The geometry of the solver region in the propagation direction, x, is determined by x min and the
The geometry in the transverse directions, y and z, are specified directly by their center/span
or min/max values.
The cell group definition table contains the list of cell groups and we will cover how
to set this up in the following unit.
"Number of cell groups" determines the number of rows of the cell group definition table.
If "allow custom eigensolver settings" is unchecked,
the number of modes solved for in each cell will be based on the "number of modes for
all cell groups" setting.
If the "display cells" option is selected, this will show cells outlined in orange in the
Otherwise, only cell groups will be outlined in orange.
Energy conservation sets boundary conditions for cell interfaces.
When "none" is selected, no energy conservation is applied and the interface S-matrix calculation
solves for results with the lowest field discontinuity at the interfaces.
"make passive" ensures no gain at the interface and is the default setting.
"Conserve energy" enforces energy conservation at all cell interfaces, allowing no gain or
Energy conservation will perturb the S-matrix to either force no gain, or no gain and no
loss, so it comes at the expense of making the field profile smooth and continuous.
If you are interested in getting a good field profile, then use "none"
If you are more interested in the correct S parameters, use "conserve energy".
This option is typically used for devices consisting of many periodic structures, like
Bragg gratings where a small amount of gain or loss will add up over many periods.
"make passive" is an intermediate option and it is the default.