The optical amplifier amplifies all the wavelengths together, thereby reducing the complexity of the system. An optical amplifier is a device that amplifies an optical signal directly, without the. An optical amplifier is a device which receives some input signal light and generates an output signal with higher optical power. Typically, inputs and outputs are laser beams (very rarely other types of light beams), either propagating as Gaussian beams in free space or in a fiber. Booster (power) amplifiers: Boost power into transmission fiber, low NF, high Psat. An illustration of the effective gainis given below. They have further enabled highly efficient, high-power laser tools contributing to many areas of industry, medicine.