Theoretical analysis on inter-core crosstalk suppression model for multi-core fiber

Decreasing mode coupling coefficient (k) is an effective approach to suppress the inter-core crosstalk. Therefore, we deploy a low index rod and rectangle trench in the middle of two neighboring cores to reduce k so that the overlap of electric field distribution can be suppressed. We also propose approximate analytical solution (AAS) for k of two crosstalk suppression models, which are two cores with one low index rod deployed in the middle and two cores with one low index rectangle trench deployed in the middle. We then do some modification for the results obtained by AAS and the modified results are proved to agree well with that obtained by finite element method (FEM). Therefore, we can use the modified AAS to get inter-core crosstalk for above-mentioned two models quickly.