How long of fiber optic cable requires a repeater

Fiber Repeaters are used to extend and repeat Ethernet data signals over multimode or single mode fiber up to 160km [100 miles]. If you need to convert Single Mode to Multimode, or extend a Multimode network, Fiber Optic Repeaters are the devices to use. Fiber optic cable can be run anywhere from 300 meters up to 80 kilometers (roughly 50 miles) depending on the cable type, transceiver used, and network standard. Just like your voice fades and blurs when you shout across a field, light pulses in fiber optics lose strength and clarity. They are the ideal solution to connect. An optical communications repeater is used in a fiber-optic communications system to regenerate an optical signal. [pdf]