This article focuses on Semiconductor Optical Amplifiers (SOAs), Thulium-Doped Fiber Amplifiers (TDFAs), Praseodymium-Doped Fiber Amplifiers (PDFAs), and Hybrid Amplifiers. An optical amplifier is a device that boosts the strength of an optical signal. They utilize a piece of optical fiber doped with. Optical amplifiers are used to create laser guide stars which provide feedback to the adaptive optics control systems which dynamically adjust the shape of the mirrors in the largest astronomical telescopes. e external pumping principles and gain mechanisms. EDFAs are widely used in the C-band (1530 to 1560) for optical communication networks.