224 research outputs found

    FWM-based wavelength conversion of 40 Gbaud PSK signals in a silicon germanium waveguide

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    We demonstrate four wave mixing (FWM) based wavelength conversion of 40 Gbaud differential phase shift keyed (DPSK) and quadrature phase shift keyed (QPSK) signals in a 2.5 cm long silicon germanium waveguide. For a 290 mW pump power, bit error ratio (BER) measurements show approximately a 2-dB power penalty in both cases of DPSK (measured at a BER of 10-9) and QPSK (at a BER of 10-3) signals that we examined

    Ancient DNA extraction and amplification of human bone samples from the area of Delphi: a pilot case study

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    The present work is a preliminary effort, an experiment on the extraction of ancient DNA from human remains from a proto-Byzantine context in the area of Delphi. The first results are encouraging; however, the interpretation of such analyses needs to be very careful. DNA and other scientific methods have to take into consideration all historical and socio-economic characteristics of a past society before the proposal, for example, of the existence or migration of specific ethnic groups in an area. The theoretical and methodological thinking of Archaeology in the last decades suggest that all scientific analyses have to evaluate the specific context and the complex nature of human existence before the application of any general-based model

    Screening for breast cancer : medicalization, visualization and the embodied experience

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    Women’s perspectives on breast screening (mammography and breast awareness) were explored in interviews with midlife women sampled for diversity of background and health experience. Attending mammography screening was considered a social obligation despite women’s fears and experiences of discomfort. Women gave considerable legitimacy to mammography visualizations of the breast, and the expert interpretation of these. In comparison, women lacked confidence in breast awareness practices, directly comparing their sensory capabilities with those of the mammogram, although mammography screening did not substitute breast awareness in a straightforward way. The authors argue that reliance on visualizing technology may create a fragmented sense of the body, separating the at risk breast from embodied experience

    Advanced nonlinear signal processing in silicon-based waveguides

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    This talk presents recent progress in optical signal processing based on compact waveguides fabricated mainly using silicon germanium alloys. Applications include supercontinuum generation, wavelength conversion and signal regeneration

    Wafer-Bonded Active/Passive Vertically Coupled Microring Lasers

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    We summarize the results of a European Project entitled WAPITI (Waferbonding and Active Passive Integration Technology and Implementation) dealing with the fabrication and investigation of active/passive vertically coupled ring resonators, wafer bonded on GaAs, and based on full wafer technology. The concept allows for the integration of an active ring laser vertically coupled to a transparent bus waveguide. All necessary layers are grown in a single epitaxial run so that the critical coupling gap can be precisely controlled with the high degree of accuracy of epitaxial growth. One key challenge of the project was to establish a reliable wafer bonding technique using BCB as an intermediate layer. In intensive tests we investigated and quantified the effect of unavoidable shrinkage of the BCB on the overall device performance. Results on cw-operation, low threshold currents of about 8 mA, high side-mode suppression ratios in the range of 40 dB and large signal modulation bandwidths of up to 5 GHz for a radius of 40 μm shows the viability of the integration process

    Athens by Sound

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    Architecture is not only that which is built. Architecture is made up of different aspects, both material and immaterial. The atmosphere, the sounds, the smells, the possibility of interaction between human bodies: these all constitute characteristics of space, characteristics that are assuming an increasing importance within architectural research worldwide. Within this field of thought about “Architecture Beyond Building”, we focus on one particular non-material spatial phenomenon that lies ‘beyond the built’: sound. We have created, thus, an interactive sonic map of Athens, which presents, in an unexpected way, fragments of the atmosphere of the city. What would a non-visual map look like? What would it feel like if you wandered within a forest of headphones, playing sounds from different places in Athens? How would it feel if you found yourself in a ‘map’ that only appeared when you walked in it? What would it be like if the map only appeared when you invited one more person to be with you? The Greek pavilion addresses these questions through an atmospheric interactive ‘game’, presenting fragments of sounds and visual sequences of Athens. The visitor recreates the space around him through his own presence and movement. The map appears only where he walks, and/or when he invites one more person to sit next to him. The bodies of the visitors react with one another and with the space itself, creating a dynamic, changing field. This walk in the pavilion takes you “out there”, through invisible Athens. The pavilion brings forth the aspects of architecture that are ‘beyond the material’: the ‘beyond the built’, the almost unreachable, elusive aspects of space, such as sound, non-visual senses, atmosphere. It challenges, thus, the limits of architecture, the limits of what can be mapped and re-located and what cannot. An edited collection by A. Karandinou, C. Achtypi, S. Giamarelos, including texts by: Ιntothepill, Katie Lloyd Thomas, Martin Parker, Panayiotis Tournikiotis, Mark Wigley, Dorian Wiszniewski, Leslie Kavanaugh, Stephen Cairns, Jonathan Hill, Vassilis Ganiatsas, Anastasios Kotsiopoulos, Constance Classen, Stavros Stavrides, Ole Bouman, William Mitchell, Richard Coyne, Neil Spiller, Kas Oosterhuis, Nora Schueler, Zissis Kotionis, Stelarc, Andreas Angelidakis, Aristide Antonas, Slavoj Žižek, Nikolaos Laskaris, Argyris Rokas, Andreas Kourkoulas, John Peponis, Yorgos Ioannou, Yorgos Tzirtzilakis, Konstantinos Vita, Dionyssis Kapsalis, United Visual Artists, Platon Rivellis, and Dimitris Filippidis. Contributors to the Greek National Participation to the 11th International Architecture Exhibition La Biennale di Venezia "Out there. Architecture beyond building" (2008) Organised by: Hellenic Ministry of Culture [yppo.gr] General Directorate of Modern Culture Directorate of Visual Arts Department for the Promotion of Contemporary Art Curators: Anastasia Karandinou Christina Achtypi Stylianos Giamarelos Video works by Intothepill net [intothepill.net] Artists: Yiannis Grigoriadis Yiannis Isidorou Lina Theodorou Sound Recording / Sound Design Dimitris Miyakis [movement.gr] Vangelis Lympouridis Exhibition Graphics / Catalogue Design Company [company-london.com] Design and Implementation of interactive environment 2monochannels [2monochannels.com] Audiovisual and interactive systems design / acoustic design / construction supervision Iraklis Lampropoulos Giorgos Lampropoulos Software programming Vassilis Boukis Electronic subsystem design Michail Kritsotakis Electrical Design Giorgos Satolias Interconnection of interactive elements Vangelis Lympouridis [inter-axions.com] Dimitris Miyakis Light design L+DG lighting architects [lightingdg.com] Thomas Gravanis Christina Frangeti Construction Gavrilos Michalis [gavrilos.gr] Digital printing Polichromo [polichromo.com] Translations Rachel Howard Nikos Masourides Catalogue photographs Intothepill – Internet video platform Catalogue published by futura publications Marketing communication Chryssa Vrouzi Communication associate Katerina Stamidi Photographer Cathy Cunliffe [cathycunliffeΑΤgmail.com] For their financial and material support for the Greek participation at the 11th International Exhibition of Architecture, La Biennale di Venezia, we express our deepest thanks to the sponsors: Alexander S. Onassis Public Benefit Foundation [onassis.gr] Akzonobel [akzonobel.com] Carteco - Architectural Materials & Design [carteco.gr] L+DG Lighting Architects [lightingdg.com] Plaisio [plaisio.gr] Polichromo Advertising Applications [polichromo.com] iGuzzini illuminazione [iguzzini.com] Diathlasis Architectural Lighting [diathlasis.gr

    Broadband telecom to mid-infrared supercontinuum generation in a dispersion-engineered silicon germanium waveguide

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    We demonstrate broadband supercontinuum generation (SCG) in a dispersion-engineered silicon-germanium waveguide. The 3 cm long waveguide is pumped by femtosecond pulses at 2.4 μm, and the generated supercontinuum extends from 1.45 to 2.79 μm (at the −30  dB point). The broadening is mainly driven by the generation of a dispersive wave in the 1.5–1.8 μm region and soliton fission. The SCG was modeled numerically, and excellent agreement with the experimental results was obtained

    FWM-based wavelength conversion of 40 Gbaud PSK signals in a silicon germanium waveguide

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    We demonstrate four wave mixing (FWM) based wavelength conversion of 40 Gbaud differential phase shift keyed (DPSK) and quadrature phase shift keyed (QPSK) signals in a 2.5 cm long silicon germanium waveguide. For a 290 mW pump power, bit error ratio (BER) measurements show approximately a 2-dB power penalty in both cases of DPSK (measured at a BER of 10-9) and QPSK (at a BER of 10-3) signals that we examined
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