Fig. 1. Structural diagram of in-fiber parallel double microdisk

Fig. 2. Mode splitting illustration (left and right insets are field distributions of antisymmetric mode and symmetric mode, respectively)

Fig. 3. x-y plane of FDTD simulation (part)

Fig. 4. Output spectral lines with coupling spacing from 0.1 μm to 0.43 μm

Fig. 5. Output spectral lines with coupling spacing from 0.5 μm to 1 μm

Fig. 6. Variation of transmittance of two modes with coupling interval

Fig. 7. Relationship between transmittance and coupling interval for coupling interval within 1 μm. (a) Relationship between transmittance and coupling interval for coupling interval of 0-0.43 μm; (b) relationship between transmittance and coupling interval for coupling interval of 0.45-1 μm

Fig. 8. Variation of resonance wavelength with coupling interval

Fig. 9. Mode splitting in octagonal microdisk when distance between two microdisks is 0.3 μm

Fig. 10. Mode splitting when distance between two microdisks is 0.1 μm, semi-major axis of ellipse is 9 μm, and semi-minor axis of ellipse is 4 μm