Posts tagged MIT
CU research: Microchips using light instead of wires boosts speed exponentially
Sep 30th
could allow for faster and faster electronics
A pair of breakthroughs in the field of silicon photonics by researchers at the University of Colorado Boulder, the Massachusetts Institute of Technology and Micron Technology Inc. could allow for the trajectory of exponential improvement in microprocessors that began nearly half a century ago—known as Moore’s Law—to continue well into the future, allowing for increasingly faster electronics, from supercomputers to laptops to smartphones.
The research team, led by CU-Boulder researcher Milos Popovic, an assistant professor of electrical, computer and energy engineering, developed a new technique that allows microprocessors to use light, instead of electrical wires, to communicate with transistors on a single chip, a system that could lead to extremely energy-efficient computing and a continued skyrocketing of computing speed into the future.
Popovic and his colleagues created two different optical modulators—structures that detect electrical signals and translate them into optical waves—that can be fabricated within the same processes already used in industry to create today’s state-of-the-art electronic microprocessors. The modulators are described in a recent issue of the journal Optics Letters.
First laid out in 1965, Moore’s Law predicted that the size of the transistors used in microprocessors could be shrunk by half about every two years for the same production cost, allowing twice as many transistors to be placed on the same-sized silicon chip. The net effect would be a doubling of computing speed every couple of years.
The projection has held true until relatively recently. While transistors continue to get smaller, halving their size today no longer leads to a doubling of computing speed. That’s because the limiting factor in microelectronics is now the power that’s needed to keep the microprocessors running. The vast amount of electricity required to flip on and off tiny, densely packed transistors causes excessive heat buildup.
“The transistors will keep shrinking and they’ll be able to continue giving you more and more computing performance,” Popovic said. “But in order to be able to actually take advantage of that you need to enable energy-efficient communication links.”
Microelectronics also are limited by the fact that placing electrical wires that carry data too closely together can result in “cross talk” between the wires.
In the last half-dozen years, microprocessor manufacturers, such as Intel, have been able to continue increasing computing speed by packing more than one microprocessor into a single chip to create multiple “cores.” But that technique is limited by the amount of communication that then becomes necessary between the microprocessors, which also requires hefty electricity consumption.
Using light waves instead of electrical wires for microprocessor communication functions could eliminate the limitations now faced by conventional microprocessors and extend Moore’s Law into the future, Popovic said.
Optical communication circuits, known as photonics, have two main advantages over communication that relies on conventional wires: Using light has the potential to be brutally energy efficient, and a single fiber-optic strand can carry a thousand different wavelengths of light at the same time, allowing for multiple communications to be carried simultaneously in a small space and eliminating cross talk.
Optical communication is already the foundation of the Internet and the majority of phone lines. But to make optical communication an economically viable option for microprocessors, the photonics technology has to be fabricated in the same foundries that are being used to create the microprocessors. Photonics have to be integrated side-by-side with the electronics in order to get buy-in from the microprocessor industry, Popovic said.
“In order to convince the semiconductor industry to incorporate photonics into microelectronics you need to make it so that the billions of dollars of existing infrastructure does not need to be wiped out and redone,” Popovic said.
Last year, Popovic collaborated with scientists at MIT to show, for the first time, that such integration is possible. “We are building photonics inside the exact same process that they build microelectronics in,” Popovic said. “We use this fabrication process and instead of making just electrical circuits, we make photonics next to the electrical circuits so they can talk to each other.”
In two papers published last month in Optics Letters with CU-Boulder postdoctoral researcher Jeffrey Shainline as lead author, the research team refined their original photonic-electronic chip further, detailing how the crucial optical modulator, which encodes data on streams of light, could be improved to become more energy efficient. That optical modulator is compatible with a manufacturing process—known as Silicon-on-Insulator Complementary Metal-Oxide-Semiconductor, or SOI CMOS—used to create state-of-the-art multicore microprocessors such as the IBM Power7 and Cell, which is used in the Sony PlayStation 3.
The researchers also detailed a second type of optical modulator that could be used in a different chip-manufacturing process, called bulk CMOS, which is used to make memory chips and the majority of the world’s high-end microprocessors.
Vladimir Stojanovic, who leads one of the MIT teams collaborating on the project and who is the lead principal investigator for the overall research program, said the group’s work on optical modulators is a significant step forward.
“On top of the energy-efficiency and bandwidth-density advantages of silicon-photonics over electrical wires, photonics integrated into CMOS processes with no process changes provides enormous cost-benefits and advantage over traditional photonic systems,” Stojanovic said.
The CU-led effort is a part of a larger project on building a complete photonic processor-memory system, which includes research teams from MIT led by Stojanovic, Rajeev Ram and Michael Watts, a team from Micron Technology led by Roy Meade and a team from the University of California, Berkeley, led by Krste Asanovic. The research was funded by the Defense Advanced Research Projects Agency and the National Science Foundation.
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CU team receives $9.2 million DOE grant to engineer E. coli into biofuels
Dec 4th
“This is a fantastic opportunity to take what we have worked on for the past decade to the next level,” said team leader Ryan Gill, a fellow of CU-Boulder’s Renewable and Sustainable Energy Institute, or RASEI. “In this project, we will develop technologies that are orders of magnitude beyond where we are currently.”
The team is working with a non-pathogenic strain of E. coli. Among the microbe’s more than 4,000 genes, the team is searching for a small set and how it can be manipulated in a combination of on and off states to change the bacteria’s behavior.
“E. coli is not going to want to make your biofuel at all,” said Gill, who’s also a CU-Boulder associate professor of chemical and biological engineering. “It doesn’t do that naturally. It’s programmed with thousands of genes controlling how it replicates. We’re figuring out what control structure we need to rewire in the bug to make it do what we want, not what it wants.”
Included in the team are Rob Knight, CU-Boulder associate professor of chemistry and biochemistry; Pin-Ching Maness, principal scientist at DOE’s National Renewable Energy Laboratory, or NREL; and Adam Arkin, physical biosciences director at DOE’s Lawrence Berkeley National Laboratory.
The researchers hope to engineer the production of ethylene and isobutanol in the modified E. coli. The two compounds are widely used commodities that can be converted into gasoline among other chemicals.
The greatest challenge is harnessing an efficient and inexpensive process that competes with abundant and low-cost fossil fuels like oil, according to Gill.
“Microorganisms and their genomes are incredibly complex machines,” said Gill. “The first step alone — of pinpointing the part of the E. coli genome that can help us make biofuels or other chemicals on a cost-competitive basis — is a daunting challenge. Then we have to determine if the results we want will take one year or decades, $5 million or $500 million.”
The team will be able to simultaneously identify numerous E. coli genes and the results of turning these genes on or off using advanced technologies. Many of the technologies have been developed by the researchers’ own labs.
The grant is the first of its kind from the DOE’s Office of Biological and Environmental Research and was awarded to only seven other research groups including teams led by MIT, Purdue University and the J. Craig Venter Institute.
In 2011, CU’s Technology Transfer Office named Gill an inventor of the year. In 2005, Gill won a National Science Foundation CAREER Award as well as a National Institutes of Health K25 Career Development Award for genomics research and teaching.
CU, MIT TOP UNIVERSITIES FOR DEPARTMENT OF ENERGY EARLY CAREER RESEARCH AWARDS
May 17th
The three CU-Boulder winners — Alireza Doostan of the aerospace engineering sciences department, Minhyea Lee of the physics department and Alexis Templeton of the geological sciences department — were among 65 winners nationwide selected by the DOE in 2011. They join four other CU-Boulder faculty selected in the 2010 — the most of any university in the nation — making CU-Boulder and MIT tops in the country with seven faculty each in the DOE Early Career Research Program.
Trailing CU-Boulder and MIT in total awards for the program in 2010 and 2011 were such schools as Princeton University, Caltech, the University of California, San Diego and the University of Wisconsin-Madison.
“For CU-Boulder to be honored by the U.S. Department of Energy with seven of these coveted Early Career Research Program awards in the past two years is testimony to our excellence as a research university and our ability to recruit extremely talented young faculty,” said CU-Boulder Vice Chancellor for Research Stein Sture. “It also is great news for our students, who will be even more involved in critical energy research efforts that benefit Colorado, the nation and world,” said Sture, also dean of the graduate school.
Templeton will be exploring chemical reactions between water, carbon dioxide and several common minerals found beneath Earth’s surface, including olivine, which become unstable in water and will dissolve. Chemical reactions caused by dissolving olivine can react with and sequester CO2, essentially taking it out of the atmosphere and water and storing it in other rocks.
The twist, said Templeton, is that all of the experiments will be conducted in the presence and absence of bacteria that can survive extreme conditions. She and her team will be using high energy X-rays to study how “extremophiles” that can survive such high temperatures and pressures in the deep subsurface might change the reaction pathway involved in dissolving the rocks, producing new minerals, or creating other greenhouse gases like methane.
Lee’s research is focused on uncovering and identifying new states of matter resulting from strong interactions between electrons. The effort involves studying new materials with unusual properties, such as novel magnetism or unconventional superconductivity.
In addition to the fundamental interest in discovering new states, there is great potential for new technological applications in the future, according to Lee.
Doostan’s research centers on developing scalable computational techniques for uncertainty representation and propagation in complex engineering systems. To enhance the credibility of simulation tools and increase confidence in model predictions, Doostan and his group construct probabilistic approaches to characterize uncertainties and their impacts on model predictions.
One of Doostan’s research efforts will be to attempt to improve simulation-based prediction of failure mechanisms in lithium-ion batteries.
To be eligible for the DOE Early Career Research awards, researchers must have received their doctorates in the past 10 years and be untenured, tenure-track assistant or associate professors at U.S. academic institutions or full-time employees at DOE laboratories. The three CU-Boulder faculty winners in 2011 were selected from a pool of more than 1,000 applicants, as were CU-Boulder’s 2010 winners.
The four 2010 recipients from CU-Boulder were Michael Hermele, Alysia Marino and Tobin Munsat of the department of physics and Arthi Jayaraman of the department of chemical and biological engineering.
There was one other DOE Early Career Award winner from Colorado in 2011 — Zhigang Wu from the Colorado School of Mines, who will be studying quantum mechanical simulations of complex nanostructures for photovoltaic applications.
For more information on the DOE awards go to http://science.energy.gov/news/in-the-news/2011/05-06-11/.