We have a silicon-on-insulator waveguide with a ridge width of 500nm. We are interested to follow a specific mode profile found at 500nm ridge width as we slowly sweep the width from 500nm to 1um.
The challenge is that the effective index and the mode number in the list of found modes will likely change as we change the structure dimensions. Therefore, to complete this objective, we will use mode overlap analysis to find out which mode from the current structure width has the best overlap with the mode from the previous run.
If we keep the sweep step small enough, it should be a fairly reliable strategy to follow the mode of our interest.
Run and results
You can produce the following results by opening the simulation file and running the script file attached.
The field profile of the mode to be tracked (the second mode in the Mode list)
Visual check of the mode profile development between 0.5um and 1um with 6 steps
neff evolution as function of ridge width