| The Venus Flower Basket sponge has an intricate mesh-like skeleton of glassy silica. Some transmit light as do man-made optical fibers. |
The sponge, Euplectella, commonly called the Venus Flower Basket, lives in tropic oceans and produces a tuft of fibers ranging from 2 to 7-in. long and about the thickness of a human hair. Each fiber has an outer layer of concentric silica cylinders containing various organic compounds surrounding an inner core of high-purity silica glass, similar to modern optical fiber with its glass cladding around a glass core. And sponge fibers conduct light in the same way as optical fibers.
The natural fibers lack the transparency needed for modern communication networks. However, they resist cracks and breaks better than man-made fibers. "You can tie these fibers in knots, and unlike commercial fiber, they won't crack," says Joanna Aizenberg, a Bell Labs material scientist who hopes to unlock the sponge's secret to growing optical fibers.
Sponge fibers are formed by chemical deposition at seawater temperatures. It currently takes a high-temperature furnace and other expensive equipment to make them. Researchers hope that by studying the sponge, they may discover inexpensive, low-temperature manufacturing methods for optical fibers.