Fig. 1. Graphene-coated elliptical nanowire pairs. (a) Waveguide structure A; (b) waveguide structure B

Fig. 2. Normalized electric field distribution of fundamental mode. (a) b/a=3, a=100 nm; (b) a/b=3, b=100 nm; (c) normalized electric field distribution curves of x-axis; (d) normalized electric field distribution curves of y-axis

Fig. 3. Relationship between modal properties and ratio of major and minor axes of ellipse. (a) Effective mode coefficient; (b) propagation length; (c) normalized mode field area

Fig. 4. Relationship between modal properties and D. (a) Effective mode coefficient; (b) propagation length; (c) normalized mode field area

Fig. 5. Relationship between modal properties and f. (a) Effective mode coefficient; (b) propagation length; (c) normalized mode field area

Fig. 6. Influence of graphene chemical potential on modal properties. (a) Effective mode coefficient; (b) propagation length; (c) normalized mode field area