What is lange coupler?

A Lange coupler is a type of optical device used to couple light between different waveguides or fibers, often employed in integrated optics and fiber optic communications. It typically consists of a series of waveguide sections arranged in a specific manner to achieve efficient light transfer through interference effects. The design allows for controlled splitting or combining of optical signals, making it useful in applications such as signal processing and sensor technology. Its name derives from the work of the physicist L. Lange, who contributed to the development of such coupling techniques.