Thesis presented November 07, 2003

Abstract:
Photonic crystals (PCs), i.e. periodic dielectric structures, allow the control of light. For example, propagation of photons can be suppressed in certain directions and for frequencies contained in what is called the photonic band gap (PBG). This thesis report on the conception, fabrication and characterization of guides, filters, planar micro-cavities and light extractors based on two-dimensional silicon photonic crystals. This structures can be etched in the planar waveguide of silicon-on-insulator (SOI) substrates and they can take advantage of well known microelectronic fabrication technology. Furthermore, the fabrication with CMOS-type technology on 8 in. wafers allows to prepare the integration of optical functions within silicon microelectronic chips. The first part of this manuscript focuses on passive structures: guides and filters. An original optical bench was build in order to perform transmission measurements on a wide wavelength range (1.1 to 1.7 µm). Monolayer waveguides, mirrors and unidimensional cavities are investigated. Resonant modes with quality factors higher than 150 are measured. This results are in very good agreement with the FDTD (Finite Difference Time Domain) simulations and with the calculated band diagrams. The second part of the thesis concerns the out-of-plane light emission from photonic crystal structures. Confinement of photons in planar micro-cavities and light extraction properties of particular points on the photonic crystal band diagram are studied. Both approaches are investigated on SOI substrates and on a new kind of substrates, called “optical substrates”, developed especially for our applications and composed of a monocrystalline silicon layer bonded a buried distributed Bragg reflector. That way, the influence of the light confinement in the third direction have been investigated. On SOI substrate, a light extraction efficiency higher than 45 % have been measured on one side and in a reduced solid angle.

Keywords:
Photonic crystals, silicon-on-insulator, SOI, photonic bandgap, waveguides, microcavities, photoluminescence, extraction, low group velocity, FDTD

On-line thesis. ​