Light coupling with a nonlinear prism.

We propose the use of a prism with nonlinear optical properties to improve the prism-coupling method. The principle is based on the inscription of an adapted waveguide inside this prism by beam self-trapping to enhance the coupling efficiency and stability. The experimental demonstration is realized with a prism diced from a LiNbO3 wafer to couple light into a resonator.

Supercontinuum generation in hydrogenated amorphous silicon waveguides at telecommunication wavelengths.

We report supercontinuum (SC) generation centered on the telecommunication C-band (1550 nm) in CMOS compatible hydrogenated amorphous silicon waveguides. A broadening of more than 550 nm is obtained in 1cm long waveguides of different widths using as pump picosecond pulses with on chip peak power as low as 4 W.

Dispersive wave emission and supercontinuum generation in a silicon wire waveguide pumped around the 1550 nm telecommunication wavelength.

We experimentally and numerically study dispersive wave emission, soliton fission, and supercontinuum generation in a silicon wire at telecommunication wavelengths. Through dispersion engineering, we experimentally confirm a previously reported numerical study and show that the emission of resonant radiation from the solitons can lead to the generation of a supercontinuum spanning over 500 nm. An excellent agreement with numerical simulations is observed.

Silicon-on-insulator integrated source of polarization-entangled photons.

We report the experimental generation of polarization-entangled photons at telecommunication wavelengths using spontaneous four-wave mixing in silicon-on-insulator wire waveguides. The key component is a 2D coupler that transforms path entanglement into polarization entanglement at the output of the device. Using quantum state tomography we find that the produced state has fidelity 88% with a pure nonmaximally entangled state. The produced state violates the CHSH Bell inequality by S=2.37 ± 0.19.

Writing and probing light-induced waveguides thanks to an endlessly single-mode photonic crystal fiber.

We demonstrate writing and probing of light-induced waveguides in photorefractive bulk LiNbO3 crystal using an endlessly single-mode photonic crystal fiber. The optical waveguides are written at visible wavelengths by slightly raising the ferroelectric crystal temperature to benefit from the pyroelectric-driven photorefractive effect and the guiding properties are investigated at telecom wavelengths using the same photonic crystal fiber. End butt coupling with this photonic crystal fiber enables writing and probing of optical waveguides due to the self-alignment properties of spatial solitons.

Surface-wave pyroelectric photorefractive solitons.

Surface-wave solitons, induced by the pyroelectric effect, are formed at the interface between a photorefractive ferroelectric medium and a linear medium. These optical solitons are trapped in both transverse dimensions and are efficiently attracted to the interface. The asymmetric shape of the nonlinear index change formed under the charge saturation regime is responsible for the surface-wave solitons' formation. Experimental demonstrations are performed in a lithium niobate sample with moderate temperature change. The phenomenon is successfully explained through numerical simulations.

Pyroliton: pyroelectric spatial soliton.

The concept of optical beam self-trapping in pyroelectric photorefractive medium is presented. We show that the temperature controlled spontaneous polarisation of ferroelectric crystals produces an optical nonlinearity that can lead to formation of 2-D spatial soliton named pyroliton. Experimental demonstrations performed in lithium niobate crystals illustrate that efficient self-trapping occurs either for ordinary or extraordinary polarisation under moderate temperature increase. For instance, a 15 microm diameter pyroliton can be formed with a 10 degree temperature raise.