Learning Forum

[Vahram Voskerchyan]

I am trying to calculate how the duty cycle of the grating affects the reflection and transmission profiles. And I am getting wrong results. The attached code is the EME setup, please help me to identify what is wrong with the simulation.  I am trying to sweep the duty cycle of the grating for 1000 periods and plot the transmission versus the duty cycle sweep. I have selected the conserve energy method and when doing so I can see that maximum peak is at 0.5 duty cycle.  But when turning off the conserve energy I get a plot like this. I want to do make passive because I want to see at which length the transmission becomes 0.

And when the conservation of energy is setup the plot is as follows. 

I was expecting to see a similar plot with the "make passive" option on. 

I have tried mode convergence sweep to see where the profile gets stable, I tried different meshings, and setting up cells differently. But the results are still confusing. Can you please help me to identify the problem ?

I have also attached the script. In the link below.

 

https://drive.google.com/file/d/1nw1Xm7zujpmfgltg5U1xedLuITUyBC3T/view?usp=sharing

 

[Guilin Sun]

Unfortunatelt we are not allowed to download any customer files from this forum.

For periodic simulation, please use "conserve energy". This is because, any minor change in S can result in huge difference when many periods are used. as you can see, (S+ds)^N so when N is large the error will be amplified significantly.

On the other hand, the convergence testing can be challenge:

Understanding EME error diagnostics

Convergence Testing - Error Diagnostics - Method for Using Diagnostics

EME Convergence Testing - An Intuitive Approach

Convergence testing process for EME simulations