An Erbium-Doped Fiber Amplifier (EDFA) is a device that amplifies light signals in optical fibers using erbium ions as the gain medium, significantly enhancing long-distance communication by boosting signal strength without converting it to electrical form. EDFAs are critical in modern telecommunications, enabling high-capacity, long-haul optical networks by providing low-noise amplification across a broad wavelength range, particularly in the C-band (1530-1565 nm).