Bell Labs Physicists Disclose Research Breakthroughs at Physics 'Mega-Conference' This Week.

Business Editors/High-Tech Writers

AUSTIN, Texas--(BUSINESS WIRE)--March 5, 2003

Research advances could lead to faster and less expensive

communications networks in the future

Physicists from Bell Labs, the research and development arm of Lucent Technologies (NYSE: LU), will reveal the results of recent research into new semiconductor lasers, novel semiconductor materials, and other areas that could potentially help improve communications networks in the future.

They will be speaking at the annual conference of the American Physical Society, the largest gathering of physicists every year, being held here this week.

"Physical science continues to be an important part of what we do at Bell Labs," said Cherry Murray, senior vice president of physical sciences research for Lucent. "Research that will be presented at the Austin meeting spans the entire range from very fundamental work on how electron gases behave in low magnetic fields to applied research on components for next-generation networks."

In an invited lecture, Bell Labs physicist Claire Gmachl will describe the world's first quantum cascade laser that emits light continuously and reliably over a broad spectrum of infrared wavelengths. Quantum cascade (QC) lasers are a class of high-performance semiconductor lasers that were invented at Bell Labs in 1994 by Federico Capasso, Alfred Cho and their collaborators. QC lasers are very convenient light sources because they can be made compact, portable, rugged, and powerful.

A QC laser operates much like an electronic waterfall. When an electric current flows through the laser, electrons cascade down an energy staircase; every time they hit a step, they emit a photon of infrared light. The emitted photons are reflected back and forth inside the semiconductor resonator that contains the electronic cascade, stimulating the emission of still more photons. This amplification process in QC lasers produces high output power.

Lasers are typically narrowband devices, emitting light of a single color or wavelength. A broadband laser offers significant advantages in that it allows for sampling of a wide swath of wavelengths at the same time, and making a reliable one that can operate under a wide variety of operating conditions was a goal for scientists for a long time.

The new broadband QC laser, made by Bell Labs scientists after overcoming many challenges, generates light at multiple infrared wavelengths, is very reliable and could have immediate applications as ultra-sensitive chemical detectors. In the long term, QC lasers may be ideal for communications networks. This is because they require less power to operate than conventional semiconductor lasers, can operate under a range of operating temperatures, and can be switched on and off rapidly, which is necessary to transmit data at high rates.

In addition, Gmachl will talk about how the Bell Labs team recently demonstrated nonlinear generation of light in a QC laser by carefully adapting a multiwavelength laser. Nonlinear effects are dramatic responses induced under certain physical conditions that, properly harnessed, may be useful to optical communications one day.

High-speed communications

In a related development, Bell Labs physicist Mark Lee and colleagues are announcing that they have built a polymer-based optoelectronic device that can operate at more than 100 gigahertz (GHz).

The major challenge to increasing the bandwidth of optical networks significantly beyond the current 40 GHz state of the art is the need for very wide bandwidth optoelectronic devices that can multiplex, demultiplex, switch and modulate the transmitted signals. Devices based on conventional materials have shortcomings that make them unsuitable for signal frequencies above 100 GHz. By contrast, the Bell Labs team has found that certain polymers have all the necessary properties to function in photonic devices at signal frequencies up to several hundred GHz. To demonstrate the speed advantages of polymers, the Bell Labs team built a polymer-based, high-bandwidth optical amplitude modulator, a common component in optical networks.

"Our device modulates light with a bandwidth of 130 to 150 GHz in the lab," said Lee. "If other network components can be built to similar specifications, they should be able to handle the bandwidth requirements of networks for the foreseeable future."

Other Bell Labs papers being presented at the meeting deal with fundamental matters, such as the electronic properties of perovskites, complex oxides that may one day be used widely in industry; X-rays studies of the phenomenon of antiferromagnetism in chromium; and experiments to determine how two-dimensional electron gases behave in low magnetic fields.

Bell Labs is the leading source of new communications technologies. It has generated nearly 30,000 patents since 1925 and has played a pivotal role in inventing or perfecting key communications technologies, including transistors, digital networking and signal processing, lasers and fiber-optic communications systems, communications satellites, cellular telephony, electronic switching of calls, touch-tone dialing, and modems. Bell Labs scientists have received six Nobel Prizes in Physics, nine U.S. Medals of Science and eight U.S. Medals of Technology. For more information about Bell Labs, visit its Web site at http://www.bell-labs.com.

Lucent Technologies, headquartered in Murray Hill, N.J., USA, designs and delivers networks for the world's largest communications service providers. Backed by Bell Labs research and development, Lucent relies on its strengths in mobility, optical, data and voice networking technologies as well as software and services to develop next-generation networks. The company's systems, services and software are designed to help customers quickly deploy and better manage their networks and create new, revenue-generating services that help businesses and consumers. For more information on Lucent Technologies, visit its Web site at http://www.lucent.com.