Menu

Discussion Forum

New Discussion
Filtern

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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.

photonic crystal fiber

Posted 14.01.2012, 10:03 GMT-5 RF & Microwave Engineering Version 4.1, Version 4.3b, Version 4.4 22 Replies

Sahin Khan
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi,

I am a beginner of comsol v 4. I tried to design a pcf with hexagonal pattern of airholes (five rings).
pitch=2um and d=1 um.
I got real part of effective mode index but don't get any imaginary part. Why?
The dispersion curve was not so good. Please help me.
22 Replies Last Post 29.12.2016, 12:55 GMT-5
COMSOL Moderator

Hello Sahin Khan

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Deepak Jain
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 17.02.2012, 08:56 GMT-5
Hi,

can you please show me your .mph file then I can comment.
Hi, can you please show me your .mph file then I can comment.
Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 16.03.2012, 11:00 GMT-4
i am facing the same problem too..

do you know how to solve it?
teach me, pls.
thx
i am facing the same problem too.. do you know how to solve it? teach me, pls. thx
Deepak Jain
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 16.03.2012, 13:42 GMT-4
Show me your mph file only then I can comment.
Show me your mph file only then I can comment.
Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 16.03.2012, 22:20 GMT-4
i dont know why i cant attach my file, maybe because it is too large, is around 15Mb.
i dont know why i cant attach my file, maybe because it is too large, is around 15Mb.
Deepak Jain
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 17.03.2012, 05:07 GMT-4
You have to use PML layer to calculate the imaginary part. Or might be your mesh is not good enough. You just send me the geometry without meshing it. Its difficult diagnose a problem this way.
You have to use PML layer to calculate the imaginary part. Or might be your mesh is not good enough. You just send me the geometry without meshing it. Its difficult diagnose a problem this way.
Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 17.03.2012, 05:22 GMT-4
will send it to you once i back to my lab tml.
my structure is without any PML, i use PEC outside my structure.

by the way, why i must use PML to calculate the imag part?
since my material properties (exap : refractive index is real value) and all other parameters are also real value,
so, from a System of pure real value, how i can get imaginary solution?

what you mean by mesh is not good enough? mesh size too small or too huge?

thx
will send it to you once i back to my lab tml. my structure is without any PML, i use PEC outside my structure. by the way, why i must use PML to calculate the imag part? since my material properties (exap : refractive index is real value) and all other parameters are also real value, so, from a System of pure real value, how i can get imaginary solution? what you mean by mesh is not good enough? mesh size too small or too huge? thx
Delwar
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 17.03.2012, 05:49 GMT-4
Hello,
I think you can attach the Comsol Model. If you clear the solution and meshes(go to edit menu, clear solution and mesh), then the size of model will be reduced and save it.

Regards
D Bhuyan
Hello, I think you can attach the Comsol Model. If you clear the solution and meshes(go to edit menu, clear solution and mesh), then the size of model will be reduced and save it. Regards D Bhuyan
Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 17.03.2012, 23:35 GMT-4
hi Deepak Jain,

i attached the mph file.
have a look and give me some comment.
thx
hi Deepak Jain, i attached the mph file. have a look and give me some comment. thx

Attachments:

Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 17.03.2012, 23:35 GMT-4
Delwar Bhuyan,

thx for the sharing......
Delwar Bhuyan, thx for the sharing......
Deepak Jain
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 22.03.2012, 03:48 GMT-4
Hi Tee,

Sorry for late replying. I was fairly busy over last week. yes I have given a look to your proble. you should have used PML. Go to Electromagnetic waves right click you will find PML. you asked why is it necessary. it is necessary to compute confinement loss from fibre the light that is being absorbed by PML. You can read about PML. there is plenty of papers search on internet. Hope this is clear.
Hi Tee, Sorry for late replying. I was fairly busy over last week. yes I have given a look to your proble. you should have used PML. Go to Electromagnetic waves right click you will find PML. you asked why is it necessary. it is necessary to compute confinement loss from fibre the light that is being absorbed by PML. You can read about PML. there is plenty of papers search on internet. Hope this is clear.
Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 22.03.2012, 05:13 GMT-4
there are some PML types, i think i will choose cylindrical.
by the way, if i want to insert my own equation for the PML, is it possible?
because i read some simulation journal, they mentioned about the equation they used for PML.

thx
there are some PML types, i think i will choose cylindrical. by the way, if i want to insert my own equation for the PML, is it possible? because i read some simulation journal, they mentioned about the equation they used for PML. thx
Deepak Jain
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 22.03.2012, 05:27 GMT-4
Hi Tee,

u have to use cylindrical in this case. u can also use cartesian one if u use square str fr ur pml. Regarding equation do not worry at this moment. It is already implemented in comsol. U have to check subnode of pml, in which u have to chose option refractive index in this case rather than permittivity. this is a small issue but not corrected can give you error.
Hi Tee, u have to use cylindrical in this case. u can also use cartesian one if u use square str fr ur pml. Regarding equation do not worry at this moment. It is already implemented in comsol. U have to check subnode of pml, in which u have to chose option refractive index in this case rather than permittivity. this is a small issue but not corrected can give you error.
Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 22.03.2012, 10:34 GMT-4
Thanks for the information..
Hv you try to calculate the dispersion for PCF?
i wonder why my dispersion curve is shifted upward when i compared it with the result reported in journal.
Thanks for the information.. Hv you try to calculate the dispersion for PCF? i wonder why my dispersion curve is shifted upward when i compared it with the result reported in journal.
Haris Saja
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 04.06.2012, 03:01 GMT-4
Hi Deepak,

I tried to use PML in my PCF model by using COMSOL 4.1, but there is an error and I don't know how to solve this error. Would you like help me to find the solution of this problem? I attach my PCF file here.

Thank's a lot
Haris
Hi Deepak, I tried to use PML in my PCF model by using COMSOL 4.1, but there is an error and I don't know how to solve this error. Would you like help me to find the solution of this problem? I attach my PCF file here. Thank's a lot Haris
S Felix
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 12.06.2012, 03:07 GMT-4
Hi Haris Saja,

I guess you will need to do the following:
1) Go to;
Model builder-------->> Materials; Here you need to select material type for your PML (domains 1,2,3,4,7,8,9) to be either Air or Silica. For the choice you can refer several discussions here on the forum.

2) Go to;
Model builder-------->> Electromagnetic waves------->> perfect matched layers------>> Wave equation, electric1;
Look at settings window (right hand side) under "electric displacement field" model and choose "refractive index" from the drop down list.

I hope this will solve your problem.

all the best





Hi Deepak,

I tried to use PML in my PCF model by using COMSOL 4.1, but there is an error and I don't know how to solve this error. Would you like help me to find the solution of this problem? I attach my PCF file here.

Thank's a lot
Haris


Hi Haris Saja, I guess you will need to do the following: 1) Go to; Model builder-------->> Materials; Here you need to select material type for your PML (domains 1,2,3,4,7,8,9) to be either Air or Silica. For the choice you can refer several discussions here on the forum. 2) Go to; Model builder-------->> Electromagnetic waves------->> perfect matched layers------>> Wave equation, electric1; Look at settings window (right hand side) under "electric displacement field" model and choose "refractive index" from the drop down list. I hope this will solve your problem. all the best [QUOTE] Hi Deepak, I tried to use PML in my PCF model by using COMSOL 4.1, but there is an error and I don't know how to solve this error. Would you like help me to find the solution of this problem? I attach my PCF file here. Thank's a lot Haris [/QUOTE]
Haris Saja
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 14.06.2012, 03:29 GMT-4
Hi Felix,

Thank's for your explanation.. :)
Hi Felix, Thank's for your explanation.. :)
Polepalli Siva Krishna
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 06.12.2013, 01:37 GMT-5
i am new to comsol, i am trying to use pml in my pcf, can any one tell me hw to use
i am new to comsol, i am trying to use pml in my pcf, can any one tell me hw to use
Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 06.12.2013, 01:46 GMT-5
Polepalli,

You can just use the built-in PML. (or you can define your own PML equation, you can find it from internet)

Just draw another domain (cylindrical or rectangular) surrounding the outer boundary of your PCF. You have to define the material for that domain too, and select that domain as your PML.

Polepalli, You can just use the built-in PML. (or you can define your own PML equation, you can find it from internet) Just draw another domain (cylindrical or rectangular) surrounding the outer boundary of your PCF. You have to define the material for that domain too, and select that domain as your PML.
Polepalli Siva Krishna
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 06.12.2013, 05:59 GMT-5
what type of material can i choose for that domain
what type of material can i choose for that domain
Tee Din Chai
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 06.12.2013, 06:25 GMT-5
Normally it is the same material as your PCF. Because you are truncating your PCF with the PML..
Normally it is the same material as your PCF. Because you are truncating your PCF with the PML..
Ouadah Chemss Eddine
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 23.04.2014, 06:25 GMT-4
Hello Sir,please what is the material of pml can me use for pcf fibers
Hello Sir,please what is the material of pml can me use for pcf fibers
Fairuz Nova
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 29.12.2016, 12:55 GMT-5
Can you post your code for plotting dispersion curve ? I need that badly
Can you post your code for plotting dispersion curve ? I need that badly

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