We report our advances in development of subwavelength engineered silicon photonic devices for near- and mid-infrared applications. By periodically patterning Si with a pitch small enough to suppress diffraction, we synthesize an effective photonic medium with refractive index between those of Si and the cladding material. This technique releases new degrees of freedom in engineering of light-matter interaction, chromatic dispersion and light propagation in Si photonic waveguides. We present an overview of our recent results in the realization of novel devices including filters and waveguides for near- and mid-infrared wavelength range.
Periodically poled lithium niobate waveguides (PPLN/W) are considered to be one of the most useful toolboxes for
enabling quantum communication experiments. Thanks to the high optical confinement over longer lengths than in bulk
configurations (a few cm in our case), such structures provide highly efficient non-linear interactions, i.e., in parametric
downconversion, or sum and difference frequency generation regimes. Within the framework of long-distance quantum
communication at telecom wavelengths, PPLN/Ws have therefore been proved to be a key ingredient for building ultrabright
sources of time-bin, as well as polarization entangled photons, and for photonic quantum interfaces providing
coherent wavelength conversions from telecom to visible wavelength range, and conversely. During the presentation, we
will discuss some recent experimental advances regarding polarization entanglement sources and quantum interfaces.
The origin and the behavior of the birefringence of solid-core
air-silica microstructured fibers is described with
the help of a simple approximate model. The first two modes of three different types of fibers are studied.
Numerical results, obtained from both finite element and boundary integral methods calculations, are presented
to support the validity of the model and to delineate its limits.