Topics related to Lumerical and more

Reducing Memory Requirements FDTD

    • Christopher Borgmeier

      My goal is to simulate a grating coupler with special interest for the Transimission S21 S-Parameter when coupling from a Single Mode Fiber to the grating coupler like the example given "Grating Coupler". Currently the memory requirements are close to 600 Gigabyte, where 91.2% is needed by my Mode Source (Port, 800-900nm). How can I reduce this by a factor of 2 or more, resulting in a faster simulation time? I am using Ports, the standard mesh sizing, standard Materials.

      Thank you in advance.

    • Guilin Sun
      Ansys Employee


      Do you mean it is due to port? please first dirable the port, and add a source with the same bandwidh, and check the memory requirement. If it is realy due to the port, since it has 3 objects: mode source, frequency domain monitor and expansion monitor, so you can first check how many frequency points for each of them:

      for mode source, use 10 or fewer points;

      for frequency domain monitor, use 20 points, as the bandwith is small;

      mode expansion monitor can use 10 or 20 points.

      What mesh accuracy you used? please first use mesh accuracy 2.

      In addition, please refer to the online example and compare the settings.


      If the grating is not curved, you can use symmetry-type BC. This is the plane out of the screen for your image.

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