Lumerical Forum May 2026

80% of questions have already been answered.

This is a typical post from a user encountering a simulation error or convergence issue.

Subject: FDTD propagation error: "Electric field values are too large" in ring resonator simulation

Body: Hi everyone,

I am currently designing a silicon ring resonator using MODE and FDTD. I am encountering a divergence error during the simulation run.

System Details:

Description: I have set up a 2D simulation of a ring resonator. I defined the silicon core with a mesh override region to resolve the 1550nm wavelength properly. However, after roughly 20% of the simulation time, the job manager reports: "WARNING: Electric field values are too large... simulation diverging." lumerical forum

I have checked my boundary conditions (PML) and ensured that the structure does not touch the simulation region edges.

Steps I have tried:

Screenshots: (Attached image showing the mesh region and the log output) 80% of questions have already been answered

Does anyone have suggestions on how to stabilize this simulation? Any advice would be appreciated.

Thanks, User123

In the high-stakes world of nanophotonics, semiconductor design, and metamaterials, simulation accuracy is everything. Engineers and researchers using Ansys Lumerical—whether for FDTD, MODE, or the INTERCONNECT suite—often find themselves at a crossroads. The software is powerful, but the physics is complex. Description: I have set up a 2D simulation

This is where the Lumerical Forum becomes an indispensable asset. Far more than a standard Q&A board, the official Lumerical community is a dynamic ecosystem of peer-to-peer support, expert verification, and script-sharing. Whether you are debugging a divergent simulation or optimizing a grating coupler, mastery of the Lumerical Forum can cut your development time in half.

The most active section. Topics range from mesh refinement strategies to multi-coefficient material models. Common threads include optimizing simulations for metal optics (e.g., silver/gold at visible wavelengths) and reducing simulation time for large-scale solar cells.