Optimizing pump-probe switching ruled by free-carrier dispersion

We address theoretically and numerically pump-probe switching in a nonlinear semiconductor nanocavity where tuning is achieved via a dominant mechanism of free-carrier plasma dispersion. By using coupled-mode approach we give a set of guidelines to optimize the switching performances both in terms of avoiding self-pulsation and keeping switching power to the minimum, ending up by showing that such devices can achieve high-performances with relatively low-power consumption

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

Bottom-Up Abstract Modelling of Optical Networks-on-Chip: From Physical to Architectural Layer

This work presents a bottom-up abstraction procedure based on the design-flow FDTD + SystemC suitable for the modelling of optical Networks-on-Chip. In this procedure, a complex network is decomposed into elementary switching elements whose input-output behavior is described by means of scattering parameters models. The parameters of each elementary block are then determined through 2D-FDTD simulation, and the resulting analytical models are exported within functional blocks in SystemC environment. The inherent modularity and scalability of theS-matrix formalism are preserved inside SystemC, thus allowing the incremental composition and successive characterization of complex topologies typically out of reach for full-vectorial electromagnetic simulators. The consistency of the outlined approach is verified, in the first instance, by performing a SystemC analysis of a four-input, four-output ports switch and making a comparison with the results of 2D-FDTD simulations of the same device. Finally, a further complex network encompassing 160 microrings is investigated, the losses over each routing path are calculated, and the minimum amount of power needed to guarantee an assigned BER is determined. This work is a basic step in the direction of an automatic technology-aware network-level simulation framework capable of assembling complex optical switching fabrics, while at the same time assessing the practical feasibility and effectiveness at the physical/technological level

Full vectorial BPM modeling of Index-Guiding Photonic Crystal Fibers and Couplers

A 3D full-vectorial Beam Propagation Method is successfully applied to compute both the propagation constants and the modal profiles in high-contrast silica-air index-guiding Photonic Crystal Fibers. The approach is intrinsically suited to investigate longitudinally varying structures or propagation and polarization effects, which are of practical interest for advanced optical applications. As an example we model a dual-core coupler, showing that efficient polarization preserving coupling can be expected

Holey fibre mode-selective couplers

Mode-selective coupling in an asymmetric holey fibre coupler is demonstrated both numerically and experimentally for the first time. The coupler's performance is shown to be ultrabroadband, with significant potential existing for the use of such couplers in high bandwidth few-mode fibre networks

Low insertion losses and high drop efficiency photonic crystal filter for advanced telecom modulation formats

International audienceA 2D photonic crystal 3-ports filter with 6 dB bus insertion losses and drop efficiency of 47 % is reported. Error-free operation with low penalty (<0.5 dB) for OOK and DQPSK modulation formats is demonstrated

Wavelength Division Demultiplexing and Cross-Talk Assessment of a Photonic Crystal Filter

International audienceWe report on the design, fabrication and characterization of a filter for demultiplexing in the wavelength division domain realized with a H0 cavity on a III-V photonic crystal (PhC) membrane. This device is single mode, the total insertion losses are about 10.5 dB, the drop efficiency is close to 40 % and the channel isolation can exceed 20 dB at 500 GHz. 28 Gbit/s NRZ wavelength demultiplexing shows less than 0.5 dB penalties. Cross talk measurements demonstrate less than 1 dB penalty when adjacent channels are spaced as closely as 235 GHz, demonstrating the good compatibility of this filter with LAN-WDM systems. Finally, 56 Gbit/s NRZ-DQPSK signal filtering is assessed revealing negligible penalty (< 0.5 dB)

A non-destructive method to measure coupling and propagation losses in optical guided structures

International audienceWe propose and demonstrate a nondestructive method for loss measurement in optical guided structures. In the proposed approach, the device under test does not require connectors at its ends, thus making this technique available for both optical fibers and integrated optical waveguides. The loss measurement is feasible over a broad range, from low (0.2 dB/km ) to high (of the order of 1 dB/mm ) loss values. This method is validated through measurements performed on a microstructured holey fiber and on a photonic-crystal waveguide. The obtained results are in good agreement with theoretical calculations and measurements obtained by other approaches

High-speed photodetectors in a photonic crystal platform

International audienceWe demonstrate a fast photodetector (f 3dB > 40GHz) integrated into a high-index contrast photonic crystal platform. Device design, fabrication and characterization are presented

Couplage entre une membrane à cristaux photoniques en matériaux III-V et une fibre micro-lentillée : simulations et mesures

session orale JNOG_2 "Nanophotonique"National audienceDans cet article nous présentons les résultats de simulations et de mesures des profils transverses d'intensité d'un guide réalisé sur une membrane à cristaux photoniques en matériaux III-V ainsi que de couplage entre ce guide et une fibre micro-lentillée. Ces résultats, obtenus dans le cadre du projet européen COPERNICUS, montrent un bon accord entre théorie et expérience