What is space laser communication technology?


Most people do not know much about space laser communication technology. The core of space laser communication technology is the word "laser", which means that laser is used as the information carrier to communicate in space (including atmospheric space, low orbit, medium orbit, synchronous orbit, interplanetary, and terrestrial space).

Compared with microwave space communication, the advantages of laser space communication are self-evident, such as the wavelength is significantly shorter than the microwave wavelength, with a high degree of coherence and spatial directionality, which determines the space laser communication has a series of advantages. Such as large communication capacity, the laser frequency than the microwave 3 to 4 orders of magnitude higher, so as a communication carrier wave has a greater use of the frequency band. Fiber optic communication technology can be transplanted to space communications, fiber optic communication data rate per beam light wave can reach more than 20Gb / s, and can be used wavelength division multiplexing technology to make communication capacity up dozens of times. Therefore, in terms of communication capacity, optical communication has a huge advantage over microwave communication. At the same time, space laser communication technology also has the characteristics of light weight, small power consumption and volume, low construction and maintenance costs.


As the laser divergence angle is very small, so the energy is highly concentrated, so that the power density falling on the receiver telescope antenna is high, the transmitter's transmit power can be greatly reduced, power consumption is relatively low; space laser communications to improve energy utilization and make the transmitter and its power supply system weight reduction; laser wavelength is short, in the same divergence angle and receiving field of view requirements, the transmitting and receiving telescope The shorter wavelength of the laser, the same divergence angle and receiving field of view requirements, the transmitting and receiving telescope diameter can be reduced. In this way, space laser communication is free from the huge dish antenna of microwave systems, with both small and compact and powerful features. The most valuable thing is that the laser has a high degree of directionality, the emission beam is slim, and the laser divergence angle is usually in the milliradians, which effectively improves the anti-jamming and anti-eavesdropping ability.


With these powerful functions, the prospect of space laser communication technology can be very broad. Along with the increasingly urgent demand for high-speed information transmission in the information age, and the improvement of the level of optics, optoelectronics, microelectronics, computer, control science, materials science and technology supporting space laser communication, space laser communication will show the following development trends. First, the communication rate is getting higher and higher, along with the core technology of high-precision dynamic tracking breakthroughs, to improve the rate and bandwidth of laser communication systems is an inevitable move. Second, the communication mode is increasingly rich, from the initial one-way information transmission, to the development of two-way symmetric information transmission, relay forwarding communication mode, and even the future information networking. Third, three-dimensional space coverage, space laser communication from the interplanetary link gradually to the star-ground, star-space, air-space, air-ground and inter-ground links to expand, to achieve three-dimensional space coverage, to build the sky, ground integration of seamless communication system.

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