May 16, 2023 at 1:40 pm
Kevin Portner
Subscriber

Thanks for the quick feedback! I assume that you are talking about the 3D simulation (where I see that the BC is anti-symmetric for ymin). However I was currently only using the 2D one. In that case I see that all the BC are PML and no symmetry is used.

Maybe I was not clear on what my goal is: I concretely want to find out what is the optimal pitch and etch depth for a fixed duty cycle of 0.5. I want to determine this for a Silicon WG with height 220nm (the one that is already implemented) and one with height 340nm. In both cases I want to know the pitch and etch depth for the fundamental TE but also for the fundamental TM mode. Here are the points that are not fully clear to me:

-It should be sufficient to use the 2D simulation only, right? Or is it necessary to go to the 3D simulation?

-The standard setting in the 2D simulation uses fundamental TM modes for both port 1 and port 2. However, for port 1 the injection axis is the y-axis while it is the x-axis for port 2. This confuses me. If the injection axis is the y-axis (as for port 1), TE would mean that the fields are polarized along y. On the other hand an injection axis along x (as for port 2) means that for TE = fields are along x. For port 2, this would however mean that I have a TE mode no? In the simulation the mode is however specified to be the fundamental TM mode. Could you explain me where I am wrong?

-What settings for Port 1 and Port 2 do I have to concretely select if I want to have the fundamental TM mode in the waveguide? And which settings do I have to select in the case of the fundamental TE mode?

 

Thanks already in advance for your answers.