Coupling Research Of Space Light-single Mode Fiber In Self-homodying Intersatellite Optical Communications

As an important means of satellite communication, satellite lasercommunication has received great attention. Developed countries and regions hasfinished various space experiments, and completed the high-speed lasercommunication of satellites to satellites and satellites to grounds, such as America,Europe, Japan and so on.The signal reception mode of satellite laser communication can be divided asdirect detection, homodyne coherent detection and self-homodyning coherentdetection. Self-homodyning detection was one of the most promising modes becauseof its simple structure and high sensitivity. It is needed to couple space light intosingle-mode fiber in the self-homodyning system, However, due to the influence ofthe manufacture of optical elements, change of temperature and machining errors,there are wavefront aberrations in the receiving beam. Besides the inevitablevibration of the satellite platform, tracking detector noise and mechanical noise ofantenna will lead to random jitter of receiving terminal. The communicationperformance of satellite was determined by the coupling efficiency of spacelight-single-mode fiber, therefore it is needed to study the influence of wavefrontaberrations and Random jitter on coupling efficiency of space light-single-modefiber.This dissertation studies the influence of temperature change and the randomjitter of light beam on the coupling efficiency of space light-single-mode fiber inself-homodying scheme.Firstly, influences of temperature change. Based on the reflection-type opticalantenna, the numerical model of influence of temperature change on couplingefficiency is established, simulated numerically by using Matlab and Code V,compared and analyzed the results. To verify the correctness of the model,experimental study was conducted, the results indicate that the simulation resultswere consistent with the experiment results, and the model is correct. Finally, influence of random jitter. Based on the influence of temperature on thecoupling efficiency of space light-single-mode fiber, the combined influence of bothis studied. The coupling model in the presence of random jitter and differenttemperature is established. Based on this model, the analytical expression of theinfluence of temperature and random jitter on the mean-coupling efficiency isderived, and the combined influence of both on the mean-coupling efficiency isanalyzed.The research work analyzes the influence of temperature change and randomjitter on coupling efficiency of space light-single-mode fiber, and provides theoreticaldirection for the optimization design of optical antenna in self-homodying scheme.