Learning Forum

[Yang Lan]

Hello, everyone. I would like to ask why there is a loss in SI3N4 after coming out of source no matter how I set it up. I have it set up in fundamental TE Mode and Wg_width = 0.8, hight = 0.4. The material I used is Luke Si3N4. If it's a matter of my choice of material, what's the difference between the other two Si3N4's and this one. Thanks a lot!

[Guilin Sun]

What the wavelength is this? have you checked the material fitting and see if there is loss from the material? usually this material has very small loss, From the screenshot, it seems the mode has some leakage. Please use log scale to check.

 

This might be due to mode source size is small, or there is another material, or the PML is too thin that causes some refelction. Please check and modify the settings. If problem still exists, please give more screenshots regarding to the waveguide and simulation settings.

As for the material data, they are from different labs so it is hard to say the reasons of the difference. Maybe the material provider is not the same, or the measurement accuracy or method are not the same. You can simply pick one that fits you, and compare the results with other materia data. If the difference is large, you may either measure the material in your lab, or manufacture the waveguide and check the propagation loss against the simulation.