A group including three telecom companies and a national research institute in Japan reports that it has demonstrated optical data transmission at a rate of 1.2 terabits per second (Tbps) per optical wavelength, across a distance of 336 km. The consortium characterizes the feat as “the world’s longest transmission link” at that per-wavelength rate, and also as the largest-capacity full-throughput data transfer (more than 1 Tbps) between “a pair of general-purpose one-socket servers.”
Showcasing technology at three firms
The demonstration project, spearheaded by Japan’s National Institute of Informatics (NII), relied on multiple fiber and communications technologies from the three corporate partners.
The fiber for the demonstration was a trial network comprising commercial fiber from Nippon Telegraph and Telephone East Corp. (NTT EAST). Another consortium partner (and NTT EAST’s parent company), Nippon Telegraph and Telephone (NTT), contributed advanced digital signal processing devices and techniques. And the network trial included Fujitsu Ltd.’s “next-generation optical transmission system,” the 1FINITY Ultra Optical System, featuring a transponder chip capable of a transmission rate of 1.2 Tbps per optical wavelength at 150 Gbaud.
The hardware technologies were pulled together in field trials that used the Massively Multi-Connection File Transfer Protocol (MMCFTP), a custom protocol developed by NII. MMCFTP is designed, according to NII, to dynamically adjust the number of TCP connections according to network conditions, and thereby to boost data transfer rates and stability.
Two field trials
In the first of two field trials, the research group sent an optical signal from an NTT EAST server in Chiyoda-ku, Tokyo, through a purpose-built fiber network that stretched to Yokohama and back—a round trip of 336 km—and confirmed data transfer rates of 1.2 Tbps per optical wavelength. In the second trial, the group linked two general-purpose, one-socket servers supplied by NII in a similar environment, and pumped about 47 terabytes of data from one server to the other, at a total data transfer rate of 1,034 Gbps. That’s the equivalent, NII points out, of one Blu-ray disk worth of data every fifth of a second.
NII and its corporate partners say that the network demonstration “opens the door to a variety of high-speed, high-capacity communication services.” Near term, the consortium is particularly targeting improvements to research and educational networks through NII’s SINET academic network, billed as “the world’s highest-performance network infrastructure.” NII says it will continue exploring ways to boost speed and capacity and reduce latencies for SINET.
More generally, the research group hopes to build on this achievement to further promote R&D “toward the realization of the Innovative Optical and Wireless Network (IOWN).” The latter is an NTT-led initiative to boost network capacity and processing power using “innovative technology focused on optics,” coupled with substantial computing power.