KDDI R&D and the Japanese NICT (National Institute of Information and Communications Technology) have been successful in experimenting with sending data in a wavelength multiplexed format over optical fiber lines, with each wavelength carrying data at a speed of 160 gigabits per second. The experiments involved eight multiplexed signals, representing 1.28 terabits of data per second, being sent over an optical fiber line currently in use from Tokyo to Tsukuba, Ibaraki Prefecture, and back for a total distance of about 200km.

 

This transmission speed had never before been reached outside of a laboratory and is 16 times faster than existing transmission systems. By sending more data on each wavelength, less equipment is needed and the management of the transmission process is easier. However, this kind of high-speed data transmission often runs into problems due to changing outside temperatures and winds, but KDDI R&D and NICT were able to stabilize transmission by using both DPSK (Differential Phase Shift Keying) and PND (Polarization Mode Dispersion). The two organizations are striving to make the technology ready for practical use within five years.