THESIS
2005
xxxiii, 208 leaves : ill. ; 30 cm
Abstract
We propose and study a new type of optical microcavities, with an embedded periodic submicrometer air-holes lattice, called photonic-crystal-embedded microcavities (PCEMs). They support two types of resonances, according to the lightwave confinement, called (1) dispersion-guided and (2) surface-wave resonances. By appropriate design of the PCEM margin width and the side-coupled waveguide width, one can selectively couple to either of the resonance types.
4 2...[
Read more ]
We propose and study a new type of optical microcavities, with an embedded periodic submicrometer air-holes lattice, called photonic-crystal-embedded microcavities (PCEMs). They support two types of resonances, according to the lightwave confinement, called (1) dispersion-guided and (2) surface-wave resonances. By appropriate design of the PCEM margin width and the side-coupled waveguide width, one can selectively couple to either of the resonance types.
We study the 2-D PCEM dispersion-guided resonance modes based on various numerical and mathematical tools. We observed a discrete set of high-Q PCEM dispersion-guided resonances (highest Q ~ 1-2 x10
4 for a ~10μm
2 silicon PCEM) exhibiting very-low group velocities within the narrow-band wavelengths where do not restrict to the PC band-edge. This makes 2-D PCEMs to be most distinguishable from other conventional PC devices. We obtain an efficient coupling (~20dB) to the high-Q PCEM resonance modes by using the slab waveguide-side-coupled PCEM configurations for sake of monolithic photonic-circuit integration.
For the surface-wave resonances, which are classified into two types: PBG-guiding and index-guiding, we showed that these surface-wave resonance modes can be efficiently coupled from the conventional slab waveguide (~30 dB) given the waveguide width satisfies the phase-matching condition between the slab waveguide and the PCEMs.
Based on the 2-D finite-difference time-domain (FDTD) simulations, we believe that a conventional slab waveguide to side-coupled with the PCEMs can be relevant in several wavelength-agile applications, e.g. passive filtering in wavelength-division multiplexing (WDM) optical communications, bio-chemical sensing, and optical switching enabled by thermal-optics effects or electro-optics effects.
We also present the PCEM device fabrication processes. Two processes were adopted: one is based on photolithography and another is based on electron-beam (e-beam) lithography. The later allowed us to fabricate device pattern on silicon substrate with good conformality and sidewall steepness. Initial experimental characterizations by reflection measurements were also performed.
Post a Comment