Optical communication is a communication method that uses light waves as the transmission medium. Light waves and radio waves are both electromagnetic waves. The frequency of light waves is higher than that of radio waves, and the wavelength is shorter than that of radio waves. Therefore, optical communication has the advantages of large communication capacity, long transmission distance, small signal crosstalk, and anti-electromagnetic interference. Optical communication is the most mainstream information transmission method in the world at present, and the cornerstone of the information age.
According to different transmission media, optical communication can be divided into atmospheric laser communication and optical fiber communication.(https://hello-signal.com/)
Atmospheric laser communication is laser communication that uses the atmosphere as a transmission medium; optical fiber communication is a communication method that uses light waves as the information carrier and optical fibers as the transmission medium. The spectrum range available for optical communication technology includes infrared, visible light and part of the ultraviolet band. Different from the spectrum that needs to be allocated for radio frequency communication, the frequency band used by optical communication belongs to white space and can be used without license.
Optical communication system consists of three parts: optical transmitter, communication channel and optical receiver.
From the perspective of physical flow, optical communication systems are divided into optical transmitters, optical fiber channels, and optical receivers. The function of optical transmitters is to convert electrical signals into optical signals, and transmit the resulting optical signals into optical fibers for transmission. The function of the optical receiver is to convert the optical signal received at the output end of the fiber into the original electrical signal.
From the perspective of information flow, it can be divided into five categories: optical signal generation, optical signal modulation, optical signal transmission, optical signal processing, and optical signal detection according to different functions. The optical transceiver module(https://hello-signal.com/fiber-optic-transceivers/)realizes photoelectric conversion, corresponding to the generation, modulation and detection of optical signals, and is the basic structural unit of the physical layer of the optical communication system. The optical splitter and the optical amplifier correspond to the optical signal processing.
The optical communication industry chain consists of optical chips, optical devices, optical modules, and optical equipment.
Optical chips can be divided into InP, GaAs, Si/SiO2, SiP, LiNbO3, MEMS and other chips according to different materials.
Optical devices are divided into active devices and passive devices according to whether or not power is required.
Active devices are mainly used for photoelectric signal conversion, including lasers, modulators, detectors, and integrated devices.
Passive devices are used to meet other functions of the optical transmission link, including optical connectors, optical isolators, optical splitters, optical filters, optical switches, etc.; optical modules are divided into optical transceiver modules, optical amplifier modules, dynamic adjustable modules, performance monitoring modules, etc.
