Learning Forum

[Joshua Worrall]

I have a structure with two sources and I'm trying to perform a parameter sweep using the global source center wavelength to vary both source center wavelengths at the same time. I'm measuring the transmission at the output waveguide on the right of the structure using a frequency domain field profile. The image below shows the simulation structure:

The next image shows the parameters and results in the sweep:

After running the simulation I get the following warning saying the results from individual simulations could not be concatenated:

Could anyone help me resolve this issue? I've read other articles about similar issues being caused by the mesh changing between simulations in the sweep, or the matrix the results are being stored in being of different sizes, but I don't understand why this would occur for a simple wavelength sweep.

I'm using a varFDTD simulation in Lumerical Mode 2023 R2.1

[Joshua Worrall]

I couldn't find an exact solution to the results not being concatenated but I think there was more an issue in my method. I discovered that you can perform a wavelength sweep by setting the wavelength center and span of the sources to the appropriate range, and then under the global monitor settings for the frequency domain field profile you can increase the number of frequency points.

[Afroditi Petropoulou]

Dear Joshua,

This is correct. You don't have to do a sweep over wavelength. You just need to set the span of the source to the desired wavelength range and run the simulation. 

Concerning the error, did you try to use a mesh override region around your monitor so that its position is not influenced by the mesh? When you use the default mesh, the mesh size changes by changing the source wavelength since the mesh size depends on both the wavelength as well as the refractive index that corresponds to the specific wavelength.

Best Regards,

Afroditi