Beam splitter splits one beam into two multimode beams

A beam splitter (or beamsplitter, power splitter) is an optical device which can split an incident light beam (e. a laser beam) into two (or sometimes more) beams, which may or may not have the same optical power (radiant flux). It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding widespread application in fibre optic telecommunications. Beamsplitters are often classified according to their construction: cube or plate. Fiber optic beam splitters are used to divide light from one fiber into two or more fibers. It is also possible to combine the separated beams. Characteristics of Beam Splitters 3. [pdf]