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Directional Coupler explanation
Posted Mar 25, 2014, 4:56 p.m. EDT Version 4.3 2 Replies
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I have a 2D directional coupler attached in this message. I know a directional coupler is analyzed using a boundary mode analysis but I don't understand why we do what we do in it. (Evaluate boundary modes for 4 modes and then use highest and third highest mode for each boundary analysis)
I just wanted to ask if you have some kind of white paper which could explain what exactly goes on in this analysis method?
Also is there any other way to do this?Like finite difference time domain method(FDTD).
Please let me know if you could provide documents which support the current method used in the directional coupler below to calculate the electric field.
I cleared all the results so that I could obtain a file smaller than 25Mb. Compute this model again and you'll obtain the results I see.
Here's the link of directional coupler guide provided by COMSOL
www.comsol.com/model/download/...optics.directional_coupler.pdf
I just wanted to ask if you have some kind of white paper which could explain what exactly goes on in this analysis method?
Also is there any other way to do this?Like finite difference time domain method(FDTD).
Please let me know if you could provide documents which support the current method used in the directional coupler below to calculate the electric field.
I cleared all the results so that I could obtain a file smaller than 25Mb. Compute this model again and you'll obtain the results I see.
Here's the link of directional coupler guide provided by COMSOL
www.comsol.com/model/download/...optics.directional_coupler.pdf
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2 Replies Last Post Jun 23, 2016, 2:19 p.m. EDT
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Posted:
1 decade ago
Hi Ravi,
I don't think there is a white paper on that example. If you explain what it is exactly that you don't understand, perhaps I or someone else could try to explain. Beam Envelop Interface is used here because the size of the coupler makes it unsuitable for modeling using FDTD or straightforward Frequency Domain analysis. On the other hand, the light in the coupler propagates in the known direction and the propagation constant can also be more or less known in advance. That's just the case for BE-interface. It's mentioned in the manual, have a look.
As for other methods - optically large structures can sometimes be effectively handled by modal analysis, that is you find all the modes supported by the structure and decompose the input field profile into those modes. You can then propagate the modes over arbitrary distance with little computing efforts (provided that your structure's cross section is invariant in the propagation direction, otherwise you have to split your structure into z-invariant sections with a set of eigenmodes in each section). Photon Design's FIMMWAVE/FIMMPROP and Lumerical's Mode Solutions are specifically designed for such simulations. However Comsol (with some Matlab scripting, perhaps) can also be used for this.
Another option is Beam Propagation Method which is suitable if the light in your structure propagates in more or less one direction, so that the BPM's par-axial approximation can be acceptable.
Good luck,
Anton.
I don't think there is a white paper on that example. If you explain what it is exactly that you don't understand, perhaps I or someone else could try to explain. Beam Envelop Interface is used here because the size of the coupler makes it unsuitable for modeling using FDTD or straightforward Frequency Domain analysis. On the other hand, the light in the coupler propagates in the known direction and the propagation constant can also be more or less known in advance. That's just the case for BE-interface. It's mentioned in the manual, have a look.
As for other methods - optically large structures can sometimes be effectively handled by modal analysis, that is you find all the modes supported by the structure and decompose the input field profile into those modes. You can then propagate the modes over arbitrary distance with little computing efforts (provided that your structure's cross section is invariant in the propagation direction, otherwise you have to split your structure into z-invariant sections with a set of eigenmodes in each section). Photon Design's FIMMWAVE/FIMMPROP and Lumerical's Mode Solutions are specifically designed for such simulations. However Comsol (with some Matlab scripting, perhaps) can also be used for this.
Another option is Beam Propagation Method which is suitable if the light in your structure propagates in more or less one direction, so that the BPM's par-axial approximation can be acceptable.
Good luck,
Anton.
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Posted:
8 years ago
hello ravi
i want to do similar simulation.
So will you please send me pdf file of this program if you have downloaded on your computer because i can not open mph file. i m using older version of comsol and link is not working that you have shown in your msg.
i want to do similar simulation.
So will you please send me pdf file of this program if you have downloaded on your computer because i can not open mph file. i m using older version of comsol and link is not working that you have shown in your msg.