What is the speed of light?
In an ad one can see From Riksgränsen to Stockholm in 2 milliseconds. Most fiber in Sweden is laid along the railroad tracks. According to this map the distance is 1418km.
To know what time it would take for light to travel to Stockholm, we have to first of all look at the speed of light in a fiber. We say it is 2.14*108m/s. The time it would take is for the light to travel along this fiber would be 6.6ms.
By looking at Google Maps I find the location for Riksgränsen is N68.425186, E18.124373 and Stockholm N59.325626, E18.071641. The distance between those two points are 1012.9398 km according to the calculations on this site.
If we divide the distance, 1012.9398 km, with the speed in glass, 2.14*108m/s, we get the time 4.7ms.
Even if we made some wrong assumptions, 4.7ms is definitely more than 2ms. Maybe they have some technology that make it possible for data to travel faster than light? Or they have drilled a hole through the planet? Light would only travel 428km in 2ms. That would take the light from Riksgränsen to Luleå. Definitely not Stockholm.