Bill Bulat
Ansys Employee

Without more details it's not clear to me exactly what you need help with, but a few things that may be relavent to your objective(s) include:

Lumerical FDTD — Monitors - ANSYS Innovation Courses

Frequency-domain Profile and Power monitor - Simulation object – Ansys Optics

and, the APDL *FFT command:

Regards,

Bill