Kerr frequency combs enable compact and robust platforms for applications such as data communications and spectroscopy. Initial demonstrations used dissipative soliton combs operating in the anomalous group velocity dispersion (GVD) regime to illustrate the promising capabilities of Kerr-comb-based technologies. However, many real-world applications, such as wavelength division multiplexing and LiDAR, benefit from higher comb-line powers that are inherently inaccessible to Kerr frequency combs. Nevertheless, nonsolitonic Kerr combs operating in the normal GVD regime offer promise as a platform for the integration of such applications due to their ability to easily access high pump-to-comb conversion efficiencies and spectral profiles with slower power falloffs. Unlike a dissipative Kerr soliton which is a single cycle periodic pattern on top of a homogenous background, a nonsolitonic Kerr comb arises through the interlocking of two switching waves of opposite polarity, each of which connects the two homogenous state solutions of the bistable cavity response. Here, we present a systematic approach for turn-key generation of Kerr combs in the normal GVD regime. We use a coupled ring geometry to induce and control avoided mode crossings for the generation of low-noise frequency combs with conversion efficiencies of up to 57%. Moreover, we explore the regime of synchronization for these nonsolitonic Kerr combs. Synchronization is a universal mechanism of coupled nonlinear oscillators that manifests itself as the spontaneous appearance of order within nature's tendency for disorder and chaos. It is a process by which the natural rhythms of interacting oscillators adjust to a common frequency and produce a mutually phase-locked state. In the realm of Kerr frequency combs, synchronization allows for the repetition rates, or equivalently the comb-line spacings, of individual Kerr combs to become identical. We reveal the universality of Kerr comb synchronization by synchronizing two nonsolitonic Kerr combs and thereby extending the scope of synchronization beyond the soliton regime. Furthermore, we introduce a method to overcome the inherently low output power of Kerr combs while maintaining the high conversion efficiency of a normal GVD Kerr comb. We demonstrate efficient comb-line power enhancement by coherently combining two nonsolitonic Kerr combs via on-chip synchronization. Our on-chip synchronization design removes the requirement for dispersion compensation of the coupling signal while increasing the overall stability of the system. Our techniques of comb generation, synchronization, and coherent combining enable nonsolitonic Kerr combs as a platform to achieve a fully integrated, high-power Kerr comb source.

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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Notre travail se consacre en premier lieu au thème de la quotidienneté conflictuelle puis, à l'analyse de la genèse et des enjeux de la division du monde qui touche l'homme contemporain. Cette division trouve d'abord son expression dans la multiplicité de discours qui tentent à partir des situations subjectivo-relatives divergentes, de fournir une explication de l'étant singulier et du monde en général; et ensuite, dans l'objectivation toujours plus poussée sur la nature par la science qui hypostase au-delà du monde de la vie naïve, le monde-objectif des formalisations mathématisantes. Dans un second temps, nous procédons en dialoguant avec l'œuvre de Jan Patocka (dont les points de passage sont (I) le motif de la Krisis et la méthode phénoménologique de Husserl, (II) l'analyse existentiale heideggerienne, et (III) le développement d'une phénoménologie asubjective) à l'ontologisation et l'historisation de la Lebenswelt. Nous découvrons alors qu'en unissant son effort à la révision de la métaphysique, la phénoménologie est à même de nous redonner l'unité apriorique du monde naturel comme monde du mouvement et de fournir les modalités de notre rapport au monde ainsi que la manière dont les choses du monde et le monde lui-même acquièrent leur signification pour l'humanité historique.

Informe de Seminario para optar al grado de Licenciado en Historia / La investigación que se da a conocer a través de estas páginas es una historia de la marginalidad urbana a comienzos del siglo XX, de actores sociales que, más allá de ser rechazados y segregados sistemáticamente por las clases propietarias y sus instituciones a lo largo y ancho de nuestra historia republicana –y más atrás aún–, han logrado construir su identidad y su proyección histórica y política desde los márgenes de la legitimidad del Estado. Es la historia de una marginalidad por opción y proyecto, no por razones de análisis sistémicos de la estructura social y económica, construidos desde la perspectiva de las clases altas, y de un modelo capitalista hegemónico, el cual redundaría más bien en el concepto de exclusión, según el cual lo que pretenderían los sujetos excluidos sería fundamentalmente la búsqueda de su inclusión al sistema político y económico, no la conflictividad que desarrollan respecto a éste.

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A presente tese, A forma confessional nos Diários de Miguel Torga, analisa os três diários iniciais do autor, escritos durante os anos de 1932 a 1946 e publicados entre 1941 e 1946. O recorte realizado procura, na primeira seção, mostrar o processo de constituição de Miguel Torga como autor intimista, que se deu na primeira metade do século passado, por meio dos debates do movimento presencista e da leitura intensa de autores confessionais. Esse percurso formativo foi fundamental para que pudesse elaborar um diário extremamente original, que soube preservar, no entanto, o lastro da tradição literária europeia, como demonstramos na segunda seção. Na seção final, realizamos a leitura imanente do Diário a fim de identificar e discutir as bem sucedidas estratégias de que Miguel Torga lançou mão para construir um texto em que sujeito, forma literária e vida social se entrelaçam profundamente. / The present thesis, The confessional form in the Diaries of Miguel Torga, analyses the authors three initial diaries, written during the years of 1932 and 1946 and published between 1941 and 1946. This work seeks to demonstrate, in the first section, the process by which Miguel Torga became an intimist author in the first half of the last century, through the debates conducted by the presencista movement and the extensive reading of confessional authors. As we demonstrate in the second section, that formative trajectory was fundamental for him to get to elaborate a highly original diary, which yet preserves the grounding of the literary European tradition. In the final section, we make an immanent reading of the Diary so to identify and discuss the successful strategies used by Miguel Torga in order to build a text in which subject, literary form and social life are intensely interwoven.