This video is taken from the varFDTD Learning Track on Ansys Innovation Courses.
Many integrated optics components are suitable for simulating using varFDTD.
Some examples that can be simulated using varFDTD are star couplers, waveguide tapers,
MMI couplers, ring modulators, and soliton propagation.
These examples can be found in our online Knowledge base, and we will introduce each
of the examples and the types of results that can be obtained later on, in the Examples
section of the course.
It’s important to be able to recognize when the varFDTD method does not work well.
These are some example cases.
Fiber optics cannot be simulated since the structure is not planar.
Structures with graded refractive index in the x or y directions cannot be simulated
since smoothly varying refractive index within the propagation plane, which is the xy plane,
is not supported, although if the refractive index is graded along the z-dimension, this
can be simulated.
Waveguides with sloped sidewalls, also cannot be simulated as the structure cross section
is smoothly-varying in the propagation plane.
Grating couplers which couple light into or out of the xy plane in the vertical direction
cannot be simulated since the light should be travelling in-plane.
Nanoparticles which scatter light in 3 dimensions cannot be simulated for the same reason that
the method does not support light propagating out of the xy plane.
Finally, grid attributes, such as permittivity rotation, np density or temperature grid attributes
imported from DEVICE simulations are also not supported.
In the following section, we will work through the process of simulating a ring resonator
device using varFDTD.