Coupled mode characteristics for the twin coupled microdisks

The characteristics for the twin coupled microdisks are investigated by finite-difference time-domain (FDTD) technique. In the twin coupled microdisks, mode coupling between the same order whispering-gallery modes (WGMs) results in coupled WGMs with split mode wavelengths and different quality factor (Q-factor). The numerical results show that the coupling between the first and the second order WGMs exists, which can greatly decrease the quality factor of the coupled first order WGMs and deduce the anti-crossing of the mode wavelength. Furthermore, we can see the coupling phenomenon from the field distribution varies with the gap.