Learning Forum

[zahra mansouri]

Hi.

I have designed a magneto optic Wave guide and simulated it in the lumerical mode solution version 2017. The results showed the difference between Neff in forward and backward direction. Now I simulate my waveguide that I designed in version 2017 in the version 2024. The answers in this version doesn't show any difference between Neff in forward and backward direction. Why I get this two different answers?

[Guilin Sun]

Which product you are using? FDE? Could you elaborate more how do you select the forward and backward direction in FDE?

If it is from 3D FDTD, you can change the source injection direction. But I tested this online case and the result is the same, since it uses bandstructure method regardless the source injection direction: https://optics.ansys.com/hc/en-us/articles/360042038613-Bandstructure-of-a-magneto-optical-waveguide

 

[zahra mansouri]

 

Thank you, dear Guilin Sun, for your guidance.  

I use the FDE solution in Lumerical Mode Solution to simulate a cylindrical magneto-optic waveguide in order to obtain the mode profile. For the forward direction, I apply the magnetic bias in the y direction, which is perpendicular to the propagation direction, and for the backward direction, I use the magnetic bias in the -y direction. I define the magneto-optic material in both forward and backward directions using matrix transformation, as outlined in the Lumerical guidelines on the Ansys website.  

Now, when I simulate this structure in Lumerical Mode Solution 2017, the propagation characteristics, such as Neff, show a significant difference between the forward and backward directions, which is important for our goals. However, when I simulate this structure in both directions using Lumerical Mode Solution 2024, the difference between Neff in the forward and backward directions is very close to each other, resulting in a negligible difference that could change our design goals

 

 

 

[Guilin Sun]

If you mean you use exactly the same file but different mode versions, it might be a bug. Please contact your account manager or CP to send us your file so we can investigate in more details.

[zahra mansouri]

yes i use the same file in different mode versions. my structure is a cylinderical magneto-optic waveguide. but when i try a plane magneto optic waveguide then the propagation characteristic is the same in two mode version. is it a bug in cylinderical analysis? how can i send you my simulation file?sorry i couldnt find in my ansys account that  how to send my file.

[Guilin Sun]

I am not sure if you are testing the same file in 2017 version and 2024 version, as you said you are trying "a plane magneto optic waveguide". Your previous file was for cylinderical magneto-optic waveguide. If something changes you may not be able to justify one is wrong. If you cannot send file, please ask your account manager to help you. 

[zahra mansouri]

Dear Guilin Sun 

I used a plane magneto optic Wave guide for testing propose. I simulate a plane magneto optic waveguide in version 2017 and 2024 and I get the same answer. But when I simulate my project ( a cylindrical magneto optic waveguide) in version 2024 and 2017, I get difference answer.

Can I send my simulation files here?

[Amrita Pati]

Hi Zahra,

I apologize for the delay in getting back to you. Guilin will be out of office for a while. Unfortunately, you will not be able to add files to your response. And even if you added a drive link, we are not allowed to download files from the ALF. Would you be able to share a screenhot of the mode list in the two versions? You can include the mode list as well as the "Modal Analysis" tab settings in you screenshot, like this:

Regards,
Amrita

[zahra mansouri]

Hi Amrita

thank you for your advise. yes i will send you the mode list in the two version of lunerical. the first image is for 2024 and the second one is for 2017