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- Item1-to- N ring power combiners with common delta ports(Institute of Electrical and Electronics Engineers (IEEE), 2019-01-04) Holzer, Kyle D.; Walling, Jeffrey S.; National Science FoundationIn this paper, we present a new 1-to-N way ring combiner that is an adaptation of the ring-hybrid (rat-race) structure. We present the general design guidelines for N-way planar ring combiners based on theoretical analysis of the structures. The proposed 1-to-N way ring structure offers a compact, planar layout that includes a single common delta port. This is beneficial to applications where power monitoring, calibration, or energy recycling can be leveraged. It offers similar loss to other N-way structures. To demonstrate the combiners operation, we present completely passive structures and structures with embedded power amplifiers for 4- and 6-way variants. The designs are optimized for operation in the 5-6 GHz unlicensed bands. The passive 4- and 6-way combiners achieve IL of 1.3 and 1 dB, respectively, with associated port isolations of <;-30 dB. The combiners with embedded amplifiers show similar performance and are validated using modulated signals and demonstrate good measured linearity when combining up to 6 amplifiers for output powers >1 W.
- Item10Gb/s low-cost directly modulated multi-electrode laser with suppressed thermal wavelength drift for burst-mode upstream transmission in TWDM-PONs(Optical Society of America, 2018-06-14) Porto, Stefano; van Veen, Doutje; Houtsma, Vincent; Basavanhally, Nagesh; Bolle, Cris; Schmuck, Harald; Townsend, Paul D.; Earnshaw, Mark; Pfeiffer, Thomas; Science Foundation IrelandWe report on a novel 10Gb/s low-cost multi-electrode DML employed as a very wavelength stable burst-mode source for upstream TWDM-PONs. 10X wavelength drift reduction is achieved compared to conventional DMLs enabling transmission on 100GHz grid.
- ItemA 10Gbps optical burst switching network incorporating ultra-fast (5ns) wavelength switched tunable laser sources(SPIE, 2017) Ryan, Neil; Todd, Michael; Farrell, Tom; Lavin, Adrian; Rigole, Pierre-Jean; Corbett, Brian M.; Roycroft, Brendan; Engelstaedter, Jan-PeterThis paper outlines the development of a prototype optical burst mode switching network based upon a star topology, the ultimate application of which could be as a transparent payload processor onboard satellite repeaters. The network architecture incorporates multiple tunable laser sources, burst mode receivers and a passive optical router (Arrayed Waveguide Grating). Each tunable optical signal should carry ≥10Gbps and be capable of wavelength switching in c. 5ns timescales. Two monolithic tunable laser types, based upon different technologies, will be utilised: a Slotted Fabry Perot laser (a Fabry Perot laser with slots added in order to introduce controlled cavity perturbations); and a Modulated Grating Y-Branch Laser (MGY: a widely tunable, multi-section device similar to the DBR laser). While the Slotted Fabry Perot laser is expected to achieve the required switching times, it is an immature technology not yet capable of achieving tunability over 80 ITU channels from a single chip. The MGY device is a more mature technology and has full C-band ITU channel coverage, but is not capable of the required short switching times. Hence, in order to facilitate the integration of this more mature technology into the prototype breadboard with the requisite switching time capabilities, a system of ‘dual laser’ transmitters is being developed to enable data transmission from one MGY laser while the other switches and vice-versa. This work is being performed under ESA contract AO 1-5025/06/NL/PM, Optical Technologies for Ultra - fast Processing.
- Item128 × 128 silicon photonic MEMS switch package using glass interposer and pitch reducing fibre array(Institute of Electrical and Electronics Engineers (IEEE), 2017-12) Hwang, How Yuan; Morrissey, Padraic E.; Lee, Jun Su; O'Brien, Peter A.; Henriksson, Johannes; Wu, Ming C.; Seok, Tae Joon; Science Foundation IrelandWe design and fabricate the packaging of 128 × 128 silicon photonic MEMS switch device using through glass via (TGV) interposer and pitch reducing fibre array. The switch device contains 16384 MEMS switch cells and 272 grating couplers spaced at 63.5 μm in a compact footprint of 17.4 mm × 16 mm. The apodised grating couplers designed for 1300 nm have an insertion loss of 2.5 dB/facet at 10° coupling angle. The 0.5 mm thick glass interposer contains 512 electrical vias while the pitch reducing optical coupling array is polished to 40° for planar coupling.
- Item(2+1)-dimensional photonic crystals from Langmuir-Blodgett colloidal multilayers(AIP Publishing, 2006) Romanov, Sergei G.; Bardosova, Maria; Pemble, Martyn E.; Torres, C. M. Sotomayor; Science Foundation Ireland; Sixth Framework ProgrammeAngle-resolved transmission spectra of multilayers of two-dimensional colloidal crystals prepared by the Langmuir-Blodgett technique have been studied. In contrast to the light diffraction in three-dimensional colloidal crystals, optical spectra revealed only very weak correlation between layers in the Langmuir-Blodgett multilayers. Two reasons for the observed transmission minima have been identified: the diffraction at a stack of layers and the scattering of the incident beam by guided modes of the two-dimensional colloidal crystals. (c) 2006 American Institute of Physics. (DOI:10.1063/1.2234568)
- ItemA 2-MS/s, 11.22 ENOB, extended input range SAR ADC with improved DNL and offset calculation(Institute of Electrical and Electronics Engineers (IEEE), 2018-11) Asghar, Sohail; Afridi, Sohaib Saadat; Pillai, Anu; Schuler, Anita; de la Rosa José; O'Connell, Ivan; Enterprise Ireland; European Regional Development Fund; Junta de AndalucíaA 12-bit successive approximation register analog-to-digital converter (ADC) with extended input range is presented. Employing an input sampling scaling technique, the presented ADC can digitize the signals with an input range of 3.2 V pp-d (±1.33 V REF ). The circuit also includes a comparator offset compensation technique that results in a residual offset of less than 0.5 LSB. The chip has been designed and implemented in a 0.13-μm CMOS process and demonstrates the state-of-the-art performance, featuring an SNDR of 69.3 dB and the SFDR of 79 dB without requiring any calibration. Total power consumption of the ADC is 0.9 mW, with a measured differential non-linearity of 1.2/-1.0 LSB and INL of 2.3/-2.2 LSB.
- Item25Gb/s PAM4 adaptive receiver equalisation requirements for burst-mode transmission systems(VDE Verlag GMBH, 2016-12-05) Dalla Santa, Marco; Antony, Cleitus; Talli, Giuseppe; Townsend, Paul D.; Science Foundation IrelandRequirements for burst-mode equalisation in a 25Gb/s PAM4 system for passive optical network upstream traffic are analysed for different linear equaliser solutions, with transmission over 40km of fibre. The impact of chromatic dispersion, transmitter bandwidth restriction and non-linearities is considered.
- Item25Gb/s PAM4 burst-mode system for upstream transmission in passive optical networks(Institute of Electrical and Electronics Engineers (IEEE), 2017-06-01) Dalla Santa, Marco; Antony, Cleitus; Power, Mark; Jain, Anil; Ossieur, Peter; Talli, Giuseppe; Townsend, Paul D.; Science Foundation IrelandA 25Gb/s PAM4 burst-mode upstream transmission is demonstrated over 25km of fiber using 10G components and a linear burst-mode TIA with a 14.7dB dynamic range and with differential chromatic dispersion equivalent to 25km of fiber.
- Item2D and 3D photonic crystal materials for photocatalysis and electrochemical energy storage and conversion(National Institute for Materials Science; Taylor & Francis, 2016-09) Collins, Gillian; Armstrong, Eileen; McNulty, David; O'Hanlon, Sally; Geaney, Hugh; O'Dwyer, Colm; National University of Ireland; Science Foundation IrelandThis perspective reviews recent advances in inverse opal structures, how they have been developed, studied and applied as catalysts, catalyst support materials, as electrode materials for batteries, water splitting applications, solar-to-fuel conversion and electrochromics, and finally as photonic photocatalysts and photoelectrocatalysts. Throughout, we detail some of the salient optical characteristics that underpin recent results and form the basis for light-matter interactions that span electrochemical energy conversion systems as well as photocatalytic systems. Strategies for using 2D as well as 3D structures, ordered macroporous materials such as inverse opals are summarized and recent work on plasmonic–photonic coupling in metal nanoparticle-infiltrated wide band gap inverse opals for enhanced photoelectrochemistry are provided.
- Item2D and 3D vanadium oxide inverse opals and hollow sphere arrays(Royal Society of Chemistry (RSC), 2014-10-24) Armstrong, Eileen; Osiak, Michal J.; Geany, Hugh; Glynn, Colm; O'Dwyer, Colm; Irish Research Council; Science Foundation Ireland; Seventh Framework ProgrammeHigh quality 2D and 3D inverse opals and hollow sphere arrays of vanadium oxide are grown on conductive substrates from colloidal polymer sphere templates formed by electrophoretic deposition or surfactant-assisted dip-coating. Inverse opals (IOs) are formed using variants of solution drop-casting, N2-gun assisted infiltration and high-rate (200 mm min−1) iterative dip-coating methods. Through Raman scattering, transmission electron microscopy and optical diffraction, we show how the oxide phase, crystallinity and structure are inter-related and controlled. Opal template removal steps are demonstrated to determine the morphology, crystallinity and phase of the resulting 2D and 3D IO structures. The ability to form high quality 2D IOs is also demonstrated using UV Ozone removal of PMMA spheres. Rapid hydrolysis of the alkoxide precursor allows the formation of 2D arrays of crystalline hollow spheres of V2O5 by utilizing over-filling during iterative dip-coating. The methods and crystallinity control allow 2D and 3D hierarchically structured templates and inverse opal vanadium oxides directly on conductive surfaces. This can be extended to a wide range of other functional porous materials for energy storage and batteries, electrocatalysis, sensing, solar cell materials and diffractive optical coatings.
- Item2D nanosheet paint from solvent-exfoliated Bi2Te3 ink(American Chemical Society, 2017-08-09) Carroll, Elaine; Buckley, Darragh; Mogili, N. V. V.; McNulty, David; Moreno, M. Sergio; Glynn, Colm; Collins, Gillian; Holmes, Justin D.; Razeeb, Kafil M.; O'Dwyer, Colm; Irish Research Council; Science Foundation Ireland; Consejo Nacional de Investigaciones Científicas y Técnicas; Agencia Nacional de Promoción Científica y Tecnológica; Horizon 2020; Analog Devices; Ministry of Science, Technology, Innovation and Communication, BrazilEmbedding 2D layered materials into polymers and other materials as composites has resulted in the development of ultrasensitive pressure sensors, tunable conductive stretchable polymers, and thermoelectric coatings. As a wettable paint or ink, many 2D materials may be penciled, printed, or coated onto a range of surfaces for a variety of applications. However, the intrinsic conductive properties of painted coatings using 2D and layered materials are not completely understood, and conductive polymer additives may mask underlying properties such as directional conductivity. We report a process for making a paint from solvent-exfoliated Bi2Te3 into solution-dispersible 2D and few-layer (multiple quintuple) nanosheet inks, that form smooth, uniform paint blends at several concentrations of Bi2Te3. The individual solvent-exfoliated nanosheets are edge-coated by (poly)ethylene glycol to produce a paint, stable over extended period in solution. Electrical transport is found to be sensitive to aspect ratio, and conduction along the painting direction is suppressed for longer strips so long as the aspect ratio is high (4–10× or more), but for short and wide paint strips (aspect ratio ≤1), conductance is improved by a factor of 3×. Square 2D paint regions show no clear directional preference for conductance at room temperature but are markedly affected by higher temperatures. Conductivity along a preferential conduction pathway through the nanosheet ensemble is modulated by 2D nanosheet stacking along the direction of paint application for a given aspect ratio. This paint and insights into geometrical 2D composite conduction may have implications for conductive composites, thermoelectrics, and writable circuits using 2D material paints or inks.
- ItemA 3D hand motion capture device with haptic feedback for virtual reality applications(Institute of Electrical and Electronics Engineers (IEEE), 2018-11-01) Torres-Sanchez, Javier; Tedesco, Salvatore; O'Flynn, Brendan; Science Foundation Ireland; European Regional Development Fund; Enterprise IrelandIn this paper, the challenges associated with the design of new generation hand motion capture devices for Virtual Reality (VR) applications are described. The need for developing a hand motion capture device with tactile feedback that integrates all the sensors and actuators associated with VR, while meeting the latency requirements is introduced. A detailed description of functional and non-functional specifications is also given. Finally, a comparison study with commercially available technology is provided highlighting that the proposed device compares favorably not only in terms of functional parameters, such as connectivity, integration of sensors and actuators, and latency, but also in terms of non-functional parameters, e.g., no need to wash, ambidextrous features and modularity.
- Item3D interconnection by FIB assisted Pt deposition and electroless nickel deposition on the sides and edges of an I-Seed(Institute of Electrical and Electronics Engineers (IEEE), 2006-05) Razeeb, Kafil M.; Nagle, Lorraine C.; Barton, John; Tassie, Paul; O'Flynn, Brendan; Rohan, James F.; Ó Mathúna, S. Cian; European CommissionThis paper reports on the development of a 3D interconnection process leading to the successful assembly of a five-layer 3-D 1mm cube module. This proof of concept module demonstrates the capability for successful integration and interconnection of commercial off the shelf components to fabricate functional modules in 1mm cube dimensions. It also demonstrates that use of established volume scale technologies like Flip-chip, dicing and patterning techniques are viable for fabricating these 1mm modules. The demonstrator consists of LED's bonded to the six sides of the 1mm cube, interconnected and powered up. The work will particularly report on two different processes to fabricate the interconnection pattern using direct Focused Ion Beam (FIB) assisted Pt deposition and electroless metal deposition, which again patterned by FIB. Uniform thickness of the deposit and excellent coverage on all six sides is achieved by electroless nickel deposition. Voltage current characterisation of the deposited Pt shows a resistivity value of 1864 +/- 100 mu Omega cm, whereas electroless Ni film shows a resistivity of 25 mu Omega cm due to boron inclusion. 100 nm An layer is deposited by chemical displacement reaction to enhance the conductivity and solderability of the film.
- Item3D open-worked inverse opal TiO2 and GeO2 materials for long life, high capacity Li-ion battery anodes(Elsevier, 2017-10-18) McNulty, David; Lonergan, Alex; O'Hanlon, Sally; O'Dwyer, Colm; Science Foundation Ireland; Irish Research CouncilIn this short review, we overview some advancements made in Li-ion battery anode development, where the structural arrangement of the material plays an important role. Specifically, we summarise the benefits of 3D macroporous structure imposed the anode material, in order to improve ionic and electronic conductivity in the absence of conductive additives and binders. Two anode materials are overviewed: TiO2 and GeO2. These are either high capacity anode materials or accessible, abundant materials that are capable of very stable and long-term cycling. We have focused this review on 3D inverse opal structures of these anodes and summarise their enhanced behaviour by comparing their performance metrics to a range of nanoscale and porous analogues of these materials.
- ItemA 3D printed electromagnetic nonlinear vibration energy harvester(IOP Publishing Ltd, 2016-08-24) Constantinou, Peter; Roy, Saibal; Science Foundation IrelandA 3D printed electromagnetic vibration energy harvester is presented. The motion of the device is in-plane with the excitation vibrations, and this is enabled through the exploitation of a leaf isosceles trapezoidal flexural pivot topology. This topology is ideally suited for systems requiring restricted out-of-plane motion and benefits from being fabricated monolithically. This is achieved by 3D printing the topology with materials having a low flexural modulus. The presented system has a nonlinear softening spring response, as a result of designed magnetic force interactions. A discussion of fatigue performance is presented and it is suggested that whilst fabricating, the raster of the suspension element is printed perpendicular to the flexural direction and that the experienced stress is as low as possible during operation, to ensure longevity. A demonstrated power of ~25 μW at 0.1 g is achieved and 2.9 mW is demonstrated at 1 g. The corresponding bandwidths reach up-to 4.5 Hz. The system's corresponding power density of ~0.48 mW cm−3 and normalised power integral density of 11.9 kg m−3 (at 1 g) are comparable to other in-plane systems found in the literature.
- Item3D ranging and tracking using lensless smart sensors(Verlag Wissenschaftliche Scripten, 2017-03) Abraham, Lizy; Urru, Andrea; Wilk, Mariusz P.; Tedesco, Salvatore; O'Flynn, Brendan; Otto, ThomasTarget tracking has a wide range of applications in Internet of Things (IoT), such as smart city sensors, indoor tracking, and gesture recognition. Several studies have been conducted in this area. Most of the published works either use vision sensors or inertial sensors for motion analysis and gesture recognition [1, 2]. Recent works use a combination of depth sensors and inertial sensors for 3D ranging and tracking [3, 4]. This often requires complex hardware and the use of complex embedded algorithms. Stereo cameras or Kinect depth sensors used for high precision ranging are instead expensive and not easy to use. The aim of this work is to track in 3D a hand fitted with a series of precisely positioned IR LEDs using a novel Lensless Smart Sensor (LSS) developed by Rambus, Inc. [5, 6]. In the adopted device, the lens used in conventional cameras is replaced by low-cost ultra-miniaturized diffraction optics attached directly to the image sensor array. The unique diffraction pattern enables more precise position tracking than possible with a lens by capturing more information about the scene.
- Item3D UAV trajectory and data collection optimisation via deep reinforcement learning(IEEE, 2022-04) Nguyen, Khoi Khac; Duong, Trung Q.; Do-Duy, Tan; Claussen, Holger; Hanzo, Llajos; Royal Academy of Engineering; European Research Council; Engineering and Physical Sciences Research CouncilUnmanned aerial vehicles (UAVs) are now beginning to be deployed for enhancing the network performance and coverage in wireless communication. However, due to the limitation of their on- board power and flight time, it is challenging to obtain an optimal resource allocation scheme for the UAV-assisted Internet of Things (IoT). In this paper, we design a new UAV-assisted IoT system relying on the shortest flight path of the UAVs while maximising the amount of data collected from IoT devices. Then, a deep reinforcement learning-based technique is conceived for finding the optimal trajectory and throughput in a specific coverage area. After training, the UAV has the ability to autonomously collect all the data from user nodes at a significant total sum-rate improvement while minimising the associated resources used. Numerical results are provided to highlight how our techniques strike a balance between the throughput attained, trajectory, and the time spent. More explicitly, we characterise the attainable performance in terms of the UAV trajectory, the expected reward and the total sum-rate.
- Item3D vanadium oxide inverse opal growth by electrodeposition(Electrochemical Society, 2015) Armstrong, Eileen; O'Sullivan, Maria; O'Connell, John; Holmes, Justin D.; O'Dwyer, Colm; Science Foundation IrelandThree-dimensional vanadium pentoxide (V2O5) material architectures in the form of inverse opals (IOs) were fabricated using a simple electrodeposition process into artificial opal templates on stainless steel foil using an aqueous solution of VOSO4.χH2O with added ethanol. The direct deposition of V2O5 IOs was compared with V2O5 planar electrodeposition and confirms a similar progressive nucleation and growth mechanism. An in-depth examination of the chemical and morphological nature of the IO material was performed using X-ray crystallography, X-ray photoelectron spectroscopy, Raman scattering and scanning/transmission electron microscopy. Electrodeposition is demonstrated to be a function of the interstitial void fraction of the artificial opal and ionic diffusivity that leads to high quality, phase pure V2O5 inverse opals is not adversely affected by diffusion pathway tortuosity. Methods to alleviate electrodeposited overlayer formation on the artificial opal templates for the fabrication of the porous 3D structures are also demonstrated. Such a 3D material is ideally suited as a cathode for lithium ion batteries, electrochromic devices, sensors and for applications requiring high surface area electrochemically active metal oxides.
- Item42.6 Gbit/s fully integrated all-optical XOR gate(Institution of Engineering and Technology, 2009-09) Dailey, James M.; Ibrahim, Selwan K.; Manning, Robert J.; Webb, Rod P.; Lardenois, Sébastien; Maxwell, Graeme D.; Poustie, Alistair J.; Science Foundation IrelandWe demonstrate an SOA-based all-optical high-speed Mach-Zehnder interferometer exclusive- OR (XOR) gate fabricated in a silica III-V hybrid-integration technology platform. The device includes integrated time delays for rapid differential operation as well as integrated phase shifters for fine tuning of power splitters and interferometer bias enabling highly optimized XOR gate operation. XOR functionality is verified through inspection of the output pulse sequence and the carrier-suppressed output spectrum. A 2.3 dB penalty for a 42.6 Gb/s RZ-OOK signal at a 10-9 bit error rate is observed.
- ItemA 4th-order continuous-time ΔΣ modulator with improved clock jitter immunity using RTZ FIR DAC(Institute of Electrical and Electronics Engineers (IEEE), 2018-12) Assom, Ian; Salgado, Gerardo; O'Hare, Daniel; O'Connell, Ivan; O'Donoghue, Keith A.; Science Foundation Ireland; European Regional Development FundThis paper highlights the influence of the main feedback DAC non-idealities affecting the performance of Continuous-Time Delta-Sigma Modulators (CTDSMs) in radio receiver Internet-of-Things (IoT) applications. It proposes the combination of the Return-To-Zero (RTZ) DAC pulse and Finite-Impulse-Response (FIR) DAC to have inherent Inter-Symbol-Interference immunity and reduced clock jitter sensitivity, which is crucial to meet the strict linearity and Signal-To-Noise-Distortion-Ratio (SNDR) requirements for integrated IoT radio receivers. The proposed design is validated through MATLAB® Simulink® simulations, showing that a 4th order single-bit CTDSM with RTZ + FIR DAC can achieve an SNDR performance only 3dB below the ideal even in the presence of 4.2 ps rms of clock jitter at 24 MHz sampling frequency in a 250 kHz signal bandwidth.