In the following units, I'll show how to simulate a ring resonator in INTERCONNECT, including
setting up the simulation, running, and analyzing results.
On this slide, you can see an image of a ring resonator with a waveguide on either side
of a ring.
As light travels down the input waveguide, light will couple into the ring, and as the
light travelling in the ring circulates, some light will couple from the ring to the output
The transmission is frequency-dependent, so it can be used as a frequency-selective filter.
We will show how to extract the transmission spectrum, free spectral range, also called the FSR, which
is the spacing between the peaks in the transmission spectrum, as well as the quality factor of the device.
To simulate this in INTERCONNECT, we can build it from component parts, as shown in this
exploded view of the circuit parts, which includes waveguide couplers where power
gets coupled between the bus waveguides and the ring, and straight waveguide segments
for the remaining portions of the ring.
This is in contrast to component-level solvers like FDTD where we model the physical dimensions
of the structure and material properties, and solve Maxwell's equations to characterize
the response of the device.
On this slide we can see the simulation setup of the same ring resonator in FDTD Solutions.
Whereas in the component-level solver, we may change the coupling coefficient between
the straight waveguide and ring by physically changing the gap distance between them, in
INTERCONNECT, in the waveguide coupler element, we can simply type in the updated coupling
coefficient which is one of the parameters of the element, and observe the change in
This is an optical simulation only, but later in the course we'll add electrical modulation
and explore time domain simulations.