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Far-field radiation pattern of an optical waveguide

Posted 11 oct. 2011, 09:36 UTC−4 RF & Microwave Engineering Version 4.2 3 Replies

pat
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Dear forum users,

I would like to calculate the far field diffraction pattern resulting from a guided mode in an optical waveguide.
My specific example: light is guided in the core of a photonic crystal fiber, reaches the end and gets diffracted into free space. How does the pattern look in the far field (or at a certain distance z away from the fiber).

I know how to calculate the mode with a Boundary Mode analysis study. But this gives me only the near-field at a cross section of the fiber (which is supposed to be infinitely long for the boundary mode analysis).

Is there a way to transform this near-field calculation into far-field?

Thanks a lot
Patrick
3 Replies Last Post 11 oct. 2011, 12:14 UTC−4
Edgar Kaiser
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Posted: 1 decade ago 11 oct. 2011, 10:01 UTC−4
Hi,

you can add the 'far-field' domain node under the 'Electromagnetic Waves' node. This makes far field variables available.
However, far field is the pattern at infinity, not a certain distance.
And a warning: plotting the far field in 3D displays is very time consuming, often much more than solving the system. I would recommend to use classical Azimuth/Elevation (1D) polar plots for that. They are fast.

Cheers
Edgar
Hi, you can add the 'far-field' domain node under the 'Electromagnetic Waves' node. This makes far field variables available. However, far field is the pattern at infinity, not a certain distance. And a warning: plotting the far field in 3D displays is very time consuming, often much more than solving the system. I would recommend to use classical Azimuth/Elevation (1D) polar plots for that. They are fast. Cheers Edgar
pat
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Posted: 1 decade ago 11 oct. 2011, 10:50 UTC−4
Dear Edgar,

thanks for the reply. However, I am not using 3D modelling but 2D. Does it work there as well?

Best
Patrick

Dear Edgar, thanks for the reply. However, I am not using 3D modelling but 2D. Does it work there as well? Best Patrick
Edgar Kaiser
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Posted: 1 decade ago 11 oct. 2011, 12:14 UTC−4
I haven't tried 2D so far but one mouseclick shows you that the far field domain is available in 2D as well.
I haven't tried 2D so far but one mouseclick shows you that the far field domain is available in 2D as well.

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