Defining elements with reconfigurable input-output characteristics is of importance to achieve flexible circuitry where light can be manipulated and routed using external control signals. We have developed an experimental approach for shaping of the transmission function of multimode silicon photonic waveguides by projecting a pattern of local nonlinear perturbations induced by an ultrafast laser pulse. Making use of the degrees of freedom offered by a spatial light modulator, the technique offers a new approach for studying light transport, for controlling its flow on ultrafast time scale, and for programming functions on a photonic chip.
The propagation of light in a 2D random medium is studied. The medium is made on dielectric scatterers with a high
permittivity allowing for the existence of Mie resonances. It is shown that, according to the polarization, it is possible to
obtain conduction bands around the resonances.verligh
We study the coupling of light between strip and rib waveguides and supercollimating photonic crystals on
silicon-on-insulator substrates. The dispersive properties of the supercollimating photonic crystal are used to
define the design requirements on the excitation waveguide and the boundary of the photonic crystal is optimized
to improve the impedance matching between the two structures. By 3D calculations, we find that rib waveguides
can yield transmission effciencies up to about 96 % and reflections lower than 0.2 % at wavelengths close to
1.55 μm, while insuring single-mode propagation. This work therefore constitutes an important step toward the
integration of supercollimation-based optical circuits on photonic chips.
We discuss properties of line defect waveguides in planar photonic crystals with a triangular lattice of ring
shaped holes (RPhCWs). We introduce slow-light RPhCWs with tailored dispersion properties and a compact
and efficient coupler to efficiently inject light into such slow-light waveguide sandwiched between strip waveguides.
We will also discuss the potential application of the RPhCW in biomedical applications and show experimental
results on the RPhCW fabricated on the silicon-on-insulator substrate.
In the past few years, self assembly colloidal structures based on opals have received large attention because they offer a
cost-effective way of designing ultra-compact and efficient all-optical devices. In this study, we present various
approaches to design waveguides and cavities in three-dimensional opal-based photonic crystals. Three practical designs
with size suitable to telecommunication technologies at 1.55 μm are presented. First, we show that the creation of a
hexagonal superlattice of defects in a direct monolayer of spheres yields the opening of a photonic band gap below the
light line so that the inclusion of a linear defect in this structure enables the creation of a theoretically lossless
waveguide. We also propose the design of a waveguide in a 2D-3D heterostructure, where a graphite lattice of rods is
sandwiched between two inverse opal claddings. This structure enables single-mode waveguiding with a maximal
bandwidth of 129 nm. Finally, we give the design of a linear cavity, whose quality factor is increased by a factor of 5
when surrounded by an inverse opal.
We demonstrate the possibility of waveguiding electromagnetic waves in a monolayer of dielectric spheres. While light is confined vertically by index guiding, a triangular superlattice monolayer of spheres was found to exhibit a photonic band gap below the light cone, thereby preventing light from propagating laterally. A gap map of this structure is presented. We propose a possible waveguide configuration that yields two non-degenerate defect modes lying within the photonic band gap. Such a structure may be particularly interesting for coupling light into self-assembled colloidal photonic crystals.