The short answer is no, you don't necessarily need a special router for fiber optic internet. Understanding compatibility, potential limitations, and when an upgrade is necessary will ensure you get the most out of your high-speed connection. This is a critical distinction from cable or DSL, where a modem performs a similar, but technologically. Most fiber ISPs, including Mercury, provide an ONT that connects directly to your router via an Ethernet cable. Most modern routers are capable of handling fiber optic internet speeds, but they. A: FTTH can deliver symmetrical speeds from 100 Mbps up to 10 Gbps, depending on the service provider and technology used.