Routers typically do not have a direct fiber optic input; the fiber connects first to an Optical Network Terminal (ONT), which then links to the router via the WAN/Ethernet port.

How Fiber Connects to Your Router

In most home or small office setups, the fiber optic cable does not plug directly into the router. Instead, the fiber line terminates at an Optical Network Terminal (ONT) provided by your Internet Service Provider (ISP), . The ONT converts the incoming light signals from the fiber into standard electrical signals that your router can understand. After this conversion, the ONT outputs data through a standard Ethernet port, which is then connected to the router's WAN (Internet) port .

Fiber-Ready Routers

Some advanced routers or enterprise-grade equipment may include SFP (Small Form-factor Pluggable) or SFP+ ports, which allow direct insertion of fiber modules. These modules accept fiber connectors such as SC/APC, SC/UPC, or LC, depending on the router and network type . These ports are specifically designed for optical signals and are usually labeled as Fiber, SFP, or WAN.

Common Fiber Connector Types

• SC (Subscriber Connector): Square-shaped, push-pull mechanism, widely used in FTTH and GPON networks. SC/APC connectors are preferred for low return loss applications .
• LC (Lucent Connector): Smaller 1.25mm ferrule, ideal for high-density setups, uses a latch mechanism similar to RJ45 .
• SC/UPC: Standard SC connector with ultra-polished ferrule for general fiber connections .

Summary

For typical home routers, the fiber optic cable connects to the ONT, and the router receives the internet signal via its WAN/Ethernet port. Only fiber-ready routers with SFP/SFP+ slots can accept fiber modules directly, using connectors like SC/APC or LC. Always handle fiber connectors carefully to avoid dirt or damage, as proper alignment is critical for signal quality .