The development of the information age requires the establishment of communication network systems with high transmission rates, mass information and extensive coverage. With laser as a carrier, space laser communication is designed to load information onto the laser for transmission in free space such as outer space; at the receiving end, the information transmission and communication can be achieved through a series of photoelectric conversions. The space laser communication system is smaller, lighter and more energy efficient. In the future, space laser communication is expected to become a key technology for data transmission between satellite and the earth and to achieve complementarity with terrestrial optical fiber networks, thereby establishing a three-dimensional laser communication network that comprises satellites and the stereo-cross laser communication network inside and outside the atmosphere; in this way, the network will completely subvert the existing global communication system and turn into a large-bandwidth high-speed communication network that suits the information transmission for the era of Internet of Things.
