News

ECE Professor Dan Blumenthal named a 2017 National Academy of Inventors (NAI) Fellow

December 13th, 2017

photo of Dan Blumenthal
Blumenthal cited for “demonstrating a highly prolific spirit of innovation in creating or facilitating outstanding inventions that have made a tangible impact on quality of life, economic development and the welfare of society.”

“Our campus is thrilled for Professor Blumenthal on his election to the National Academy of Inventors, a proud and prestigious peer recognition of his creativity in engineering,” said UCSB Chancellor Henry T. Yang. “While celebrating his commitment to innovation, this honor also acknowledges Professor Blumenthal’s important contributions to society through the creative application of his research at the frontier of technology.”

Blumenthal’s UCSB lab develops new hardware and communications technologies to solve complex communications, transmission, switching and signal processing problems out of reach with today’s technologies. Its primary research undertaking is to develop new functions integrated on small chips called photonic circuits and use them to build networks in ways that save energy and increase the scale of connectivity and bandwidth of data centers and the internet.

“It is a great honor to be nominated as a fellow of the NAI and recognized for work that has come to fruition over so many years through working with so many collaborators,” said Blumenthal, head of the ECE’s Optical Communications and Photonic Integration Group and director of UCSB’s Terabit Optical Ethernet Center. “The challenge of combining creativity and engineering to operate on the edge of technology innovation is in itself hugely satisfying. Seeing this technology take root and positively impact generations of fiber communications networks that people use in their everyday lives to be more energy efficient and communicate, conduct business and solve some of today’s toughest problems — as well as train future engineers and create jobs — continues to motivate my desire to innovate and make positive impacts on society.”

Blumenthal holds 3 degrees in EE: a B.S. from the U. of Rochester, an M.S. from Columbia and a doctorate from the U. of Colorado Boulder. He is a fellow of the IEEE and of the Optical Society. He received a Presidential Early Career Award for Scientists and Engineers from the White House in 1999, a National Science Foundation Young Investigator Award in 1994 and an Office of Naval Research Young Investigator Program Award in 1997. Blumenthal has authored or co-authored more than 410 papers, holds 22 patents and is co-author of “Tunable Laser Diodes and Related Optical Sources” (New York: IEEE–Wiley, 2005).

This year’s class of NAI fellows will be inducted during the seventh annual NAI Conference to be held in April in Washington, D.C. Andrew H. Hirshfeld, U.S. commissioner for patents, will provide the keynote address for the induction ceremony.

The UCSB Current – "The Spirit of Innovation" (full article)

Blumenthal's COE Profile

Blumenthal's Lab – Optical Communications and Photonic Integration Group (OCPI)

ECE Professors Li-C. Wang and Clint Schow named 2018 Fellows of the Institute of Electrical and Electronics Engineers (IEEE)

December 13th, 2017

photos of schow and wang
COE’s Schow, Wang and Giovanni Vigna (CS) selected by IEEE for their extraordinary accomplishments in their respective fields

“Ensuring the integrity of computer chips and circuits, using opto-electronic technology to move more data faster and with greater efficiency, and securing computer systems against cybercrime are critical pursuits in the digital age — professors Wang, Schow and Vigna are playing key roles in these important areas,” said Rod Alferness, dean of the UCSB College of Engineering. “We offer congratulations to each of them for receiving this high honor.”

Li-C. Wang

A professor of electrical and computer engineering, Wang is an expert in computer engineering as well as electronic design automation and test, in which intelligent software tools are used to automate the processes of hardware design and verification. Modern hardware design can comprise billions of devices and integrate heterogeneous components that perform a variety of functions, involving complex algorithms and architectures in which their performance and properties must be thoroughly verified and tested to ensure product quality, reliability and safety.

Wang is a recipient of numerous honors and awards, including seven best paper awards presented at leading international conferences, and the Technical Excellence Award for his research contributions to member companies of Semiconductor Research Corporation. He was cited by IEEE for “contributions to statistical timing analysis for integrated circuits,” where his research pioneers the use of statistical data analytics to verify design timing assumptions with silicon measurement data.

This innovative methodology, also called design-silicon timing correlation, later became the foundation for developing other data mining-based methodologies in a variety of design automation and test applications such as functional verification, yield improvement and quality assurance.

Clint Schow

For rapid movement of ever-increasing amounts of data, engineers have turned to photonics, which uses light to transmit information at, well, the speed of light. Light is ideal for efficiently transmitting large amounts of information over long distances (think: fiberoptic cables), but within the confines of computers and other data devices, light becomes a challenge to manipulate.

Schow, also a professor of electrical and computer engineering, focuses his research on integrating photonics and electronics, developing hardware that can translate the information between photon and electron, between optical fiber and wire. He was cited by IEEE for “contributions to high-bandwidth optical interconnects,” which will accelerate the development of higher-performance computers and data centers that can accommodate the growing flood of data. Schow also is a fellow of the Optical Society of America.

IEEE is the world’s largest technical professional organization dedicated to advancing technology for the benefit of humanity through its more than 423,000 members in over 160 countries, and its highly cited publications, conferences, technology standards and professional and educational activities.

Institute of Electrical and Electronics Engineers (IEEE) Fellow Program

The UCSB Current – "High Honors" (full article)

Wang's COE Profile

Schow's COE Profile

ECE graduate student Bowen Song receives the Asia Communications and Photonics Conference (ACP) Best Student Paper Award

December 8th, 2017

photo of bowen song
Song given the Optical Society of America (OSA) sponsored award by its president Eric Mazur for the paper “Tunable 3D Integrated Hybrid Silicon Laser”

The ACP Best Student Paper Awards are given to students who are first authors and presenters of exceptional contributed talks and the selection was made by the subcommittees during the conference. Song presented on tunable 3D integrated hybrid silicon lasers that were demonstrated with side-mode suppression ratio of 43 dB, output power of 2 mW, laser linewidth of 1.5 MHz, and relative intensity noise of -132 dB/Hz. Additional authors of the paper include Sergio Pinna (UCSB), Sasa Ristic (McGill U) and ECE Professor Jonathan Klamkin (UCSB).

The Asia Communications and Photonics Conference (ACP) is the largest conference in the Asia-Pacific region on optical communication, photonics and relevant technologies. ACP has been held annually tracing back to 2001 and is jointly sponsored by OSA, SPIE, IEEE Photonics Society. The 2017 ACP was held in Guangzhou, China on November 10-13, 2017.

Song is currently a Ph.D. student in the ECE department at UCSB in Professor Jonathan Klamkin’s integrated photonics lab (iPL). His research focus is on 3D Hybrid integration for silicon photonics aimed to integrate laser or gain material to silicon chips; indium phosphide photonics integrated circuits and silicon phonics. In 2014 he received his Master of Science degree as a member of the Wide Bandgap Semiconductor Laboratory at Boston University working on developing nano-patterned sapphire substrate for AlGaN-based deep UV LEDs.

Asia Communications and Photonics Conference (ACP)

Song's Google Scholar page

ECE Professor Sanjit Mitra receives the IEEE Educational Activities Board (EAB) Vice-President’s Recognition Award

December 7th, 2017

sanjit mitra Mitra receives award for “outstanding contributions in analog and digital signal processing and image processing, and authoring pioneering textbooks that inspire and educate students worldwide”

IEEE Educational Activities Board (EAB) Awards recognize and honor major contributions to engineering and technical education. Awards are given for meritorious activities in accreditation, continuing education, educational innovation, pre-university education, service to the IEEE EAB, employee professional development, informal education systems, and related achievements that advance the practice of engineering and of engineering education.

The IEEE EAB awards are given out during the EAB Awards Ceremony, which is held in conjunction with the November IEEE Meeting Series each year.

Mitra is a Professor Emeritus at the University of California, Santa Barbara and the University of Southern California, in Los Angeles. He was the 1986 president of the IEEE Circuits and Systems Society. He has published more than 700 papers on analog and digital signal processing and image and video processing, and he has authored or coauthored 13 books. He holds six patents

The Institute – “Awards Honor People Making a Difference in Engineering Education”

COE website – "Sanjit Mitra: 50 Years of Signaling the Future"

IEEE Educational Activities Board (EAB) Awards

Mitra's COE Profile

UCSB’s Manjunath (ECE), Pollock (Materials), Miller (MSI) and teams from UCR and U. of AZ receive a $3.4M NSF grant to research scientific image processing

December 1st, 2017

illustration of a scientific imageUCSB researchers given the award from NSF’s Office of Advanced Cyberinfrastructure to build a large-scale distributed image-processing infrastructure (LIMPID) through a broad, interdisciplinary collaboration. Encompassing databases, image analysis and various scientific disciplines, their creation, BisQue, is an image informatics platform that shares, distributes and collaborates with large image datasets.

“Think of BisQue as Google Docs for scientific images,” said UCSB principal investigator B. S. Manjunath, who directs the campus’s Center for Multimodal Big Data Science and Healthcare. “Imaging data is ubiquitous and much of big-data science is image-centric. Working with such data should be as simple as working with text files in Google Docs.”

BisQue is unique in its ability to handle a wide range of imaging data across diverse scientific applications, ranging from marine and materials science to neuroscience and medical imaging. For example, Manjunath is working with co-PI Tresa Pollock, the Alcoa Distinguished Professor of Materials at UCSB, to integrate algorithms developed specifically for processing materials imaging data into BisQue. Recent advances in materials tomography (cross-sectional imaging) are generating an enormous quantity of imaging data that must be reconstructed, shared with the community and further analyzed. According to Pollock, “LIMPID will greatly enhance our ability to work with large material data sets and will leverage advances made in computer vision and machine learning.”

“In marine science, and particularly marine ecology, the technology to capture underwater images is growing exponentially, but most of the imaging data is manually processed,” said co-PI Robert Miller, a research biologist in UCSB’s Marine Science Institute. “In the Santa Barbara Channel Marine Biodiversity Observation Network, which is supported by NASA and the Bureau of Ocean Energy Management, we are developing image-analysis pipelines and models to process underwater imagery and automate the processes of identifying and quantifying marine organisms. LIMPID will expand that work dramatically to the point where UCSB will become the epicenter of image analysis technology for marine science.”

A team at UC Riverside, the home campus of LIMPID collaborator Amit Roy-Chowdhury, will work with neuroscience researchers to analyze large volumes of live imaging data that capture neuronal activities in the Drosophila nervous system. The UCSB scientists also are collaborating with Nirav Merchant of the University of Arizona, where BisQue and the cyberinfrastructure CyVerse will be leveraged to further enable image-based scientific discoveries.

The UCSB Current – "Share, Test and Refine" (full article)

UCSB Center for Bio-Image Informatics

Manjunath's COE Profile

ECE Professor Kaustav Banerjee’s work on novel quantum-transport simulator among most significant papers at IEDM 2017

November 30th, 2017

IEDM logo The selection of four IEDM papers on two-dimensional (2D) materials and devices from the Nanoelectronics Research Lab highlights its role in research on 2D electronics, as well as the interest in these materials in the semiconductor industry

At the upcoming IEEE International Electron Devices Meeting (IEDM), the technical program committee of the conference has selected Professor Banerjee’s work on a novel quantum-transport simulator as one of the sixteen most significant contributions from around 225 papers, which will be presented at the meeting during December 3-6 in San Francisco, CA, for pre-conference publicity. The work reports the first study of a critical leakage mechanism in 2D memory transistors, and establishes their superiority over silicon.

Prof. Banerjee’s selected paper titled “Computational Study of Gate-Induced Drain Leakage in 2D-Semiconductor Field-Effect Transistors” will be presented on Wed, December 6, 2017, in Session 31 by recent ECE alum Dr. Jiahao Kang. The paper is co-authored by several other members in his Nanoelectronics Research Lab (NRL) and researchers from Micron Technology.

In addition, three of Professor Banerjee’s current graduate students – Junkai Jiang, Arnab Pal, and Xuejun Xie – will each present a paper on new innovations on 2D Electronics at this meeting. The selection of four papers from a single research group is a significant achievement in IEDM, which has been the world’s leading forum for reporting innovation, discovery, and breakthroughs in electron device technology for over 60 years.

IEDM 2017 – Most Significant Papers

IEEE Spectrum: "Carbon Nanomaterials Could Push Copper Aside in Chip Interconnects"

Banerjee's Nanoelectronics Research Lab (NRL)

ECE Professor Chris Palmstrom & UCSB scientists are on the cusp of a major advance in topological quantum computing.

November 21st, 2017

Deterministic growth of InSb nanowire networks
Paper in the journal Nature describes a method by which “hashtag”– shaped nanowires may be coaxed to generate Majorana quasiparticles. These particles are exotic states that if realized, can be used to encode information with very little risk of decoherence — one of quantum computing’s biggest challenges — and thus, little need for quantum error correction.

“This was a really good step toward making things happen,” said Palmstrøm. In 2012, Dutch scientists Leo Kouwenhoven and Erik Bakkers (also authors on the paper) from the Delft and Eindhoven Universities of Technology in the Netherlands, reported the first observation of states consistent with these quasiparticles. At the time, however, they stopped short of definitive proof that they were in fact the Majoranas, and not other phenomena.

Under the aegis of Microsoft Corporation’s Research Station Q headquartered on the UCSB campus, this team of scientists is part of a greater international effort to build the first topological quantum computer.

“Quantum technology is now being advanced through large academic – industry collaborations,” said Michael Freedman, Fields Medal-winning mathematician and director of Station Q. “The scale of the work, in most cases, is too large for university labs alone, but the imagination and inventiveness of these labs make them essential partners in any industrial effort. Inventiveness and imagination is precisely what is on display in this recent collaboration involving UCSB, Delft, Eindhoven, Copenhagen, and Microsoft. The ‘hashtag’ structures whose quantum properties are studied in this paper have an unworldly beauty and look nearly as impossible as a tower by Escher. They are single crystals with the topology of a circle. Hats off to the grows and the experimentalists.”

The quasiparticles are named for Italian physicist Ettore Majorana, who predicted their existence in 1937, around the birth of quantum mechanics. They have the unique distinction of being their own antiparticles — they can annihilate one another. They also have the quality of being non-Abelian, resulting in the ability to “remember” their relative positions over time — a property that makes them central to topological quantum computation.

“If you are to move these Majoranas physically around each other, they will remember if they were moved clockwise or anticlockwise,” said Mihir Pendharkar, a graduate student researcher in the Palmstrøm Group. This operation of moving one around the other, he continued, is what is referred to as “braiding.” Computations could in theory be performed by braiding the Majoranas and then fusing them, releasing a poof of energy — a “digital high” — or absorbing energy — a “digital low.” The information is contained and processed by the exchange of positions, and the outcome is split between the two or more Majoranas (not the quasiparticles themselves), a topological property that protects the information from the environmental perturbations (noise) that could affect the individual Majoranas.

However, before any braiding can be performed, these fragile and fleeting quasiparticles must first be generated. In this international collaboration, semiconductor wafers started their journey with patterning of gold droplets at the Delft University of Technology. With the gold droplets acting as seeds, Indium antimonide (InSb) semiconductor nanowires were then grown at the Eindhoven University of Technology. Next, the nanowires traveled across the globe to Santa Barbara, where Palmstrøm Group researchers carefully cleaned and partially covered them with a thin shell of superconducting aluminum. The nanowires were returned to the Netherlands for low temperature electrical measurements.

“The Majorana has been predicted to occur between a superconductor and a semiconductor wire,” Palmstrøm explained. Some of the intersecting wires in the infinitesimal hashtag-shaped device are fused together, while others barely miss one another, leaving a very precise gap. This clever design, according to the researchers, allows for some regions of a nanowire to go without an aluminum shell coating, laying down ideal conditions for the measurement of Majoranas.

“What you should be seeing is a state at zero energy,” Pendharkar said. This “zero-bias peak” is consistent with the mathematics that results in a particle being its own antiparticle and was first observed in 2012. “In 2012, they showed a tiny zero-bias blip in a sea of background,” Pendharkar said. With the new approach, he continued, “now the sea has gone missing,” which not only clarifies the 2012 result and takes the researchers one step closer to definitive proof of Majorana states, but also lays a more robust groundwork for the production of these quasiparticles.

Majoranas, because of their particular immunity to error, can be used to construct an ideal qubit (unit of quantum information) for topological quantum computers, and, according to the researchers, can result in a more practicable quantum computer because its fault-tolerance will require fewer qubits for error correction.

“All quantum computers are going to be working at very low temperatures,” Palmstrøm said, “because ‘quantum’ is a very low energy difference.” Thus, said the researchers, cooling fewer fault-tolerant qubits in a quantum circuit would be easier, and done in a smaller footprint, than cooling more error-prone qubits plus those required to protect from error.

The final step toward conclusive proof of Majoranas will be in the braiding, an experiment the researchers hope to conduct in the near future. To that end, the scientists continue to build on this foundation with designs that may enable and measure the outcome of braiding.

“We’ve had the funding and the expertise of people who are experts in the measurements side of things, and experts in the theory side of things,” Pendharkar said, “and it has been a great collaboration that has brought us up to this level.”

Article from The UCSB Current – “Finding Majoranas”

Nature – "Epitaxy of Advanced Nanowire Quantum Devices"

Chris Palmstrøm Research Group

Palmstrøm's COE Profile

The Association for Computing Machinery (ACM) interviews ECE Professor Yuan Xie in their November 2017 “People of ACM – Bulletin”

November 15th, 2017

photo of yuan xie
“People of ACM” highlights the unique scientific accomplishments and compelling personal attributes of ACM members who are making a difference in advancing computing as a science and a profession. These bulletins feature ACM members whose personal and professional stories are a source of inspiration for the larger computing community.

What research area(s) is receiving the most of your attention right now?
I am looking at application-driven and technology-driven novel circuits/architectures and design methodologies. My current research projects include novel architecture with emerging 3D integrated circuit (IC) and nonvolatile memory, interconnect architecture, and heterogeneous system architecture. In particular, my students and I have put a lot of effort into novel architectures for emerging workloads with an emphasis on artificial intelligence (AI). These novel architectures include computer architectures for deep learning neural networks, neuromorphic computing, and bio-inspired computing.

In your recent book Die-Stacking Architecture co-authored with Jishen Zhao, you predict that 3D memory stacking will be a computer architecture design that will become prevalent in the coming years. Will you tell us a little about 3D memory stacking?
Die-stacking technology is also called three-dimensional integrated circuits (3D ICs). The concept is to stack multiple layers of integrated circuits vertically, and connect them together with vertical interconnections called through-silicon vias (TSVs). My research group has been working on die-stacking architecture for more than a decade. We’ve been looking at different ways to innovate the processor architecture designs with this revolutionary technology. Recently, memory vendors have developed multi-layer 3D stacked DRAM products, such as Samsung’s High-bandwidth Memory (HBM) and Micron’s Hybrid-Memory Cube (HMC). Using interposer technologies, processors can be integrated with 3D stacked memory into the same package, increasing the in-package memory capacity dramatically. The first commercial die-stacking architecture is the AMD Fury X graphic processing unit (GPU) with 4GB HBM die-stacking memory, which was officially released in 2015. Since then, we have seen many other products that integrate 3D memory, such as Nvidia’s Volta GPU, Google’s TPU2, and, most recently, Intel and AMD’s partnership on Intel’s Kaby Lake G series, which integrates AMD’s Radeon GPU and 4GB HBM2.

More questions & answers and Xie’s ACM Bio

  • How might the introduction of radically new hardware impact the existing ecosystem of software?
  • What are the possible architectural innovations in the AI era?

The Association for Computing Machinery (ACM)

Xie's COE Profile

Xie's Scalable Energy-efficient Architecture Lab (SEAL)

ECE Professor Kaustav Banerjee and researchers reveal an advance in precision superlattices materials

September 28th, 2017

illustration of an electron beam creating a 2D superlattice Illustration on the right shows an electron beam (in purple) being used to create a 2D superlattice made up of quantum dots having extraordinary atomic-scale precision and placement

Control is a constant challenge for materials scientists, who are always seeking the perfect material — and the perfect way of treating it — to induce exactly the right electronic or optical activity required for a given application.

One key challenge to modulating activity in a semiconductor is controlling its band gap. When a material is excited with energy, say, a light pulse, the wider its band gap, the shorter the wavelength of the light it emits. The narrower the band gap, the longer the wavelength.

As electronics and the devices that incorporate them — smartphones, laptops and the like — have become smaller and smaller, the semiconductor transistors that power them have shrunk to the point of being not much larger than an atom. They can’t get much smaller. To overcome this limitation, researchers are seeking ways to harness the unique characteristics of nanoscale atomic cluster arrays — known as quantum dot superlattices — for building next generation electronics such as large-scale quantum information systems. In the quantum realm, precision is even more important.

New research conducted by UC Santa Barbara’s Department of Electrical and Computer Engineering reveals a major advance in precision superlattices materials. The findings by Professor Kaustav Banerjee, his Ph.D. students Xuejun Xie, Jiahao Kang and Wei Cao, postdoctoral fellow Jae Hwan Chu and collaborators at Rice University appear in the journal Nature Scientific Reports.

Their team’s research uses a focused electron beam to fabricate a large-scale quantum dot superlattice on which each quantum dot has a specific pre-determined size positioned at a precise location on an atomically thin sheet of two-dimensional (2-D) semiconductor molybdenum disulphide (MoS2). When the focused electron beam interacts with the MoS2 monolayer, it turns that area — which is on the order of a nanometer in diameter — from semiconducting to metallic. The quantum dots can be placed less than four nanometers apart, so that they become an artificial crystal — essentially a new 2-D material where the band gap can be specified to order, from 1.8 to 1.4 electron volts (eV).

This is the first time that scientists have created a large-area 2-D superlattice — nanoscale atomic clusters in an ordered grid — on an atomically thin material on which both the size and location of quantum dots are precisely controlled. The process not only creates several quantum dots, but can also be applied directly to large-scale fabrication of 2-D quantum dot superlattices. “We can, therefore, change the overall properties of the 2-D crystal,” Banerjee said.

Each quantum dot acts as a quantum well, where electron-hole activity occurs, and all of the dots in the grid are close enough to each other to ensure interactions. The researchers can vary the spacing and size of the dots to vary the band gap, which determines the wavelength of light it emits.

“Using this technique, we can engineer the band gap to match the application,” Banerjee said. Quantum dot superlattices have been widely investigated for creating materials with tunable band gaps but all were made using “bottom-up” methods in which atoms naturally and spontaneously combine to form a macro-object. But those methods make it inherently difficult to design the lattice structure as desired and, thus, to achieve optimal performance.

The UCSB Current – “Band Gaps, Made to Order” (full article)

Nature Scientific Reports – "Designing artificial 2D crystals with site and size controlled quantum dots"

Banerjee's COE Profile

Banerjee's Nanoelectronics Research Lab (NRL)

Professor Shuji Nakamura receives the 2017 Mountbatten Medal from the Great Britain-based Institution of Engineering and Technology (IET)

September 26th, 2017

photo of shuji nakamura
Nakamura selected by IET “in recognition of his pioneering development of blue LEDs as high-efficiency, low-power light sources, and in particular their contribution to the reduction of the world’s carbon footprint”

“This year we had a large number of entries and the standard was extremely high,” said Tim Constandinou, chair of the IET Awards and Prizes Committee. “The Achievement Awards allow us to recognize the huge impact that engineers have on all our lives. The winners are extremely talented and have achieved great things in their careers, whether they are a young professional demonstrating outstanding ability at the start of their journey or an engineer at the pinnacle of their career.”

Nakamura, who joined the UCSB faculty in 2000, is most certainly in the latter category. He is best known for his invention of the bright blue LED, for which he was selected as one of three winners of the Nobel Prize in Physics in 2014. Considered at the time a holy grail of solid-state lighting, the invention of the blue LED paved the way for the creation of white LED, which has since revolutionized the world of lighting with its energy efficiency, sustainability and durability.

“It is a great honor to receive the IET’s Mountbatten Medal award,” Nakamura said. “The blue LEDs have been used as an efficient solid state lighting, which has contributed to overcome the global warming issues by reducing the consumption of energy, and thereby reducing carbon containing greenhouse gases.”

Nakamura and colleagues at UCSB’s Solid State Lighting and Energy Electronics Center continue to develop high-efficiency, high-power lighting by refining fabrication techniques, and creating laser-based lighting. They are also developing extremely energy efficient power electronics that could in the future reduce the energy consumption and improve the performance of electronics from cell phones to computers to automotive equipment and even the power grid.

Nakamura will receive his medal November 15 at the 2017 IET awards ceremony in London.

The UCSB Current – “At the Pinnacle” (full article)

IET Awards – Mountbatten Medal

The Solid State Lighting & Energy Electronics Center (SSLEEC)