The typical structure of an optical fiber is a thin multilayer coaxial cylindrical solid composite fiber.
From the inside out: the core (core layer) a cladding layer a coating layer (coated layer). The core part is the core and the cladding layer, which together constitute the medium optical waveguide, forming the conduction and restraint of the optical signal to achieve the transmission of light, so the optical fiber composed of the two is called bare fiber.
The coating layer, also known as the cladding layer, mainly provides mechanical protection to the bare fiber and can be divided into primary and secondary coatings.
