They are devices that amplify an incoming optical signal directly, without the need to convert it to an electrical signal first. Explore the fundamentals of optical amplifiers, their types, applications in communication systems, and future prospects in this comprehensive guide. In-line amplifiers: Periodically amplify signal due to fiber attenuation, high G, high Psat. An illustration of the effective gainis given below. In this comprehensive guide, we will explore the fundamentals and applications of optical amplifiers. An optical amplifier amplifies light as it is without converting the optical signal to an electrical signal, and is an extremely important device that supports the long-distance optical communication networks of today.