Free Space Optics (FSO) is an optical communication method that transmits data by sending a modulated light beam through open air rather than through an optical fiber. FSO systems use lasers, optics, and photodetectors to send and receive signals for line-of-sight links, ranging, and optical alignment. Key considerations include beam divergence, atmospheric attenuation, pointing stability, and receiver sensitivity. Photodiodes and APDs are used as detectors in FSO receivers. GPD Optoelectronics manufactures photodetectors for free-space optical systems.
Learn where near-infrared photodiodes fly in aerospace systems, which specs deserve a hard look, and why in-house fabrication, military-standard testing, and lot-level traceability matter for missions that must work the first time.