Optical amplifiers are devices used to amplify optical signals in fiber optic communication systems. They are essential in boosting signal strength to ensure reliable long-distance transmission of data. There are several types of optical amplifiers, including erbium-doped fiber amplifiers (EDFAs), semiconductor optical amplifiers (SOAs), and Raman amplifiers. EDFAs are commonly used in long-haul and metro networks, while SOAs are typically used in short-reach applications. Optical amplifiers play a crucial role in improving signal quality, increasing transmission distance, and reducing the need for costly signal regeneration equipment in fiber optic networks.