This is only throughput. The latency is given by the speed of light in the fibre (~c/1.5). That said Microsoft bought a company that develops hollow core fibre which yields a factor 1.5 improvement in latency. They just presented their latest results which is a 0.11 dB/km loss. This is actually the biggest result from the conference, because it is a massive improvement over regular fibre which has been hovering at about 0.15 dB/km loss for the last 40 years, with improvements below 1% over that time.