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    Experimental and numerical study of the symbolic dynamics of a modulated external-cavity semiconductor laser  Open access

     Aragoneses Aguado, Andres; Sorrentino Amaral, Taciano; Perrone, Sandro; Gauthier, Daniel; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    Optics express
    Date of publication: 2014-02-21
    Journal article

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    We study the symbolic dynamics of a stochastic excitable optical system with periodic forcing. Specifically, we consider a directly modulated semiconductor laser with optical feedback in the low frequency fluctuations (LFF) regime. We use a method of symbolic time-series analysis that allows us to uncover serial correlations in the sequence of intensity dropouts. By transforming the sequence of inter-dropout intervals into a sequence of symbolic patterns and analyzing the statistics of the patterns, we unveil correlations among several consecutive dropouts and we identify clear changes in the dynamics as the modulation amplitude increases. To confirm the robustness of the observations, the experiments were performed using two lasers under different feedback conditions. Simulations of the Lang-Kobayashi (LK) model, including spontaneous emission noise, are found to be in good agreement with the observations, providing an interpretation of the correlations present in the dropout sequence as due to the interplay of the underlying attractor topology, the external forcing, and the noise that sustains the dropout events.

    We study the symbolic dynamics of a stochastic excitable optical system with periodic forcing. Specifically, we consider a directly modulated semiconductor laser with optical feedback in the low frequency fluctuations (LFF) regime. We use a method of symbolic time-series analysis that allows us to uncover serial correlations in the sequence of intensity dropouts. By transforming the sequence of inter-dropout intervals into a sequence of symbolic patterns and analyzing the statistics of the patterns, we unveil correlations among several consecutive dropouts and we identify clear changes in the dynamics as the modulation amplitude increases. To confirm the robustness of the observations, the experiments were performed using two lasers under different feedback conditions. Simulations of the Lang-Kobayashi (LK) model, including spontaneous emission noise, are found to be in good agreement with the observations, providing an interpretation of the correlations present in the dropout sequence as due to the interplay of the underlying attractor topology, the external forcing, and the noise that sustains the dropout events.

    Missatge de l'editor: "This paper was published in Optics express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/oe/fulltext.cfm?uri=oe-22-4-4705&id=279795. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law."

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    Unveiling the complex organization of recurrent patterns in spiking dynamical systems  Open access

     Aragoneses Aguado, Andres; Perrone, Sandro; Sorrentino Amaral, Taciano; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    Scientific reports
    Date of publication: 2014-04-15
    Journal article

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    Complex systems displaying recurrent spike patterns are ubiquitous in nature. Understanding the organization of these patterns is a challenging task. Here we study experimentally the spiking output of a semiconductor laser with feedback. By using symbolic analysis we unveil a nontrivial organization of patterns, revealing serial spike correlations. The probabilities of the patterns display a well-defined, hierarchical and clustered structure that can be understood in terms of a delayed model. Most importantly, we identify a minimal model, a modified circle map, which displays the same symbolic organization. The validity of this minimal model is confirmed by analyzing the output of the forced laser. Since the circle map describes many dynamical systems, including neurons and cardiac cells, our results suggest that similar correlations and hierarchies of patterns can be found in other systems. Our findings also pave the way for optical neurons that could provide a controllable set up to mimic neuronal activity.

    Complex systems displaying recurrent spike patterns are ubiquitous in nature. Understanding the organization of these patterns is a challenging task. Here we study experimentally the spiking output of a semiconductor laser with feedback. By using symbolic analysis we unveil a nontrivial organization of patterns, revealing serial spike correlations. The probabilities of the patterns display a well-defined, hierarchical and clustered structure that can be understood in terms of a delayed model. Most importantly, we identify a minimal model, a modified circle map, which displays the same symbolic organization. The validity of this minimal model is confirmed by analyzing the output of the forced laser. Since the circle map describes many dynamical systems, including neurons and cardiac cells, our results suggest that similar correlations and hierarchies of patterns can be found in other systems. Our findings also pave the way for optical neurons that could provide a controllable set up to mimic neuronal activity.

  • Experimental study of feedback-induced dynamics in semiconductor lasers:from symbolic analysis to subwavelength position sensing

     Aragoneses Aguado, Andres
    Defense's date: 2014-06-18
    Department of Physics and Nuclear Engineering, Universitat Politècnica de Catalunya
    Theses

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    El objetivo de esta tesis es el estudio de la dinámica inducida por realimentación óptica en láseres de semiconductor. Dicho estudio persigue, por un lado, profundizar en el conocimiento de aspectos generales de los sistemas complejos, y por otro lado, utilizar dicha dinámica para crear un protocolo para medir desplazamientos en dos dimensiones con una resolución mucho menor que la longitud de onda del láser utilizado. La intensidad de la luz emitida por un láser de semiconductor es estable salvo fluctuaciones debidas al ruido de emisión espontánea. Sin embargo, cuando la luz del láser se refleja en una superficie y parte de esta luz vuelve a entrar en el láser, la intensidad de la luz emitida se puede desestabilizar y mostrar una amplia gama de comportamientos dinámicos. Uno de los regímenes dinámicos presentes en láseres con realimentación óptica es el de fluctuaciones de baja frecuencia (LFF de sus siglas en inglés). Está dinámica se caracteriza por caídas abruptas de la intensidad del láser (hasta casi apagarse), seguidas de recuperaciones graduales, siendo la separación temporal entre dos caídas consecutivas irregular. La primera parte de esta tesis está entrada en este régimen dinámico, habiéndose realizado un detallado estudio experimental para caracterizarlo. Se ha utilizado un análisis simbólico de series de datos basado en patrones ordinales, definidos mediante la comparación de tiempos consecutivos entre caídas. En la dinámica del láser de semiconductor con realimentación intervienen varios factores: la interacción no lineal entre luz y materia en el medio activo del láser, el ruido cuántico debido a la emisión espontánea y la señal retardada de la realimentación. Por ello las caídas en el régimen de LFFs pueden ser inducidas tanto por ruido como por procesos deterministas. En esta tesis, mediante el análisis simbólico se ha conseguido distinguir estadísticamente, qué caídas pueden ser inducidas por ruido y cuales presentan una estadística que muestra señales de determinismo. En esta tesis también se ha estudiado la dinámica simbólica del régimen de LFF y se han encontrado correlaciones entre varias caídas consecutivas. También se ha encontrado una estructura jerárquica en la dinámica simbólica que incluye emparejamientosde las probabilidades de los patrones simbólicos. Además se ha encontrado un modelo simple a tiempo discreto (mapa) que describe adecuadamente la dinámica simbólica del régimes de LFF. Debido a la importancia de forzamientos externos en sistemas dinámicos, se han realizado experimentos incorporando modulación en la corriente de inyección del láser. Estos experimentos han permitido caracterizar el efecto de la amplitud de la modulación en la dinámica simbólica, encontrando cambios claros en la estructura simbólica, inducidos por la modulación, pero que se conservan los emparejamientos observados sin modulación. El modelo simple ha sido verificado ya que reproduce satisfactoriamente la dinámica simbólica encontrada en los datos experimentales. Asimismo, en esta tesis se ha demostrado experimentalmente un protocolo que permite detectar desplazamientos de doegimens objetos independientes en una escala muy inferior a la longitud de onda de la luz empleada (lambda/160). Para ello se ha diseñado un experimento donde el láser esta sometido a realimentación de dos espejos que se mueven de manera independiente. Además de la alta resolución, otra ventaja de este protocolo reside en que únicamente es preciso medir una variable para calcular los dos desplazamientos.

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    Distinguishing signatures of determinism and stochasticity in spiking complex systems  Open access

     Aragoneses Aguado, Andres; Rubido, Nicolás; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    Scientific reports
    Date of publication: 2013-05-07
    Journal article

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    Multidimensional subwavelength position sensing using a semiconductor laser with optical feedback  Open access

     Cohen, Seth; Aragoneses Aguado, Andres; Rontani, Damien; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina; Gauthier, Daniel
    Optics letters
    Date of publication: 2013-11-01
    Journal article

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    We demonstrate experimentally how to harness quasi-periodic dynamics in a semiconductor laser with dual optical feedback for measuring subwavelength changes in each arm of the cavity simultaneously. We exploit the multifrequency spectrum of quasi-periodic dynamics and show that independent frequency shifts are mapped uniquely to two-dimensional displacements of the arms in the external cavity. Considering a laser diode operating at telecommunication wavelength ¿¿1550¿¿nm, we achieve an average nanoscale resolution of approximately 9.8 nm (~¿/160).

    We demonstrate experimentally how to harness quasi-periodic dynamics in a semiconductor laser with dual optical feedback for measuring subwavelength changes in each arm of the cavity simultaneously. We exploit the multifrequency spectrum of quasi-periodic dynamics and show that independent frequency shifts are mapped uniquely to two-dimensional displacements of the arms in the external cavity. Considering a laser diode operating at telecommunication wavelength λ≈1550nm, we achieve an average nanoscale resolution of approximately 9.8 nm (∼λ∕160).

  • ESTOCASTICIDAD EN SISTEMAS COMPLEJOS NOLINEALES

     Pons Rivero, Antonio Javier; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina; Pigolotti, Simone; Ramirez de La Piscina Millan, Laureano; Peñaranda Ayllon, Angelina; Malagarriga Guasch, Daniel; Dies Miracle, Marta; Aragoneses Aguado, Andres; Deza, Juan Ignacio; Garcia Ojalvo, Jorge
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  • Zero-lag synchronization and bubbling in delay-coupled lasers

     Tiana Alsina, Jordi; Hicke, K.; Porte, X.; Soriano, M.C.; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2012-02-21
    Journal article

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  • Interspike-interval correlations induced by two-state switching in an excitable system

     Schwalger, T.; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Lindner, B.
    Europhysics letters
    Date of publication: 2012-07
    Journal article

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  • NEURAL ENGINEERING TRANSFORMATIVE TECHNOLOGIES

     Torrent Serra, Maria Del Carmen; Pons Rivero, Antonio Javier; Masoller Alonso, Cristina; Garcia Ojalvo, Jorge
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  • Nonlinear time-series analysis of low-frequency fluctuations in semiconductor lasers with optical feedback

     Aragoneses Aguado, Andres; Rubido, Nicolás; Sorrentino, T.; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    European Optical Society Annual Meeting
    Presentation's date: 2012-09-25
    Presentation of work at congresses

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  • Ordinal time-series analysis of low-frequency fluctuations in semiconductor lasers with optical feedback

     Aragoneses Aguado, Andres; Rubido, Nicolás; Sorrentino, T.; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    Congreso de Física Estadística
    Presentation's date: 2012-10-18
    Presentation of work at congresses

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  • Experimental study of the spiking activity of semiconductor lasers with time-delayed optical feedback

     Aragoneses Aguado, Andres; Rubido, Nicolás; Sorrentino, T.; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    International Symposium on Nonlinear Theory and its Applications
    Presentation's date: 2012-10-25
    Presentation of work at congresses

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  • Language organization and temporal correlations in the spiking activity of an excitable laser: experiments and model comparison

     Rubido, Nicolás; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Masoller Alonso, Cristina
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2011-08-09
    Journal article

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  • Research activities of the group on nonlinear dynamics, nonlinear optics and lasers (DONLL) at the universitat politècnica de catalunya (Campus de Terrassa)

     Tiana Alsina, Jordi; Zamora Munt, Jordi; Nistor, Ioan Cristian; Roppo, Vito; Maigyte, Lina; Aragoneses Aguado, Andres; Khumar, N.P.; Martinez Gonzalez, Maria Cristina; Fernandez Soler, Juanjo; Serrat Jurado, Carles; Font Garcia, Josep Lluís; Herrero Simon, Ramon; Cojocaru, Crina Maria; Trull, Jose; Masoller Alonso, Cristina; Staliunas, Kestutis; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Vilaseca Alavedra, Ramon
    Óptica pura y aplicada
    Date of publication: 2011-06
    Journal article

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  • Dynamical and synchronization properties of delay-coupled lasers

     Martinez Gonzalez, Maria Cristina; Soriano, M. C.; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Fischer, Ingho
    Date of publication: 2011
    Book chapter

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  • STOCHASTICITY,COMPLEXITY AND SYNCHRONIZATION IN SEMICONDUCTOR LASERS  Open access

     Tiana Alsina, Jordi
    Defense's date: 2011-11-10
    Department of Applied Physics, Universitat Politècnica de Catalunya
    Theses

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    The purpose of this Thesis is study the dynamical behavior of semiconductor lasers with optical feedback, as well as analyze the synchronization of this kind of systems under different coupling arquitectures. This study has been done from an experimental point of view, but in some cases we have used numerical models in order to verify and/or extend the experimental results. A semiconductor laser in absence of any optical feedback emits light at constant power. If one wants to induce dynamics in the laser, a good strategy is to introduce an external cavity able to reflect the emitted light back into the laser. Due to this feedback, the laser can show a large variety of dynamical behaviors. In this Thesis we will focus mainly in a dynamical regime known as low frequency fluctuations regime (LFF). The LFF regime takes place when the pump current of the laser is close to its threshold current and the feedback strength is sufficiently large, and it consists in sudden intensity dropouts arising at irregular times, followed by a gradual and stepwise recovery. During this Thesis, we have characterized in detail the dynamical behavior of the time between intensity dropouts for a semiconductor laser with feedback, by using different statistical techniques based on information theory concepts. We have quantified the probability of appearance of certain patterns within the temporal series, as well as its degree of complexity. As a result of these studies, we can conclude that the dynamics of a semiconductor laser with optical feedback is stochastic for pump current values close to the laser threshold. On the other hand, for larger pump currents the dynamics is basically deterministic (chaotic). Numerical simulations have shown a good qualitative and quantitive agreement with the experimental results. During this Thesis we have also studied the ability of semiconductor lasers to synchronize under different coupling architectures. First, we have characterized the leader-laggard dynamics showed by two semiconductor lasers bidirectionally coupled operating at the LFF regime, with a method that takes into account the number of forbidden patterns that appears in the temporal series. We have quantified the degree of stochasticity of the system as a function of the pump current of both lasers. A second coupling architecture studied here, consists in two lasers unidirectionally coupled via two paths. In this case, we have analyzed how the synchronization is affected under different values of the coupling strength of both paths, as well as the potential of this system (or rather, the lack thereof) to be used in chaotic communications. Finally we have characterized the synchronization at zero lag for two lasers coupled bidirectionally via a passive relay. In particular, we have studied the desynchronization events and their statistics for different pump currents. The experimental results obtained in this Thesis give a global perspective of the dynamical statistical properties of semiconductor laser dynamics, both isolated or coupled to other lasers, which contributes to a better understanding of this kind of dynamical systems.

    L’objectiu d’aquesta Tesi ´es l’estudi de la din`amica de l`asers de semiconductor amb retroalimentaci´o `optica, aix´ý com l’an`alisis de la sincronitzaci´o d’aquest tipus de sistemes sota diferents arquitectures d’acoblament. Aquest estudi s’ha fet sempre des d’un punt de vista b`asicament experimental, tot i que en alguns casos hem utilitzat models num`erics per tal de verificar i/o ampliar els resultats experimentals. Un l`aser de semiconductor en abs`encia de retroalimentaci´o `optica o altres perturbacions externes, emet llum a una intensitat pr`acticament constant. Aix´ý doncs, si el que es vol ´es indu¨ýr din`amica en el l`aser, una bona estrat`egia ´es introdu¨ýr una cavitat externa capa¸c de reflexar la llum cap al l`aser. Un cop la llum ´es reinjectada, els l`asers de semiconductor poden mostrar una gran varietat de comportaments din`amics. En aquesta tesis ens centrarem principalment en un r`egim din`amic anomenat r`egim de fluctuacions de baixa frequ`encia (LFF en les seves sigles en angl`es). El r`egim d’LFF es d´ona quan el corrent d’injecci´o del l`aser es troba a prop del seu corrent llindar i la intensitat de la retroalimentaci´o ´es suficientment gran, i est`a caracteritzat per sobtades caigudes de la intensitat a temps irregulars, seguides per una recuperaci´o gradual i escalonada. Durant aquesta Tesi, hem caracteritzat de forma detallada el comportament din`amic de la distribuci´o dels temps entre les caigudes d’intensitat d’un l`aser de semiconductor amb retroalimentaci´o `optica, utilitzant diferents m`etodes estad´ýstics basats en conceptes de teoria de la informaci´o. En particular, hem quantificat la probabilitat d’aparici´o de certs patrons dins les s`eries temporals, aix´ý com el grau de complexitat d’aquestes. Durant aquest estudi hem observat que la din`amica d’un l`aser de semiconductor amb retroalimentaci´o es estoc`astica per valors del corrent d’injecci´o propers al corrent llindar del l`aser. D’altra banda, per a valors m´es grans del corrent d’injecci´o la din`amica ´es m´es determinista (ca`otica). Les simulacions num`eriques realitzades han mostrat un acord qualitatiu i quantitatiu amb els resultats experimentals. Durant aquesta Tesi tamb´e hem estudiat la sincronitzaci´o entre l`asers de semiconductor. Hem analitzat diferents arquitectures d’acoblament. Primer hem caracteritzat la din`amica leader-laggard que presenten dos l`asers de semiconductor acoblats bidireccionalment operant en r`egim de LFFs, amb un m`etode que t´e en compte el nombre de patrons prohibits que apareixen en la s`erie temporal. Hem quantificat el grau d’estocasticitat del sistema en funci´o del nivell de bombeig al qual est`an sotmesos els dos l`asers. La seg¨uent arquitectura d’acoblament que hem estudiat consisteix en dos l`asers acoblats unidireccionalment a trav´es de dos camins. En aquest cas hem analitzat com es veu afectada la sincronitzaci´o sota diferents valors de l’acoblament dels dos camins, aix´ý com el potencial d’aquest esquema experimental per realitzar comunicacions ca`otiques. Per ´ultim hem caracteritzat la sincronitzaci´o a retard zero per dos l`asers acoblats bidireccionalment, a on els dos l`asers tenen la seva pr`opia realimentaci´o `optica. En particular, hem estudiat els events de desincronitzaci´o i la seva estad´ýstica per a diferents corrents d’injecci´o. Els resultats experimentals obtinguts en aquesta Tesi, ofereixen una prespectiva global de les propietats estad´ýstiques de la din`amica de l`asers de semiconductor, tant a¨ýllats com acoblats a altres l`asers, que contribueixen a entendre millor aquests sistemes din`amics.

  • Experimental study of different LFF regimes in semiconductor lasers with an external cavity

     Aragoneses Aguado, Andres; Zamora Munt, Jordi; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    Congreso de Física Estadística
    Presentation's date: 2011-06-03
    Presentation of work at congresses

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  • Quantifying the statistical complexity of low-frequency fluctuations in semiconductor lasers with optical feedback

     Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Rosso, Osvaldo A.; Masoller Alonso, Cristina; Garcia Ojalvo, Jorge
    Physical review A
    Date of publication: 2010
    Journal article

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  • Quantifying stochasticity in the dynamics of delay-coupled semiconductor lasers via forbidden patterns

     Tiana Alsina, Jordi; Buldu, Jm; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Philosophical transactions of the Royal Society A. Mathematical physical and engineering sciences
    Date of publication: 2010-01
    Journal article

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  • DINAMICA NOLINEAL Y ESTOCASTICA EN SISTEMAS FISICOS Y BIOFISICOS

     Zamora Munt, Jordi; Domedel Puig, Nuria; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Espinar Calvo, Maria Lorena; De Sancristobal Alonso, Belen; Pons Rivero, Antonio Javier; Tiana Alsina, Jordi; Rue Queralt, Pau; Dies Miracle, Marta; Garcia Ojalvo, Jorge
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  • Dynamics of globally delay-coupled neurons displaying subthreshold oscillations

     Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Philosophical transactions of the Royal Society A. Mathematical physical and engineering sciences
    Date of publication: 2009-08
    Journal article

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    We study an ensemble of neurons that are coupled through their time-delayed collective mean field. The individual neuron is modelled using a Hodgkin–Huxley-type conductance model with parameters chosen such that the uncoupled neuron displays autonomous subthreshold oscillations of the membrane potential. We find that the ensemble generates a rich variety of oscillatory activities that are mainly controlled by two time scales: the natural period of oscillation at the single neuron level and the delay time of the global coupling. When the neuronal oscillations are synchronized, they can be either in-phase or out-of-phase. The phase-shifted activity is interpreted as the result of a phase-flip bifurcation, also occurring in a set of globally delay-coupled limit cycle oscillators. At the bifurcation point, there is a transition from in-phase to out-of-phase (or vice versa) synchronized oscillations, which is accompanied by an abrupt change in the common oscillation frequency. This phase-flip bifurcation was recently investigated in two mutually delay-coupled oscillators and can play a role in the mechanisms by which the neurons switch among different firing patterns.

  • Dynamical behavior of delay-coupled semiconductor lasers.

     Martinez Gonzalez, Maria Cristina
    Defense's date: 2009-01-30
    Department of Applied Physics, Universitat Politècnica de Catalunya
    Theses

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  • PROPIETATS DINÀMIQUES I NO LINIALS DE MATERIALS I SITEMES FOTÒNICS, ELÈCTRICS I BIOLÒGICS

     Belana Punseti, Juan; Nistor, Ioan Cristian; Domedel Puig, Nuria; Diego Vives, Jose Antonio; Cañadas Lorenzo, Juan Carlos; Mudarra Lopez, Miguel; Masoller Alonso, Cristina; Òrrit Prat, Jordi; Aragoneses Aguado, Andres; Trull, Jose; Staliunas, Kestutis; Font Garcia, Josep Lluís; Cojocaru, Crina Maria; Herrero Simon, Ramon; Torrent Serra, Maria Del Carmen; Vilaseca Alavedra, Ramon; Espinar Calvo, Maria Lorena; De Sancristobal Alonso, Belen; Pons Rivero, Antonio Javier; Sellarès González, Jordi; Tiana Alsina, Jordi; Zamora Munt, Jordi; Roppo, Vito; Garcia Ojalvo, Jorge
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    Lag alternance in unidirectional coupled semiconductor lasers  Open access

     Tiana Alsina, Jordi; García López, J.H.; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Conference on lasers and electro-optics
    Presentation's date: 2009-06-14
    Presentation of work at congresses

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  • Research activities of the Group on Nonlinear Dynamics, Nonlinear Optics and Lasers (DONLL) at the Universitat Politència de Catalunya (Campus de Terrassa)

     Martínez, Cristina; Tiana Alsina, Jordi; Zamora Munt, Jordi; Nistor, Ioan Cristian; Roppo, Vito; Espinar Calvo, Maria Lorena; Fernandez Soler, Juanjo; Font Garcia, Josep Lluís; Cojocaru, Crina Maria; Trull, Jose; Herrero Simon, Ramon; Staliunas, Kestutis; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Vilaseca Alavedra, Ramon
    Reunión Nacional de Óptica
    Presentation's date: 2009-09-14
    Presentation of work at congresses

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  • Interplay of subthreshold activity, time-delayed feedback, and noise on neuronal firing patterns

     Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2008-10
    Journal article

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  • Synchronization via clustering in a small delay-coupled laser network

     Martinez Gonzalez, Maria Cristina; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Europhysics letters
    Date of publication: 2007-09
    Journal article

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  • Controlling the leader-laggard dynamics in delay-synchronized lasers

     Martinez Gonzalez, Maria Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Chaos
    Date of publication: 2007
    Journal article

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  • Synchronization via clustering in a small semiconductor laser network

     Martinez Gonzalez, Maria Cristina; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Conference on Lasers and Electro-Optics/Europe
    Presentation of work at congresses

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  • GABA: Global Approach to Brain Activity (FP6-2005-NEST-Path-043309)

     Garcia Ojalvo, Jorge; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Pons Rivero, Antonio Javier
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  • Neuronal multistability induced by delay

     Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    International conference on artificial neural networks
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    Processing distributed inputs in coupled excitable lasers  Open access

     Martinez Gonzalez, Maria Cristina; Martín Buldú, Javier; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review A
    Date of publication: 2007-11
    Journal article

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    In many instances, networks of dynamical elements are subject to distributed input signals that enter the network through different nodes. In these cases, processing of the input signals may be mediated by coupling, in what constitutes an emerging property of the network. Here we study experimentally this effect in two mutually injected semiconductor lasers with optical feedback, operating in an excitable regime. The lasers are subject to different periodic input signals in their pump current, with distinct frequencies. Our results show that when the signals are harmonics of an absent fundamental, the laser array is able to process these signals and respond at the missing fundamental frequency. When the input frequencies are rigidly shifted from their harmonic values, the response frequency follows a simple law derived from a linear sum of the inputs, even though the array integrates the electrical inputs after having transduced them optically. The results are reproduced numerically with a dynamical model of the laser array.

    In many instances, networks of dynamical elements are subject to distributed input signals that enter the network through different nodes. In these cases, processing of the input signals may be mediated by coupling, in what constitutes an emerging property of the network. Here we study experimentally this effect in two mutually injected semiconductor lasers with optical feedback, operating in an excitable regime. The lasers are subject to different periodic input signals in their pump current, with distinct frequencies. Our results show that when the signals are harmonics of an absent fundamental, the laser array is able to process these signals and respond at the missing fundamental frequency. When the input frequencies are rigidly shifted from their harmonic values, the response frequency follows a simple law derived from a linear sum of the inputs, even though the array integrates the electrical inputs after having transduced them optically. The results are reproduced numerically with a dynamical model of the laser array.

  • Controlling the leader-laggard dynamics in delay-synchronized lasers

     Gonzalez, C; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Chaos
    Date of publication: 2007-09
    Journal article

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  • Synchronization via clustering in a small delay-coupled laser network

     Gonzalez, C; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Europhysics letters
    Date of publication: 2007-09
    Journal article

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  • Synchronization in Semiconductor Laser Rings

     Martin Buldu, Javier; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Journal of lightwave technology
    Date of publication: 2007-06
    Journal article

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  • Grup de Recerca "Làsers i propietats elèctriques i òptiques dels materials

     Garcia Ojalvo, Jorge; Herrero Simon, Ramon; Torrent Serra, Maria Del Carmen; Vilaseca Alavedra, Ramon; Font Garcia, Josep Lluís; Botey Cumella, Muriel; Cañadas Lorenzo, Juan Carlos; Cojocaru, Crina Maria; Diego Vives, Jose Antonio; Fernandez Soler, Juanjo; Masoller Alonso, Cristina; Mudarra Lopez, Miguel; Sellarès González, Jordi; Serrat Jurado, Carles; Staliunas, Kestutis; Trull, Jose
    Participation in a competitive project

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  • Dinámica y sincronización de láseres de semiconductor y aplicaciones (TEC2005-07799-C02-02)

     Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen
    Participation in a competitive project

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  • Ghost stochastic resonance with distributed inputs in pulse-coupled electronic neurons

     Lopera, A; Martin Buldu, Javier; Torrent Serra, Maria Del Carmen; Chialvo, D R; Garcia Ojalvo, Jorge
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2006-02
    Journal article

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  • Episodic synchronization via dynamic injection

     Martin Buldu, Javier; Heil, T; Fischer, I; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review letters
    Date of publication: 2006-01
    Journal article

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  • Zero-lag long-range synchronization via dynamical relaying

     Fischer, I; Vicente, R; Martin Buldu, Javier; Peil, M; Mirasso, C; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review letters
    Date of publication: 2006-09
    Journal article

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  • Coupling-mediated ghost resonance in mutually injected lasers

     Martin Buldu, Javier; Martinez Gonzalez, Maria Cristina; Trull, Jose; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Chaos
    Date of publication: 2005-03
    Journal article

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  • Noise and coupling in diode lasers

     Garcia Ojalvo, Jorge; Buldú, J M; González, C M; Torrent Serra, Maria Del Carmen
    5th EUROMECH Nonlinear Dynamics Conference
    Presentation of work at congresses

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  • Grup Consolidat: Làsers i Propietats Elèctriques i Optiques dels Materials

     Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen; Vilaseca Alavedra, Ramon
    Participation in a competitive project

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  • Dinàmiques no lineals d'autoorganització espai-temporal (2004XT-00013)

     Garcia Ojalvo, Jorge; Auguet Sangra, Carlota Eugenia; Mercader Calvo, Maria Isabel; Ramirez de La Piscina Millan, Laureano; Torrent Serra, Maria Del Carmen; Alonso Maleta, Maria Aranzazu
    Participation in a competitive project

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  • Coupling-mediated ghost resonance in mutually injected lasers

     Martin Buldu, Javier; González, C M; Trull, Jose; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Chaos
    Date of publication: 2005-03
    Journal article

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  • Demultiplexing chaos from multimode semiconductor lasers

     Martin Buldu, Javier; Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen
    IEEE journal of quantum electronics
    Date of publication: 2005-02
    Journal article

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  • External noise in semiconductor lasers

     Buldú, J M; Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen; Sancho, J M; Mirasso, C; Chialvo, D
    Fluctuations and Noise in Photonics and Quantum Optics II - 2nd SPIE Symposium on Fluctuations and Noise
    Presentation of work at congresses

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  • Ghost resonance in coupled lasers

     Garcia Ojalvo, Jorge; Buldú, J M; González, C M; Torrent Serra, Maria Del Carmen; Trull, Jose; Mirasso, C R
    Experimental Chaos Conference 8 (ECC8)
    Presentation of work at congresses

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  • Autoorganización en sistemas complejos bajo fuctuaciones

     Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen
    Participation in a competitive project

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  • External noise in semiconductor lasers

     Martin Buldu, Javier; Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen; Sancho, J M; Mirasso, C R; Chialvo, D R
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2004-05
    Journal article

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