The optocoupler consists of two parts: a light source and a light receiver. It covers a wide range of fiber optic devices such as optical splitters, optical combiners, and optical couplers. A fiber optic coupler is a device that can distribute the optical signal. Fiber optic couplers are optical devices that connect three or more fiber ends, dividing one input between two or more outputs, or combining two or more inputs into one output. Optical fiber couplers generally have the following characteristics: First, the device is composed of optical fiber, which is an all-fiber device; second, the demultiplexing and.