Reply To: 2D inverse design grating coupler

[anna.wirth-singh]

Hi Rahul,

Thanks for your question. Could you please clarify which example you are working with? We have a few grating coupler design examples, so I want to check that I am looking at the right one to answer your question. 

We have one here using the built-in particle swarm optimization tool: Grating coupler – Ansys Optics

This one uses the Python-based inverse design package lumopt: Inverse Design of Grating Coupler (2D) – Ansys Optics

For a sweep over source position, there is typically a well-defined maximum. The sweep over source position probably looks something like this, where the y-axis is the transmission into the waveguide and the x-axis is the source position:

For this parameter, it is clear that the optimal value is somewhere near the center. Most likely, the designer of the example file restricted the sweep range so that they could run fewer points (and therefore get results faster), with the knowledge that the optimal value would not be near the endpoints of the sweep.