Graphene, with its high and broadband optical nonlinearity, has attracted the interest of many researchers the last few years, as it appears to be a promising candidate for integrated photonics. In our work, we report the use of the ultrafast optical Kerr effect method with optical heterodyne detection (OHD-OKE) for the characterization of the third order optical nonlinearity of monolayer CVD graphene on quartz, at telecom wavelength. Our measurements show that the nonlinear refractive index of graphene is negative, in contrast to previously reported results. We also performed measurements of the nonlinear absorption of graphene and we studied the temperature dependence of the nonlinearity, as well as the relaxation time of the OHD-OKE signal.

Supercontinuum generation in CMOS compatible hydrogenated amorphous silicon waveguides with femtosecond pulses at telecommunication wavelengths is experimentally studied. It is shown that stable 540 nm broad supercontinua can be obtained in 1 cm-long waveguides.

We study the spontaneous photon scattering that arises in silicon waveguides at low power. Power dependence, temperature dependence, spectrum and response time point out its origin as pump scattering on a thermal bath of excitons.

Integrated quantum optics using silicon wire waveguides is presented. The Kerr nonlinearity of silicon allows the generation of photon pairs within straight waveguides, within micro-ring resonators, as well as the realisation of more complex circuits.

Thanks to simulations, we discuss the choice of the optimal rolloff in realistic Nyquist-WDM systems, while accounting for transmitter/receiver impairments, namely the finite impulse response length of root-raised-cosine pulse shapes, jitter and vertical DAC/ADC resolution.

We study quantitatively the weak source of noise that is present when correlated photons are produced via four wave mixing in silicon nanophotonic waveguides. First, we deduce the amont of noise from the dependance of the photon flux on the pump power. Second we caracterise the spectrum of the noise and of the pairs of photons which shows that the noise is due to a scattering of photons by a thermal bath. Third we show that the photon flux (noise plus pairs) is essentially instantaneous, and cannot therefore be attributed to carrier induced effects. We discuss our results and compare them to photon pair generation in silica fibers.

The transition between the standard snake instability of bright solitons of the hyperbolic nonlinear Schrödinger equation and the recently theoretically predicted oscillatory snake instability is experimentally demonstrated. The existence of this transition is proven on the basis of spatiotemporal spectral features of bright soliton laser beams propagating in normally dispersive Kerr-type nonlinear planar waveguides.

Few-photon systems are best described by their wave function rather than by the usual quantum field formalism. In this work, we develop a photon wave function (PWF) formalism suitable for analyzing a wide variety of quantum optical problems related to propagation, diffraction and imaging with quantum states of light. We establish a generalized Huygens-Fresnel (GH-F) principle that describes the propagation of any paraxial N-photon state. This tool is very helpful for predicting photo-detection correlations in space and time due to an initial N-particle entanglement, even in complex situation. The effect of lenses, beam splitters, filters... on the photon paths can be easily taken into account. We apply the PWF formalism and the GH-F principle to three specific problems in quantum optics. First, we revisit the Hong-Ou-Mandel two-photon interference effect and analyze the effect of photon shape mismatch in space, time and polarization using the PWF formalism. Second, we show how to use the GH-F principle to analyze "ghost" imaging and diffraction experiments with entangled photon pairs such as those realized by Strekalov et al. [Phys. Rev. Lett. 74, 3600 (1995)] and Pittman et al. [Phys. Rev. A 52, R3429 (1995)] in the nineties. Finally, we use the GH-F principle to analyze the resolution enhancement in a recent quantum imaging proposal based on N incoherent single-photon sources [Phys. Rev. Lett. 99, 133603 (2007) and Phys. Rev. A 80, 013820 (2009)].

We report the first (to our knowledge) observation of correlated photon emission in hydrogenated amorphous-silicon waveguides. We compare this to photon generation in crystalline silicon waveguides with the same geometry. In particular, we show that amorphous silicon has a higher nonlinearity and competes with crystalline silicon in spite of higher loss.

Using the spectral-interferometry method for the short pulse complete characterization, we demonstrate the nature and distinctive properties of the similariton generated in single-mode fiber without gain (passive fiber) due to the combined impacts of nonlinearity and dispersion. The nonlinear-spectronic character of such a similariton, with the key specificity of linear chirping, leads to its self-spectrotemporal imaging, important for applications to the signal analysis - synthesis problems in ultrafast optics.

The breakup of spatial bright optical solitons due to oscillatory neck instability is experimentally studied by propagating a laser beam in normally dispersive and self-focusing Kerr media. This intriguing and unusual phenomenon, recently predicted for solitons of the (2+1)-dimensional hyperbolic nonlinear Schrödinger (NLS) equation, is observed in the spatially resolved temporal spectrum. The snake instability that is known to occur in hyperbolic systems is also demonstrated to validate our experimental approach. Our results not only apply to photonics but also to other fields of physics, such as hydrodynamics or plasma physics, in which the hyperbolic NLS equation is used as a canonical model.

We present evidences of time correlated photon pairs generated by the four-wave mixing process in a silicon racetrack cavity. A coincidence measurement and an emission spectrum are presented and discussed.

Silicon waveguides are promising chi(3)-based photon pair sources. Demonstrations so far have been based on picosecond pulsed lasers. Here, we present the first investigation of photon pair generation in silicon waveguides in a continuous regime. The source is characterized by coincidence measurements. We uncover the presence of unexpected noise which had not been noticed in earlier experiments. Subsequently, we present advances towards integration of the photon pair source with other components on the chip. This is demonstrated by photon pair generation in a Sagnac loop interferometer and inside a micro-ring cavity. Comparison with the straight waveguide shows that these are promising avenues for improving the source. In particular photon pair generation in the micro-ring cavity yields a source with a spectral width of approximately 150 pm resulting in a spectral brightness increased by more than 2 orders of magnitude.

A simple technique that allows for the repetition rate multiplication of optical pulse trains generated in passively modelocked fibre lasers is experimentally demonstrated. This is achieved by initiating higher-order passive modelocking by using both a dual-channel fibre Bragg grating and a Fabry-Perot filter inside the fibre cavity. Continuous dark pulse trains with a repetition rate of 60 GHz were generated, which is a four-fold multiplication of the Fabry-Perot free spectral range.

We experimentally demonstrate the spectronic nature of the similariton generated in a nonlinear-dispersive fiber without gain and its key specificity of spectro-temporal similarity using the spectral-interferometric method of pulse complete characterization.

We demonstrate the forming of a similariton of nonlinear-spectronic nature in single-mode fiber without gain caused by combined impact of Kerr-nonlinearity and normal dispersion. Spectro-temporal similarity and imaging accuracy of the nonlinear-spectronic similariton are discussed.

We fully characterize the stationary spatial-gap soliton through the measurement of the phase function of its nearly periodic transverse intensity distribution. The spatial-gap soliton is generated in one-dimensional photonic crystal consisting of a corrugated semiconductor planar optical waveguide. The measured phase function allows us to determine the detuning parameter that provides the position of the gap soliton within the photonic band gap.

Vacuum-fluctuations influence on pulses propagating through birefringent Kerr media is investigated using stochastic nonlinear Schrödinger equations. Computation tools are presented, and numerical results for vector modulation instabilities in the anomalous dispersion regime compared to experiments.

We report the first experimental observation of recurrence in the dynamics of modulational instability in fibers. This observation has been made possible thanks to the use of a specially-designed 550-ps square pulse source at a wavelength of 1550 nm.

We study theoretically and experimentally the so-called modulational instability laser and show that the passive mode-locking mechanism that is at play in this laser relies on a dissipative four-wave mixing process leading to dark pulse train generation in the normal dispersion regime.