I am having problem with loading the farfield mode profile to the deck. Even though I select only farfield mode while saving the mode to ldf file, when I try to load into the mode deck, it always loads the main mode but not the farfield mode.
Overall I want to calculate the farfield of the mode and calculate overlap with another calculated mode.
That is correct. It looks like when you try to export the farfield data in the .ldf format, it actually saves the near field data. You can test this by loading the .ldf file directly into workspace and plotting them as is explained in the link below:
You will see that exported .ldf file has near field data even if you have selected to export the farfield data.
I discussed this with one of our R&D team members, and looks like there is a limitation into what you actually can import into DECK card. For example, you can not import a random field distribution or farfield data.
Considering the current limitations, I think one option would be to export the farfield data into matlab file, and then do the post processing. You can use the equations described in overlap page and test your script for the near field overlap data. Once they matched with the Lumerical ones, you can try it for far field data.
Sorry for any inconvenience. Please go ahead preparing your scripts and I will be more than happy to be of a help at any time.