Dear Sir /Madam
I have put Q analyzer in my structure and I have set the wavelength in source and monitor (1.5 to 1.6nm)
but the Q factor result is between 1.8 to 1.9 nm, I want to know what is the reason and how can I solve this problem I have tried both these solution but I couldn’t solve it.
Thank you for your kind help
The Q analysis group uses time domain monitors and uses the fftw (low Q analysis) or fft (high Q analysis) script command to perform the Fourier transform of the time domain data to get the frequency-domain data with peaks at the resonant frequencies. Since the source uses a broadband pulse in the time-domain by default, it will include a wider range than the specified range of 1500-1600 nm. One way you could limit the range is by using a more narrowband source, and this can be done by un-checking the “optimize for short pulse” option discussed on this page:
Another method which would be more complicated is to go into the analysis script of the Q analysis group and change it to use the czt script command where you can specify the frequency range of the transform instead of using fft or fftw script commands: