Optimal coupling condition analysis of free-space optical communication receiver based on few-mode fiber

Effective coupling between space light and optical fiber is one of the key technologies in free space optical communication. Few-mode fiber coupling is becoming a promising method to improve the performance of free space optical communication receiver. The dependence of the few-mode fiber coupling efficiency on the focal ratio, the central occlusion ratio and the numerical aperture are analyzed in this paper. The research results may be beneficial for the design of the receiver based on FMF coupling in the FSOC system.