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  • 251.
    Isheden, Christian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Source and drain engineering in SiGe-based pMOS transistors2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    A new shallow junction formation process, based on selective silicon etching followed by selective growth of in situ B-doped SiGe, is presented. The approach is advantageous compared to conventional ion implantation followed by thermal activation, because perfectly abrupt, low resistivity junctions of arbitrary depth can be obtained. In B-doped SiGe layers, the active doping concentration can exceed the solid solubility in silicon because of strain compensation. In addition, the compressive strain induced in the Si channel can improve drivability through increased hole mobility. The process is integrated by performing the selective etching and the selective SiGe growth in the same reactor. The main advantage of this is that the delicate gate oxide is preserved. The silicon etching process (based on HCl) is shown to be highly selective over SiO2 and anisotropic, exhibiting the densely packed (100), (311) and (111) surfaces. It was found that the process temperature should be confined between 800 ºC, where etch pits occur, and 1000 ºC, where the masking oxide is attacked. B-doped SiGe layers with a resistivity of 5×10-4 Ωcm were obtained. Well-behaved pMOS transistors are presented, yet with low layer quality. Therefore integration issues related to the epitaxial growth, such as selectivity, loading effect, pile-up and defect generation, were investigated. Surface damage originating from reactive-ion etching of the sidewall spacer and nitride residues from LOCOS formation were found to degrade the quality of the SiGe layer. Various remedies are discussed. Nevertheless, high-quality selective epitaxial growth could not be achieved with a doping concentration in the 1021 cm-3 range. The maximum doping level resulting in a high-quality layer, with the loading effect taken into account, was 6×1020 cm-3. After this careful process optimization, a high-quality layer was obtained in the recessed areas. Finally, Ni mono-germanosilicide was investigated as a material for contact formation to the epitaxial SiGe layers in the recessed source and drain areas. The formation temperature is 550 ºC and it is stable up to 700 ºC. The observation of a recessed step and lateral growth of the silicide led to a detailed treatment of the contact resistivity of the NiSi0.8Ge0.2/Si0.8Ge0.2 interface using 2-D as well as 3-D modeling. Different values were obtained for square shaped and rounded contacts, 5.0x10-8 Ωcm2 and 1.4x10-7 Ωcm2, respectively.

  • 252.
    Isheden, Christian
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hellström, Per-Erik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    von Haartman, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    pMOSFETs with recessed and selectively regrown Si1-xGex source/drain junctions2005In: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 8, no 1-3, p. 359-362Article in journal (Refereed)
    Abstract [en]

    A new source/drain formation concept based on selective Si etching followed by selective regrowth of in situ B-doped Si(1-x)Ge(x)is presented. Both process steps are performed in the same reactor to preserve the gate oxide. Well-behaved transistors are demonstrated with a negligibly low gate-to-substrate leakage current.

  • 253. Ismail, Mohammed
    et al.
    Rodriguez, De Llera Gonzal DeliaKTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Radio design in nanometer technologies2006Collection (editor) (Other academic)
    Abstract [en]

    Radio Design in Nanometer Technologies addresses current trends and future directions in radio design for wireless applications. As radio transceivers constitute the major bottleneck in a wireless chipset in terms of power consumption and die size, the radio must be designed in the context of the entire system, end to end. Therefore the book will address wireless systems as well as the DSP parts before it gets into coverage of radio design issues. As such, the book is the first volume that looks at the integrated radio design problem as a "piece of a big puzzle", namely the entire chipset or single chip that builds an entire wireless system. This is the only way to successfully design radios to meet the stringent demands of today's increasingly complex wireless systems.

  • 254. Ivanov, A
    et al.
    Kalinina, E
    Kholuyanov, G
    Strokan, N
    Onushkin, G
    Konstantinov, A
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kuznetsov, A
    High energy resolution detectors based on 4H-SiC2005In: SILICON CARBIDE AND RELATED MATERIALS 2004 / [ed] Nipoti, R; Poggi, A; Scorzoni, A, ZURICH-UETIKON: TRANS TECH PUBLICATIONS LT , 2005, Vol. 483, p. 1029-1032Conference paper (Refereed)
    Abstract [en]

    The spectrometric characteristics of the detectors based on 4H-SiC using 4.8-7.7 MeV a-particles were determined. The Cr Schottky barriers with areas of 1x10(-2) cm(2) were performed by vacuum thermal evaporation on 4H-SiC epitaxial layers grown by chemical vapor deposition (CVD) with thickness 26 and 50 μ m. The concentrations of the uncompensated donors into CVD epitaxial layers were (6-10) x10(14) cm(-3), that allowed to develop a detector depletion region up to 30 μ m using reverse bias of 400 V. The energy resolution less than 20 keV (0.34%) for lines of 5.0-5.5 MeV was achieved that is twice as large of the resolution of high-precision Si-based detectors prepared on specialized technology. The maximum signal amplitude of 4H-SiC - detectors corresponding to the average electron-hole pair generation energy was found to be 7.70 eV.

  • 255. Jacquart, R.
    et al.
    Brade, Dirk
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Voogd, J.
    Yi, C. -H
    WEAG THALES JP11.20 (REVVA) results and perspectives2005In: European Simulation Interoperability Workshop 2005, 2005, p. 162-172Conference paper (Refereed)
    Abstract [en]

    Within the WEAG THALES Joint Program 11.20 "Common Framework for Verification, Validation, and Accreditation of Simulations" (nicknamed "REVVA") between Denmark, France, Italy, Sweden, and The Netherlands, a new customer-based and product-oriented VV&A methodology was developed. It includes: (1) The REVVA Generic Process, a stand-alone VV&A process, which can be easily linked to numerous types of model development processes; (2) The concepts of Target of Acceptance (ToA) and Target of Verification and Validation (ToVV), which put a strong emphasis on V&V requirements definition and traceability from the individual Items of Evidence acquired during V&V implementation up to the intended purpose of model use; (3) The explicit distinction between the properties "correctness" and "validity", which are inherent to a simulation model on the one hand, and the processes of "verification" and "validation" to reveal them on the other hand; (4) Hooks for the integration of methods for estimation of uncertainty introduced by the current inability to prove neither correctness nor validity; (5) A role model, which clearly distinguishes technical and managerial roles and parties from which the actors may come. The follow-on project "REVVA2" shall formalize these former results and its own methodological basis. REVVA2 must also show its complementarities with other approaches such as the International Test Operations Procedure on V&V (WGE7.2) and the combined effort on HLA Federation VV&A by the NATO MSG019/TG016 and the SISO VV&A PDG. The ultimate objective of REVVA2 is the production of a set of documents that have to satisfy two kinds of goals: they have to be written in a style suitable for their submission to international standardization organizations, and need to be immediately applicable by VV&A practitioners. This paper, based on the Spring 05 SIW paper 041, outlines the results achieved by the first study and motivates future research and standardization directions.

  • 256.
    Jalali-Roudsar, Amir Abbas
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Denysenkov, V.P.
    Khartsev, Sergiy
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Determination of magnetic anisotropy constants for magnetic garnet epitaxial films using ferromagnetic resonance2005In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 288, p. 15-21Article in journal (Refereed)
    Abstract [en]

    The constants of magnetocrystalline anisotropy K-l and uniaxial anisotropy K-u are determined precisely by using ferromagnetic resonance (FMR) and a fitting procedure oil a (1 1 1) yttrium iron garnet (YIG) film made by pulsed laser deposition (PLD) technique. By applying a magnetic field in the azimuthal orientation we introduce measurement in a geometry which yields the anisotropy constants with a high accuracy. The new technique is compared with the previous analysis employing characteristic plane measurements. The new geometry yields at least 15% better accuracy in determining constant K, than by the previous method with FMR.

  • 257.
    Jalali-Roudsar, Amir Abbas
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Friberg, Ari
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Faraday rotation in a two-dimensional photonic crystal with magneto-optic defect2005In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 30, no 10, p. 1213-1215Article in journal (Refereed)
    Abstract [en]

    We study the magneto-optic (MO) Faraday rotation in a two-dimensional square-lattice photonic crystal with a central MO defect layer in the optical wavelength range. We show that when a TM plane wave is incident upon a photonic crystal, an enhancement of Faraday rotation takes place in a region where a resonance peak appears in the photonic bandgap. In this region the mode conversion is high.

  • 258.
    Jalali-Roudsar, Amir Abbas
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Friberg, Ari T.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Faraday rotation in two-dimensional magneto-optic photonic crystal2005In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 253, no 1-3, p. 145-150Article in journal (Refereed)
    Abstract [en]

    We study the enhancement of Faraday rotation in a two-dimensional square-lattice magneto-optic photonic crystal at optical wavelengths. We show that on incidence of a TM plane wave onto the magneto-optic photonic crystal, high TM-TE mode conversion takes place in the transmission bands of TM and TE fields. The photonic crystal structure increases the average wave path length, which in turn leads to a growth in the polarization rotation. We also show that associated with this phenomenon is a widening of the photonic crystal transmission band.

  • 259. Janda, Petr
    et al.
    Valenta, Jan
    Rehspringer, Jean-Luc
    Mafouana, Rodrigue R.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Elliman, Robert G.
    Modified spontaneous emission of silicon nanocrystals embedded in artificial opals2007In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 40, no 19, p. 5847-5853Article in journal (Refereed)
    Abstract [en]

    Si nanocrystals (NCs) were embedded in synthetic silica opals by means of Si-ion implantation or opal impregnation with porous-Si suspensions. In both types of sample photoluminescence (PL) is strongly Bragg-reflection attenuated (up to 75%) at the frequency of the opal stop-band in a direction perpendicular to the ( 1 1 1) face of the perfect hcp opal structure. Time-resolved PL shows a rich distribution of decay rates, which contains both shorter and longer decay components compared with the ordinary stretched exponential decay of Si NCs. This effect reflects changes in the spontaneous emission rate of Si NCs due to variations in the local density of states of real opal containing defects.

  • 260.
    Jantsch, Axel
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lauter, Robert
    KTH.
    Vitkowski, Arseni
    KTH.
    Power analysis of link level and end-to-end data protection in networks on chip2005In: Proceedings - IEEE International Symposium on Circuits and Systems, 2005, p. 1770-1773Conference paper (Refereed)
    Abstract [en]

    We provide a power analysis for the communication in the Nostrum NoC concluding that power consumption is dominated by the links between switches while the switches and network interfaces contribute with a mere few percent to the power consumption. Further we analyze link level low power encoding techniques with the conclusion, that they spend several times more power than no encoding at all, if normalized for the same performance, which is done by adjusting supply voltage and frequency. Data protection schemes also have the potential to reduce power if voltage levels can be reduced and certain faults can be tolerated. We experiment with link level and end-to-end data protection schemes. They only moderately increase power consumption and have indeed the potential to save power. However, this potential strongly depends on the application traffic patterns and fault models of future technology generations.

  • 261.
    Jantsch, Axel
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Sander, Ingo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Models of computation and languages for embedded system design2005In: IEE Proceedings - Computers and digital Techniques, ISSN 1350-2387, E-ISSN 1359-7027, Vol. 152, no 2, p. 114-129Article in journal (Refereed)
    Abstract [en]

    Models of computation (MoC) are reviewed and organised with respect to the time abstraction they use. Continuous time, discrete time, synchronous and untimed MoCs are distinguished. System level models serve a variety of objectives with partially contradicting requirements. Consequently, it is argued that different MoCs are necessary for the various tasks and phases in the design of an embedded system. Moreover, different MoCs have to be integrated to provide a coherent system modelling and analysis environment. The relation between some popular languages and the reviewed MoCs is discussed to find that a given MoC is offered by many languages and a single language can support multiple MoCs. It is contended that it is of importance for the quality of tools and overall design productivity, which abstraction levels and which primitive operators are provided in a language. However, it is observed that there are various flexible ways to do this, e.g. by way of heterogeneous frameworks, coordination languages and embedding of different MoCs in the same language.

  • 262.
    Jarrar, Asim
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Context Server support for opportunistic andadaptive mobile communication2003Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master’s thesis extends the functionality and intelligence of the Personal Digital Assistant (PDA) when roaming in a WLAN or a GPRS network. This is accomplished by introducing a Context Server database in the new mobile IP network. The Context Server collects knowledge called Context Data, concerning the network topology, network quality at various locations, sensor data from PDAs, and network services provided at various locations and by various hosts. This distributed knowledge will enhance and extend the functionality of the PDAs by providing and facilitating more network services to the user. With the help of this Context Data the PDA will extend it’s intelligence and make routing and data transmission decisions that are more adapted to the network topology and the service that is available to the user at a specific geographical location. The PDAs will roam and access multimedia services via different wireless access networks (e.g., GPRS, WLAN, UMTS, etc.). PDAs requesting services achieve more optimal quality and utilize the best available data transmission rate by using the Context Data. Example of services that can be provided are downloading of MP3 encoded songs from a database or other PDAs, communication with other GPRS and WLAN enabled devices, streaming Internet radio, weather reports on demand, watching video clips, and Internet access. These services can be received on a laptop, mobile host, or any device with an interface to a GPRS and a WLAN network.

    Today the telecom industry is having financial problems. Everyone wants to decrease costs and achieve more functionality and offer new services with little additional investment in the existing wireless networks. This thesis should contribute to future wireless network architecture by enabling access at the appropriate cost and quality by using the available network resources more intelligently. Based upon a prototype with all the network elements involved, we are able to analyze if this idea is technically possible to implement and scaleable for use by today’s society with it’s increasing demands and desire for high quality services while they are mobile.

  • 263.
    Jaskorzynska, Bozena
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berrier, Audrey
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Dainese, Matteo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Zawistowski, Zygmunt J.
    Applications of wavelength dispersion in 1D and 2D photonic crystals2005In: Proceedings of SPIE - The International Society for Optical Engineering / [ed] Waclaw Urbanczyk, Bozena Jaskorzynska, Philip St. J. Russell, SPIE - International Society for Optical Engineering, 2005, p. 1-9Conference paper (Refereed)
    Abstract [en]

    One of the most distinctive features of photonic crystals (PhCs) is their unique wavelength dispersion allowing novel device concepts for enhancement of photonic functionality and performance. Here, we present examples of our design and demonstrations utilizing dispersion properties of 1D and 2D photonic crystals. This includes the demonstration of negative refraction in 2D PhC at optical wavelengths, filters based on 1D and 2D PhC waveguides, and the design of a widely tunable filter involving 1D PhC.

  • 264.
    Jaskorzynska, Bozena
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Zawistowski, Jacek
    Polish Academy of Sciences, Poland .
    Dainese, Matteo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Cardin, Julien
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Widely tunable directional coupler filters with 1D photonic crystal2005In: 2005 7th International Conference on Transparent Optical Networks, Vol 1, Proceedings, IEEE , 2005, p. 136-139Conference paper (Refereed)
    Abstract [en]

    We present two concept examples for adding a wide range tunability to Si/SiO2 devices involving a photonic crystal element. They are based on a directional coupler filter of two different geometries, where one of the arms is a Bragg Reflection Waveguide (BRW) used for the bandwidth improvement. The tuning relies on changing the properties of the BRW core. As an illustration we consider the smectic A* liquid crystal as the core material and show that ca 100 nm tuning range is achievable by the core index variations of 0.006 under applying electric field of 5 V/mu m.

  • 265.
    Jennehag, Ulf
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Video streaming over multicast enabled wired IP networks2005Licentiate thesis, comprehensive summary (Other scientific)
  • 266. Ji, C.
    et al.
    Broeke, R. G.
    Du, Y.
    Cao, J.
    Chubun, N.
    Bjeletich, P.
    Olsson, F.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Welty, R.
    Reinhardt, C.
    Stephan, P. L.
    Yoo, S. J. B.
    Monolithically integrated InP-based photonic chip development for O-CDMA systems2005In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 11, no 1, p. 66-77Article in journal (Refereed)
    Abstract [en]

    This paper discusses photonic integration efforts toward developing an InP-based inonolithically integrated photonic chip for optical code-division multiple-access (O-CDMA) system applications. The chip design includes the colliding pulsed mode (CPM) locked laser, the. Mach-Zehnder interferometer-based threshold detector (MZI), and the monolithic O-CDMA encoder/decoder chip based on array-waveguide-gratings and phase modulator arrays. The compact 4 x I cm monolithic chip can replace a complex and large O-CDMA setup based on bulk optics. The integration technique involves active-passive integration using dry etching, metal organic chemical vapor deposition growth, and lateral hydride vapor phase epitaxy regrowth technologies. The fabricated CPM showed stable 1.54 ps modelocked laser output, the MZI showed excellent O-CDMA threshold detection, and the O-CDMA encoder showed Walsh-code O-CDMA, encoding. Further, the fabricated devices showed excellent planarity, which accelerate our progress toward monolithic integration of O-CDMA systems.

  • 267. Jia, L.
    et al.
    Li, Z.
    Li, Shuo
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    NoC architecture study with DFG model2010In: Proceedings - 2010 1st International Conference on Pervasive Computing, Signal Processing and Applications, PCSPA 2010, 2010, p. 903-906Conference paper (Refereed)
    Abstract [en]

    Generic reconfigurable network on chip (GRNoC) is an advanced technology of application specified SoC design for digital signal process system (DSPS). A novel GRNoC mapping method based on data flow graph (DFG) is addressed in this paper. For modules of heterogeneous processors, central memory, and IPs (intellectual properties), DFG model analysis shows that DFG model provides important data transmission properties included the direction and contents of data transmitting, requirements of synchronization and speed of data transmission. The DFG model combined with graph model of GRNoC, therefore, can be the base of route mapping design for the GRNoC. In addition, node architecture of simple router used in GRNoC is also proposed in this paper. The simple router can increases the properties of data transmission in GRNoC and is more suitable for mapping design with DFG model.

  • 268. Jia, L.
    et al.
    Zheying, L.
    Li, Shou
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    NoC design for the soc of image process system of road mark recognition2010In: Proceedings - International Conference on Electrical and Control Engineering, ICECE 2010, 2010, p. 3912-3916Conference paper (Refereed)
    Abstract [en]

    With the analysis of basic properties, this paper proposed a SoC design of Image Process System of Road Mark Recognition (IPSRMR) based on data flow graph (DFG) model and generic regulable NoC (GRNoC). It is provided of properties of data transmission and timing for each resource module with building the system DFG model with analyzing functions and algorithm. The basic method for optimizing resources and mapping is shown by analyzing DFG model of the IPSRMR. Following the analysis results of DFG, the SoC for IPSRMR has optimized GRNoC architecture, achieves shortest data transmission paths among the resources, implements straight data transmission, increases the speed of data transmission, and reduced the requirement for data process speed of each resource. In addition, the power consumption is reduced with such a optimized architecture.

  • 269. Jiang, W.
    et al.
    Okamoto, K.
    Soares, F. M.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Yoo, S. J. B.
    5 GHz channel spacing InP-based 32-channel Arrayed-Waveguide Grating2009In: OFC: 2009 Conference on Optical Fiber Communication, IEEE , 2009, p. 2660-2662Conference paper (Refereed)
    Abstract [en]

    We realize a 32-channel InP-based Arrayed-Waveguide Grating (AWG) with a 5-GHz channel spacing. The AWG shows approximately 14 dB excess-loss, 9 dB crosstalk, and 21 × 22 mm2 dimensions.

  • 270. Jiang, W.
    et al.
    Soares, F. M.
    Seo, S. W.
    Baek, J. H.
    Fontaine, N. K.
    Broeke, R. G.
    Cao, J.
    Yan, J.
    Okamoto, K.
    Olsson, Fredrik E.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Pham, A.
    Yoo, S. J. B.
    A monolithic inp-based photonic integrated circuit for optical arbitrary waveform generation2008Conference paper (Refereed)
    Abstract [en]

    We demonstrate a compact monolithically-integrated InP optical arbitrary waveform generator, consisting of an arrayed waveguide grating pair with 10 GHz channel spacing, 10 high-speed optical amplitude modulators, and 10 high-speed optical phase modulators.

  • 271.
    Jonsson, Björn
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Bluetooth QoS Scheduler2003Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Bluetooth is a low cost, short-range radio technology that enables electronic devices to communicate wirelessly via ad-hoc networks. Different kinds of applications may run over these networks, some of these applications with particular Quality of Service (QoS) requirements. One such application could for instance be an Audio application which need data frames to be delivered at regular interval to work properly.

    The communication over Bluetooth links is totally controlled by one of the participating nodes. Since this node controls the traffic and thereby controls the QoS within the network its communicating behaviour is of great importance for maintaining QoS reservations. A central part in maintaining QoS reservations is the scheduler, which prioritises between different tasks to be done such as which device that is allowed to transmit next.

    There is no standardised way to implement the Bluetooth scheduler. However, a Bluetooth scheduler should be able to handle QoS reservations, maintain fairness among the participating nodes, and utilise the available bandwidth efficiently. Furthermore a key requirement in Bluetooth is simplicity, therefore a Bluetooth scheduling algorithm should be of low complexity.

    This master thesis presents a new patented solution for an intra-piconet scheduling algorithm that is capable of maintaining QoS reservation, while being fair and also meet the low complexity requirement. This algorithm is presented in detail in the thesis and has been implemented in an ns2- based Bluetooth simulator. Simulations in this simulator are presented that verifies the scheduling algorithms functionality.

  • 272.
    Juhasz, Robert
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Silicon nanowires, nanopillars and quantum dots: Fabrication and characterization2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Semiconductor nanotechnology is today a very well studied subject, and demonstrations of possible applications and concepts are abundant. However, well-controlled mass-fabrication on the nanoscale is still a great challenge, and the lack of nanofabrication methods that provide the combination of required fabrication precision and high throughput, limits the large-scale use of nanodevices. This work aims in resolving some of the issues related to nanostructure fabrication, and deals with development of nanofabrication processes, the use of size-reduction for reaching true nanoscale dimensions (20 nm or below), and finally the optical and electrical characterization to understand the physics of the more successful structures and devices in this work. Due to its widespread use in microelectronics, silicon was the material of choice throughout this work.

    Initially, a fabrication process based on electron beam lithography (EBL) was designed, allowing controlled fabrication of devices of dimensions down to 30 nm, although, generally, initial device dimensions were above 70 nm, allowing the flexible but low-throughput EBL, to be replaced by state-of-the-art optical lithography in the case of industrialization of the process. A few main processes were developed throughout the course of this work, which were capable of defining silicon nanopillar and nano-wall arrays from bulk silicon, and silicon nanowire devices from silicon-on-insulator (SOI) material.

    Secondly, size-reduction, as a means of providing access to few-nanometer dimensions not available by current lithography techniques was investigated. An additional goal of the size-reduction studies was to find self-limiting mechanisms in the process, that would limit the impact of variations in the size and other imperfections of the initial structures. Thermal oxidation was investigated mainly for self-limited size-reduction of silicon nanopillars, resulting in well-defined quantum dot arrays of few-nm dimensions. Electrochemical etching was employed to size-reduce both silicon nanopillars and silicon nanowires down into the 10-nm regime. This being a novel application, a more thorough study of electrochemical etching of low-dimensional and thin-layer structures was performed as well as development of a micro-electrochemical cell, enabling electrochemical etching of fabricated nanowire devices with improved control.

    Finally, the combination of nanofabrication and size-reduction resulted in two successful device structures: Sparse and spatially well-controlled single silicon quantum dot arrays, and electrically connected size-reduced silicon nanowires. The quantum dot arrays were investigated through photoluminescence spectroscopy demonstrating for the first time atomic-like photoemission from single silicon quantum dots. The silicon nanowire devices were electrically characterized. The current transport through the device was determined to be through inversion layer electrons with surface states of the nanowire surfaces greatly affecting the conductance of the nanowire. A model was also proposed, capable of relating physical and electrical properties of the nanowires, as well as demonstrating the considerable influence of charged surface states on the nanowire conductance.

  • 273.
    Juhasz, Robert
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kylmänen, Kai
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Galeckas, Augustinas
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Size-reduced silicon nanowires: Fabrication and electrical characterization2005In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 25, no 5-8, p. 733-737Article in journal (Refereed)
    Abstract [en]

    Silicon nanowires of diameters down to 100 nm and typical lengths of 1-3 μm have been fabricated in silicon-on-insulator material by electron beam lithography and plasma etching. They were subsequently size-reduced by photoelectrochemical etching resulting in wire widths down to 10 nm. To enable accurate control of the photoelectrochemical size-reduction, a micro-electrochemical cell was developed, enabling single nanowires to be exposed to the etching solution while being illuminated by a laser or a lamp. The arrangement allows contact leads to be extended to metal contact pads located outside the cell, which can be connected by probes, allowing in situ electrical characterization of a nanowire during etching. In this paper, we describe the experimental setup, the fabrication method and show examples of achieved wire widths together with some preliminary results from the electrical characterization.

  • 274.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    ACTIVE PHOTONIC DEVICE2010Patent (Other (popular science, discussion, etc.))
  • 275.
    Junique, Stéphane
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Surface-normal multiple quantum well electroabsorption modulators based on GaAs-related materials2005Licentiate thesis, comprehensive summary (Other scientific)
  • 276.
    Kahl, Sören
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Grishin, Alexander
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Magneto-optical response of a one-dimensional all-garnet photonic crystal in transmission and reflection2005In: Magneto-Optical Materials For Photonics and Recording / [ed] Ando, K; Challener, W; Gambino, R; Levy, M, WARRENDALE: MATERIALS RESEARCH SOCIETY , 2005, Vol. 834, p. 35-46Conference paper (Refereed)
    Abstract [en]

    We present spectra of transmittance, reflectance, and Faraday rotation of transmitted and reflected light for a periodic garnet multilayer structure with a central defect layer. The multilayer consists of alternating layers of bismuth and yttrium iron garnet, is 1.5 mu m thick, and was prepared by pulsed laser deposition. For the reflection measurements, a silver mirror was evaporated on top of the multilayer. Faraday rotation is strongly enhanced at resonances in transmission and reflection. The peak value obtained at 748 nm in transmission is 5:3 deg and at 733 nm in reflection is 18 deg. A single layer BIG film of equivalent thickness shows 2.2 deg Faraday rotation at 748 nm. We find rather good agreement between measured and calculated spectra. Using calculations of the distributions of light intensities at different wavelengths inside the multilayer, we are able to give consistent qualitative explanations for the enhancement of Faraday rotation. We also find numerically that - at moderate strengths of the optical resonances - a linear relation exists between Faraday rotation and the intensity integrated over all magneto-optically active layers, if absorption is neglected. We suggest to modify the usual sensor film for magneto-optical imaging by introducing a Bragg mirror consisting of heteroepitaxial garnet layers between the substrate and sensor film. For one example situation, we show by calculation that the quality factors of image contrast and optical efficiency can be higher for heteroepitaxial garnet multilayers than for single-layer iron garnet films currently in use as sensor films.

  • 277. Kalinina, E
    et al.
    Kholuyanov, G
    Onushkin, G
    Davydov, D.
    Strel'chuk, A.
    Konstantinov, A.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Skuratov, V.
    Kuznetsov, A.
    Comparative study of 4H-SiC irradiated with neutrons and heavy ions2005In: SILICON CARBIDE AND RELATED MATERIALS 2004 / [ed] Nipoti, R; Poggi, A; Scorzoni, A, ZURICH-UETIKON: TRANS TECH PUBLICATIONS LTD , 2005, Vol. 483, p. 377-380Conference paper (Refereed)
    Abstract [en]

    The influence of the irradiation with neutrons, Kr+ (245 MeV) and Bi+ (710 MeV) ions on the optical and electrical properties of high-resistivity, high-purity 4H-SiC epitaxial layers grown by chemical vapor deposition was investigated using photoluminescence and deep-level transient spectroscopy. Electrical characteristics were studied using Al and Cr Schottky barriers as well as p(+)-n-n(+) diodes fabricated by Al ion implantation on this epitaxial layers. It was found that both "light" neutrons and high energy heavy ions introduced identical defect centers in 4H-SiC. So, even at extremely high density of the ionization energy of 34 keV/mn, typical for Bi+ ion bombardment, damage structure formation in SiC single crystal is governed by energy loss in elastic collisions.

  • 278. Kamp, M.
    et al.
    Zimmermann, J.
    März, R.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Forchel, A. W.
    Low loss InP based photonic crystal waveguides and resonators2005In: Optoelectronic Integrated Circuits VII, SPIE - International Society for Optical Engineering, 2005, p. 249-256Conference paper (Refereed)
    Abstract [en]

    We report on low-loss light propagation at the communication wavelength of 1.55 μm through straight two-dimensional photonic crystal waveguides patterned into InGaAsP/InP heterostructures. The linear defect waveguides along the ΓK direction of a triangular lattice of air holes were etched deeply into the semiconductor by Cl 2/Ar electron cyclotron resonance reactive ion etching. Efficient waveguiding was observed for both polarization directions, although a photonic band gap exists for only one of the polarization states. Propagation losses, determined by the Fabry-Pérot resonance method, are as low as 0.2 dB/mm and 1.5 dB/mm for waveguides based on seven and three missing rows of holes, respectively. Waveguide resonators with 100 GHz channel spacing and quality factors up to 15,000 have been realized by inserting photonic crystal mirrors into the waveguides. The dispersion of the resonators was measured using a phase shift technique. Values for the group velocity dispersion range from -250 ps/nm to +250 ps/nm at wavelengths around 1.55 μm, which is sufficient to compensate for the dispersion of 15 km standard single-mode fiber. Controlling the device temperature allows to tune the dispersive properties of the devices.

  • 279.
    Kamrani, Farzad
    et al.
    KTH, School of Information and Communication Technology (ICT), Electronic, Computer and Software Systems, ECS.
    Ayani, Rassul
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Simulation-aided path planning of UAV2007In: Proceedings Of The 2007 Winter Simulation Conference: Vols 1-5, 2007, p. 1285-1293Conference paper (Refereed)
    Abstract [en]

    The problem of path planning for Unmanned Aerial Vehicles (UAV) with a tracking mission, when some a priori information about the targets and the environment is available can in some cases be addressed using simulation. Sequential Monte Carlo Simulation can be used to assess the state of the system and target when the UAV reaches the area of responsibility and during the tracking task. This assessment of the future is then used to compare the impact of choosing different alternative paths on the expected value of the detection time. A path with a lower expected value of detection time is preferred. In this paper the details of this method is described. Simulations are performed by a special purpose simulation tool to show the feasibility of this method and compare it with an exhaustive search.

  • 280.
    Kamrani, Farzad
    et al.
    KTH, School of Information and Communication Technology (ICT), Electronic, Computer and Software Systems, ECS.
    Ayani, Rassul
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Using on-line simulation for adaptive path planning of UAVs2007In: DS-RT 2007: 11TH IEEE INTERNATIONAL SYMPOSIUM ON DISTRIBUTED SIMULATION AND REAL-TIME APPLICATIONS, PROCEEDINGS / [ed] Roberts, DJ; Theodoropoulos, GK; ElSaddik, A, LOS ALAMITOS: IEEE COMPUTER SOC , 2007, p. 167-174Conference paper (Refereed)
    Abstract [en]

    In a surveillance mission, the task of Unmanned. Aerial Vehicles (UAV) path planning can in some cases be addressed using Sequential Monte Carlo (SMC) simulation. If sufficient a priori information about the target and the environment is available an assessment of the future state of the target is obtained by the SMC simulation. This assessment is used in a set of "what-if" simulations to compare different alternative UAV paths. In a static environment this simulation can be conducted prior to the mission. However if the environment is dynamic, it is required to run the "what-if" simulations on-line i.e. in real-time. In this paper the details of this on-line simulation approach in UAV path planning is studied and its performance is compared with two other methods: an off-line simulation aided path planning and an exhaustive search method. The conducted simulations indicate that the on-line simulation has generally a higher performance compared with the two other methods.

  • 281.
    Kamrani, Farzad
    et al.
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Garcia Lozano, Marianela
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Ayani, Rassul
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Path planning for UAVs using symbiotic simulation2006In: Modelling and Simulation 2006 / [ed] Nketsa, A; Paludetto, M; Bertelle, C, 2006, p. 207-213Conference paper (Refereed)
    Abstract [en]

    The problem of efficient path planning for Unmanned Aerial Vehicles (UAV) with a surveillance mission in a dynamic environment can in some cases be solved using Symbiotic Simulation (S2), i.e. an on-line simulation that interacts in real-time with the UAV and chooses its path. Sequential Monte Carlo Simulation, known also as Particle Filtering (PF) is an instance of such a simulation. In this paper we describe a methodology and an algorithm to use PF for efficient path planning of a UAV which searches a road network for a target. To verify whether this method is feasible and to supply a tool to compare different methods a simulator is developed. This simulator and its features are presented in this paper as well.

  • 282.
    Kanter, Theo G.
    et al.
    Ericsson.
    Maguire Jr., Gerald Q.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Escudero, Alberto
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Measurement of minimum handover time in IEEE 802.11b managed mode2001Report (Other academic)
  • 283.
    Karlsson, A.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Bjork, G.
    On the modulation bandwidth of semiconductor microcavity lasers1994In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 6, p. 1312-1314Article in journal (Refereed)
    Abstract [en]

    The small signal injection current modulation bandwidth of vertical cavity microlasers in the conventional macroscopic regime and in the microscopic regime of "controlled spontaneous emission" is investigated. A microlaser, under constraint of nonlinear gain or current density limitations, is found to have the same intrinsic modulation bandwidth as conventional edge-emitting lasers with the same cavity losses and photon density.<>

  • 284.
    Karlsson, Anders
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Microcavity lasers in communication applications: Present status and prospects1994In: Proceedings of European Conference on Optical Communication, Firenze, Italy, Sept 26 - 30, 1994, 1994Conference paper (Refereed)
  • 285.
    Karlsson, Anders
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Nilsson, Olle
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Modulation and Noise Properties of Multi-element Semiconductor Lasers1991Report (Other academic)
    Abstract [en]

    In this report a previously presented theory for the modulation and noise properties of multi-element lasers is revised. Explicit formulas for modulation response, amplitude and frequency noise are found. The theory is illustrated by numerical examples.

  • 286.
    Karlsson, Magnus
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Modelling and Evaluation of a Bluetooth Data Logger in the Presence of Interference Sources2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Industrial Development Centre (IUC) in Olofström inc. has constructed a measurement value logger which can sample values from eight channels, buffer them and then send them wireless with the Bluetooth technology to e.g. a computer.</p> In this thesis the data transfer rate, i.e. the number of values per second has been studied for different logger settings and when there are interferences in the Bluetooth traffic. How Bluetooth is affected by interferences has been studied with a number of experiments performed at IUC's RF-damped Faraday's cage.

    The thesis provides a model for this Bluetooth logger. The model extends the existing simulation system NS2-UCBT with a 'logger protocol'. NS2-UCBT was also extended to better support modeling of losses (due to Bluetooth channel impairments) and for the model of these losses to be based on experiments. The resulting simulation program allows developers to construct and evaluate a measurement system utilizing such a Bluetooth logger. Using the simulation model, the data rate measured in samples per second was examined for the logger. The simulations shows that optimizing the logger's configuration will improve that data rate considerable.

    This report contains: a summary of the problem and earlier research, an explanation of the simulation system and the simulation program, comparisons between simulations and experiments, some conclusions, and proposes future work in this area.

  • 287.
    Karlsson, S.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Brorsson, Mats
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Software and Computer Systems, SCS.
    An Infrastructure for Portable and Efficient Software DSM1999Conference paper (Refereed)
  • 288.
    Karlsson, S.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Brorsson, Mats
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Software and Computer Systems, SCS.
    Priority Based Messaging for Software Distributed Shared Memory2003In: Cluster Computing, Vol. 6, p. 161-169Article in journal (Refereed)
  • 289.
    Karlsson, Stefan E.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Yu, Yichuan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Liu, C. P.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Chuang, C. H.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tsegaye, T.
    Seeds, A. J.
    Low cost packaging of a reflective electroabsorption Modulator/Detector with optimized spurious free dynamic range - art. no. 61850M2006In: Micro-Optics, VCSELs, and Photonic Interconnects II: Fabrication, Packaging, and Integration / [ed] Thienpont, H; Taghizadeh, MR; Daele, P; Mohr, J, BELLINGHAM, WA: SPIE-INT SOC OPTICAL ENGINEERING , 2006, Vol. 6185, p. M1850-M1850Conference paper (Refereed)
    Abstract [en]

    A packaged high speed reflective electroabsorption transceivers for radio-over-fiber applications is demonstrated. The transceiver, an AFPMD (Asymmetric vertically addressed Fabry-Perot Modulator/Detector), is successfully packaged into a standard module, originally intended for 10 Gbit/s Ethernet detectors. The packaging process and the electrical, optical and thermal performance of the packaged component are presented. A bandwidth of 6 GHz, a total reflective optical coupling loss of 7.1 dB and a responsitivity of 0.14 mA/mW are accomplished. By optimizing the operation optical wavelength and bias voltage, fifth-order nonlinearity dominates the intermodulation distortion and a spurious free dynamic range (SFDR) of 101dB center dot Hz(4/5) at 5.554GHz can be achieved experimentally.

  • 290.
    Karlsson, Stefan
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Yu, Yichuan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Liu, C.P.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chuang, C.H.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tsegaye, Tedros
    Seeds, A.J.
    A Packaged Reflective Electroabsorption Modulator/Detector with Optimized Dynamic Range2005In: Broadband Europe 2005, Bordeaux, 2005Conference paper (Refereed)
  • 291.
    Karlsson, Stefan
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Yu, Yichuan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Liu, C.P.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chuang, C.H.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tsegaye, Tedros
    Krysa, A. B.
    Roberts, J.S.
    Seeds, A. J.
    A Packaged Resonant Electroabsorption Transceiver for Fiber-Radio Applications2005In: Photonics in Wireless Communication, PWCom 2005, Särö, 2005Conference paper (Refereed)
  • 292.
    Karlsson, Sven
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    An introduction to Balder - An OpenMP run-time library for clusters of SMPs2008In: Openmp Shared Memory Parallel Programming, Proceedings / [ed] Mueller, MS; Chapman, BM; DeSupinski, BR; Malony, AD; Voss, M, 2008, Vol. 4315, p. 78-91Conference paper (Refereed)
    Abstract [en]

    In this paper a run-time library, called Balder, for OpenMP 2.0 is presented. OpenMP 2.0 is an industry standard for programming shared memory machines. The run-time library presented can be used on SMPs and clusters of SMPs and it will provide a shared address space on a cluster. The functionality and design of the library is discussed as well as some features that are being worked on. The performance of the library is evaluated and is shown to be competitive when compared to a commercial compiler from Intel.

  • 293.
    Karlsson, Sven
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Brorsson, Mats
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Software and Computer Systems, SCS.
    A comparative characterization of communication patterns in applications using MPI and shared memory on an IBM SP21998Conference paper (Refereed)
    Abstract [en]

    In this paper we analyze the characteristics of communication in three different applications, FFT, Barnes and Water, on an IBM SP2. We contrast the communication using two different programming models: message-passing, MPI, and shared memory, represented by a state-of-the-art distributed virtual shared memory package, TreadMarks. We show that while communication time and busy times are comparable for small systems, the communication patterns are fundamentally different leading to poor performance for TreadMarks-based applications when the number of processors increase. This is due to the request/reply technique used in TreadMarks that results in a large fraction of very small messages. However, if the application can be tuned to reduce the impact of small message communication it is possible to achieve acceptable performance at least up to 32 nodes. Our measurements also show that TreadMarks programs tend to cause a more even network load compared to MPI programs

  • 294.
    Karlsson, Sven
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Brorsson, Mats
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Software and Computer Systems, SCS.
    Priority Based Messaging for Software Distributed Shared Memory – Model and Implementation2001Conference paper (Refereed)
  • 295.
    Karlsson, Sven
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lee, S. -W
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Brorsson, Mats
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Software and Computer Systems, SCS.
    A Fully Compliant OpenMP implementation on Software Distributed Shared Memory2002Conference paper (Refereed)
    Abstract [en]

    OpenMP is a relatively new industry standard for programming parallel computers with a shared memory programming model. Given that clusters of workstations are a cost-effective solution to build parallel platforms, it would of course be highly interesting if the OpenMP model could be extended to these systems as well as to the standard shared memory architectures for which it was originally intended. We present in this paper a fully compliant implementation of the OpenMP specification 1.0 for C targeting networks of workstations. We have used an experimental software distributed shared memory system, CVM, to implement a run-time library which is the target of a source-to-source OpenMP translator also developed in this project. The system has been evaluated using an OpenMP microbenchmark suite used to evaluate the effect of some memory coherence protocol improvements. We have also used OpenMP versions of three Splash-2 applications concluding in reasonable speedups on an IBM SP machine with eight nodes. This is the first study to investigate the subtle mechanisms of consistency in OpenMP on software DSM systems.

  • 296.
    Khartsev, Sergiy
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Grishin, Michael A.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Characterization of heteroepitaxial Na0.5K0.5NbO3/La0.5Sr0.5CoO3 electro-optical cell2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, no 6, p. 062901-1-062901-3Article in journal (Refereed)
    Abstract [en]

    Heteroepitaxial Na0.5K0.5NbO3(1.5 mum)/La0.5Sr0.5CoO3(0.5 mum) (NKN/LSCO) films were grown on an Al2O3(0112) single crystal (r-cut sapphire) by rf-magnetron sputtering (NKN) and pulsed laser deposition (LSCO) techniques. Prism coupling waveguide refractometry has been employed to characterize vertical capacitive electro-optical cells with 2 X 8 mm(2) semitransparent Au top electrodes. Fitting reflectivity spectra to Fresnel formulas yields extraordinary and ordinary refractive indices n(e) = 2.232 and n(o) = 2.234 as well as electro-optic coefficient r(13) = 17.4 pm/V. Dispersion of the refraction index follows the Sellmeier formula n(2) = 1 + 3.46/[1-(244 nm/lambda)(2)] in the range from 400 nm to 850 nm.

  • 297.
    Khartsev, Sergiy
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Grishin, Michael A.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Karlsson, Ulf O.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Heteroepitaxial Na0.5K0.5NbO3/La0.5Sr0.5CoO3 electro-optical cell2006In: Integrated Ferroelectrics, ISSN 1058-4587, E-ISSN 1607-8489, Vol. 80, p. 133-143Article in journal (Refereed)
    Abstract [en]

    We report electro-optic performance of heteroepitaxial Na0.5K0.5NbO3(1.5 mu m)/La0.5Sr0.5CoO3 (0.5 mu m) (NKN/LSCO) films grown on Al2O3(01 (1) under bar2) single crystal (r-cut sapphire) by rf-magnetron sputtering (NKN) and pulsed laser deposition (LSCO) techniques. Vertical capacitive electro-optical cells were defined by a thermal evaporation of 2 x 8 mm(2) Au electrodes through the contact mask on top the NKN film. Processing parameters have been specially optimized to obtain electrosoftNKN films with a non-linear fatigue-free P-E characteristics: low remnant P-r = 7.7 mu C/cm(2) high induced polarization P = 23 mu C/cm(2) @ 400 km/cm , and the coercive field E-c = 70 kV/cm. Electro-optical characterization of NKN films has been performed using waveguide refractometry: a prism coupling of a light beam into the thin-film waveguide modes. Intensity of TM- and TE-polarized light of 655 nm laser diode reflected from the free surface of NKN film and Au-clad NKN/LSCO waveguide was recorded at zero and 15 V (100 kV/cm) bias electric field. Fitting reflectivity spectra to Fresnel formulas yields extraordinary and ordinary refractive indices n(c) = 2.232 and n(o) = 2.234 as well as electro-optic coefficient r(13) = 17.4 pm/V. Dispersion of the refraction index follows Sellmeier formula n(2) = 1+ 3.46/[1 + (244 nm/lambda)(2)] in the range from 400 nm to 850 nm.

  • 298.
    Khartsev, Sergiy
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Kim, Joo-Hyung
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT).
    Integration of colossal magnetoresistors with GaAs2005In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 284, no 02-jan, p. 1-5Article in journal (Refereed)
    Abstract [en]

    Colossal magnetoresistive (CMR) La0.67Ca0.33MnO3 (LCMO) and La0.67Sr0.33MnO3 (LSMO) films have been grown by pulsed laser deposition technique on GaAs(001) substrates buffered with epitaxial MgO layer. X-ray diffraction revealed strong c-axis out-of-plane orientation and strong in-plane texture of CMR/MgO bilayers on GaAs single crystal. The maximum temperature coefficient of resistivity TCR = 9.0% K-1 at 223 K and 2.0% K-1 at 327 K. and the magnetoresistance Delta rho/rho similar to-7.95% kOe(-1) and -1.47% kOe(-1) have been achieved for LCMO/MgO/GaAs and LSMO/MgO/GaAs heteroepitaxial structures, respectively. Comparison with the test LCMO and LSMO films grown directly onto the bulk MgO(001) single cry tal demonstrates the identity of LSMO/MgO/GaAs and LSMO/MgO films properties whereas the LCMO films grown on MgO buffered GaAs show lower transition temperature T-c = 242 K compared to 253 K in LCMO/MgO.

  • 299.
    Khatib, Iyad Al
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Bertozzi, Davide
    Poletti, Francesco
    Benini, Luca
    Jantsch, Axel
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Bechara, Mohamed
    Khalifeh, Hasan
    Hajjar, Mazen
    Nabiev, Rustam
    Jonsson, Sven
    MPSoC ECG biochip: A multiprocessor system-on-chip for real-time human heart monitoring and analysis2006In: Proceedings of the 3rd Conference on Computing Frontiers 2006, CF '06, 2006, p. 21-28Conference paper (Refereed)
    Abstract [en]

    The interest in high performance chip architectures for biomedical applications is on the rise. Heart diseases remain by far the main cause of death and a challenging problem for biomedical engineers to monitor and analyze. Electrocardiography (ECG) is an essential practice in heart medicine, which faces computational challenges, especially when 12 lead signals are to be analyzed in parallel, in real time, and under increasing sampling frequencies. Another challenge is the analysis of huge amounts of data that may grow to days of recordings. Nowadays, doctors use eyeball monitoring of the 12-lead ECG paper readout, which may seriously impair analysis accuracy. Our solution leverages the advance in multi-processor system-on-chip architectures, and is centered on the parallelization of the ECG computation kernel. It improves upon state-of-the-art mostly for its capability to perform real-time analysis of input data, leveraging the computation horsepower provided by many concurrent DSPs, more accurate diagnosis of cardiac diseases, and prompter reaction to abnormal heart alterations. The design methodology to go from the 12-lead ECG application specification to the final hardware/software architecture, modeling, and simulation is the focus of this paper. Our system model is based on industrial components. The architectural template we employ is scalable and flexible.

  • 300.
    Khatib, Iyad Al
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Jantsch, Axel
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kayal, Bassam
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Nabiev, Rustam
    Jonsson, Sven
    Wireless Network-on-Chips as Autonomous Systems: A Novel Solution for Biomedical Healthcare and Space Exploration Sensor-Networks2005In: Proceedings of the Infocom 2005 Conference - Student Workshop, 2005Conference paper (Refereed)
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