German and Japanese scientists recently collaborated to achieve just such a quantum leap in obliterating the world record for data transmission. By transmitting a data signal at 2.56 terabits per second over a 160-kilometer link (equivalent to 2,560,000,000,000 bits per second or the contents of 60 DVDs) the researchers bettered the old record of 1.28 terabits per second held by a Japanese group. By comparison, the fastest high-speed links currently carry data at a maximum 40 Gbit/s, or around 50 times slower.

A few weeks ago the scientist and his team established a new world record together with colleagues from Fujitsu. Data is transmitted in fiber-optic cables using ultrashort pulses of light and is normally encoded by switching the laser on and off. A pulse gives the binary 1, off the 0. You therefore have two light intensity states to transmit the data. The Fraunhofer researchers have now managed to squeeze more data into a single pulse by packing four, instead of the previous two, binary data states in a light pulse using phase modulation."