Can I use my current DSL router for Fibre?

Probably not, as Fibre works very differently to DSL. If the router has a WAN port then it potentially may be used as a fibre router. But you may, in some cases, be able to use your existing DSL Wi‑Fi enabled router to extend your Fibre connection via Wi‑Fi. This will depend on which router you have and how the provider installs your Fibre.