1,721,243 research outputs found
Optical Modulators in Silicon Photonic Circuits
No full textThis text provides an important and timely overview of the ‘hot topics’ in thefield, covering the various aspects of the technology that form the research ..
Silicon Photonic Waveguides
No full textThis text provides an important and timely overview of the ‘hot topics’ in thefield, covering the various aspects of the technology that form the research ..
Silicon Photonic Waveguides
No full textThis text provides an important and timely overview of the ‘hot topics’ in thefield, covering the various aspects of the technology that form the research ..
Experimental evidence of modal properties using directional couplers in silicon-on-insulator - art. no. 61250N
No full textThe single-mode optical rib waveguide is a fundamental building block for many, more complex optical circuits. Recent modelling has been provided in the literature that has investigated polarisation and modal properties of small, deeply-etched rib waveguides in SOL In this paper we present work that has utilised a total of 160 directional couplers fabricated from rib waveguides of various waveguides dimensions, to investigate the validity of the published modelling. In particular 5 waveguide designs have been used to fabricate directional couplers of differing lengths, to map out the variation in coupling of power within the directional couplers. For a singlemode device, a characteristic sinusoidal variation is expected, but the sinusoid will be corrupted in the presence of higher order modes, each of which will have a different coupling length as compared to the fundamental mode. We have observed experimental results that are consistent with the modelling for each of the 5 waveguide designs, and hence we present experimental evidence of higher-order mode behaviour that is consistent with modelling
Silicon waveguides for the mid-infrared wavelength region - art. no. 68980T
No full textMid-infrared wavelength region is interesting for several application areas including sensing, communications, signal processing, and imaging. Its importance stems from the two atmospheric windows and the fact that nearly all important molecular gases have strong absorption lines in the mid-infrared. In this paper, we discuss the design, fabrication and propagation loss measurements of three silicon waveguide structures that can find applications in the mid-infrared region
Sub-micron optical waveguides for silicon photonics formed via the Local Oxidation of Silicon (LOCOS) - art. no. 68980R
Full text linkIn this paper we report a novel fabrication technique for silicon photonic waveguides with sub-micron dimensions. The technique is based upon the Local Oxidation of Silicon (LOCOS) process widely utilised in the fabrication of microelectronics components. This approach enables waveguides to be fabricated with oxide sidewalls with minimal roughness at the silicon/SiO2 interface. It is also sufficiently flexible to enable the depth of the oxidised sidewall to be varied to control the polarisation performance of the waveguides.We will present preliminary results on submicron waveguide fabrication and loss characteristics (less than 1 dB/cm), as well as effects of varying waveguide width on modal properties of the waveguides. We consider the ease of fabrication, as well as the quality of the devices produced in preliminary experimental fabrication results, and compare the approach to the more conventional requirements of high resolution photolithographically produced waveguides. We also discuss preliminary optical results, as measured by conventional means. Issues such as the origins of loss are discussed in general terms, as are the fabrication characteristics such as waveguide wall roughness and waveguide profile. We will discuss further work that will help to establish the potential of the technique for future applications
Novel fabrication techniques for silicon photonics - art. no. 64770E
No full textIn this paper we report two novel fabrication techniques for silicon photonic circuits and devices. The techniques are sufficiently flexible to enable waveguides and devices to be developed for telecommunications wavelengths or indeed other wavelength ranges due to the inherent high resolution of the fabrication tools. Therefore the techniques are suitable for a wide range of applications. In the paper we discuss the outline fabrication processes, and discuss how they compare to conventional processing. We compare ease of fabrication, as well as the quality of the devices produced in preliminary experimental fabrication results. We also discuss preliminary optical results from fabricated waveguide devices, as measured by conventional means. In these preliminary results we discuss fundamental properties of the waveguides such as loss and spectral characteristics, as it is these fundamental characteristics that will determine the viability of the techniques. Issues such as the origins of the loss are discussed in general terms, as resulting fabrication characteristics such as waveguide surface roughness (and hence loss), or waveguide profile and dimensions may be traded off against cost of production for some applications. We also propose further work that will help to establish the potential of the technique for future applications
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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