Search results for " Integrated"
showing 10 items of 307 documents
Experimental demonstration of Bloch mode parity change in photonic crystal waveguide
2004
We experimentally show coupling between two photonic crystal waveguide Bloch modes having a different parity. A monomode ridge waveguide etched in a silicon-on-insulator substrate and connecting to the photonic crystal waveguide allows us to excite the even Bloch mode. Transmission measurements, performed on a broad spectral range, show the even mode propagation along the defect line. Then, spectrally resolved near-field patterns obtained by using a scanning near-field optical microscope in collection mode for wavelengths, inside and outside the multimode region of the photonic crystal waveguide, clearly demonstrate coupling phenomenon between even and odd modes.
Evaluation of performance of a hybrid electro-optic directional coupler and a Mach–Zehnder switch
2017
The efficiency of an electro-optic (EO) directional coupler (DC) and a Mach–Zehnder (MZ) switch is discussed. The specific designs employ a passive waveguide core and an EO cladding. The performance of a DC switch was evaluated by numerical methods, namely coupled mode theory (CMT), eigenmode expansion (EME) method, and beam envelope method. Using the CMT and EME methods, it is shown that in the DC with a passive waveguide core and EO cladding at certain waveguide parameters the switching effect does not take place. The effect is demonstrated for the first time and suggests that careful optimization of the DC switch should be done before experimental realization of the device. The efficienc…
Synchronized photonic modulators driven by surface acoustic waves
2013
Photonic modulators are one of the most important elements of integrated photonics. We have designed, fabricated, and characterized a tunable photonic modulator consisting of two 180 degrees-dephased output waveguide channels, driven by a surface acoustic wave in the GHz frequency range built on (Al,Ga)As. Odd multiples of the fundamental driven frequency are enabled by adjusting the applied acoustic power. A good agreement between theory and experimental results is achieved. The device can be used as a building block for more complex integrated functionalities and can be implemented in several material platforms. (C) 2013 Optical Society of America
Integrated optic surface plasmon resonance measurements in a borosilicate glass substrate
2008
The surface plasmon resonance (SPR) technique is a well-known optical method that can be used to measure the refractive index of organic nano-layers adsorbed on a thin metal film. Although there are many configurations for measuring biomolecular interactions, SPR-based techniques play a central role in many current biosensing experiments, since they are the most suited for sensitive and quantitative kinetic measurements. Here we give some results from the analysis and numerical elaboration of SPR data from integrated optics experiments in a particular borosilicate glass, chosen for its composition offering the rather low refractive index of 1.4701 at 633 nm wavelength. These data regard the…
Emission standards versus immission standards for assessing the impact of urban drainage on ephemeral receiving water bodies
2010
In the past, emission standard indicators have been adopted by environmental regulation authorities in order to preserve the quality of a receiving water body. Such indicators are based on the frequency or magnitude of a polluted discharge that may be continuous or intermittent. In order to properly maintain the quality of receiving waters, the Water Framework Directive, following the basic ideas of British Urban Pollution Manual, has been established. The Directive has overtaken the emission-standard concept, substituting it with the stream-standard concept that fixes discharge limits for each polluting substance depending on the self-depurative characteristics of receiving waters. Stream-…
Quantification of diffuse and concentrated pollutant loads at the watershed-scale: an Italian case study
2009
In this study, diffuse and point source pollutant loads were evaluated using an Italian case study: the Nocella catchment, which has been subject to extensive monitoring. The Nocella catchment is located in Sicily (Italy) and has an area of about 60 km2. The river receives wastewater and stormwater from two urban areas drained by combined sewers. The two sewer systems, two wastewater treatment plants and a river reach were monitored during both dry and wet weather periods. Thereafter, an integrated catchment-scale model was applied to simulate point pollutant sources, i.e., pollution coming from the urban drainage system, and nonpoint pollutant sources, i.e., pollution coming from agricultu…
Towards A New Decision Support System for Design, Management and Operation of Wastewater Treatment Plants for the Reduction of Greenhouse Gases Emiss…
2015
The increasing attention paid to the environment has led to a reduction in the emissions from wastewater treatment plants (WWTPs). Moreover, the increasing interest in the greenhouse gas (GHG) emissions from WWTPs suggests that we reconsider the traditional tools used for designing and managing WWTPs. Indeed, nitrous oxide, carbon dioxide and methane can be emitted from wastewater treatment, significantly contributing to the greenhouse gas (GHG) footprint. The reduction of energy consumption as well as GHG emission are of particular concern for large WWTPs which treat the majority of wastewater in terms of both volume and pollution load. Nowadays, there is an increasing need to develop new …
Design of MOS Current Mode Logic Gates – Computing the Limits of Voltage Swing and Bias Current
2005
Minimizing a quality metric for an MCML gate, such as power-delay product or energy-delay product, requires solving a system of nonlinear equations subject to constraints on both bias current and voltage swing. In this paper, we will show that the limits of the swing and the bias current are affected by the constraints on maximum area and maximum delay. Moreover, methods for computing such limits are presented.
The impact of foreign language mediated teaching on teachers’ sense of professional integrity in the CLIL classroom
2011
Content and language integrated learning (CLIL) has received significant interest in recent years as a practical means of creating a plurilingual European community. A key feature of CLIL is the non-native speaking teacher responsible for developing learners’ content and language knowledge in a foreign language mediated environment. Teachers often enter the CLIL classroom with established expertise in either content or language learning; however, the impact of entering the foreign language mediated environment is little explored in existing literature. This investigative research is based on six teacher interviews intended to access the teachers’ own understanding of how foreign language me…
New organisation for follow-up and assessment of treatment efficacy in sleep apnoea.
2019
Obstructive sleep apnoea (OSA) is a highly prevalent disease, and there is an increased demand for OSA diagnosis and treatment. However, resources are limited compared with the growing needs for OSA diagnosis and management, and alternative strategies need to be developed to optimise the OSA clinical pathway. In this review, we propose a management strategy for OSA, and in general for sleep-disordered breathing, to be implemented from diagnosis to follow-up. For this purpose, the best current options seem to be: 1) networking at different levels of care, from primary physicians to specialised sleep laboratories; and 2) use of telemedicine. Telemedicine can contribute to the improved cost-ef…