Manjunatha,
I will do my best to answer your questions but a couple will need clarifications.
- The transverse (spatial) width is measured as Full width at 1/e^2. So if the peak of the Gaussian is at 1 then the width at an amplitude of 1/e^2 will be the full width as set in the transverse tab. The half-width has no meaning without an amplitude point to measure it in this context and the only place half-width is used is when defining a rectangular field not a Gaussian.
- The wavelength range and the resolution of the wavelength range are both specified in the “Spectrum” option within the “DFT Options” of your simulation parameter window. It must be set BEFORE a simulation runs as the observation line is performing cumulative DFT during the simulation so the entire time information is not being stored. As we do not keep the full time information you will not be able to recalculate the DFT after the simulation.
- I am not certain what you are saying or asking in this question. The paper you link discusses a resonator structure to minimize cross talk in waveguide intersections. It does not discuss shifting of the resonant peak with refractive index changes in the resonator. However, I can say that if you are changing the refractive index of the central hole to represent a sample or lack there of then you are changing the resonant cavity and will see a shift in the resonant peak. As the paper does not discuss resonant shifts, are you referring to your own simulations and are you saying that you are not seeing a shift?
Scott