Why the transmission auto generated by the code is different from selecting port and "visualize->S/T" about siepic_ebeam_pdk

[lukasc-ubc]

I suggest plotting the bottom graphs in the dB scale. What your two graphs show are the linear values, and furthermore the Real part of the field (Scalar operation). You need to plot Abs^2 of the S-parameters by changing the Scalar operation. Then convert to dB (which isn't possible in the Lumerical GUI).

[Zwlzzm]

@lukasc-ubc,

Thank you very much for your respond.
I am sorry, but I don't really understand, the bottom graphs are already showing Abs^2 of S parameter.

I plot the left bottom graphs in the dB scale,
for port3,

for port4,

So it seems that the transmission of auto generated are different from that of Abs^2 of S parameter, even they are plotting the same thing and they are from the same FDTD file.

I am very confused with it. What is the transmission of auto generated stand for? Why they are different?