Tunable Nonreciprocal Graphene Waveguide With Kerr Nonlinear Material

A novel nonreciprocal graphene waveguide with Kerr nonlinear material in mid-infrared region is proposed and the corresponding transmission characteristics are investigated. In the proposed graphene waveguide, a transmission contrast ratio up to 19.2 dB can be achieved between forward and backward transmission by using the finite-difference time-domain (FDTD) method, revealing an excellent nonreciprocal effect. Moreover, the proposed nonreciprocal graphene waveguide can also be flexibly controlled as forward transmission or backward transmission at different wavelengths by adjusting the structural parameters and input intensity. Therefore, our results can offer a new possibility and important application in highly integrated optical circuits.