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Primeur weekly 2018-04-23

Special

Commissioner Mariya Gabriel sees a growing sense of community in EuroHPC exascale initiative ...

Focus

ETAIS and eInfraCentral: a national and a European approach for offering e-Infrastructure services ...

Exascale supercomputing

The Exascale Computing Project (ECP) appoints GE's Brunon (Dave) Kepczynski as Industry Council Chair ...

Quantum computing

Novel thermal phases of topological quantum matter in the lab ...

Focus on Europe

ISC STEM Student Day opens for sign-up, includes free HPC & Machine Learning tutorial ...

Key role for University of Bristol in new supercomputer collaboration ...

e-IRG Open Workshop to focus on EuroHPC and development of e-Infrastructures in South-Eastern European (SEE) and Eastern-Mediterranean (EM) region ...

The JUWELS supercomputer in Juelich ...

KTH Sweden to organize PDC Summer School - Introduction to High Performance Computing ...

Hardware

Memorandum of Understanding on future international collaboration projects ...

New direct link from South Africa enables global science ...

Integrating optical components into existing chip designs ...

Russian RSC Group deployed the world first 100% hot water liquid cooled supercomputer at Joint Institute for Nuclear Research ...

DDN Storage builds major new engineering facility in Colorado focused on solving AI, Cloud and large-scale enterprise data challenges ...

Cray debuts AMD EPYC processors in supercomputer product line ...

Fujitsu upgrades RIKEN's AI research computer RAIDEN; reaches top tier of processing performance in Japan ...

Fujitsu launches new GS21 mainframe models supporting next-generation mission-critical systems ...

Applications

EMBO Practical Course on Integrative modelling of biomolecular interactions at Barcelona Supercomputing Center ...

Your digital twin: closer than you think - How computer models can predict health and help to prevent and cure diseases ...

From insulator to conductor in a flash ...

Oregon scientists decipher the magma bodies under Yellowstone ...

Some superconductors can also carry currents of 'spin' ...

Improving citizen science and big data analysis ...

Diamond-like carbon is formed differently to what was believed - machine learning enables development of new model ...

AI projected to replace thousands of banking jobs ...

The Cloud

UTSA Open Cloud Institute supports Cloud research & launches certificate programme ...

Integrating optical components into existing chip designs


Researchers have developed a technique for assembling on-chip optics and electronic separately, which enables the use of more modern transistor technologies. Credit: Amir Atabaki.
19 Apr 2018 Cambridge - Two and a half years ago, a team of researchers led by groups at the Massachusetts Institute of Technology (MIT), the University of California at Berkeley, and Boston University (BU) announced a milestone: the fabrication of a working microprocessor, built using only existing manufacturing processes, that integrated electronic and optical components on the same chip.

The researchers' approach, however, required that the chip's electrical components be built from the same layer of silicon as its optical components. That meant relying on an older chip technology in which the silicon layers for the electronics were thick enough for optics.

In the latest issue ofNature, a team of 18 researchers, led by the same MIT, Berkeley, and BU groups, reports another breakthrough: a technique for assembling on-chip optics and electronic separately, which enables the use of more modern transistor technologies. Again, the technique requires only existing manufacturing processes.

"The most promising thing about this work is that you can optimize your photonics independently from your electronics", stated Amir Atabaki, a research scientist at MIT's Research Laboratory of Electronics and one of three first authors on the new paper. "We have different silicon electronic technologies, and if we can just add photonics to them, it'd be a great capability for future communications and computing chips. For example, now we could imagine a microprocessor manufacturer or a GPU manufacturer like Intel or Nvidia saying, 'This is very nice. We can now have photonic input and output for our microprocessor or GPU'. And they don't have to change much in their process to get the performance boost of on-chip optics."

Moving from electrical communication to optical communication is attractive to chip manufacturers because it could significantly increase chips' speed and reduce power consumption, an advantage that will grow in importance as chips' transistor count continues to rise: The Semiconductor Industry Association has estimated that at current rates of increase, computers' energy requirements will exceed the world's total power output by 2040.

The integration of optical - or "photonic" - and electronic components on the same chip reduces power consumption still further. Optical communications devices are on the market today, but they consume too much power and generate too much heat to be integrated into an electronic chip such as a microprocessor. A commercial modulator - the device that encodes digital information onto a light signal - consumes between 10 and 100 times as much power as the modulators built into the researchers' new chip.

It also takes up 10 to 20 times as much chip space. That's because the integration of electronics and photonics on the same chip enables Amir Atabaki and his colleagues to use a more space-efficient modulator design, based on a photonic device called a ring resonator.

"We have access to photonic architectures that you can't normally use without integrated electronics", Amir Atabaki explained. "For example, today there is no commercial optical transceiver that uses optical resonators, because you need considerable electronics capability to control and stabilize that resonator."

Amir Atabaki's co-first-authors on theNaturepaper are Sajjad Moazeni, a PhD student at Berkeley, and Fabio Pavanello, who was a postdoc at the University of Colorado at Boulder, when the work was done. The senior authors are Rajeev Ram, a professor of electrical engineering and computer science at MIT; Vladimir Stojanovic, an associate professor of electrical engineering and computer sciences at Berkeley; and Milos Popovic, an assistant professor of electrical and computer engineering at Boston University. They're joined by 12 other researchers at MIT, Berkeley, Boston University, the University of Colorado, the State University of New York at Albany, and Ayar Labs, an integrated-photonics start-up that Rajeev Ram, Vladimir Stojanovic, and Milos Popovic helped found.

In addition to millions of transistors for executing computations, the researchers' new chip includes all the components necessary for optical communication: modulators; waveguides, which steer light across the chip; resonators, which separate out different wavelengths of light, each of which can carry different data; and photodetectors, which translate incoming light signals back into electrical signals.

Silicon - which is the basis of most modern computer chips - must be fabricated on top of a layer of glass to yield useful optical components. The difference between the refractive indices of the silicon and the glass - the degrees to which the materials bend light - is what confines light to the silicon optical components.

The earlier work on integrated photonics, which was also led by Rajeev Ram, Vladimir Stojanovic, and Milos Popovic, involved a process called wafer bonding, in which a single, large crystal of silicon is fused to a layer of glass deposited atop a separate chip. The new work, in enabling the direct deposition of silicon - with varying thickness - on top of glass, must make do with so-called polysilicon, which consists of many small crystals of silicon.

Single-crystal silicon is useful for both optics and electronics, but in polysilicon, there's a tradeoff between optical and electrical efficiency. Large-crystal polysilicon is efficient at conducting electricity, but the large crystals tend to scatter light, lowering the optical efficiency. Small-crystal polysilicon scatters light less, but it's not as good a conductor.

Using the manufacturing facilities at SUNY-Albany's Colleges for Nanoscale Sciences and Engineering, the researchers tried out a series of recipes for polysilicon deposition, varying the type of raw silicon used, processing temperatures and times, until they found one that offered a good tradeoff between electronic and optical properties.

"I think we must have gone through more than 50 silicon wafers before finding a material that was just right", Amir Atabaki stated.

Source: Massachusetts Institute of Technology - MIT

Back to Table of contents

Primeur weekly 2018-04-23

Special

Commissioner Mariya Gabriel sees a growing sense of community in EuroHPC exascale initiative ...

Focus

ETAIS and eInfraCentral: a national and a European approach for offering e-Infrastructure services ...

Exascale supercomputing

The Exascale Computing Project (ECP) appoints GE's Brunon (Dave) Kepczynski as Industry Council Chair ...

Quantum computing

Novel thermal phases of topological quantum matter in the lab ...

Focus on Europe

ISC STEM Student Day opens for sign-up, includes free HPC & Machine Learning tutorial ...

Key role for University of Bristol in new supercomputer collaboration ...

e-IRG Open Workshop to focus on EuroHPC and development of e-Infrastructures in South-Eastern European (SEE) and Eastern-Mediterranean (EM) region ...

The JUWELS supercomputer in Juelich ...

KTH Sweden to organize PDC Summer School - Introduction to High Performance Computing ...

Hardware

Memorandum of Understanding on future international collaboration projects ...

New direct link from South Africa enables global science ...

Integrating optical components into existing chip designs ...

Russian RSC Group deployed the world first 100% hot water liquid cooled supercomputer at Joint Institute for Nuclear Research ...

DDN Storage builds major new engineering facility in Colorado focused on solving AI, Cloud and large-scale enterprise data challenges ...

Cray debuts AMD EPYC processors in supercomputer product line ...

Fujitsu upgrades RIKEN's AI research computer RAIDEN; reaches top tier of processing performance in Japan ...

Fujitsu launches new GS21 mainframe models supporting next-generation mission-critical systems ...

Applications

EMBO Practical Course on Integrative modelling of biomolecular interactions at Barcelona Supercomputing Center ...

Your digital twin: closer than you think - How computer models can predict health and help to prevent and cure diseases ...

From insulator to conductor in a flash ...

Oregon scientists decipher the magma bodies under Yellowstone ...

Some superconductors can also carry currents of 'spin' ...

Improving citizen science and big data analysis ...

Diamond-like carbon is formed differently to what was believed - machine learning enables development of new model ...

AI projected to replace thousands of banking jobs ...

The Cloud

UTSA Open Cloud Institute supports Cloud research & launches certificate programme ...