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Ansys Learning Forum › Forums › Discuss Simulation › Photonics › Cinvergence of RCWA simulations › Reply To: Cinvergence of RCWA simulations

May 9, 2024 at 10:41 pm
Ruzan Sokhoyan
Subscriber

Hi Guilin,

 

Thank you for your response. 

  1. First I checked the convergence of FDTD. for 10 nm mesh, I observed that changing the number of PML layers does not affect the result. Then I reduced the mesh and observed that the simulation results for 3 nm mesh and 5 nm mesh are very close. Based on this I can conclude that FDTD simulation has converged. Do you agree with this?
  2. Then I started comparing the RCWA simulation results with FDTD. I change k numbers and also a number of mesh points from within the RCWA solver. I use 40 threads and 100 or 70 wavelength points in RCWA simulation and the simulation runs much longer than FDTD. Still, I haven't been able to achieve convergence. Even for values k=1700, I do not see convergence. When I increase the number of mesh points in RCWA  to 200 (from default 100) the discrepancy between RCWA and FDTD increases. Do you have a piece of specific advice on how to proceed here? Would you suggest keeping indefinitely increasing k? Note that in RCWA, the number of mesh points 200 and 400 yielded identical result that's why I decided to stick with 200.

Thanks!

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