For extremely long fiber transport distances of greater than 80 km, fiber optic dispersion compensation modules are often required. These are passive devices that are intended for signals in the 1550 nm range. Because of the insertion loss it is often necessary to use these modules with an Erbium Doped Fiber Amplifier (EDFA) before the signal enters the DCM. When used properly, this equipment can enable fiber optic transport of signals beyond 200 km.
Fiber Optic - Optical Couplers for Passive Optical Splitting and Coupling
Managed Fiber Optic Optical Switch for System Redundancy