Optical fiber is a transmission medium. Its characteristic is that it can transmit light over a long distance with low loss. In addition, it also has the characteristics of strong anti-interference ability. The main principle of optical fiber transmitting light is the total reflection characteristic of light. Generally, an electrical signal is converted into an optical signal by a photoelectric conversion device, and the optical signal is also transmitted through an optical fiber, and then the optical signal is converted into an electrical signal by a photoelectric conversion device at one end of an optical fiber receiving device to realize the transmission of the electrical signal through the optical fiber. Optical fiber is generally made of plastic or glass.