Bell Labs Scientists Find Novel Optical Fibers in Deep-SeaSponges; Study Reveals How Nature Creates Robust OpticalFibers in Marine Sponges

MURRAY HILL, N.J.--(BUSINESS WIRE)--Aug. 21, 2003--Scientists from Lucent Technologies'(NYSE: LU) Bell Labs have found that a deep-sea sponge contains optical fiber that is remarkablysimilar to the optical fiber found in today's state-of-the-art telecommunications networks.

The deep-sea sponge's glass fiber, designed through the course of evolution, may possess certaintechnological advantages over industrial optical fiber, the scientists report in today's issue of thejournal Nature.

"We believe this novel biological optical fiber may shed light upon new bio-inspired processes thatmay lead to better fiber optic materials and networks," said Joanna Aizenberg, the Bell Labsmaterials scientist who led the research team. "Mother Nature's ability to perfect materials isamazing, and the more we study biological organisms, the more we realize how much we can learnfrom them."

The discovery of marine optical fiber is the latest Bell Labs contribution in the emerging field ofscience known as biomimetics, which takes engineering principles from the natural world andapplies them to man-made materials and technologies.

The sponge in the study, Euplectella, lives in the depths of the ocean in the tropics and grows toabout half a foot in length. Commonly known as the Venus Flower Basket, it has an intricatecylindrical mesh-like skeleton of glassy silica and a pair of mating shrimp often lives inside it. At thebase of the sponge's skeleton is a tuft of fibers that extends outward like an inverted crown.Typically, these fibers are between two and seven inches long and about the thickness of a humanhair.

The Bell Labs team found that each of the sponge's fibers comprises of distinct layers with differentoptical properties. Concentric silica cylinders with high organic content surround an inner core ofhigh-purity silica glass, a structure similar to industrial optical fiber, in which layers of glasscladding surround a glass core of slightly different composition. The researchers found duringexperiments that the biological fibers of the sponge conducted light beautifully when illuminated,and used the same optical principles that modern engineers have used to design industrial opticalfiber. "These biological fibers bear a striking resemblance to commercial telecommunications fibers,as they use the same material and have similar dimensions," said Aizenberg.

Though these natural bio-optical fibers do not have the superbly high transparency needed formodern telecommunication networks, the Bell Labs researchers found that these fibers do have a bigadvantage in that they are extremely resilient to cracks and breakage. Although extremely reliable,one of the main causes for outages in commercial optical fiber is fracture resulting from crackgrowth within the fiber. Infrequent as an outage is, when it occurs, replacing the fiber is often acostly, labor-intensive proposition, and scientists have sought to make fiber that is less susceptibleto this problem.

The sponge's solution is to use an organic sheath to cover the biological fiber, Aizenberg and hercolleagues discovered. "These bio-optical fibers are extremely tough," she said. "You could tie them

in tight knots and, unlike commercial fiber, they would still not crack. Maybe we can learn how toimprove on existing commercial fiber from studying these fibers of the Venus Flower Basket," shesaid.

Another advantage of these biological fibers is that they are formed by chemical deposition at thetemperature of seawater. Commercial optical fiber is produced with the help of a high-temperaturefurnace and expensive equipment. Aizenberg said, "If we can learn from nature, there may be analternative way to manufacture fiber in the future."

Should scientists succeed in emulating these natural processes, they hair chalking may also helpreduce the cost of producing optical fiber. "This is a good example where Mother Nature can helpteach us about engineering materials," said Cherry Murray, senior vice president of physicalsciences research at Bell Labs. "In this case, a relatively simple organism has a solution to a verycomplex problem in hair chalking integrated optics and materials design. By studying the VenusFlower Basket, we are learning about low-cost ways of forming complex optical materials at lowtemperatures. While many years away from being applied to commercial use, this understandingcould be very important in reducing the cost and improving the reliability of future optical andtelecommunications equipment."

Other members of the research team were Bell Labs materials scientists Vikram Sundar and JohnGrazul, as well as zoologist Micha Ilan of Tel Aviv University and optics researcher Andrew Yablon ofOFS Laboratories.

The study of biomimetics at Bell Labs is part of the quest to find better materials for technology andindustry, and has proved remarkably fruitful. Two years ago, Aizenberg and her collaborators madethe surprising discovery that thousands of chalk-like calcite crystals spread throughout theexoskeletons of brittlestars, starfish-like marine invertebrates, collectively form an unusual kind ofcompound eye for the animals. The brittlestar's calcite microlenses expertly compensate forbirefringence and spherical aberration, two common types of distortions in lenses. This led the BellLabs scientists to attempt to mimic nature's success and design crystals based on the brittlestarmodel, with the ultimate goal of building complex arrays of microlenses similar to the brittlestar'sown lenses.

Earlier this year, Aizenberg and her colleagues developed a new crystallization approach thatallowed them to directly fabricate single crystals of calcite that were about one-tenth of a centimeteracross. These had patterns less than ten micrometers across, which is approximately one-tenth thediameter of a human hair -- an approach that may revolutionize how crystals are made in the futurefor a wide variety of applications. Single crystals patterned at the micron scale or smaller andintegrated into opto-electronic circuits are important components needed to engineer highlyadvanced electronic, sensory and optical devices.

Bell Labs is the leading source of new communications technologies. It has generated more than30,000 patents since 1925 and has played a pivotal role in inventing or perfecting keycommunications technologies, including transistors, digital networking and signal processing, lasersand fiber-optic communications systems, communications satellites, cellular telephony, electronicswitching of calls, touch-tone dialing, and modems. Bell Labs scientists have received six NobelPrizes in Physics, nine U.S. National Medals of Science and eight U.S. National Medals ofTechnology(R). 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 theworld'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 assoftware and services to develop next-generation networks. The company's systems, services andsoftware are designed to help customers quickly deploy and better manage their networks andcreate new, revenue-generating services that help businesses and consumers. For more informationon Lucent Technologies, visit its Web site at http://www.lucent.com.