Complex dynamics of delay-coupled semiconductor lasers: fundamentals and applications

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dc.contributor.author Porte Parera, Javier
dc.date 2015
dc.date.accessioned 2019-03-29T10:35:58Z
dc.date.available 2019-03-29T10:35:58Z
dc.date.issued 2019-03-29
dc.identifier.uri http://hdl.handle.net/11201/149201
dc.description.abstract [cat] La present tesi est`a dedicada a l’estudi dels l`asers de semiconductor sotmesos a realimentaci ´o i a acoblament `optics amb retard. Les complexes propietats din`amiques i espectrals d’aquests sistemes han sigut investigades emprant les actuals tecnologies de detecci´o en l’`ambit de les telecomunicacions. Mitjan¸cant aquestes eines, hem sigut capa¸cos de caracterizar experimentalment propietats dels nostres sistemes fins aleshores desconegudes. Durant aquest treball, ambd´os tipus de resultats, fonamentals i aplicats, s´on presentats pels diferents experiments que hem realitzat. La primera part de la tesi se centra en el sistema d’un l`aser sotm`es a realimentaci´o `optica amb retard. El problema de la caracteritzaci´o de la din`amica s’aborda des de la perspectiva de les escales de temps del sistema, relacionant els r`egims din`amics amb les freq¨u`encies caracter´ıstiques del l`aser amb realimentaci´o `optica. Hem trobat emp´ıricament que els quocients entre aquestes freq¨u`encies caracter´ıstiques determina completament la din`amica resultant, el que constitueix un enfocament independent de qualsevol model que es pot utilitzar, al mateix temps, per testejar la validesa dels models num`erics que tinguin la intenci´o d’explicar el comportament din`amic d’aquests l`asers. A m´es, la validesa general del nostre enfocament s’ha confirmat mitjan¸cant la seva aplicaci ´o a l`asers de caracter´ıstiques diferents. Les propietats espec´ıfiques de la din`amica d’aquest sistema tamb´e s’han caracteritzat a partir de la funci´o d’autocorrelaci´o de la intensitat. Per aquest prop`osit, l’autocorrelaci´o experimental es compara amb l’autocorrelaci´o obtinguda a partir del model per a un oscil·lador lineal estoc`astic amb retard. La relaci´o entre els par`ametres del model i els par`ametres del sistema experimental s’analitzen i discuteixen juntament amb els l´ımits de validesa d’aquest enfocament. En la segona part, hem estudiat diferents sistemes de dos l`asers acoblats amb retard. El fenomen de sincronitzaci´o del caos ´es explorat en dues configuracions diferents: una configuraci´o d’acoblament unidireccional on el senyal del l`aser amb realimentaci´o retardada tamb´e est`a acoblat `opticament a un segon l`aser, i un esquema bidireccional de dos l`asers acoblats m´utuament amb realimentaci´o pr`opia. A la primera configuraci´o, hem estudiat b`asicament la relaci´o entre la consist`encia de la din`amica i la possibilitat de sincronitzar el segon l`aser. En aquest ´ultim esquema, la robustesa de l’estat sincronitzat es caracteritza en funci´o del desajustament en els par`ametres i de l’efecte del soroll. A la pr`actica, utilitzam el coneixement adquirit en els experiments de sincronitzaci´o per implementar un protocol d’intercanvi de clau segura a trav´es d’un canal p´ublic en l’esquema d’acoblament bidireccional. A m´es de demostrar experimentalment la possibilitat d’implementar aquest protocol, analitzam els seus avantatges i debilitats. Finalment, presentam una implementaci´o fot`onica d’un sistema din`amic que experimenta dos temps de retard diferents depenent de l’estat del sistema. En aquest sistema experimental hem estudiat les caracter´ıstiques espectrals promitjades en el temps, aix´ı com tamb´e les condicions necess`aries perqu`e la din`amica ocorri en estats separats. Tamb´e hem investigat la intensitat i la din`amica dels espectres `optics en temps real per demostrar l’exist`encia i estudiar les propietats d’aquesta din`amica on el retard dep`en de l’estat del sistema. Curiosament, propietats qualitativament similars es poden trobar a partir d’un model num`eric adequat d’aquest sistema. En resum, al llarg d’aquesta tesi s’han presentat resultats d’`ambits fonamental i aplicat en el camp de l`asers de semiconductor acoblats `opticament amb retard. La fenomenologia presentada ´es de potencial utilitat en una varietat d’aplicacions que van des de la computaci´o de reservoris basada en sistemes fot`onics fins a les comunicacions amb senyals ca`otiques. A m´es, els aven¸cos de caire fonamental poden ser potencialment aplicats a altres classes de sistemes din`amics m´es enll`a dels l`asers de semiconductor. ca
dc.description.abstract [eng] Introduction: The present thesis is devoted to the study of semiconductor lasers subject to delayed optical feedback and coupling. The complex spectral and dynamical properties of these systems have been investigated using state-of-the-art telecommunications detection technologies. With such tools, we have been able to experimentally characterize previously unknown features in our delay-coupled systems. Along this work, both fundamental and applied results are presented for the different experiments investigated. Results: The first part of the thesis is focusing on the system of the single delayed feedback laser. The problem of feedback characterization is approached from a time scale perspective, relating the dynamical regimes to the characteristic frequencies of the delayed feedback laser. We have empirically found that the ratios of these characteristic frequencies completely determine the dynamical behavior. This constitutes a model independent approach that can be used, for example, to test the validity of numerical models that aim at explaining the dynamical behavior of these lasers. Furthermore, the general extent of our approach is validated by measuring various laser diodes with distinct characteristics. Specific properties of the dynamics of the single laser with feedback system have also been characterized by means of the intensity autocorrelation function. For this purpose, the experimental autocorrelation is compared with the autocorrelation obtained from a model of a stochastic linear oscillator with delay. The relation between the model parameters and the experimental system parameters is analyzed and discussed together with the limits of validity of this approach. In the second part, systems with two delay-coupled lasers are studied. The phenomenon of chaos synchronization is explored in two different configurations: a unidirectional coupling configuration where the delayed feedback laser signal is optically coupled to a second laser, and a bidirectional scheme of two mutually coupled lasers with self-feedback. In the first configuration, the relation between the consistency of the dynamics and the synchronizability with the second laser is studied. In the latter scheme, the robustness of the synchronized state is characterized against detuning in parameters and noise. The knowledge gained in the synchronization experiments is used to implement a classical public-channel secure-key exchange protocol in the bidirectional coupling scheme. This protocol is demonstrated experimentally, and its advantages and weaknesses are analyzed. Finally, we present a practical photonic implementation of a dynamical system experiencing two different delay times depending on the state of the system. The stationary spectral characteristics of this experimental system are studied and the conditions for the dynamics to occur in separated states are highlighted. We have also investigated the real-time intensity and optical spectrum dynamics to demonstrate the existence and properties of state-dependent delay dynamics. Qualitatively similar properties can be found from a proper numerical model of this system. Conclusions: Altogether, we have presented fundamental and applied aspects of semiconductor lasers optically coupled with delay. The presented phenomenology is of immediate potential use for a variety of applications that range from photonics-based reservoir computing to chaos communications. In addition, the presented fundamental insights can potentially be extended to other classes of dynamical systems. ca
dc.format application/pdf
dc.format.extent 177 ca
dc.language.iso eng ca
dc.publisher Universitat de les Illes Balears
dc.rights all rights reserved
dc.rights info:eu-repo/semantics/openAccess
dc.subject.other Semiconductor lasers ca
dc.subject.other Delay-coupled systems ca
dc.subject.other Nonlinear dynamics ca
dc.subject.other Chaos cryptography ca
dc.subject.other Statedependent delays ca
dc.title Complex dynamics of delay-coupled semiconductor lasers: fundamentals and applications ca
dc.type info:eu-repo/semantics/doctoralThesis
dc.type info:eu-repo/semantics/publishedVersion
dc.subject.udc 53 - Física ca
dc.subject.ac Física no lineal i de sistemes complexes ca
dc.contributor.director Fischer, Ingo
dc.contributor.codirector Cornelles Soriano, Miguel


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