Title: Method to enhance the single mode fiber coupling efficiency for obscured receiver by beam shaping 

Author(s): Rui, DM (Rui, Daoman); Liu, C (Liu, Chao); Chen, M (Chen, Mo); Lan, B (Lan, Bin); Xian, H (Xian, Hao) 

Source: PHYSICA SCRIPTA  Volume: 95  Issue: 3  Article Number: 035501  DOI: 10.1088/1402-4896/ab5a91  Published: MAR 2020   

Abstract: Since the aperture obstruction contributes to an energy leak from the core to the sidelobe of the far field spot, the Gaussian mode of the single-mode fiber (SMF) will receive less energy leading to the coupling efficiency (CE) degradation. A method based on diffraction optical element (DOE) and wavefront corrector is introduced to reshape the plane wave with hollow uniform intensity into the plane wave with uniform intensity to improve the core energy of spot. The SMF CE with and without DOE for different central obscuration ratio e<i is studied by numerical simulation. The DOE is effective to improve the SMF CE. Without the DOE, the CE eta ee<i of 0.4, the CE eta<i can increase to 72%, 78% and 80% with 4 level, 8 level and 16 level quantized DOE, respectively. It is not necessary to use the DOE beam shaper when the central obscuration ratio e<i is small. The 4 level, 8 level and 16 level quantized DOE can obtain benefits of the CE when the central obscuration ratio e<i is above 21.6%, 11.5% and 7%, respectively. 

ISSN: 0031-8949 

eISSN: 1402-4896