Optical fiber communication is also called optical fiber communication. Optical fiber communication is a kind of wired communication with light as the information carrier and optical fiber as the transmission medium. First, it converts electrical signals into optical signals, and then transmits them through optical fibers. Light can carry information after modulation. Since1980s, the optical fiber communication system has completely changed the telecommunications industry and played a very important role in the digital age. Optical fiber communication has the advantages of large transmission capacity and good confidentiality. Optical fiber communication has now become the most important wired communication mode.

2. Optical fiber communication principle-components

The most basic optical fiber communication system consists of optical transmitter, optical receiver, optical fiber line, repeater and passive devices. Among them, the optical transmitter is responsible for converting signals into optical signals suitable for transmission on optical fibers, the optical fiber line is responsible for transmitting signals, and the optical receiver is responsible for receiving optical signals, extracting information from them, then converting them into electrical signals, and finally obtaining corresponding voice, image, data and other information.

(1) optical transmitter-an optical transceiver which consists of a light source, a driver and a modulator and realizes electrical/optical conversion. Its function is to modulate the light wave emitted by the light source into modulated light wave through the electrical signal of the terminal, and then couple the modulated light signal to the optical fiber or optical cable for transmission.

(2) Optical receiver-an optical receiver consisting of a photodetector and an optical amplifier to realize optical/electrical conversion. Its function is to convert the optical signal transmitted by optical fiber or optical cable into electrical signal through optical detector, and then amplify the weak electrical signal to a sufficient level through amplifier circuit, and send it to the receiving end for absorption.

(3) Optical fiber line-its function is to couple the modulated optical signal sent by the sender to the optical detector of the receiver after long-distance transmission by optical fiber or optical cable, so as to complete the task of transmitting information.

(4) Repeater —— It consists of photodetector, light source and decision regeneration circuit. It has two functions: one is to compensate the attenuation of optical signals when they are transmitted in optical fibers; The other is pulse proximity management of waveform distortion.

(5) Passive devices, including optical fiber connectors and couplers, complete the connection between optical fibers and the connection and coupling between optical fibers and optical terminals.