Optical fiber (optical fiber ) is a type of thin , transparent fiber , usually made of glass or plastic , which is used to transmit light. Fiber optics is the branch of applied science and engineering that deals with this optical fiber. The information we want to send first goes to the electric transmitter. The information is converted into electricity i.e. analog signal - via microphone. This analog signal is converted to binary signal i.e. digital signal through PCM (Pulse code modulation) and becomes a light source. This light source travels through the light transmitter যেখানে where the signal is converted into light, and this light signal travels through the light fiber to the receiver end. Through the reverse step on the receiver end we get the pathan information from the sender. In this way our information goes to the recipient through the light fiber.