Guilin Sun
Ansys Employee

This is common. Please refer to this article: Troubleshooting convergence errors in CHARGE – Ansys Optics

Please consider the following suggestions in addtion to the article:

1: using local mesh constraint for the thin layer

2: using larger min and max edge lengths in general

3: reduce the sensitivity

4: in advanced options, increase the max plc edge length except the thin layer is thinner than 10nm.

5: increase the iteration limits.

6: please check if any material used has large bandgap, which can lead to huge difficulty for concerging.

Please also refer to

Quality mesh constraint (Finite element) - Simulation object – Ansys Optics

Mesh constraint (Finite element) - Simulation object – Ansys Optics


Lastly, please write post in Photonics forum later: Photonics (