Japanese researchers achieve a speed of 319Tbit/s over 3001km via fiber optics

Researchers at Japan’s National Institute of Information and Communications Technology have set a new internet speed record over a fiber optic connection. The researchers achieved a long-distance transmission of 319Tbit/s.

The previous world record of 178Tbit/s was set last year by British and Japanese researchers, but has almost doubled by employees of the NICT from Japan. Researchers used an optical fiber optic cable with four cores and a diameter of 0.125mm. This achieved a speed of 319Tbit/s with a transmission bandwidth of more than 120nm.

The system uses, among other things wavelength division multiplexing. That is a process of combining multiple optical channels on a single fiber optic cable. This is achieved by using different wavelengths. In doing so, NICT used a combination of optical amplification technologies to enable long-haul transmission with 552 such WDM channels. Each channel had a wavelength between 1487.8nm and 1608.33nm. The channels also all used pdm-16qam modulation.

Wavelengths of the different optical bands. Source: NICT

Researchers used the optical for the experiment S-, C– and L-ties. The former band is not usually used for long-distance transmissions, but this was made possible by signal amplification in an ‘experimental setup’, where small amounts of the rare thulium and erbium metals were added to the material of the fiber optic cable used. At certain wavelengths, this could have a signal-amplifying effect. was also used Raman amplification.

The researchers who set a record of 178Tbit/s last year also used the S-band, although that was only forty kilometers away. NICT’s 319Tbit/s record was achieved over a considerably longer distance of 3001 kilometers. The researchers say they measured no signal loss or speed delays over that distance. According to NICT, a regular fiber optic infrastructure can also theoretically be compatible with the technologies used, although this would first require adjustments to such a network.

Source: NICT