Ring Resonator Port Error



I am attempting to create a ring resonator using silicon nitride in FDTD but I am having an issue with the ports. I receive the following messages when trying to visualize the mode:

And after trying to run the simulation I get the following error:

Can anyone assist me in this?
I have attached the file below:

FDTDring_2.fsp (357.5 KB)

Thank you!


Dear @grodal1

This error basically saying that your port object could not find the mode to propagate. At the moment you are using a very coarse mesh and port object can’t inject a proper mode. The area of port object is defined by white box and part of it is located outside the FDTD region.

I look at source frequency under ports, and looks like you are injecting a pulse from 750 - 850um. I am assuming that this is typo and should be corrected to 0.75 - 0.85 um.

Please let me know if this solves the problem.



Thank you so much for responding! Yes, those are the wavelengths I meant, and I have adjusted the FDTD region to encompass the port objects. Do you have a suggested mesh?


Dear @grodal1

We recommend to start with a coarse mesh (mesh order of 1 or 2) to run some quick simulations and make sure that everything is set properly. A key step for every simulation is to perform convergence test, in which you change PML layer, FDTD span, mesh size etc, and you expect the results to be unchanged. Only after these examinations you can say that your simulation results are reliable.

I hope this answered your question.