Conferences, Lectures, & Seminars
Events for December
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Eli Yablonovitch
Fri, Dec 01, 2006 @ 11:00 AM - 12:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
University of California, Los AngelesEngineering design is sometimes inspired by Nature. The natural world is filled with crystals, periodic structures that interact with electron waves. Drawing on this analogy, photonic crystals are artificial periodic structures that are intended for electromagnetic waves, instead. Such nano-photonic structures are now being designed and patterned into Silicon-on-Insulator (SOI) to provide for commercial nano-photonic integration, as a component part of conventional CMOS circuits.Further optical frequency miniaturization will take us toward nano-plasmonics, metallic-wired electrical circuits, running at optical frequencies. At lower frequencies, new electronic switching devices that have a sub-threshold slope steeper than kT/q are expected to emerge. The research of the next 10 years will answer what comes after the semiconductor roadmap.
Location: Hedco Neurosciences Building (HNB) - 100
Audiences: Everyone Is Invited
Contact: Ericka Lieberknecht
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor. -
Waveguiding in Periodic Coupled Micro-resonator
Mon, Dec 04, 2006 @ 10:00 AM - 11:00 AM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Joyce PoonCalifornia Institute of TechnologyAbstract:
Coupled-Resonator Optical Waveguides (CROWs) are chains of resonators in which light propagates by virtue of the coupling between the resonators. The dispersive properties of these waveguides are controllable by the inter-resonator coupling and the geometry of the resonators. For example, if the inter-resonator coupling is weak, light can be engineered to propagate slowly in CROWs. The small group velocities possible in CROWs may enable applications in and technologies for optical delay lines, interferometers, buffers, nonlinear optics, and lasers. In this presentation, I will report on our progress in achieving and controlling optical delay in passive and active CROWs. Both theoretical and experimental results will be presented. I will show how transfer matrices can be used to analyze and design a variety of coupled resonator systems. I will also present measurements of the spectral and group delay properties of high-order (>10) coupled polymer microring resonators. Finally, I will discuss our ongoing work on active CROWs in III-V semiconductors for loss compensation and electrical control.Brief Biography:
Joyce Poon is a Ph.D. candidate in Electrical Engineering at the California Institute of Technology (Caltech) in the group of Prof. Amnon Yariv. She received the M.S. in Electrical Engineering in 2003 from Caltech and the B.A.Sc. in Engineering Science (Physics Option) from the University of Toronto in 2002. She is grateful for fellowships from the Natural Science and Engineering Research Council of Canada (NSERC), OSA Dekker Foundation, and IEEE-LEOS for supporting her graduate studies. Joyce's current research is on slow light propagation in coupled resonators, polymer microrings, and compound semiconductor (InP-InGaAsP) resonator devices. Her research interests include the theory, design, and experimental studies of optical wave propagation in waveguides, micro-resonators, and periodic structures for active and passive photonics.
Location: Hedco Neurosciences Building (HNB) - 100
Audiences: Everyone Is Invited
Contact: Ericka Lieberknecht
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor. -
Quantum Network Communication -- The Butterfly and Beyond
Mon, Dec 04, 2006 @ 11:00 AM - 12:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
SPEAKER: Prof. Debbie Leung, University of WaterlooABSTRACT: We study the communication of quantum information in networks of (directed) quantum channels. We consider the asymptotic rates of high fidelity quantum communication between specific sender-receiver pairs. In networks that are shadow, we find that rerouting of quantum information is optimal. Consequently, the achievable rate regions are given by counting edge avoiding paths, and precise achievable rate regions can be obtained. Slight twists to the above results are obtained when side classical channels are available. These complete solutions apply to many networks, including the butterfly network.Joint work with Jonathan Oppenheim and Andreas WinterBio: After a B.S. in Ph/Ma from Caltech in 1995, Debbie completed a PhD on Robust quantum computation at Stanford in 2000 under the supervision of Prof. Yoshihisa Yamamoto and Prof. Isaac Chuang. She then worked at IBM TJ Watson Research Center in 2000-2002, MSRI in 2002, and Caltech in 2003-2005 on quantum communication and cryptography. She joined the Institute for Quantum Computing and the Department of Combinatorics and Optimization at the University of Waterloo in 2005.Host: Prof. Igor Devetak, devetak@usc.edu
Location: Frank R. Seaver Science Center (SSC) - 319
Audiences: Everyone Is Invited
Contact: Mayumi Thrasher
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor. -
Protocols for Adaptive Modulation and Coding in Dynamic Spectrum Access Networks
Tue, Dec 05, 2006 @ 11:00 AM - 12:30 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
SPEAKER: Michael B. Pursley, Holcombe Professor, Clemson UniversityABSTRACT: A protocol suite is presented for controlling transmissions in dynamic spectrum access networks. A framework is provided for the selection of the initial modulation to be used in a session after a frequency band has been designated. During the first few packet transmissions in a new session, a power-adjustment protocol compensates for uncertainties in the propagation characteristics and interference in the designated frequency band. Throughout the session, the error-control code and modulation are adapted to accommodate time-varying interference and propagation loss. Because increases in transmitter power can disrupt other sessions that are underway in the network, the transmitter power is increased only if adaptation of coding and modulation cannot compensate fully for deteriorations in the channel conditions. Protocol performance results are provided for static channels with unknown characteristics and for dynamic channels that are modeled as finite-state Markov chains. Comparisons with Shannon capacity limits are employed to assess the efficiency of the adaptive coding protocol for a wide range of modulation techniques and channel models.Host: Prof. Robert Scholtz, scholtz@usc.edu
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Mayumi Thrasher
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor. -
Spectrum Sharing: System Design Perspective
Wed, Dec 06, 2006 @ 03:00 PM - 04:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Danijela CabricUniversity of California, BerkeleyA major shift in wireless communications is now emerging with the development of cognitive radios, which attempt to share spectrum in a fundamentally new way. Cognitive radios address the problem of poor spectrum utilization exhibited in many frequency bands. On a conceptual level, cognitive radio networks sense the spectral environment and adapt transmission parameters to dynamically reuse available spectrum. The novelty of this approach requires us to re-architect the mechanisms for using radio frequencies and find a way for multiple systems to co-exist through sharing rather than fixed allocations.This talk addresses fundamental questions in cognitive radios system design and investigates its feasibility by bridging the theoretical and practical aspects of the physical and network layers. We begin with spectrum sensing, the key enabling functionality for cognitive radios, which requires detection of very weak signals of different types in a minimum time with high reliability. We show that the biggest barrier for sensing in very low signal to noise ratio regimes is the variability in the noise and interference that cannot be perfectly calibrated during sensing time. Robustness can be increased by differentiating signals from noise by detecting signal features or by exploiting channel diversity with network cooperation. Through physical implementation and experiments of proposed sensing methods, we identify the minimum possible sensing times and detectable signal levels. Moreover, we include the sensitivities exhibited by these methods to radio and channel impairments. Next, we consider radio architecture for wideband spectrum sharing radios and show that large dynamic range requirements present major challenge in their implementation. This calls for the development of novel mixed signal techniques. By exploiting spatial dimension for selective processing of desired signals through antenna array architectures, strong interferers can be adaptively suppressed. We conclude with a discussion of the requirements for the signaling and protocol designs that support dynamic spectrum access and spectrum sensing coordination.Brief Biography:
Danijela Cabric is a Ph.D. candidate in Electrical Engineering at the University of California, Berkeley in the group of Prof. Robert Brodersen. She received the M.S. in Wireless Communications and VLSI System Design in 2001 from the University of California at Los Angeles and the Diploma in Electrical Engineering from the University of Belgrade, Serbia, in 1998.
Location: Hedco Neurosciences Building (HNB) - 100
Audiences: Everyone Is Invited
Contact: Ericka Lieberknecht
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor. -
Teaching Silicon New Tricks
Thu, Dec 07, 2006 @ 12:00 PM - 01:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Bahram JalaliUniversity of California, Los AngelesAbstract:
Conventional wisdom holds that silicon cannot amplify light and what's worse, it has no useful nonlinearities so it cannot manipulate light. Taking this axiom as a motivation rather than a deterrent, several research groups, including mine, have been on a crusade to prove it wrong and to unleash the mighty silicon photonics technology. We've been partially successful! This talk will elucidate the relevant physics that determines silicon's prospect as an active optical medium. It will review the recent breakthroughs based on nonlinear optics in silicon, including optical amplification, lasing, wavelength conversion, energy harvesting, and a new class of devices based on nonlinear optics in multi-mode waveguides. It will close with a previously unforeseen, yet exciting application of silicon photonics: THz real-time analog-to-digital conversion.Biography:
Bahram Jalali is a Professor of Electrical Engineering, the and the Director of the Optoelectronic Circuits and System Laboratory at UCLA. From 1988-1992, he was a Member of Technical Staff at the Physics Research Division of AT&T Bell Laboratories in Murray Hill, N.J. where he conducted research on ultrafast electronics and optoelectronics. His current research interests are in silicon photonics and ultrafast photonic signal processing.Dr. Jalali has published over 200 scientific papers in and holds 6 US patents. He is a Fellow of IEEE and of Optical Society of America (OSA) and the Chair of the Los Angeles Chapter of the IEEE Lasers and Electro Optics Society (LEOS). In 2005, he was chosen by the Scientific American Magazine as the 50 Leaders Shaping the Future of Technology. He is a member of the California Nano Systems Institute (CNSI).While on leave from UCLA from 1999-2001, Dr. Jalali founded Cognet Microsystems, a Los Angeles based fiber optic component company. He served as Company's CEO, President and Chairman, from the company's inception through its acquisition by Intel Corporation in April 2001. He has received the BridgeGate 20 Award for his contribution to the southern California economy. From 2001-2004, he served as a consultant to Intel Corporation. Dr. Jalali serves on the Board of Trustees of the California Science Center.
Location: Hedco Neurosciences Building (HNB) - 100
Audiences: Everyone Is Invited
Contact: Ericka Lieberknecht
This event is open to all eligible individuals. USC Viterbi operates all of its activities consistent with the University's Notice of Non-Discrimination. Eligibility is not determined based on race, sex, ethnicity, sexual orientation, or any other prohibited factor.
