New world record for internet data transmission set in Japan

Engineers at Japan's National Institute of Information and Communications Technology have set a new data transmission record of 319 terabits per second using optical fibers over 3,000 kilometers. This achievement nearly doubles the previous record. The system employs wavelength division multiplexing, splitting light signals into 552 channels and transmitting them through four optical fiber cores. Amplifiers with thulium and erbium reduce transmission loss. The new method is compatible with existing infrastructure, though no consumer application timeline is provided.

What is the new data transmission rate achieved by engineers at Japan's National Institute of Information and Communications Technology?

How does the new system transmit data according to the text?

What technology is used to split light signals into channels?

What elements are used in the amplifiers to reduce transmission loss?

What is the significance of the diameter of the four optical fiber cores mentioned in the text?