Yes, though in this instance they pulled of 44terrabits rate per second, so with that you would be looking at 156 megabits inflight over a 1km cable if my napkin maths are correct. Thats 18 megabytes, sure error rate etc and correction would limit that a bit as nothing works as ideal, but sure does seem like may have some uses come into play.

Is that an optical fibre delay line?