This requires a standard Ethernet cable running from the ONT's designated LAN or Ethernet output port. Optical splitters offer a cost-effective and dependable solution across various fiber optic applications. Also known as optical splitters, fiber splitters, or beam splitters, these devices are integrated waveguides ensuring wide bandwidth and minimal loss in high-frequency applications. They. To connect your fiber optic cable to a router, ensure you have the following: Fiber optic modem (ONT): Most fiber connections require an Optical Network Terminal (ONT), provided by your ISP. Your internet service provider (ISP) usually supplies this.