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Effective area calculation for PCF design
Posted 27 janv. 2010, 22:36 UTC−5 Version 4.2 15 Replies
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The equation for effective area is attached.
In that equation how can I calculate the electric field 'E' value?
I have an idea about it, we can calculate it from the option postprocessing-subdomain integration.
I want to know the expressions for 2nd and 4th order integration of that E value...
Thanks.....
Attachments:
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Well you double integration over dxdy is the "Integration Coupling Variables" - "Boundary Integration Variables" for 3D or a "Subdomain Integration Variable" for 2D.
You need to identify the name of your "E" and integrate abs(E)^2 or E*conj(E) I would expect, if E is complex. Respectively to the forth power.
These integrations are in facts sum over the nodes/elements, so just be careful that the sum of a product is not necesarily the product of the sums, etc.
It is as when you want to know the surface of the side of a cube: you select the side and type "1" in the Boundary Integrand and you get the boundary area, respectively "1" in the sub-domain integrand and you get your cube=subdomain in 3D total volume.
Hope this helps
Ivar
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Thank you for your guidline. I am also designing PCF using comsol 4.2. As per your instruction i have defined effective area as follows:
intop1(abs(Ez)^2)^2/intop1(abs(Ez)^4)
Geometry entity level: entire model
i have done this intregation over entire model and got some results but my found results are about 1 um^2 higher with compare to finite diffirence method (FDM). Using same parameters, I am getting always 1 um^2 higher effective area with compare to FDM. Would please clarify me?
Thank in advanced
Anwar
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Well I cannot unfortunately calculate the effective modal area of a PCF. I am using COMSOL 3.5 and the equation I used to calculate the area was the one Md. Anwar Hossain mentioned in his previous reply i.e. intop1(abs(Ez)^2)^2/intop1(abs(Ez)^4).
The error is:
Error :6099
Evaluation of post processing expression failed
Unknown function
- function: intop1
Failed to evaluate expression
- Expression: into1(abs(Ez)^2)^2/intop1(abs(Ez)^4)
Could you please help me to find the effective area of the fundamental mode? I am new in COMSOL
Thanks guys,
Take care
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then define integration (intop1) by right clicking on definition. This integration (intop1) you will get under model couplings.
Finally, run the program after defining the domain on which you want to perform integration for having Aeff.
Hope you will have good results.
Anwar
Hello guys,
Well I cannot unfortunately calculate the effective modal area of a PCF. I am using COMSOL 3.5 and the equation I used to calculate the area was the one Md. Anwar Hossain mentioned in his previous reply i.e. intop1(abs(Ez)^2)^2/intop1(abs(Ez)^4).
The error is:
Error :6099
Evaluation of post processing expression failed
Unknown function
- function: intop1
Failed to evaluate expression
- Expression: into1(abs(Ez)^2)^2/intop1(abs(Ez)^4)
Could you please help me to find the effective area of the fundamental mode? I am new in COMSOL
Thanks guys,
Take care
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Thanks a lot for your reply and your time. I tried to define the equation but unfortunately I couldn't. The reason is i am really dummy with COMSOL and even the simplest thing it is really hard for me to find. Could you please be more specific with the steps I have to follow? My apologies and thanks again
Take care,
Chris
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Anwar
Dear Anwar,
Thanks a lot for your reply and your time. I tried to define the equation but unfortunately I couldn't. The reason is i am really dummy with COMSOL and even the simplest thing it is really hard for me to find. Could you please be more specific with the steps I have to follow? My apologies and thanks again
Take care,
Chris
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intop() is the V4 operator default name, its different in 3.5, chceck our doc for model coupling integration variables
--
Good luck
Ivar
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I checked out the integration operator in 3.5 (postint) and I still cant get any result. Could you please verify that this is the correct operator that I am using?
Thanks a lot
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Sorry but I do not have access to 3.5 any longer, I have jumped fully into the v4 waters ;)
(and I'm not from COMSOL neither so I have no insentives to keep older versions)
--
Good luck
Ivar
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one things that i want to make clear that in domain for integration you should not chose entire domain. Select only core that might give more result. Please check and let us know also.
regards
deepak
Sorry Guys I was wrong. You need to chose whole domain.
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Thank you so much for your kind cooperation. You are right as I have got a very good results using the domain of core only.
Best Regards
Anwar
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How do I set domain of the core?
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The easiest way to calculate effective area is to use the z-component of the power flow. If you integrate Pozav_rfwv over the cross-section and divide it by the integral of Pozav_rfwv^2 you'll get the right Aeff value, provided that the z-component of the electric field is small enough (which is true in most cases).
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Thanks in advance
I don't think you can use the core domain only.
The easiest way to calculate effective area is to use the z-component of the power flow. If you integrate Pozav_rfwv over the cross-section and divide it by the integral of Pozav_rfwv^2 you'll get the right Aeff value, provided that the z-component of the electric field is small enough (which is true in most cases).
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I would like to know more details about the ''Aeff'' equation of a PCF. What is actually the meaning of the numerator and denominator part in the ''Aeff'' equation :
- why the numerator is square of double integral of abs(E)^2 over dx dy.
- why the denominator is double integral of abs(E)^4 over dx dy.
Thanks in advance.
Jincy
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