Reply To: Convergence testing for modes number in EME

[anna.wirth-singh]

Hi Xiao,

I am sorry to hear that you are having issues with EME. Possibly the issue is not the number of modes but some other setting. I would first suspect the number of cells or that the cells correspond to your structure correctly; have you tried convergence testing for the number of cells as well? The cell properties can be adjusted in the EME solver properties: 

Secondly, unexpected results can occur if the simulation boundaries are too close to the strucutre. Especially if you are using PML, please check that the boundaries are at least half a wavelength away from the structure. 

It may also be worth checking for any material fitting issues because that can cause unexpected results. 

We do have an example in the App Gallery for simulating a Bragg grating with EME: Bragg Grating full device simulation with EME – Ansys Optics. If you used this as your starting point, would it be possible to describe the changes you have made to adapt the simulation to your model?

I can also share these related links about convergence testing in EME:

• Convergence testing process for EME simulations – Ansys Optics
• EME Convergence Testing - An Intuitive Approach – Ansys Optics
• EME Solver analysis window overview – Ansys Optics
• Understanding EME error diagnostics – Ansys Optics

I hope this information is helpful. Please reply back if you can provide any further information about your simulation setup that may help diagnose the issue. 

Best,

Anna