Optoelectronics is a branch of electronics that overlaps with physics. The field concerns the theory, design, manufacture, and operation of hardware that converts electrical signals to visible or infrared radiation (infrared) energy, or vice-versa.
Examples of optoelectronic components include photocells, solar cells, optoisolators (also called optical couplers or optocouplers), LEDs (light-emitting diodes), and laser diodes. Applications include electric eyes, photovoltaic power supplies, various monitoring and control circuits, and optical fiber communications systems.