A team of researchers at Japan’s National Institute of Information and Communications Technology (NICT) has broken the Internet speed record with a stunning 319 terabits per second (TB/s).

The speed test was performed in a lab using advanced fiber-optic technology. Many fiber optic cables contain one core and a lot of cladding, or covering, to protect the data inside, Vice reported.

NICT’s system used an experimental strand of fiber optic cable with four cores housed in a cable roughly the size of a standard fiber optic line.

“The 4-core (multi-core fibers) with standard cladding diameter is attractive for early adoption of (space division multiplexing) fibers in high-throughput, long-distance links, since it is compatible with conventional cable infrastructure and expected to have mechanical reliability comparable to single-mode fibers,” NICT said in a paper about the experiment.

NICT looped the data through coiled bits of fiber optic that simulated a transmission distance of 3,001 km or about 1,864 miles without degradation of the signal or speed.

The researchers used a 552-channel comb laser firing at multiple wavelengths and pushed through amplifiers made of rare earth minerals to achieve incredible speed.

“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,” they said in their paper.