Communication with the fiber from the outer cover of plastic protective layer composed of glass as thin as a hair. Glass substantially consists of two parts: the core diameter of 9 to 62.5μm, the cover having a diameter of 125μm low refractive index of a glass material. Although according to the materials used and the dimensions of different points there are other types of fiber, but mentioned here are the most common that several. Light in the core portion of the fiber to the "total internal reflection" mode for transmission, but also refers to an end after the light enters the fiber, at the interface between the core and the cladding reflected back and forth, and then transferred to the other end of the fiber. Core diameter of 62.5μm, cladding outer diameter of 125μm fiber called 62.5/125μm light.

Fiber is the transmission of light wave conductors. Optical fiber from the optical transmission mode can be divided into single-mode fiber and multimode fiber.

Fiber optic transceiver is a twisted pair electrical short distance and long-distance optical signal transmission swap Ethernet media conversion unit, also known as the photoelectric converter or fiber optic converters. Today a wide range of fiber optic transceivers, but generally classified as single-mode and multimode. Singlemode multimode fiber is by nature classification.

Single-mode fiber is only a single path, and generally used for long-distancetransmission, there are multiple propagation paths of Multimode Fiber, multimodefiber bandwidth for 50MHz~500MHz/km, single mode fiber optic bandwidth up to2000MHz/km, optical fiber wavelength 1550nm and 850nm,1310nm, etc.