Learning Forum

[Ekaterina Pshenay-Severin]

I need to calculate the mode overlap between a WG mode and an elliptical Gaussian beam. I would like to do it in MODE using overlap. How can I create an appropriate object with an elliptical Gaussian field profile? I use "rectilineardataset" to generate the filed distribution but I don't understand how copy it to a DECK.

Thank you in advance!

Ekaterina

[Guilin Sun]

Unfortunately it is difficult to load ldf data into the Global deck as it only accept save dcard data. You can use  zbf data: https://optics.ansys.com/hc/en-us/articles/360034928293-zbfwrite-Script-command

I tried and it works.

You can also use script to calculate the overlap as you have already the elliptical beam data. What you need is to get the mode fields:

E=getresult("mode1","E");

H=getresult("mode1","H")

and then get components, and follow this link for the formula: https://optics.ansys.com/hc/en-us/articles/360034405254-overlap-Script-command

 

[Ekaterina Pshenay-Severin]

Thank you a lot for the answer! But I still have a question. Firstly, the additional issue I face is that the WG I simulate with MODE is oriented along the x-axis (injection x-axis). To use overlap, I need the elliptical beam in the Y-Z plane. Of course, I can rearrange the WG geometry, but I wanted to find out if there is a way to generate an elliptical beam in the Y-Z plane.

Concerning zbf, it seems that the zbf export works in a way that the resulting field distribution is in the X-Y plane. Actually, I tried this approach by following the tutorial: "Import Source in Ansys Lumerical FDTD" (https://courses.ansys.com/index.php/courses/lumerical-fdtd-sources/lessons/import-source-in-ansys-lumerical-fdtd-lesson-7/). I defined the source and the monitor so that x is the injection direction and saved the field from the monitor to the zbf. However, when I import it to the DECK in MODE for the overlap analysis, the field is in the X-Y plane.

Is there is a way to get field in zbf in Y-Z plane ?  

Thank you in advance!

 

[Guilin Sun]

You can modify your script for the generation of elliptical Gaussian beam in yz plane.

However since import zbf not in xy plane does not work right now, the simpler way to do this is to write your own script. Of course you can rotate the waveguide cross section to be in xy plane.