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Waveguide S parameter calculation, boundary mode analysis problem

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Hi,

My task is to analyze the resonance property of a 3D optical waveguide cavity. As the first step, I am now following the "waveguide adapter" model to calculate the S parameters (reflection and transmission) of a straight waveguide (see my mph file attached).

My problem is that the eigenmode calculated by the "boundary mode analysis" looks strange, and the calculated effective mode index also largely deviates from the one obtained by 2D mode analysis. It is also interesting to see that the calculated S21 (transmission) is close to 0 dB, which is reasonable, at the frequency that I set for boundary mode analysis. But S21 will exceed 0 dB as the frequency becomes smaller. So, anything stupid in the model? Something wrong with the boundary condition setting?

Any comments will be very appreciated !!

Z



3 Replies Last Post Aug 2, 2011, 11:58 a.m. EDT

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Posted: 1 decade ago Aug 2, 2011, 6:19 a.m. EDT
I don't think the S21 parameter will exceed 0 dB (becoming positive) unless the medium is a gain medium. I feel you should checking out the mode index calculation again...
I don't think the S21 parameter will exceed 0 dB (becoming positive) unless the medium is a gain medium. I feel you should checking out the mode index calculation again...

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Posted: 1 decade ago Aug 2, 2011, 9:34 a.m. EDT
Hi,

I finally found the problem, the boundary mode analysis should be applied to all the sections of the input facet. I previously only apply the analysis in the waveguide core section.

Hi, I finally found the problem, the boundary mode analysis should be applied to all the sections of the input facet. I previously only apply the analysis in the waveguide core section.

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Posted: 1 decade ago Aug 2, 2011, 11:58 a.m. EDT
Hi,

Great ! :)
Hi, Great ! :)

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