Design Of Coupling System For Optical Antenna Array

With the rapid development of communication technology,the quality requirements for communication in various environments have been greatly improved.Space optical communication technology combined with optical fiber communication and microwave communication has a great prospect.Compared with the traditional wireless communication field,space optical communication,which is widely used in various fields,possesses the advantages of large bandwidth,good confidentiality,and can carry more information.In free space optical communication,the Cassegrain antenna has attracted the attention of researchers for its wide band range,good radiation directivity,and compact structure.The Cassegrain antenna array system can solve several problems of single aperture optical antenna such as small field angle,low resolution,and low transmission efficiency,which has important theoretical significance and practical value in the development of wireless space optical communication.This thesis mainly studies the transmission characteristics of laser beam in optical antenna array,proposes a new design method of array optical antenna to fiber coupling system,and optimizes the structure of the coupling system to improve the coupling efficiency of the system.The research contents are as follows:The research progress of space optical communication at home and abroad,the research status and development direction of optical antenna array,as well as the research progress of fiber coupling technology are analyzed.The system structure design method of optical antenna array and the application of laser beam transmission in the antenna system are studied,and the array optical antenna system is optimized.This thesis studies the design method of optical antenna array to optical fiber coupling system,and the transmission of laser beam in the whole optical system is simulated by Matlab.The optical spot pattern obtained on the imaging surface under the unaligned state between the transmitting end and the receiving end of the optical antenna array and the unaligned state between the antenna system and the optical fiber is analyzed by using the theory of geometric optics,and the aberration in each case is calculated.In order to obtain the optimal coupling efficiency of laser beam coupling to fiber in the array optical antenna system,the parameters of the coupling system were optimized to achieve the research purpose.According to the optimized coupling parameters,the coupling system structure is designed and the final design scheme is obtained.After the simulation work,the coupling efficiency of the optical system is analyzed by using the mode field matching theory,and the coupling efficiency of the laser beam coupling from the antenna array system to the optical fiber under the conditions of defocus,lateral offset,and tilt is analyzed considering the error factors that will be generated in the practical application.The simulation results show that the maximum coupling efficiency of 1550 nm center coupling system is 73.83%,and the average coupling efficiency of seven groups of coupling systems is 78.08%.