Simulation numérique de la propagation d'une source laser incohérente dans une fibre optique

International audienceLe présent travail concerne les lasers à fibre impulsionnels de puissance de type MOPFA (oscillateur laser maître suivi d'un amplificateur à fibre). Un travail expérimental a permis d'établir que les non-linéarités observées (effet Kerr, mélange à quatre ondes, effet Raman) pouvaient être de nature très différentes selon les caractéristiques de la source issue du laser maître sans toutefois permettre de déterminer si la statistique des photons est seule responsable des différents scénarios non-linéaires observés. Nous avons développé un code de simulation numérique afin de pouvoir valider l'hypothèse selon laquelle les propriétés du laser maître en termes de cohérence jouent un rôle prépondérant dans la manifestation des non-linéarités

All-optical time-domain demultiplexing of 170.8 Gbit/s signal in chalcogenide GeAsSe microstructured fibre

International audienceWe report on four-wave-mixing-based all-optical time-domain demultiplexing of a 170.8 Gb/s signal down to 42.7 Gb/s in a chalcogenide GeAsSe microstructured fiber. The high nonlinearity of the fiber allows error-free and low power penalty operation with only 56 mW of total input average power

Adult education and the social economy : rethinking the communitarian pedagogy of Watson Thomson

The goal of this thesis is to analyze the philosophy and pedagogy of an almost forgotten figure in Saskatchewan history, whose work has had a lasting impact on the theory and practice of adult education. Watson Thomson, who was appointed as director of the Adult Education Division (AED) by the newly elected CCF government of Tommy Douglas in 1944, initiated an ambitious program designed to animate the citizenry of Saskatchewan, bring a variety of educational services to the common person, and develop co-operative and community enterprises throughout the province. Thomson’s work is significant for a number of reasons. First, I compare and contrast it with the pedagogy of Brazilian educator, Paulo Freire. Second, I show that it was influenced by the humanistic philosophy of Personalism, especially that of Emmanuel Mounier. Third, and perhaps most importantly, Watson’s philosophy embodies insights from the depth psychology of Alfred Adler enabling him to advocate a distinctive, dialogical pedagogy. Fourth, his influence as director of the AED was considerable as can be gauged from the fact that within one year of its formation, the division had organized over 500 study-action groups and more than 100 cooperative enterprises. Fifth, Watson’s educational achievements are important not only for historical reasons but as a model for the development of social economy enterprises today, as evidence from a recent UNESCO report shows. The thesis uses an interdisciplinary approach of intellectual biography, historical documentation, and philosophical and psychological analysis in order to establish a comprehensive account of the theory and practice of this important figure

Wavelength conversion in a highly nonlinear chalcogenide microstructured fiber

International audienceWe report on all-optical wavelength conversion of a 56 Gb/s differential quadrature phase shift keying signal and a 42.7 Gb/s on-off keying signal. Wavelength conversion is based on four-wave mixing effect in a 1 m long highly nonlinear GeAsSe chalcogenide fiber. The high nonlinearity of the fiber allows low-power penalty operation with a total average power of less than 60 mW

A photonic basis for deriving nonlinear optical response

Nonlinear optics is generally first presented as an extension of conventional optics. Typically the subject is introduced with reference to a classical oscillatory electric polarization, accommodating correction terms that become significant at high intensities. The material parameters that quantify the extent of the nonlinear response are cast as coefficients in a power series - nonlinear optical susceptibilities signifying a propensity to generate optical harmonics, for example. Taking the subject to a deeper level requires a more detailed knowledge of the structure and properties of each nonlinear susceptibility tensor, the latter differing in form according to the process under investigation. Typically, the derivations involve intricate development based on time-dependent perturbation theory, assisted by recourse to a set of Feynman diagrams. This paper presents a more direct route to the required results, based on photonic rather than semiclassical principles, and offers a significantly clearer perspective on the photophysics underlying nonlinear optical response. The method, here illustrated by specific application to harmonic generation and down-conversion processes, is simple, intuitive and readily amenable for processes of arbitrary photonic order. © 2009 IOP Publishing Ltd

Entangled Stories: The Red Jews in Premodern Yiddish and German Apocalyptic Lore

“Far, far away from our areas, somewhere beyond the Mountains of Darkness, on the other side of the Sambatyon River…there lives a nation known as the Red Jews.” The Red Jews are best known from classic Yiddish writing, most notably from Mendele's Kitser masoes Binyomin hashlishi (The Brief Travels of Benjamin the Third). This novel, first published in 1878, represents the initial appearance of the Red Jews in modern Yiddish literature. This comical travelogue describes the adventures of Benjamin, who sets off in search of the legendary Red Jews. But who are these Red Jews or, in Yiddish, di royte yidelekh? The term denotes the Ten Lost Tribes of Israel, the ten tribes that in biblical times had composed the Northern Kingdom of Israel until they were exiled by the Assyrians in the eighth century BCE. Over time, the myth of their return emerged, and they were said to live in an uncharted location beyond the mysterious Sambatyon River, where they would remain until the Messiah's arrival at the end of time, when they would rejoin the rest of the Jewish people. This article is part of a broader study of the Red Jews in Jewish popular culture from the Middle Ages through modernity. It is partially based on a chapter from my book, Umstrittene Erlöser: Politik, Ideologie und jüdisch-christlicher Messianismus in Deutschland, 1500–1600 (Göttingen: Vandenhoeck & Ruprecht, 2011). Several postdoctoral fellowships have generously supported my research on the Red Jews: a Dr. Meyer-Struckmann-Fellowship of the German Academic Foundation, a Harry Starr Fellowship in Judaica/Alan M. Stroock Fellowship for Advanced Research in Judaica at Harvard University, a research fellowship from the Heinrich Hertz-Foundation, and a YIVO Dina Abramowicz Emerging Scholar Fellowship. I thank the organizers of and participants in the colloquia and conferences where I have presented this material in various forms as well as the editors and anonymous reviewers of AJS Review for their valuable comments and suggestions. I am especially grateful to Jeremy Dauber and Elisheva Carlebach of the Institute for Israel and Jewish Studies at Columbia University, where I was a Visiting Scholar in the fall of 2009, for their generous encouragement to write this article. Sue Oren considerably improved my English. The style employed for Romanization of Yiddish follows YIVO's transliteration standards. Unless otherwise noted, translations from the Yiddish, Hebrew, German, and Latin are my own. Quotations from the Bible follow the JPS translation, and those from the Babylonian Talmud are according to the Hebrew-English edition of the Soncino Talmud by Isidore Epstein

The Aussie, 1918-1931: cartoons, digger remembrance and First World War identity

Feelings of community, cultural definition and memory were kept alive through the soldiers’ mass circulation tabloid, the Aussie, examined here in the light of theorization of memory and representation, applied to both text and cartoons. The publication’s aim for veterans’ values to become shared national values is analysed in the light of its high profile usage of soft cartoon humour and also of nostalgia – highlighting the limitations as well as the effectiveness in terms of Australia’s evolving national identity. When the post-war economic situation worsened, deeper issues of national tension were glossed over by the use of scapegoats such as ‘profiteers’ and ‘lazy workers’. The armed forces were obliged to take on a political role of lobbying for their cause, but the Aussie as ‘cheerful friend’ experienced its own identity crisis that proved to be terminal

D7.3 First set of recommendations for the development of future rural policies (Version 1)

The aim of this Deliverable 7.2 is to summarise mechanisms by which SHERPA contributed recommendations for European Union (EU) policies, specifically on the EU Long-Term Vision for Rural Areas (LTVRA) and associated actions. The focus on this policy area was agreed with the EU, reflecting its relevance to the remit of SHERPA, and the timeliness of the evolution of the policy in relation to the operationalising of the SHERPA processes