1,720,963 research outputs found
All-UV-written integrated planar Bragg gratings and channel waveguides with no phase mask
No full textDirect UV writing provides an attractive route towards low-cost integrated optical components in photosensitive silica-on-silicon wafers. Combining closely packed channel waveguides with a Bragg grating tailored spectral response would allow the creation of compact systems for wavelength division multiplexing on a single optical chip. To this end, we present our new technique for simultaneous definition of channel waveguides with integral Bragg gratings based on the interference of two focussed UV-writing beams. This single-step approach promotes optimal use of sample photosensitivity for both the waveguide geometry and Bragg grating structure and allows implementation of many aspects of advanced grating design, such as chirp and apodisation, with no need for a phase mask
All-UV-written integrated planar Bragg gratings and channel waveguides through single-step direct grating writing
No full textWe present a single-step technique for defining 2-dimensional integrated channel waveguide structures with internal Bragg gratings in photosensitive germanosilica-on-silicon substrates using two interfering focussed UV beams. Detailed device analysis of the relationship between the photosensitive properties of the glass, UV writing conditions, and subsequent refractive index change and channel waveguide strength is presented based on grating characterisation. Through software control, 300nm wide grating detuning across the E, S, C, L, and U wavelength bands is demonstrated
Ultra-wide planar Bragg grating detuning and 2D channel waveguide integration through direct grating writing
No full textWe present a technique for defining 20 channel waveguide structures with internal Bragg gratings in photosensitive germanosilica-on-silicon using two interfering focussed UV beams. Grating detuning across the S, C, and L bands is demonstrated
Small-spot interference pattern for single-step 2D integration and wide wavelength detuning of planar Bragg gratings
No full textA single-step technique for defining 2D channel waveguide structures with internal Bragg gratings in photosensitive germanosilica-on-silicon using two interfering focused UV beams is presented. Through software control, grating detuning across the S-, C-, and L-wavelength bands is also demonstrated
Photosensitivity locking technique applied to UV written planar Bragg gratings
No full textA technique is presented for thermally processing deuterium loaded silica-on-silicon samples to provide air enhanced photosensitivity lifetime of at least one year at room temperature. Subsequent simultaneous writing of channel waveguides and Bragg gratings resulted in grating reflections of ~80% with a FWHM of 0.1 nm
Single-step definition of channel waveguides with integral Bragg gratings in germanosilica-on-silicon wafers by direct UV writing
No full textWe present a single-step technique for defining channel waveguides with internal Bragg gratings in photosensitive germanosilica-on-silicon using two interfering focussed UV beams. Early devices exhibit reflection intensities of 80% with <0.15nm bandwidth
Direct UV writing of Bragg grating channel waveguides in a single step process
No full textWe present a development of Direct UV writing that allows simultaneous definition of channel waveguides with or without Bragg gratings in a single process in photosensitivity locked planar silica-on-silicon samples
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
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