Optical Fiber Nutation Tracking Technology For Space Laser Communication System

Space laser communication has the advantages of wide communication frequency bandwidth,large information capacity,large optical gain,anti-interference,strong anti-interception ability,small size,light weight low power consumption,and so on,so it has become a hot research field.Fiber coupling technology can play a huge advantage in the application of the atmospheric laser communication systems,so the effectively coupling of the space light to an single-mode fiber has become a key technology for atmospheric laser communication.In fiber-optic laser communication systems,in order to overcome the effects of alignment errors,random angular jitter errors and atmospheric turbulence aberrations,this paper studies the fiber laser nutation tracking technology for space laser communication systems for the aiming and tracking of beams and single-mode fibers thus improving coupling efficiency.In this paper,to improve the coupling efficiency of space light-single-mode fiber,according to the principle of mode matching of space light-single-mode fiber,the coupling efficiency of the system is improved through the fiber nutating tracking system to obtain the maximum coupling efficiency of single-mode fiber It is 81.4%,and the conclusion that the coupling efficiency is affected by radial deviation,spot size,nutation amplitude,and the number of sampling points has been experimentally verified.Firstly,the research status of fiber nutation tracking technology is introduced,and the principle of space light-single mode fiber coupling is explained,which points the maximum single-mode fiber coupling efficiency is 81.4%.The effects of radial deviation,atmospheric turbulence aberration and adaptive optical system on the coupling efficiency of single-mode optical fiber are simulated and analyzed.Secondly,the working principle of optical fiber nutation tracking technology is described,and the implementation scheme is designed.The software design is completed.Thirdly,the device selection is optimized,and the platform is built for testing.Under static conditions,the coupling efficiency of the fiber nutation tracking system is 53.5%.The effects of radial deviation,spot size,nutation amplitude,and number of sampling points on the coupling efficiency are studied.Finally,the fiber optic nutation tracking system is tested experimentally for capture and closed-loop tracking performance.The average capture time is 14.2 ms.The average coupling efficiency of the system on the closed-loop tracking stage is about 49.9%,which has an increase of 14.8% compared with the open-loop.It takes about 1s from the beginning of capture to the time when the coupling efficiency reaches the highest.Through theoretical research,simulation analysis and experimental testing,this paper designs a fiber nutation tracking system which meets the requirements of today's space laser communication systems.