Time varying ISI model for nonlinear interference noise

We show that the effect of nonlinear interference in WDM systems is equivalent to slowly varying inter-symbol-interference (ISI), and hence its cancellation can be carried out by means of adaptive linear filtering. We characterize the ISI coefficients and discuss the potential gain following from their cancellation.Comment: Submitted to the optical fiber communication conference (OFC), 201

Characterisation of cascaded Raman-assisted fibre optical parametric amplifiers using WDM QPSK signals

We report the first WDM numerical characterisation of crosstalk growth in cascaded Raman-Assisted Fibre Optical Parametric Amplifiers (RA-FOPAs). A cascade of ten RA-FOPAs results in ∼13dB lower crosstalk than the equivalent cascade of conventional FOPAs

Generation of 21.3 Gbaud 8PSK signal using an SOA-based all-optical phase modulator

We describe a novel SOA-based all-optical pure-phase modulator, and show how deleterious cross-gain modulation from the SOAs can be suppressed by utilizing an integrated interferometer structure. We experimentally demonstrate the use of the optical gate as a π/4 phase modulator producing 21.3 Gbaud 8PSK from 21.3 Gbit/s OOK and 21.3 Gbaud QPSK inputs. The modulator produces 3 dB of gain and coherent detection-based bit error rate measurements indicate a 2.4 dB excess penalty

Calculation of Mutual Information for Partially Coherent Gaussian Channels with Applications to Fiber Optics

The mutual information between a complex-valued channel input and its complex-valued output is decomposed into four parts based on polar coordinates: an amplitude term, a phase term, and two mixed terms. Numerical results for the additive white Gaussian noise (AWGN) channel with various inputs show that, at high signal-to-noise ratio (SNR), the amplitude and phase terms dominate the mixed terms. For the AWGN channel with a Gaussian input, analytical expressions are derived for high SNR. The decomposition method is applied to partially coherent channels and a property of such channels called "spectral loss" is developed. Spectral loss occurs in nonlinear fiber-optic channels and it may be one effect that needs to be taken into account to explain the behavior of the capacity of nonlinear fiber-optic channels presented in recent studies.Comment: 30 pages, 9 figures, accepted for publication in IEEE Transactions on Information Theor

Nonlinear Propagation in Multimode and Multicore Fibers: Generalization of the Manakov Equations

This paper starts by an investigation of nonlinear transmission in space-division multiplexed (SDM) systems using multimode fibers exhibiting a rapidly varying birefringence. A primary objective is to generalize the Manakov equations, well known in the case of single-mode fibers. We first investigate a reference case where linear coupling among the spatial modes of the fiber is weak and after averaging over birefringence fluctuations, we obtain new Manakov equations for multimode fibers. Such an averaging reduces the number of intermodal nonlinear terms drastically since all four-wave-mixing terms average out. Cross-phase modulation terms still affect multimode transmission but their effectiveness is reduced. We then verify the accuracy of our new Manakov equations by transmitting multiple PDM-QPSK signals over different modes of a multimode fiber and comparing the numerical results with those obtained by solving the full stochastic equation. The agreement is excellent in all cases studied. A great benefit of the new equations is to reduce the computation time by a factor of 10 or more. Another important feature observed is that birefringence fluctuations improve system performance by reducing the impact of fiber nonlinearities. Finally multimode fibers with strong random coupling among all spatial modes are considered. Linear coupling is modeled using the random matrix theory approach. We derive new Manakov equations for multimode fibers in that regime and show that such fibers can perform better than single-modes fiber for large number of propagating spatial modes.Comment: Submitted to journal of lightwave technology on the 17-Jul-2012. Ref number: JLT-14391-201

Exploration d'un espace sonore : une recherche dramaturgique menée par l'acteur-créateur

Dans cette recherche-création, je m’interroge sur la position de l’acteur-performeur au sein d’un processus de création. Appuyé sur une méthodologie de collaboration, je cherche à le rendre créateur d’une dramaturgie sonore en évolution. Pour cela, je m’intéresse aux qualités sonores d’un espace in situ. Je pose mes ancrages théoriques à partir du théâtre environnemental (Schechner), de la notion d’approche performative (Féral,) et des concepts d’écologie sonore et de paysage sonore (Shafer, Deshays et Nancy). Je m’interroge à savoir comment à travers une écoute d’un environnement sonore en mouvance l’acteur-performeur, peut trouver des modèles d’actions qui lui permettront, de développer une relation dialogique avec l’espace, ses collaborateurs et les spectateurs. Je me positionne sur le plan esthétique grâce à des références qui m’aident à concrétiser ma démarche pratique. Précisons, dans un mode combinatoire entre l’approche dramaturgique d’un espace in situ (Théâtre Nulle part, le Squat théâtre) et la mise en place de différents parcours sonores (Choinière, Cardiff, les compagnies : Espace sonore et Le bruit que ça coûte). Le résultat pratique de cette recherche prend la forme interdisciplinaire d’un parcours théâtral, sonore et in situ intitulé J’étais dans ma maison. Ce dernier témoigne d’un engagement personnel dans tout le processus créatif. Il reflète le passage de nombreuses écoutes dans l’espace choisi, soit le chalet de la forêt d’enseignement et de recherche Simoncouche (FERS)

Analyse écotoxicologique du trichloroéthylène à la municipalité de shannon

La nappe phréatique sous la municipalité de Shannon au Québec est contaminée au trichloroéthylène (TCE), une substance considérée toxique et probablement cancérogène chez l’humain. L’objectif de ce travail est de faire un portrait global de la contamination au TCE à la municipalité de Shannon. À cette fin, une analyse toxicologique des habitants de Shannon est présentée et une analyse écotoxicologique de la faune et la flore est effectuée. L’analyse toxicologique montre un risque formel cancérogène et non cancérogène tandis que l’analyse écotoxicologique ne décèle pas de risque formel chez les mammifères, poissons et végétaux étudiés. Toutefois, il serait intéressant, pour confirmer les résultats, de faire une étude sur le terrain pour vérifier si la faune et la flore sont réellement affectées par la contamination au TCE

Expressions for the nonlinear transmission performance of multi-mode optical fiber

We develop an analytical theory which allows us to identify the information spectral density limits of multimode optical fiber transmission systems. Our approach takes into account the Kerr-effect induced interactions of the propagating spatial modes and derives closed-form expressions for the spectral density of the corresponding nonlinear distortion. Experimental characterization results have confirmed the accuracy of the proposed models. Application of our theory in different FMF transmission scenarios has predicted a ~10% variation in total system throughput due to changes associated with inter-mode nonlinear interactions, in agreement with an observed 3dB increase in nonlinear noise power spectral density for a graded index four LP mode fiber