Graphene Based Far-Infrared Junction Circulator

In this paper, a simple far-infrared circulator based on non-reciprocal features by graphene is proposed and investigated. Non-reciprocal feature of the component is provided via magneto-optical characteristics of graphene layer imposed by a perpendicular external magnetic bias field. The structure is analyzed through an electromagnetic approach and simulated numerically by the finite element method. The isolation between the incident and isolated ports is calculated to be 15.2 dB under moderate value of magnetic flux density bias of 0.3 Tesla in the designed operating frequency. The tunable characteristic of graphene chemical potential is exploited to provide tunable circulator. An improvement in performance of the circulator is realized utilizing a double arrangement of symmetric graphene layers and also, patterned graphene layer instead of the uniform ones. The device can be employed in various subwavelength photonic systems.