In this section of the course we will show how to set up, run, and collect data for a
double bus ring resonator.
This device is a silicon-on-insulator device with two straight silicon waveguides and a
ring in between, on top of a glass substrate.
The cladding above is air.
Some of the light which enters from the straight waveguide at the top will couple into the
ring, and into the straight waveguide at the bottom, exiting through the drop port.
Only certain resonant frequencies will exit through the drop channel, so the device acts
like a frequency selective filter.
The coupling efficiency between the straight waveguide and ring depends on the gap distance
and coupling length.
The free spectral range, or FSR, is the spacing between these frequencies, and the FSR depends
on the path length of the ring, and the group index of the waveguide.
It's important to recognize that this device satisfies the requirements of the varFDTD
In particular, it is a single mode device
The structure is planar, and all propagation is in the XY plane
For the ring resonator that we will be simulating, the results that we want to collect are the
power spectrum from the through and drop ports of the ring resonator over the wavelength
range from 1.5-1.6 um.
We will also compare the results with 3D FDTD results.