Open AccessOptimizing free space to few-modefiber coupling efficiency
Author(s) -
Alireza Fardoost,
He Wen,
Huiyuan Liu,
Fatemeh Ghaedi Vanani,
Guifang Li
Publication year - 2019
Publication title -
applied optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 197
eISSN - 2155-3165
pISSN - 1559-128X
DOI - 10.1364/ao.58.000d34
Subject(s) - free space , coupling (piping) , optics , space (punctuation) , mode (computer interface) , physics , mode coupling , materials science , computer science , composite material , operating system
We evaluate the coupling efficiency from free space to few-mode fibers (FMF). A theoretical coupling model is developed based on the imaging properties of free-space modes and the inner products between the free-space modes and the FMF modes. Numerical results for six- and ten-mode free-space-to-FMF coupling are presented. It is found that in order to maximize the total coupling efficiency, the size of the highest-order free-space and fiber modes should be approximately matched, and there is an optimum value for the V number of the FMF. In addition, the axial alignment tolerance for free-space-to-FMF coupling is more stringent than for single-mode cases.