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March 16, 2006

Other tech: Fast communications - optical/wireless

Telecommunications researchers have demonstrated a novel communications network design that would provide both ultra-high-speed wireless and wired access services from the same signals carried on a single optical fiber. The system could provide 32 different channels, each providing 2.5 gigabit-per-second service. That capacity is already working in the lab.

Using a technique developed at Georgia Tech, wireless and baseband signals carried by multiple wavelengths would be converted onto the millimeter-wave carrier simultaneously. The conversion would be done using one of several all-optical techniques such as external modulator, four-wave mixing (FWM) or cross-phase modulation (XPM) that would not require costly high-frequency electronic devices. The resulting signal would be split into two components and carried by passive optical network (PON) infrastructure installed throughout a building.

One component of the signal would be detected by high-speed receivers built into the ceilings of rooms, then amplified for short-range wireless transmission at frequencies of 40 to 60 gigahertz. The other signal component carrying identical information would be accessed through standard wall outlet throughout the building using a low-cost receiver and optical filter.

Either way, users could receive signals at data rates of up to 2.5 gigabits per second.

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