Cardiff, UK, September 9, 2002 -- A research team, led by Dr Stuart Walker from Essex University, claims to have developed a data transmission method that can achieve world record telecommunications data rates, of over a terabit (one trillion binary digits) per second, on optical fibers that already exist in the majority of in-building communications networks throughout the world. These optical fibers are known as multimode fibers.
Dr Stuart Walker presented the concept on at Photon02 in Cardiff. His scheme combines the data transmission techniques commonly used in communications networks to allow many signals to travel simultaneously along a fiber optic cable.
Traditional networks send a number of single data transmission signals along fiber optic cables at the same time. This is possible as each signal occupies a different part or wavelength of the light spectrum. Dr Walker's team uses subcarrier signals, which consist of two data signals on top of each other occupying the same wavelength, making two signals appear as one. The scheme combines many of these subcarrier signals onto the same transmission path, allowing all of them to travel down the cable on the same wavelength. This means that where traditionally only one signal could occupy one wavelength, many signals can now occupy that single wavelength.
By using this technique on all available wavelengths, the group's preliminary experiments showed that a data rate of 1.02 terabits per second could be achieved over a distance of up to 3km on conventional multimode fiber.
As the number of Internet users continues to grow and users demand more bandwidth, to run faster programs, the data transfer requirements of local area networks are steadily growing. As the majority of these existing LANs use multimode fiber already, the team's work could save telecommunications companies money by allowing them to increase the data traffic on their existing networks, instead of laying new more expensive fiber.
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