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July 2, 2024 at 2:53 pm
hamid.h.javadi
Subscriber

Hi,

I need some guidance of how to correctly setup a nonlinear optical model involving both FDTD and DEVICE. The answer may be in plain sight but it is hidden for a novice.

In FDTD, Two (2) CW optical sources are incident on plasmonic grating on GaAs substrate thus generating electron and hole pairs. The applied voltage between electrodes accelerates the charges. At the same time, other parameters of the DEVICE model are also in play (mobility, diffusion, recombination,…)

Nonlinearity is approached by modelling cyclic perturbations (optical source à e-h pairs, that are moved under the influence of DC voltage à change of index of refraction à impacting optical response).

I need to know how to correctly setup FDTD and DEVICE models.

  1. FDTD generates e-h pairs by using the analysis script “CW generation rate“ in “Optoelectronics - CW generation rate” in Object Library 
  2. eh concentration is saved in “export file" name in (.mat) format. source intensity is set here.
  3. DEVICE loads the e-h concentration under “CHARGE - Optical Generation Rate”. File name in (.mat) format.
  4. DEVICE applies DC voltage specified under the "boundary conditions". a charge monitor saves n-p data in a new (.mat) file.
  5. In FDTD, “NPDensityGridAttribute” is added as analysis structure to import n-p concentration in (.mat) format.
  6. In FDTD, the new material is added to include "np density". The original material is replaced with a new one that uses "Drude model" to calculate change in the index of refraction.
  7. FDTD --> DEVICE/CHARGE --> FDTD --> DEVICE/CHARGE is run in cycles till convergence is achieved.

Does this setup guarantee full account of the intended nonlinear model?

Thanks,

Hamid Javadi