Why the transmission (without any device) is different from the source profile?

I tried to figure out the spectrum of the source where there is no any device involved. I just used a monitor to collect the transmission, which I thought of the source profile. However, the collected transmission is quite different from the source profile. why?

Does anyone knows why? i am interested to know why as well.

Is there any staff who can help this?

Hi @bob and @george_chen

Transmission normalized the results to sourcepower and thus returns a value of 1 in free space:
https://kb.lumerical.com/ref_scripts_transmission.html

You can obtain the “spectrum” and “time signal” by running the simulations, and then right clicking on the source and visualizing the property of interest.

Thank you very much for your help.@ bkhanaliloo