Fiber Coupler is a device which distributes light from a main fiber into one or more branch fibers. Power transfer can take place either through fiber core cross-section by butt‐jointing the fibers (core interaction) or through surface-interaction (normal to axis). Fiber Couplers come in variety of forms and types such as three/four-port couplers for signal splitting, combining couplers, distribution (Star) couplers with single input and multiple outputs, wavelength division multiplexing and wavelength division de‐multiplexing couplers and more. Fiber Couplers are used in cable TV system, fiber interferometers, resonators of a fiber laser, as well as in fiber amplifiers.