Yes, you can often use your existing router with fiber optic internet, but there are crucial considerations. Understanding compatibility, potential limitations, and when an upgrade is necessary will ensure you get the most out of your high-speed connection. Is Your Existing Router Actually Fiber-Ready? Fiber optic internet represents a. The most common and effective solutions include installing a network switch, using a dedicated Ethernet extender (or repeater), or converting the signal to run over fiber optic cable with media converters. And depending on what type of cables and SFP transceivers you use, you can extend your network up to 60-80km, ideal for long-range network deployments.