The Erbium-Doped Fiber Amplifiers have significantly boosted network transmission capabilities, development of other optical amplifiers based on, Raman amplification, non-Er-doped fibers, planar waveguide technology, and Semiconductor Optical Amplifiers (SOAs) are changing the structure and demands on the optical networking industry. The new issue is based C-, L- and S-band optical amplifiers. It contains following types of optical fiber amplifiers: C- and L-band EDFAs Raman amplifiers (both distributed and discrete) Erbium Doped Waveguide Amplifiers Semiconductor Optical Amplifiers Non-Erbium-Doped Fiber Amplifiers Hybrid amplifiers (e.g. Hybrid Raman/Erbium Fiber Amplifiers).