What is fiber
Fiber conveys signals using light pulsations, unlike copper pairs that still use an electrical method. The limits that you may notice with copper such as the distance or quality of the copper pair are no longer applicable with fiber. This makes it possible to reach much higher speeds.
If you are connected to the fiber network, the fiber goes directly into your house and it is converted to an internet signal locally in your home. In this way you can reach the maximum speeds!