Stable integrated hyper-parametric oscillator based on coupled optical microcavities

We propose a flexible scheme based on three coupled optical microcavities which permits to achieve stable oscillations in the microwave range, the frequency of which depends only on the cavity coupling rates. We find the different dynamical regimes (soft and hard excitation) to affect the oscillation intensity but not their period. This configuration may permit to implement compact hyper-parametric sources on an integrated optical circuit, with interesting applications in communications, sensing and metrology.Comment: 4 pages, 5 figure

Suppression and splitting of modulational instability sidebands in periodically tapered optical fibers due to fourth-order dispersion

We study the modulational instability induced by periodic variations of group-velocity dispersion in the proximity of the zero dispersion point. Multiple instability peaks originating from parametric resonance coexist with the conventional modulation instability due to fourth order dispersion, which in turn is suppressed by the oscillations of dispersion. Moreover isolated unstable regions appear in the space of parameters due to imperfect phase matching. This confirms the dramatic effect of periodic tapering in the control and shaping of MI sidebands in optical fibers

Strong Raman-induced non-instantaneous soliton interactions in gas-filled photonic crystal fibers

We have developed an analytical model based on the perturbation theory in order to study the optical propagation of two successive intense solitons in hollow-core photonic crystal fibers filled with Raman-active gases. Based on the time delay between the two solitons, we have found that the trailing soliton dynamics can experience unusual nonlinear phenomena such as spectral and temporal soliton oscillations and transport towards the leading soliton. The overall dynamics can lead to a spatiotemporal modulation of the refractive index with a uniform temporal period and a uniform or chirped spatial period

Recurrence in the high-order nonlinear Schr\"odinger equation: a low dimensional analysis

We study a three-wave truncation of the high-order nonlinear Schr\"odinger equation for deepwater waves (HONLS, also named Dysthe equation). We validate our approach by comparing it to numerical simulation, distinguish the impact of the different fourth-order terms and classify the solutions according to their topology. This allows us to properly define the temporary spectral upshift occurring in the nonlinear stage of Benjamin-Feir instability and provides a tool for studying further generalizations of this model

Nonlinear stage of Benjamin-Feir instability in forced/damped deep water waves

We study a three-wave truncation of a recently proposed damped/forced high-order nonlinear Schr\"odinger equation for deep-water gravity waves under the effect of wind and viscosity. The evolution of the norm (wave-action) and spectral mean of the full model are well captured by the reduced dynamics. Three regimes are found for the wind-viscosity balance: we classify them according to the attractor in the phase-plane of the truncated system and to the shift of the spectral mean. A downshift can coexist with both net forcing and damping, i.e., attraction to period-1 or period-2 solutions. Upshift is associated with stronger winds, i.e., to a net forcing where the attractor is always a period-1 solution. The applicability of our classification to experiments in long wave-tanks is verified.Comment: 8 pages, 4 figure

Oscillatory dynamics in nanocavities with noninstantaneous Kerr response

We investigate the impact of a finite response time of Kerr nonlinearities over the onset of spontaneous oscillations (self-pulsing) occurring in a nanocavity. The complete characterization of the underlying Hopf bifurcation in the full parameter space allows us to show the existence of a critical value of the response time and to envisage different regimes of competition with bistability. The transition from a stable oscillatory state to chaos is found to occur only in cavities which are detuned far off-resonance, which turns out to be mutually exclusive with the region where the cavity can operate as a bistable switch

Fourth-order dispersion mediated modulation instability in dispersion oscillating fibers

We investigate the role played by fourth-order dispersion on the modulation instability process in dispersion oscillating fibers. It not only leads to the appearance of instability sidebands in the normal dispersion regime (as in uniform fibers), but also to a new class of large detuned instability peaks that we ascribe to the variation of dispersion. All these theoretical predictions are experimentally confirmed. (C) 2013 Optical Society of Americ

Suppression of transverse instabilities of dark solitons and their dispersive shock waves

We investigate the impact of nonlocality, owing to diffusive behavior, on transverse instabilities of a dark stripe propagating in a defocusing cubic medium. The nonlocal response turns out to have a strongly stabilizing effect both in the case of a single soliton input and in the regime where dispersive shock waves develop "multisoliton regime". Such conclusions are supported by the linear stability analysis and numerical simulation of the propagation

Modelling and Characterization of Guiding Micro-structured Devices for Integrated Optics

In this thesis we show several modelling tools which are used to study nonlinear photonic band-gap structures and microcavities. First of all a nonlinear CMT and BPM were implemented to test the propagation of spatial solitons in a periodic device, composed by an array of parallel straight waveguides. In addition to noteworthy theoretical considerations, active functionalities are possible by exploiting these nonlinear regimes. Another algorithm was developed for the three-dimensional modelling of photonic cavities with cylindrical symmetry, such as microdisks. This method is validated by comparison with FDTD. We also show the opportunity to confine a field in a region of low refractive index lying in the centre of a silicon microdisk. High Q-factor and small mode volumes are achieved. Finally the characterization of microdisks in SOI with Q-factor larger than 50000 is presente