2D simulation of a configuration with the following specification: background refractive index nb = 1.0, refractive index of the guiding regions ng = 3.2, cavity extension W = 1.54 µm, waveguide width w = 0.2 µm, gap width g = 0.29 µm. All calculations are meant for TE polarization, i.e. Ey is the single nonvanishing component of the electrical field.
The parameters were adopted from C. Manolatou, M.J. Khan, S. Fan, P.R. Villeneuve, H.A. Haus, and J.D. Joannopoulos, Coupling of modes analysis of resonant channel add-drop filters, IEEE Journal of Quantum Electronics, 35(9):1322--1331, 1999.
Spectral response of the resonator element:
The device is excited in port A by the guided mode of the lower waveguide with the specified vacuum wavelength lambda. PB - PD and PA are the relative power transmissions to ports B, C, and D, and the relative power reflected into port A. Note that the curves related to PA, PC, and PD are almost superimposed. The links at the positions indicated by the the blue tick marks lead to illustrations of the time dependent electric field, and of the local electromagnetic energy density, respectively.
The pronounced resonance at 1.532 µm:
While the plots connected to the former spectrum had their colour schemes adjusted to the individual field / energy range, the colour levels of the images linked to this figure are comparable.