FDTD Solutions Knowledge Base

Ring Resonator Tutorial


Problem definition


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 Solutions to study the same ring resonator in 3D that was designed in a 2.5D simulation using MODE Solutions, see Ring resonator. 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 Solutions getting started example.


Associated files

We recommend downloading all associated files before beginning the tutorial.  Files can be downloaded from the online help section of Lumerical's website, or copied from the examples subdirectory of the FDTD Solutions installation directory.



In this topic

Simulation set up


Parameter extraction

Convergence testing

2D Approximation to 3D Geometries

Modeling Instructions


See also

Online User Guide -> Monitors and Analysis Groups -> Making a cw movie




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