designed including line waveguide, 60°bend waveguide, right-angle bend waveguide, T-junction, Y-junction, resonant cavity, coupled cavity waveguide, Mach-Zehnder circuit, etc. FFT and Pade approximation are used to calculate Q-factor. Optimization is done on photonic structures, refractive indices, pitches, diameters of holes, and details of corners. To fabricate PhC waveguide two methods are studied. One is using 248nm deep UV (DUV) lithography and chemically assisted ion-beam etching; the other is electron-beam (EB) lithography and inductively coupled plasma (ICP) etching. The samples of waveguides have been got and which are observed through scanning electron microscope (SEM) and atomic force microscope (AFM). To get appropriate manufacture conditions the micro structures of samples are analyzed and the graphs of samples are given. The setup of measurement is studied and the fiber-lens for coupling input signal light is eroded.This work about PhC based on SOI from the perspectives of theory and fabrication has built a solid foundation for next research on two-dimensional PhC waveguides.