Optical fiber splitter is a device used to split and combine light wave energy. It distributes the light energy transmitted in one optical fiber to two or more optical fibers according to a predetermined ratio, or combines the light energy transmitted in multiple optical fibers into one optical fiber. According to the principle, optical splitters can be divided into two types: fusion taper type and planar waveguide type. The fusion taper type product is formed by fusion splicing two or more optical fibers on the side; the planar waveguide type is a micro-optical component type product. Photolithography technology forms an optical waveguide on a medium or semiconductor substrate to realize the branch distribution function. The two types of optical splitting principles are similar. They achieve different branching quantities by changing the evanescent field coupling between the fibers (coupling degree, coupling length) and changing the fiber radius. Conversely, multiple optical signals can be combined into one signal. It's called a synthesizer.