The device being studied in this example is a ring resonator filter. It consists of two waveguides (through and drop channels) connected by a ring. As the input mode propagates past the ring, a fraction will couple into the ring. Due to the circular nature of a ring, the mode will circulate around the ring many times. As the mode circulates, it will interfere with itself. The interference pattern is strongly wavelength dependent, which is why these devices can be used as filters. Some wavelengths will pass through the device, while other wavelengths will be re-directed into the drop channel.
We will use FDTD to study the same ring resonator in 3D that was designed in a varFDTD simulation using MODE. We will then show how we can extract S parameters that can be used for circuit level simulations in INTERCONNECT.
We will start with the geometric parameters determined in the MODE getting started example.
NOTE: If you are using an older version of FDTD (v.8.16.1022 or older) please refer to the archived KB page as the current tutorial uses features which have been added since.