NEC has demonstrated a transmission capacity of 34.9 terabits per second (Tbps on a single optical fiber over a distance greater than 6,300 km.
The results, which were presented earlier this year at OFC 2016 in California, broke previous the spectral efficiency record for transoceanic transmission of 7.1 bit/s/Hz, achieving 8.3 bit/s/Hz using the C-band spectrum. This is a 16.9% improvement on the previous record.
NEC said this level of capacity comes very close to the Shannon limit, which is the fundamental spectral efficiency limit of optical communications. In fact, the demonstration came within 0.5 decibels (dB) of the theoretical maximum value.
"We are proud to have come so close to Shannon's cornerstone of communication theory," said Toru Kawauchi, General Manager of the Submarine Network Division at NEC Corporation. "NEC's research and development teams will continue to explore the limits of even greater subsea capacity, flexibility, and cost-effectiveness."
The demonstration used a new type of optical fiber (developed by NTT) that contains seven cores (glass threads) instead of the single core used in standard fiber.
DTU noted that its researchers have previously helped achieve the highest combined data transmission speed in the world—an incredible 1 petabit per second—although this involved using hundreds of lasers.