Bare fiber optical waveguide, also known as "bare device", is the core device in optical passive network. Its function is to divide optical signals into multiple channels or synthesize them. Its structure is composed of optical shunting chip and optical fiber array. Bare fiber optical waveguide is an integrated optical waveguide power distribution device based on quartz substrate. It has the advantages of small volume, wide working wavelength range, high reliability and compact structure. It is widely used in the construction of passive optical network and FTTX system.