An optical module is a small device that moves data using light. It changes electrical signals into light signals and back again. This helps data travel faster and farther than with copper cables. Optical modules typically have an electrical interface on the side that connects to the inside of the system and an optical interface on the side that connects to the outside. The optical module serves as a crucial component in optical fiber communication systems, operating at the physical layer, which is the lowest layer in the OSI model.