1,720,963 research outputs found
0.15 dB/cm loss in Unibond SOI waveguides
No full textThe optical loss of Unibond waveguides is measured and reported for the first time, using grating couplers. At a wavelength of 1.3 µm, a loss of 0.15 ±0.05 dB/cm is obtained for TE polarisation. This allows good quality low loss integrated optical circuits to be fabricated at low cost
Silicon-on-Insulator based grating couplers
No full textAbout the meeting:PREP '99 was held in Manchester, UK at the University of Manchester Institute of Science and Technology when some hundred oral and poster presentations were made by postgraduate students. One of the most important features of this student conference was that many were presenting their work in public for the first time. There was no doubt that the young researchers responded enthusiastically to the challenge of presenting and publishing their research results to a wider audience and, particularly to their own generation of researchers. This was claimed to be the first student-focused conference in the UK that concentrated on electrons, photonics and related fields.The range of topics covered included presentations that covered innovative ideas in many areas such as: computer methods, sensors, device physics, materials fabricator techniques and digital and analogue circuitry.PREP was sponsored by the Engineering and Physical Sciences Research Council (EPSRC, UK), the IEE, the IEEE and IOP
Effects of grating heights on highly efficient Unibond SOI waveguide grating coupler
No full textWe report the first successful experimental evaluation of the effect of grating height upon the output efficiency of grating couplers as predicted using perturbation theory. In addition, we have also produced a grating with an output efficiency of 70%, which is the highest efficiency yet reported for a silicon-on-insulator waveguide grating coupler
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
Fabrication of Silicon blazed gratings for couplers
No full textTo our knowledge, no blazed grating has been fabricated in silicon (Si) at a pitch of less than half a micron. In this article, we report the fabrication of Si-blazed gratings at the period of 400 nm, using electron beam lithography and ion beam etching techniques. The blazed grating is extremely useful as a grating coupler in integrated optics, operating at the telecommunication wavelength of 1.3 µm, because very high output efficiency of the grating coupler is expected. This will allow coupling to thin film devices in silicon, previously not regarded as promising because coupling to them was very inefficient
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
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