NTT sends 10T bps down single fiber

Researchers at Nippon Telegraph and Telephone Corp. (NTT) have developed a new multiplexer which will allow optical fibers to transmit data at 10T bps (bits per second), the company said Thursday. It plans to commercialize the technology before March 2002 on its optical trunk network between cities in Japan.

Using a technique called wavelength-division multiplexing (WDM), multiple data streams can be carried simultaneously in optical fibers on different wavelengths of light, in much the same way that multiple radio signals can be broadcast simultaneously on different frequencies. The multiplexer is a key part of WDM technology: it bundles many different wavelengths of light together so they can be sent on a single fiber at the same time. The more wavelengths it can put together, the more data can be sent down an optical fiber.

NTT's new multiplexer allows one fiber to carry 256 wavelengths, four times more than the current best multiplexer, according to Takeshi Kitagawa, a development team leader at NTT Photonics Laboratories. Until now, in order to increase the number of wavelengths above 64, more than one multiplexer was required.

With present optical fiber network technology, the maximum speed of data transmission is typically 40G bits per second (bps) per wavelength, but earlier this year Germany's Siemens AG and WorldCom Inc. said they had reached a new speed record of 3.2T bps for data transmission over a real-world fiber optic network.

Last year, NEC Corp. said it had achieved a transmission capacity of 6.4T bps in the laboratory, making it one of the front-runners for high-volume data transmission over optical fibers.So far, NTT researchers have tested their new device in the laboratory and confirmed that it works with a fiber, Kitagawa said.