High index contrast platform for silicon photonics

Abstract

This thesis focuses on silicon-based high index contrast (HIC) photonics. In addition to mature fiber optics or low index contrast (LIC) platform, which is often referred to as Planar Lightwave Cirrcuit (PLC) or Silica Optical Bench (SiOB), the use of HIC platform has been attracting considerable attention recently for the purpose of dense integration of optical components on chip. There are two ultimate solutions to mold of the flow of light. One is high index contrast HIC optics, where the index difference ([delta]n) of core and cladding is more than 0.5 and light is strongly confined in the core, which enables us to integrate optical circuits in m order. Another technique is the introduction of photonic crystal, with which the flow of light is controlled by its photonc bandgap (PBG) and the defect. The concept of photonic crystal can be applied to optical wavgeuides by placing the defect, which is surrounded with photonic crystal structures. In addition to wavgeuide applications, there are lots of unexplored attractive applications for photonic crystal, especially for high index contrast photonic crystal (HIC-PC or HIC-PBG), such as Si/SiO₂ or Si/Si₃N₄ materials systems, due to the wide stop-band. In this thesis, the various applications based on HIC-PBG platform are proposed and investigated. All of the works in this thesis are based on Silicon CMOS-compatible techniques for practical applications. In first three chapters (chapter 2,3 and 4), waveguide applications are mainly focused based on HIC or HIC-PBG platform. In the latter chapters (chapter 5, 6 and 7), the applications of HIC-PBG are explored such as visible-light reflector, semiconductor saturable absorber (SESAM) and thermophotovoltaic (TPV) applications.