Discussion Forum

Hi,

I have few questions about the port definition at optical waveguides. As far as I see from Comsol´s example file, two ports(excitation and output ) are required for each waveguide. In the example file, each waveguide was excited from input and someone included phase difference (pi) between two ports; someone did not. I noticed that the effective index of ports was also different.
I want to excite only one waveguide and look coupling between two waveguides but it did not work.
My questions are following:
1) Why could I not excite only one waveguide? (There are two waveguides in the simulation)
2) Is it possible to deactivate the excitation of other waveguide?
3) Why are the refractive indices of ports different, even they are same and I would like to excite with fundamental mode?
4) How does program define the sequence of ports in relative to waveguides? Which one will be Port 1, Port2 and Port 3, if I put a waveguide above two waveguides? In the example file, the port of waveguides share the same surface.

I attached an document to better visualise it. I am looking forward to getting an answer for that.

Thanks