Lumerical Forum Today

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If you use Lumerical for more than one hour per week, the Lumerical Forum should be a permanent tab in your browser. It is the single fastest way to move from a broken simulation to a publishable result. The combination of peer wisdom, official support, and a searchable archive of edge cases makes it the most valuable resource in computational photonics.

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Focused on waveguide eigenmodes, bent waveguide analysis, and propagation loss. Here, you will find deep discussions on calculating effective indices for SOI (silicon-on-insulator) rib waveguides and troubleshooting variational FDTD for long-range propagation.

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."

I have checked my boundary conditions (PML) and ensured that the structure does not touch the simulation region edges. 80% of questions have already been answered

Steps I have tried:

Screenshots: (Attached image showing the mesh region and the log output)

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

Thanks, User123