Using a common comparison metric of optical fiber transmission the data-rate and distance produce of 957 petabits per second x km, is a world record for optical fibers with standard outer diameter. Researchers at Japan's National Institute of Information and Communications Technology developed an experimental optical fiber with four cores, instead of just one.

In addition to the C and L-bands, typically used for high-data-rate, long-haul transmission, we utilize the transmission bandwidth of the S-band, which has not yet been used for further than single span transmission. The combined >120nm transmission bandwidth allowed 552 wavelength-division multiplexed channels by adopting 2 kinds of doped-fiber amplifier together with distributed Raman amplification, to enable recirculating transmission of the wideband signal. The standard cladding diameter, 4-core optical fiber can be cabled with existing equipment, and it is hoped that such fibers can enable practical high data-rate transmission in the near-term, contributing to the realization of the backbone communications system, necessary for the spread of new communication services Beyond 5G.