High Q Photonic crystal cavity and field profile possible in first simulation run?



Hi Lumerical KX

This is my first post, and it might already be answered but so far I haven’t been able to find it.

When I simulate photonic crystals cavities my simulations include a Q-analysis and a frequency domain field profile. Because of how the tutorial on photonic crystals are set up (I still pretty much follow that for new simulations) I run the simulation once, get the resonance frequency from the Q-analysis and then rerun the simulation with that resonance frequency as input in the frequency domain field profile monitor.

My ultimate wish is to do both in a single simulation and cut my simulation time in half, but I’m unsure if this is possible due to the nature of FDTD? (I come from a FEM background)
My slightly less demanding wish is to automate the simulation, so it doesn’t reduce the total simulation time, but runs the simulation twice and I in the end get all the infoI require. (I often simulate on a cluster, so this would ease my workflow.)

I hope you can help me with either or both!

BR Kristoffer


Dear @krsma

You are right, in FEM software automatically outputs the eigenmode. If I understood your question properly, you expect to get eigenmodes by running only one simulation (rather than calculating the resonance locations first and then updating monitors to checking their profile) in FDTD.

Unfortunately, this will not be possible in FDTD. One workaround, though, is to use a higher number of frequency points from Edit -> General -> Frequency points of frequency domain field profile (DFT) monitor. Please note that downside of the approach is that it will require larger memory to save the profile. This is somehow similar to running FEM for a larger number of modes to locate the eigenmode as not all them are of interest.

You should be able to do by scripting. You can write an script that runs the simulations to calculate the resonance frequency from Q-analysis. Then, it switches to layout mode and updates the DFT monitor frequency point to resonance frequency and runs the simulation again.

We have a full section for scripting, which you can use to prepare your script.

Please go ahead preparing your script and let me know if you need any help.