December 14, 2022 at 1:41 pmFrederic WuSubscriber
I would like to know if the interference between waves affect the DFT monitor's measurement. I am interested in transmitted power and I wonder if destructive interference will affect and thus decrease the reading.
Thanks for your time
December 14, 2022 at 5:10 pmGuilin SunAnsys Employee
FDTD solves the Maxwell Equations discretely. It involves all the physics, including interference, whether it is constructive or destructive. You cannot isolate them as this is physics. The DFT monitor will give you "net" transmitted power (ratio to source power).
December 15, 2022 at 1:21 amFrederic WuSubscriber
So when waves pass through a DFT monitor and destructively interfere with one another, the "net power" will be lower than if the waves constructively interfere?
December 15, 2022 at 4:57 pmGuilin SunAnsys Employee
I am not sure if you can control the interference, because it is the device behavior. AS mentioned previously, you cannot sepatate them. I am not sure for your device what exactly the quesiton is. What do you concern here? what determines the constructive/destructive interference and how do you interven this? could you please give draft about the device , the source and the monitor and what the final result do you want?
December 16, 2022 at 4:17 amFrederic WuSubscriber
I simply wonder how the DFT monitor works. The structure I build reflects light in different layers (it's called DBR reflector), so when the waves reach the monitor, the waves will be out of phase. Does the phase difference and interference reflect on the measurement of the DFT monitor?
December 16, 2022 at 6:28 pmGuilin SunAnsys Employee
Yes, the DFT monitor actually uses Fourier transform of the signal to the frequency domain result. Please refer
December 21, 2022 at 1:12 pmFrederic WuSubscriber
- Just to confirm my understanding, the DFT monitor takes phase shift into account. So if the reflected waves are out of phase, interference will affect the reading of the reflected power?
- Does waves with different frequencies interfere with one another? So for example, there are a 3000nm and a 5000nm wave. Does the two waves interfere or does fourier transform ignore the interference across waves with different frequencies?
December 21, 2022 at 3:06 pmGuilin SunAnsys Employee
A1: this is definitely correct.
A2: In simulation, no, waves with different frequencies DO NOT interfere with one another by Maxwell Equations. This is physics, as FDTD solves the Equations through the first principle, with discretization.
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