Fiber amplifiers are devices that boost the strength of optical signals in fiber optic communication systems. They use a length of optical fiber doped with rare-earth elements, such as erbium or ytterbium, to amplify light signals without converting them to electrical signals. This process allows for longer transmission distances and improved signal quality. These amplifiers are commonly used in telecommunications and data networks to enhance the performance of fiber optic cables. By increasing the signal power, fiber amplifiers help maintain data integrity over long distances, making them essential for modern communication infrastructure.