First Terabit Speed Computing Technology

Photo: Calit2 research scientist Nikola Alic with optical test equipment in the UC San Diego lab.

Electrical engineers at the University of California, San Diego have achieved world-record speeds for real-time signal processing in an effort to meet ambitious goals set by the Defense Advanced Research Projects Agency (DARPA) to develop the first Terabit-scale technology for optical processing. The technology could have widespread ramifications for networking, computing, defense and other industries.

UC San Diego electrical and computer engineering professor Stojan Radic and his team have demonstrated the first real-time sampling of a 320 Gigabits per second (Gb/s) channel, setting multiple records in the process. The results were outlined in papers delivered at the IEEE LEOS Society for Photonics Winter Topical Meeting Jan. 12-14 in Innsbruck, Austria, at the Photonics West Conference this week in San Jose, Calif., and in recent submissions to IEEE Photonics Technology Letters and the IEEE Journal of Lightwave Technology.

Developed in the Photonics Systems Lab of the California Institute for Telecommunications and Information Technology (Calit2), the UC San Diego technology is part of an advanced program on parametric optical processing funded by DARPA. The program was envisioned and managed by Dr. Henryk Temkin of DARPA's Microsystems Technology Office.

"For the first time we have been able to process signals as fast as 320 Gb/s by making more than eight copies of the signal and simultaneously sampling all the copies - thereby allowing us to do real-time processing," said Radic, a professor in UCSD's Jacobs School of Engineering. The aggregate speed was a record, as were the number of copies simultaneously sampled. The demonstration also registered a five-fold improvement in a published optical delay demonstration.

"Calit2 has a strong interest in very fast optical processing in order to bridge the gap between transmission and real-time processing speeds," said Calit2 Director Larry Smarr. "The future of the Internet - especially for data-intensive collaborative science - is predicated on finding ways to process data on the fly, even at the highest transmission rates. The techniques invented by Professor Radic and his team are a major step forward to realizing this vision."

"The goal of the four-year project is to reach one Terabit per second processing with a single technology platform," said Radic. "A little over one year into the project, we have achieved one-third of that speed, which is about an order-of-magnitude faster than the advanced commercial optical transport at 40 Gb/s."

The latest advances build on development of wideband optical mixers, a key technology of this effort. UC San Diego research led to a new technique capable of mapping dispersive fluctuations in fiber that are on the order of the diameter of a molecule. The technique maps an optical fiber's geometry for any variations of more than a couple of nanometers. "Once you can do that," said Radic, "you can synthesize a parametric mixer with true bandwidths exceeding tens of Terahertz." In the past, the use of a fluctuating nonlinear waveguide limited the mixer bandwidth and efficiency to a point that researchers coined the term 'stochastic mixer barrier' to describe it.

The sensitivity of conventional waveguide mapping techniques was off by orders of magnitude and could not address the mixer waveguides even in principle. The technique developed at UC San Diego can map nearly dispersionless fiber with 100-fold higher resolution and sensitivity. The dispersive mapping technique is now the subject of a pending patent application, and is expected to revolutionize general mixer construction. The research will be described at invited talks at this week's Photonics West conference and at OFC 2009 this March in San Diego.

Armed with the new class of optical mixer, the UC San Diego system can process more than eight duplicates of the 320Gb/s data stream simultaneously - allowing for the