TITLE:
Calculation of the Coupling Coefficient of Twin-Core Fiber Based on the Supermode Theory with Finite Element Method
AUTHORS:
Tianhao Zhao, Wenhua Ren, Tingya Yin, Fan Wang
KEYWORDS:
Coupling Coefficient, Twin-Core Fiber, Supermode Theory, Finite Element Method, Coupled Mode Theory
JOURNAL NAME:
Optics and Photonics Journal,
Vol.11 No.8,
August
30,
2021
ABSTRACT: Currently, coupled mode theory (CMT) is widely used for calculating the coupling coefficient of twin-core fibers (TCFs) that are used in a broad range of important applications. This approach is highly accurate for scenarios with weak coupling between the cores but shows significant errors in the strong coupling scenarios, necessitating the use of a more accurate method for coupling coefficient calculations. Therefore, in this work, we calculate the coupling coefficients of TCFs using the supermode theory with finite element method (FEM) that has higher accuracy than CMT, particularly for the strong coupling TCF. To investigate the origin of the differences between the results obtained by these two methods, the modal field distributions of the supermodes of TCF are simulated and analyzed in detail.