Study On UV Communication System Based On 266 Nm UV Solid-state Laser

The processing of ultraviolet(UV) communication, scattering effects of atmospheric aerosol particles and molecules to UV light, making it in the transmission process can over obstacles, so that it can be realized non-line-of-sight(NLOS) communication. At the same time, UV light will be absorbed by molecules, defining transmission distance in the atmosphere to ensure the confidentiality of communication. Because of its good privacy is very suitable for military communication. Moreover, UV communication also has a strong anti-jamming capability, SNR advantages.This thesis mainly studies on the theory and technology of solar-blind UV communication. First, UV transmission characteristics in the atmosphere have been studied, and NLOS communication link geometry is given. In NLOS UV scattering environments, transmitted signals suffer from severe atmospheric attenuation and fading before arriving at a receiver, such as absorption, scattering, and turbulence. Using Pc Modwin to simulate UV attenuation effects on the atmosphere, and studying the limit communication distance of the solar blind UV communication system in case of certain transmittance threshold. Then, the principle and performance of light-emitting used to be introduced accordingly. Next, the design of the experiment platform is elaborated minutely. Finally, test conditions are selected at different times, distances to simulate and test the system. What’s more, the experimental results are also analyzed.The system uses the FPGA coding, modulation, and the electrical signal processed is loaded into the laser. Optical signals through the atmospheric channel, is received by the photo detector. The signal is processed by a pre-processing circuit which acts as current voltage(IV) converter. Then send FPGA to demodulate and decode, and ultimately recover the electrical signal. 266 nm UV solid-state lasers are used as light source. Because of good scattering properties of the UV light, and the high power relatively of solid-state lasers, which advantage is the traditional communication cannot match. Photo detector bears the faint signal detection task. Optical signal received is amplified and converted to electrical signals.Experimental results show that the indoor short-range communication system works well. Experiments demonstrate 10 m indoor short-range communication. Results are almost independent of the elevation angle of receiver and transmitter terminals. 10 m outdoor daytime short-distance communication quality is good as well, but its biggest transmitter elevation angle is about 47 °. 10 m outdoor nighttime communicate results are better than the day slightly, and it can reach a maximum elevation angle of 53 °. UV laser communication for long distance, day or night, is poor quality relatively, and the transmitter maximum elevation angle is very small. For instance, at night, under a communication condition 450 m, the maximum transmitter elevation angle is defined as 3 °。...