Learning Forum

[fa146088]

Hi,

I have a question regarding the inverse design of a Y-branch example. I want to write a code for the example using the EME solver. What code should I write for the figure of merit (FOM) section? The EME solver does not have any monitors, so how can I optimize one of the output ports for maximum transmission (100 percent)? Additionally, for the code pt = Optimization(use_var_fdtd = True), what should I write instead of "use_var_fdtd" because "use_eme" command does not exist in the code basis.

Best regards

[Guilin Sun]

Using inverse design for EME is quite new. no "use_eme" fucntionality is available. You may need to develop your own code. Please note that EME works for waveguide modes. and every iteration it needs to build the EME cells, calculate the modes and then propagate to get s parameters.

As mentioned in this exmaple: https://optics.ansys.com/hc/en-us/articles/360042800573-Inverse-Design-of-Grating-Coupler-2D  EME gives result from  ports. You will need first to get S parameters, and then extract one of them, and with some manipulation and assign to FOM. Eg,

s=getresult("user s matrix");

fom=abs(s(2,1))^2;

this is to use transmission at port 2 for mode 1 at port 1 injection, for one input port and one output port device.

 

[fa146088]

Thank you very much for your response.

 

When I tried to write this command 's=getresult("user s matrix");' in a Python script in Lumerical, I faced the error '"name getresult is not defined." Additionally, I wanted to import my material file in a Python script using 'importmaterialdb("file name.mdf")', but I received the error that it's not a valid command in Python.

 

Also, I have another question. Should I use an 'if'  or a 'for' loop for optimizing my structure using inverse design by the EME module?

 

I would appreciate if you could help me with these issues.