Why my simulation (FDTD) is diverging

alharbigalharbig Member Posts: 1

I am a beginner in Lumerical and I have got a diverging issue After seconds of running simulation, the auto-shutoff level will increase dramatically and it will display: Warning! The simulation that created the data in the monitors and sources below diverged, and the data is likely invalid. Please see the Diverging simulation page 1 for help on solving this problem.


  • gsungsun Posts: 751Ansys Employee

    Diverging is one of the most often asked questions. Have you visited that page and test if it is due to PML or dt factor? Those two factors are the common causes of diverging. Please visit the page, modify and test to see if it improves. Another cause might be material fitting: please check each material fitting and make sure they have no gains: eg, negative value of imaginary part of refractive index and permittivity. This can happen for very small values of the imaginary part: you can zoom in and check all the data is positive.

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