Researchers Take Step Toward Faster Communication

By Nicole Hemsoth

January 13, 2006

By using electromagnetic waves instead of electrical current for switching, researchers have operated an optical modulator at terahertz frequencies – an accomplishment that could one day facilitate data transmission rates in the trillions of bits per second.

The work represents a key step toward a new generation of optical communication systems that would be as much as 100 times faster than current technology, bringing closer such applications as real-time telemedicine and movies on demand. While operating their terahertz modulator, the research team observed an effect that is well known in atomic physics – but until now hadn't been seen in the semiconductor materials that make up optical modulators.

“This is just one piece, but potentially a very important piece, of a very high bit-rate optical communication system for telecommunications and other applications,” said David Citrin, an associate professor in the School of Electrical and Computer Engineering at the Georgia Institute of Technology. “The point of the experiment was to show that we can operate a modulator at terahertz frequencies, though we are still a long way from a practical device.”

Supported by the National Science Foundation, the research was reported in the October 28, 2005 issue of the journal Science.

Existing telecommunication systems depend on modulators to encode data onto beams of light that then can be carried long distances by optical fibers. Modulators work by rapidly changing their reflectivity, which varies the intensity of light beams passing through them. These variations correspond to the ones and zeroes that are the language of digital communication.

Modulators are also used as switches to reroute data streams by alternately reflecting light or allowing it to pass.

But most current modulators have a drawback – they cannot operate faster than the electronic circuitry used to control them. To boost data speeds, researchers have been seeking alternative control technologies.

“Conventional optical modulators use a voltage change to alter the properties of a material which changes the reflectivity,” explained Citrin. “Electrically switched systems are just too slow to go much beyond where we are now. But by using very high frequency electromagnetic energy to modulate the signal, the hope is that we can generate signals that have much higher data rates than what we can achieve with today's electrical circuits.”

To gain those higher rates, Citrin and colleagues at the University of California, Santa Barbara and the NASA Ames Research Center used very high-frequency waves from a free-electron laser to control the modulator. These electromagnetic waves consist of an oscillating electric field and have the advantage of being able to move through free space without the need for circuitry.

“In principal, you can modulate light much more quickly than you can switch electrical current,” said Citrin, a theoretician who has been working as part of the team for more than a decade. “Instead of connecting the modulator to an electrical circuit, we placed it into the beam of the free-electron laser, a unique research facility at the University of California Santa Barbara.”

Because terahertz oscillation is difficult to measure directly with existing technology, the researchers used indirect means to verify the modulation speed.

Before this approach can lead to faster communication systems, the modulation must be optimized – and the remainder of the system advanced to terahertz speeds.

For example, researchers will have to develop inexpensive and convenient sources of the electromagnetic energy they use for switching. Another challenge will be to optimize the bit depth – the difference in light intensity that represents ones and zeros. And to minimize energy requirements, they must reduce the amount of power required to operate such a system. Finally, the other components of a communications system will also have to advance to terahertz operation

The research team, which included S.G. Carter, V. Birkedal, C.S. Wang, L.A. Coldren, A. V. Maslov and Mark Sherwin in addition to Citrin – also wants to understand the science of the modulation system.

“There is a lot of interesting science going on into how the modulation works,” Citrin said. “We want to understand the issues that influence the ultimate limits of the modulation rate. If we can really understand the physics, we should be able to understand the limits not only of the modulate rates, but also the modulation depth and what are the weakest fields we might be able to use.”

As part of the “signature” of terahertz operation, the researchers observed an effect known as the Autler-Townes Splitting. The effect is well-known in atomic physics, but the Science paper was the first report of it in the semiconductor quantum wells which are part of the modulator.

The splitting occurs when the devices are driven to operate at high frequencies, and its signature is a “double-peak” in the reflectivity of the quantum wells.

“This is an interesting physical effect that can change the optical properties of the medium from reflective to transparent,” explained Citrin. “That may have its own interest for many other applications as well.”

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industy updates delivered to you every week!

SODALITE: Towards Automated Optimization of HPC Application Deployment

May 29, 2020

Developing and deploying applications across heterogeneous infrastructures like HPC or Cloud with diverse hardware is a complex problem. Enabling developers to describe the application deployment and optimising runtime p Read more…

By the SODALITE Team

What’s New in HPC Research: Astronomy, Weather, Security & More

May 29, 2020

In this bimonthly feature, HPCwire highlights newly published research in the high-performance computing community and related domains. From parallel programming to exascale to quantum computing, the details are here. Read more…

By Oliver Peckham

DARPA Looks to Automate Secure Silicon Designs

May 28, 2020

The U.S. military is ramping up efforts to secure semiconductors and its electronics supply chain by embedding defenses during the chip design phase. The automation effort also addresses the high cost and complexity of s Read more…

By George Leopold

COVID-19 HPC Consortium Expands to Europe, Reports on Research Projects

May 28, 2020

The COVID-19 HPC Consortium, a public-private effort delivering free access to HPC processing for scientists pursuing coronavirus research – some utilizing AI-based techniques – has expanded to more than 56 research Read more…

By Doug Black

What’s New in Computing vs. COVID-19: IceCube, TACC, Watson & More

May 28, 2020

Supercomputing, big data and artificial intelligence are crucial tools in the fight against the coronavirus pandemic. Around the world, researchers, corporations and governments are urgently devoting their computing reso Read more…

By Oliver Peckham

AWS Solution Channel

Computational Fluid Dynamics on AWS

Over the past 30 years Computational Fluid Dynamics (CFD) has grown to become a key part of many engineering design processes. From aircraft design to modelling the blood flow in our bodies, the ability to understand the behaviour of fluids has enabled countless innovations and improved the time to market for many products. Read more…

Supercomputer Simulations Explain the Asteroid that Killed the Dinosaurs

May 28, 2020

The supercomputing community has cataclysms on the mind. Hot on the heels of supercomputer-powered research delving into the fate of the neanderthals, a team of researchers used supercomputers at the DiRAC (Distributed R Read more…

By Oliver Peckham

COVID-19 HPC Consortium Expands to Europe, Reports on Research Projects

May 28, 2020

The COVID-19 HPC Consortium, a public-private effort delivering free access to HPC processing for scientists pursuing coronavirus research – some utilizing AI Read more…

By Doug Black

$100B Plan Submitted for Massive Remake and Expansion of NSF

May 27, 2020

Legislation to reshape, expand - and rename - the National Science Foundation has been submitted in both the U.S. House and Senate. The proposal, which seems to Read more…

By John Russell

IBM Boosts Deep Learning Accuracy on Memristive Chips

May 27, 2020

IBM researchers have taken another step towards making in-memory computing based on phase change (PCM) memory devices a reality. Papers in Nature and Frontiers Read more…

By John Russell

Hats Over Hearts: Remembering Rich Brueckner

May 26, 2020

HPCwire and all of the Tabor Communications family are saddened by last week’s passing of Rich Brueckner. He was the ever-optimistic man in the Red Hat presiding over the InsideHPC media portfolio for the past decade and a constant presence at HPC’s most important events. Read more…

Nvidia Q1 Earnings Top Expectations, Datacenter Revenue Breaks $1B

May 22, 2020

Nvidia’s seemingly endless roll continued in the first quarter with the company announcing blockbuster earnings that exceeded Wall Street expectations. Nvidia Read more…

By Doug Black

Microsoft’s Massive AI Supercomputer on Azure: 285k CPU Cores, 10k GPUs

May 20, 2020

Microsoft has unveiled a supercomputing monster – among the world’s five most powerful, according to the company – aimed at what is known in scientific an Read more…

By Doug Black

HPC in Life Sciences 2020 Part 1: Rise of AMD, Data Management’s Wild West, More 

May 20, 2020

Given the disruption caused by the COVID-19 pandemic and the massive enlistment of major HPC resources to fight the pandemic, it is especially appropriate to re Read more…

By John Russell

AMD Epyc Rome Picked for New Nvidia DGX, but HGX Preserves Intel Option

May 19, 2020

AMD continues to make inroads into the datacenter with its second-generation Epyc "Rome" processor, which last week scored a win with Nvidia's announcement that Read more…

By Tiffany Trader

Supercomputer Modeling Tests How COVID-19 Spreads in Grocery Stores

April 8, 2020

In the COVID-19 era, many people are treating simple activities like getting gas or groceries with caution as they try to heed social distancing mandates and protect their own health. Still, significant uncertainty surrounds the relative risk of different activities, and conflicting information is prevalent. A team of Finnish researchers set out to address some of these uncertainties by... Read more…

By Oliver Peckham

[email protected] Turns Its Massive Crowdsourced Computer Network Against COVID-19

March 16, 2020

For gamers, fighting against a global crisis is usually pure fantasy – but now, it’s looking more like a reality. As supercomputers around the world spin up Read more…

By Oliver Peckham

[email protected] Rallies a Legion of Computers Against the Coronavirus

March 24, 2020

Last week, we highlighted [email protected], a massive, crowdsourced computer network that has turned its resources against the coronavirus pandemic sweeping the globe – but [email protected] isn’t the only game in town. The internet is buzzing with crowdsourced computing... Read more…

By Oliver Peckham

Global Supercomputing Is Mobilizing Against COVID-19

March 12, 2020

Tech has been taking some heavy losses from the coronavirus pandemic. Global supply chains have been disrupted, virtually every major tech conference taking place over the next few months has been canceled... Read more…

By Oliver Peckham

DoE Expands on Role of COVID-19 Supercomputing Consortium

March 25, 2020

After announcing the launch of the COVID-19 High Performance Computing Consortium on Sunday, the Department of Energy yesterday provided more details on its sco Read more…

By John Russell

Supercomputer Simulations Reveal the Fate of the Neanderthals

May 25, 2020

For hundreds of thousands of years, neanderthals roamed the planet, eventually (almost 50,000 years ago) giving way to homo sapiens, which quickly became the do Read more…

By Oliver Peckham

Steve Scott Lays Out HPE-Cray Blended Product Roadmap

March 11, 2020

Last week, the day before the El Capitan processor disclosures were made at HPE's new headquarters in San Jose, Steve Scott (CTO for HPC & AI at HPE, and former Cray CTO) was on-hand at the Rice Oil & Gas HPC conference in Houston. He was there to discuss the HPE-Cray transition and blended roadmap, as well as his favorite topic, Cray's eighth-gen networking technology, Slingshot. Read more…

By Tiffany Trader

Honeywell’s Big Bet on Trapped Ion Quantum Computing

April 7, 2020

Honeywell doesn’t spring to mind when thinking of quantum computing pioneers, but a decade ago the high-tech conglomerate better known for its control systems waded deliberately into the then calmer quantum computing (QC) waters. Fast forward to March when Honeywell announced plans to introduce an ion trap-based quantum computer whose ‘performance’ would... Read more…

By John Russell

Leading Solution Providers

SC 2019 Virtual Booth Video Tour

AMD
AMD
ASROCK RACK
ASROCK RACK
AWS
AWS
CEJN
CJEN
CRAY
CRAY
DDN
DDN
DELL EMC
DELL EMC
IBM
IBM
MELLANOX
MELLANOX
ONE STOP SYSTEMS
ONE STOP SYSTEMS
PANASAS
PANASAS
SIX NINES IT
SIX NINES IT
VERNE GLOBAL
VERNE GLOBAL
WEKAIO
WEKAIO

Contributors

Fujitsu A64FX Supercomputer to Be Deployed at Nagoya University This Summer

February 3, 2020

Japanese tech giant Fujitsu announced today that it will supply Nagoya University Information Technology Center with the first commercial supercomputer powered Read more…

By Tiffany Trader

Tech Conferences Are Being Canceled Due to Coronavirus

March 3, 2020

Several conferences scheduled to take place in the coming weeks, including Nvidia’s GPU Technology Conference (GTC) and the Strata Data + AI conference, have Read more…

By Alex Woodie

Exascale Watch: El Capitan Will Use AMD CPUs & GPUs to Reach 2 Exaflops

March 4, 2020

HPE and its collaborators reported today that El Capitan, the forthcoming exascale supercomputer to be sited at Lawrence Livermore National Laboratory and serve Read more…

By John Russell

Cray to Provide NOAA with Two AMD-Powered Supercomputers

February 24, 2020

The United States’ National Oceanic and Atmospheric Administration (NOAA) last week announced plans for a major refresh of its operational weather forecasting supercomputers, part of a 10-year, $505.2 million program, which will secure two HPE-Cray systems for NOAA’s National Weather Service to be fielded later this year and put into production in early 2022. Read more…

By Tiffany Trader

‘Billion Molecules Against COVID-19’ Challenge to Launch with Massive Supercomputing Support

April 22, 2020

Around the world, supercomputing centers have spun up and opened their doors for COVID-19 research in what may be the most unified supercomputing effort in hist Read more…

By Oliver Peckham

Summit Supercomputer is Already Making its Mark on Science

September 20, 2018

Summit, now the fastest supercomputer in the world, is quickly making its mark in science – five of the six finalists just announced for the prestigious 2018 Read more…

By John Russell

15 Slides on Programming Aurora and Exascale Systems

May 7, 2020

Sometime in 2021, Aurora, the first planned U.S. exascale system, is scheduled to be fired up at Argonne National Laboratory. Cray (now HPE) and Intel are the k Read more…

By John Russell

TACC Supercomputers Run Simulations Illuminating COVID-19, DNA Replication

March 19, 2020

As supercomputers around the world spin up to combat the coronavirus, the Texas Advanced Computing Center (TACC) is announcing results that may help to illumina Read more…

By Staff report

  • arrow
  • Click Here for More Headlines
  • arrow
Do NOT follow this link or you will be banned from the site!
Share This