In a communication cable, the optical signal is transmitted by refracting along the fiber wall. Optical fiber transmission has many advantages, such as high sensitivity, no interference from noise; small size, light weight, long life, high quality and low price; insulation, high voltage resistance, high temperature, corrosion, suitable for special environments; can be adjusted according to environmental requirements, Easy signal transmission; high bandwidth, reduced communication volume, long distance; small crosstalk, high quality; high confidentiality; easy to lay and transport materials.

According to relevant research, the speed of light in silica glass fiber is 31% slower than that in vacuum, and there are problems of transmission delay and signal attenuation. The new fiber is constantly making breakthroughs in this regard.

In the optical fiber communication system, the basic mode of Z is: optical transceiver---optical fiber---optical transceiver, so the main body that affects the transmission distance is the optical transceiver and the optical fiber. There are four factors that determine the optical fiber transmission distance, namely optical power, dispersion, loss, and receiver sensitivity. Optical fibers can not only be used to transmit analog and digital signals, but also meet the needs of video transmission.