Supermode Coupling Analysis in FM‐MCF With Core Group Layout Variation

ABSTRACT The design of trench assisted heterogeneous uncoupled‐coupled group few mode multi‐core fiber which is capable of supporting fundamental supermodes as well as higher order supermodes is presented in this paper. The coupling characteristics of modes in the proposed fiber design are analyzed with selective mode excitation and the supermode coupling behavior in relation to the group pitch and trench region is studied for fundamental degenerate supermodes. The obtained results for mode confinement and effective mode area indicate the importance of the selective mode launch technique for multi‐core fiber. The characteristics of supermode coupling with orientation change in the core group layout is also analyzed in this paper for 3 core and 4 core uncoupled‐coupled group few mode multi‐core fiber. The obtained results reveal that it is necessary to identify proper core group orientation besides the need for optimisation of design of cores, cladding and trench regions.