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Ge photodiode integrated with a Si ring modulator. 1V, 40Gb/s at 3.3V) for the electrical-to-optical (E-to-O) signal conversion. In a prototyping example, Absil showcased the 3D heterogenous integration of a 40nm CMOS driver chip on top of a photonics chip, assembled through a 150μm-pitch flip-chip process. Running at 10Gb/s, the drivers and the photonics elements (modulators, passive filters for multiplexing/de-multiplexing, thermo-optic tuners and single fiber I/Os) dissipated 0.38pJ/bit from a 1V power supply. Absil also disclosed a Ge photodiode integrated with a Si ring modulator capable of 20Gb/s operation. Such combinations have already led to proprietary silicon photonics bio sensors aimed at the analysis of clinical samples. Capable of sensing surface molecular bindings directly, offering real-time results for multiple arrays of tests on a single-chip, the photonics sensors could accelerate diagnostics and drug developments. The prototypes are produced via the ePIXfab and Europractice IC service. A roadmap for the internet of power Focusing on energy-related topics, Business Development Director Philip Pieters detailed imec’s research strategy as a roadmap to the internet of power. Pieters noted that with the democratization of photovoltaic technology, the same decentralization trend that the internet had enabled with data (generated by users locally rather than centrally controlled, and stored anywhere on portable devices) had to be replicated with the power generation industry, shifting from centrally-controlled large-scale power plants with grid balancing, to decentralized energy production by prosumers (i.e consumers with their own roof-top or façade PV installations) combined with distributed energy storage solutions. While for decentralized energy production, imec looks into silicon and also organic photovoltaics, for distributed storage, the research centre explores electrochemical solutions for solidstate batteries. Looking at further deployments of photovoltaic capacity in Europe, research from the European Photovoltaic Industry Association (EPIA - www.Epia.org) suggests that local PV-energy production throughout Europe would require 10% of additional PV capacity compared to a “PV in the South” approach. Yet, it would still be more efficient and cost effective to locate PV installations where consumption is located, instead of adopting a “PV in the South” scenario which would somehow “centralize” PV-energy production in the sunnier South and drastically increase total energy costs through additional power transmission and distribution lines. Pieters highlighted that reaching grid-parity in terms of PV-generated electricity price (as it is the case in Germany for example) is not enough to make photovoltaics a winner, the cost of local energy storage has to be taken into account when calculating the levelized cost of electricity. This not only means that PV modules should output more (hence the on-going research), it also means that localized energy storage should be implemented at very low cost. Through the Solliance organic PV program, imec has demonstrated stacked polymer triple junction cells reaching efficiencies over 9.5%, which can be manufactured through a low-temperature IMEC TECHNOLOGY FORUM solution-based process. Potentially much cheaper than silicon-based approaches, such cells would prove useful when laminated onto large building areas. Imec’s roadmap for solid-state batteries starts from the characterisation of a planar thin-film Li-ion battery, studying one interface at a time to determine the right solid electrolyte (with high ionic conductivity but small electronic conductivity). Initial research started with a demonstration platform using a Li4Ti5O12 anode and a LiMn2O4 cathode using the respective Lithium-free precursors TiO2 and MnO2. Imec’s exploration roadmap for solid-state batteries. With this approach, imec plans to look into two directions, one relying on thin film deposition over metal foils (in a roll-toroll process) while also exploring 3D microstructures (such as silicon micro-pillars) to design solid-state flex batteries. Another direction would be to develop ceramic batteries built around pressed pellets and bipolar stacks. Pieters sees 3D thin-film batteries evolve into a large area technology by 2020. The toolbox for this research includes materials modelling to screen materials and establish physical models, but also all the thin-film deposition and patterning techniques, with chemical modification processes. Fifty shades of light: smart lenses as a blue-sky experiment PhD candidate at Gent University, Jelle De Smet gave us a lecture on smart lenses, or what electronically active lenses ought to bring to their wearers, not just improved sight, but possibly extra information. With no definite time line, the ultimate goal would be to integrate an LCD to provide readable information sent wirelessly from a mobile. For now, De Smet has designed a cable-tied A smart lens concept presented by Jelle De Smet. 14 Electronic Engineering Times Europe November 2013 www.electronics-eetimes.com


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