Three-ring photonic molecule
2D simulations of configurations with the following specification: background refractive index 1.0, refractive index of the guiding regions 1.5, waveguide core widths 0.6 µm (bus), 0.75 µm (cavities), cavity radius 7.5 µm (outer rim), gaps 0.3 µm. All calculations are meant for TE polarization, i.e. for a single nonvanishing electrical field component, perpendicular to the plane of the computational window.
The approximate (!) HCMT model relies on a field template that includes the radially fundamental whispering gallery modes of angular order ±39 (two WGMs per cavity, resonance wavelength 1.5637 µm), together with directional variants of the bus waveguides slab modes (amplitudes discretized by 1-D finite elements).
T and R are the guided wave transmittance and reflectance, respectively, for excitation at vacuum wavelength λ in the lower port. The links at the positions indicated by the gray tick marks lead to illustrations of the time harmonic electric field.
The upper markers indicate supermode eigenfrequencies, determined with an HCMT ansatz for the molecule only (WGMs, black), and for the full composite configuration (WGMs & bus, blue; here also the associated linewidth is shown). The links lead to animations of the corresponding fields. Note that these are modes with complex eigenfrequencies; the animations merely rerun one oscillation at the resonance wavelength, i.e. neglect the (slow) field decay.