The Future of Optical Communication

The world’s largest international conference on optical communications begins later this month and continues from Feb. 24-28 at the San Diego Convention Center in San Diego. The Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference (OFC/NFOEC) is the premier meeting where experts from industry and academia intersect and share their results, experiences, and insights on the future of electronic and wireless communication and the optical technologies that will enable it.

Journalists are invited to attend the meeting, where more than 15,000 attendees are expected. This year’s lineup will have many engaging talks and panels, including:

• MARKET WATCH, a three-day series of presentations and panel discussions featuring esteemed guest speakers from the industrial, research, and investment communities on the applications and business of optical communications.
• PLENARY PRESENTATIONS: “Toward Terabit Ethernet” by Bob Metcalfe, general partner of Polaris Ventures; “Perspectives on Optical Communications” by Herwig Kogelnik, adjunct photonics systems research vice president, Bell Labs, Alcatel-Lucent; “Evolving Carrier Networks to Cost-Effectively Manage Proliferating Traffic Growth” by Pieter Poll, chief technology officer, Qwest Communications Corporation Inc.
• FUTURE INTERNET SYMPOSIUM, which aims to create a venue where the optical networking aspects of future Internetworking can be debated alongside computer science, related applications and other future Internet research topics, encouraging significant discussions between different research communities.

SCIENTIFIC HIGHLIGHTS

The conference also features a comprehensive technical program with talks covering the latest research related to all aspects of optical communication. Some of the highlights at OFC/NFOEC 2008 include the following.

GOING WIRELESS THROUGH OPTICAL FIBERS

Getting the most out of limited bandwidth will be more and more essential as wireless demands increase in the near future. Zhensheng Jia and Professor Gee-Kung Chang’s optical networking group at the Georgia Institute of Technology in Atlanta is showing how to get the most of wireless capacity and bandwidth by splitting wireless signals into separate components and then using optical fiber to carry wireless signals to their destination where they are re-integrated. The long-range linkages are provided by optical fiber, but the last few tens of meters are provided by wireless. The result: users can communicate wirelessly at a much higher bandwidth over a longer distance than is possible without using a fiber.

This convergence of optics and wireless technology is a marriage of necessity—but in the end a happy one because it means potentially supplying a greater and longstanding bandwidth to the end user, who will get the signal wirelessly. In his OFC paper in collaboration with NEC Labs America, Jia will discuss an efficient and flexible method that has been shown via experiments to be able to carry multi-channel wireless signals transmitted over 160 km of optical fiber and through 12 straight-line switches. Talk OMO3, “Transport of 8x2.5-Gb/s Wireless Signals over Optical Millimeter Wave through 12 Straight-Line WSSs and 160-km Fiber for Advanced DWDM Metro Networks” (5:15 p.m. Monday, Feb. 25 in room 4)

RATCHETING UP DATA RATES

IBM has developed a transceiver capable of boosting chip-to-chip bandwidth on printed circuit boards to 300 Gigabits per second (Gb/s) – the fastest rate to date and a development that ultimately will enable even faster speeds for data transmission in homes and businesses. The device, assembled from relatively low-cost components that might someday be easily mass-manufactured, allows for a bi-directional data rate nearly twice that of an earlier generation IBM transceiver described just a year ago at the 2007 OFC/NFOEC meeting.

This increased bandwidth is the result of two specific advances. First, the new transceiver includes 24 channels for sending and receiving data compared to 16 such channels in the previous device. Second, the modulation rate of each of the transceiver's vertical cavity surface emitting lasers (VCSELs) has been increased by 25 percent to 12.5 billion bits per second. In an effort to speed commercialization efforts, IBM has incorporated lasers and detectors that operate at the industry-standard wavelength of 850 nanometers (nm) instead of the proprietary 985-nn technology used in the earlier transceiver.

The device was produced as part of an ongoing Defense Advanced Research Projects Agency (DARPA) program at the U.S. Department of Defense to speed up chip-to-chip communications for supercomputers. However, better input/output technology also is related to performance of large-scale computer systems for businesses and demand by individuals for ubiquitous connectivity and on-demand access to content. Clint Schow of IBM will announce details of this work in talk OMK5, "300-Gb/s, 24-Channel Full-Duplex, 850-nm, CMOS-Based Optical Transceivers" (2:45 p.m. Monday, Feb. 25 in room 6D).

ALTERNATIVE ROUTES ON THE INFORMATION SUPERHIGHWAY

Any savvy commuter can tell you that one of the only things to do if there are too many cars on the road is to exit and explore new routes. Likewise local governments seek to ease traffic congestion not by limiting the number of cars but by building new roads. The same analogy is true of traffic in optical communication. Data transmission capacity has grown enormously in recent years, but so has the demand for this capacity. Although the band currently used for optical communication (1.5 micron wavelength) is sufficient for the moment, the enormous increase of traffic expected in the future demands that scientists and engineers begin exploring new bands now.

Now Kenji Kurokawa and his colleagues at NTT Access Network Service Systems Laboratories in Ibaraki, Japan are investigating optical communication in the 1.0 micron band, introducing a brand new channel for communications and opening up a new “road” for data transmission. They are exploring high-capacity, “wavelength division multiplexed” (WDM) transmission in photonic crystal fiber. In WDM transmission, multiple optical signals are multiplexed on a single optical fiber by using different colors or wavelengths of light to carry different signals. Photonic crystal fibers offer a theoretical endless communication wavelength region, which can enable ultra high capacity transmission.

In his talk, Kurokawa will describe the first WDM transmission experiment using a broadband continuum light source in the 1.0 micron band. He will discuss the possibility of terabit optical communication in the new band and its potential impact on optical communication—essentially, no need to worry about traffic congestion for commuters on the information superhighway. Talk OMH5, “High Capacity WDM Transmission in 1.0 µm Band over Low Loss PCF Using Supercontinuum Source” (2:45 p.m. Monday, Feb. 25 in room 5).

THE ELECTROMAGNETIC SPECTRUM—A NEW VIEW

The terahertz band is relatively unexplored and unexploited because its range of frequencies is too high for conventional electronics and too small for semiconductor lasers and detectors, but new research to be presented at OFC/NFOEC reflects what scientists have always known - the terahertz band has great potential.

Dr. Bernd Sartorius of the Fraunhofer Heinrich-Hertz-Institute for Telecommunications in Berlin will explore the use of the terahertz band for applications in security, medicine, and materials science and the role telecommunications technologies play in its developments. Terahertz radiation, unlike other scanning technologies, can penetrate materials like paper, clothing and plastics and remain harmless to humans. So, terahertz spectra can indicate explosives or analyze complex pharmaceutical substances where today’s technologies, such as X-rays, cannot.

However, terahertz systems are impractical because they require expensive lasers, liquid helium-cooled detectors, and bulky optical benches that make field work unfeasible. Sartorius will examine the state of the art for terahertz instrumentation, stressing especially new ways that telecom technology can make terahertz systems low cost, flexible, and easily transported. Talk OMS3, “Terahertz Transmitters and Receivers” (5:30 p.m. Monday, Feb. 25 in room 6D).