The tiny optical fiber is encapsulated in a plastic sheath, enabling it to bend without breaking. Generally, the transmitting device at one end of the optical fiber uses a light emitting diode (LED) or a laser beam to transmit light pulses to the optical fiber, and the receiving device at the other end of the optical fiber uses a photosensitive element to detect the pulses. In daily life, because the transmission loss of light in optical fiber is much lower than that of electricity in wire, optical fiber is used for long-distance information transmission.

Generally, the terms optical fiber and optical cable are confused. Most optical fibers must be covered by several layers of protective structures before use, and the covered cables are called optical cables. The protective layer and insulating layer of the outer layer of the optical fiber can prevent the damage of the surrounding environment to the optical fiber, such as water, fire, electric shock, etc.