1,720,957 research outputs found
Mach-Zehnder-based 1×16 multiplexer in SOI and analysis of phase noise properties
No full textA Silicon Photonic 1×16 Mach-Zehnder-based demultiplexer is presented. The device shows insertion loss values lower than 1.5dB and channel isolation of ∼20dB. A phase noise analysis is also presented showing the different statistics of intra-die and inter-die phase fluctuations
Wide-band polarization controller for Si photonic integrated circuits
No full textA circuit for the management of any arbitrary polarization state of light is demonstrated on an integrated silicon (Si) photonics platform. This circuit allows us to adapt any polarization into the standard fundamental TE mode of a Si waveguide and, conversely, to control the polarization and set it to any arbitrary polarization state. In addition, the integrated thermal tuning allows kilohertz speed which can be used to perform a polarization scrambler. The circuit was used in a WDM link and successfully used to adapt four channels into a standard Si photonic integrated circuit
Polarization Controller for Si photonic integrated circuits with an active closed loop control
No full textA polarization insensitive silicon photonic circuit for the management of any arbitrary polarization state of light coming from a fiber linked to a remote source is demonstrated. WDM channels with a common arbitrary polarization at the input are automatically equalized
Geometrical Representation of a Polarisation Management Component on a SOI Platform
Full text linkGrating couplers, widely used in Silicon Photonics (SiPho) for fibre-chip coupling are polarisation sensitive components, consequently any polarisation fluctuation from the fibre optical link results in spurious intensity swings. A polarisation management componentis analytically considered, coupled with a geometrical representation based on phasors and Poincaré sphere, generalising and simplifying the treatment and understanding of its functionalities. A specific implementation in SOI is shown both as polarisation compensator and polarisation controller, focusing on the operative principle. Finally, it is demonstrated experimentally that this component can be used as an integrated polarimeter
Simulazione di un filtro ottico accordabile a cristallo fotonico
No full textSi è simulato, con COMSOL 3.5a, lo spettro di trasmissione di un filtro ottico accordabile.
Tale filtro è formato da 2 membrane parallele di GaAs, sulle quali è realizzato un cristallo fotonico, con una cavità risonante al suo interno, in modo che il filtro sia passa-banda.
Il filtro viene accordato variando la distanza tra le membrane tramite attuazione elettrostatica.
Tale dispositivo è collegato al resto del circuito ottico integrato tramite ridge waveguides.
Dalle simulazioni è emerso che l'intervallo di lunghezze d'onda cu cui si ha sintonizzazione è dell'ordine della decina di nm.
Tale dispositivo è stato studiato per usarlo come componente all'interno di un laser accordabile. Altri utilizzi potrebbero essere, ad esempio, la realizzazione di uno spettrometro integrat
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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