Menu

Discussion Forum

New Discussion
Filter

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

How to define the incident light area in Mode Analysis?

Posted Nov 25, 2014, 7:20 p.m. EST Electromagnetics, RF & Microwave Engineering, Structural & Acoustics 4 Replies

Huashun Wen
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi all,

I want to do mode analysis of a rib waveguide, as shown in attached figure (a). But the modes I got are not guided in the waveguide, as shown in attached figure (b).

I think the incident light area (or something like this) should be defined, so that the modes can be guided in the waveguide, as shown in attached figure (c). So question is how to define the incident light area, or how to set in Mode Analysis? So the modes will be guided in the waveguide. Thank you.

Best regards,

Huashun

Attachments:

4 Replies Last Post Dec 8, 2014, 1:59 p.m. EST
Felipe Beltran-Mejia
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 10 years ago Nov 27, 2014, 8:16 a.m. EST
Dear Huashun,

My suggestions:

First, refine your mesh inside the rib.

Second, temporarily declare the upper Si region with a lower refractive index (for example air n=1). Same thing with the Si substrate.

Run your study computing for 6 modes and using the Si refractive index as the first shoot for the effective refractive index. Look for the computed effective refractive index of the computed mode, as it will be a good "second shoot" for the next step.

Reestablish the correct refractive index for the top layer and the substrate. Now use your "second shoot".

good luck!
Felipe Beltran-Mejia
Dear Huashun, My suggestions: First, refine your mesh inside the rib. Second, temporarily declare the upper Si region with a lower refractive index (for example air n=1). Same thing with the Si substrate. Run your study computing for 6 modes and using the Si refractive index as the first shoot for the effective refractive index. Look for the computed effective refractive index of the computed mode, as it will be a good "second shoot" for the next step. Reestablish the correct refractive index for the top layer and the substrate. Now use your "second shoot". good luck! Felipe Beltran-Mejia
Huashun Wen
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 10 years ago Dec 1, 2014, 1:57 p.m. EST
Hi Felipe,

Thanks a lot for your suggestions, they are very helpful.

I'd like to ask another question, how to do the Mode Analysis which is only for the TE polarization light? Thank you.

Best regards,

Huashun Wen
Hi Felipe, Thanks a lot for your suggestions, they are very helpful. I'd like to ask another question, how to do the Mode Analysis which is only for the TE polarization light? Thank you. Best regards, Huashun Wen
Felipe Beltran-Mejia
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 10 years ago Dec 1, 2014, 2:03 p.m. EST
Huashun,

I don't know if I really understand your question, but I'll give a shoot:

Compute for various modes. Locate your TE mode and copy the effective refractive index.
Compute again but just for one mode and using the effective refractive index as the value to search around for.

You should get only your TE mode. Now you can start working with it.
Also, if you want to modify any material or geometrical parameter, you shall do it in small steps so you can keep track of the TE mode effective refractive index.

I hope that helps,
Felipe Beltran-Mejia
Huashun, I don't know if I really understand your question, but I'll give a shoot: Compute for various modes. Locate your TE mode and copy the effective refractive index. Compute again but just for one mode and using the effective refractive index as the value to search around for. You should get only your TE mode. Now you can start working with it. Also, if you want to modify any material or geometrical parameter, you shall do it in small steps so you can keep track of the TE mode effective refractive index. I hope that helps, Felipe Beltran-Mejia
Huashun Wen
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 10 years ago Dec 8, 2014, 1:59 p.m. EST
Hi Felipe,

Thanks a lot for answering my question.

My question is how to choose TE or TM for mode analysis, as described here www.comsol.com/community/forums/general/thread/7478

Hope you could help me. Thank you.

Best regards,

Huashun Wen
Hi Felipe, Thanks a lot for answering my question. My question is how to choose TE or TM for mode analysis, as described here http://www.comsol.com/community/forums/general/thread/7478 Hope you could help me. Thank you. Best regards, Huashun Wen

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content