Interpretation - working principle of optical fiber communication system

In the Internet era, we use optical signals for information transmission. Optical communication is a communication mode with light waves as carriers. Maybe you don't know what optical communication is, but you must be using optical communication. For example, when you make a phone call or open your browser to browse the web, you are already using optical communication. Optical communication has been integrated into everyone's life.

The information sent by commonly used mobile phones, computers and other communication products exists in the form of electrical signals. When carrying out optical communication, first convert the electrical signal into optical signal, and then convert the optical signal into electrical signal after transmission through optical fiber and optical cable, so as to achieve the purpose of information transmission. The basic optical communication system (as shown in the figure below) is composed of optical transmitter, optical receiver and optical fiber loop for transmitting light. In order to ensure the long-distance signal transmission quality and improve the transmission bandwidth, optical repeater, optical fiber amplifier and wavelength division multiplexer are generally used.

The following is a brief introduction to the working principle of each device in the optical fiber communication system.

Optical transmitter: it converts electrical signals into optical signals, which is mainly composed of signal routing and light source.

Signal multiplexer: multiple optical carrier signals with different wavelengths are coupled to the same optical fiber for transmission to achieve the effect of doubling the transmission capacity.
Optical fiber amplifier: it realizes amplification by converting the energy of pump light into the energy of signal light.
Optical repeater: in the transmission process, the waveform and intensity of the signal will deteriorate. Therefore, it is necessary to restore the waveform to the neat waveform as the original signal and increase the light intensity.
Signal demultiplexer: decomposes the multiplexed signal into the original single signal.
Optical receiver: converts the received optical signal into electrical signal, which is mainly composed of photodetector and demodulator.

Application of optical communication
Optical communication has many advantages. Up to now, optical communication has been integrated into every corner of our life. Mobile phones, computers, IP phones and other network devices connect everyone with their region and the whole country, and even connect to the global communication network. For example, signals from computers and mobile phones are gathered in the base stations of local communication operators and network supplier equipment, and then transmitted to all parts of the world through optical fibers in submarine optical cables. The realization of daily activities such as video call, online shopping, video game and drama chasing is inseparable from its power support behind. The emergence of optical network makes our life more comfortable and convenient.