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Electromagnetic wave / refractive index depends of Electromagnetic field
Posted May 15, 2015, 11:21 a.m. EDT Version 4.2 2 Replies
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Good afternoon everyone,
I'm student in an engineering school, and for an internship I need to use comsol. I have to study , electro-optic, and particularly modes at the exit of an light guide. For that I use maxwell equation given by the software , but theses equations consider the index of refraction constant and mine is not : I have some equation to know the evolution of the refractive index due to the Electromagnetic field .
So I have , on the one hand : Maxwell equation which give me the Electromagnetic field depending on the refractive index. (equation 1)
And on the other hand : My refractive index is depending of the Electromagnetic field. (equation 2)
So I would like to make iteration between theses 2 equations until the convergence, but I think that is not possible. Do you have any idea to consider the fact that the refractive index depends of the Electromagnetic field ?
I'm student in an engineering school, and for an internship I need to use comsol. I have to study , electro-optic, and particularly modes at the exit of an light guide. For that I use maxwell equation given by the software , but theses equations consider the index of refraction constant and mine is not : I have some equation to know the evolution of the refractive index due to the Electromagnetic field .
So I have , on the one hand : Maxwell equation which give me the Electromagnetic field depending on the refractive index. (equation 1)
And on the other hand : My refractive index is depending of the Electromagnetic field. (equation 2)
So I would like to make iteration between theses 2 equations until the convergence, but I think that is not possible. Do you have any idea to consider the fact that the refractive index depends of the Electromagnetic field ?
2 Replies Last Post May 22, 2015, 3:55 a.m. EDT
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Posted:
10 years ago
Jean:
I must admit I am not sure how to link a field-dependent refractive index, but if there is any way to do it, I would think you might set it up similarly as you would for a frequency-dependent index. I explained how to set this up in the past:
www.comsol.com/community/forums/general/thread/40533
In this case you set up an interpolation of a known index across a given spectral range, and use root.freq to pick out the interpolated value during computation. Perhaps it can be done the same way for the field: set up a range of field values (if you can guess a range of values that would bound all expected field values) and link your dependent variable (ewfd.Ex, for example) to the index. So instead of your index value given as n(root.freq) you would have n(root.comp1.ewfd.Ex), perhaps?
Good luck!
-Ado
I must admit I am not sure how to link a field-dependent refractive index, but if there is any way to do it, I would think you might set it up similarly as you would for a frequency-dependent index. I explained how to set this up in the past:
www.comsol.com/community/forums/general/thread/40533
In this case you set up an interpolation of a known index across a given spectral range, and use root.freq to pick out the interpolated value during computation. Perhaps it can be done the same way for the field: set up a range of field values (if you can guess a range of values that would bound all expected field values) and link your dependent variable (ewfd.Ex, for example) to the index. So instead of your index value given as n(root.freq) you would have n(root.comp1.ewfd.Ex), perhaps?
Good luck!
-Ado
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Posted:
10 years ago
Thanks for your answer , I have finaly just changed the index in the material properties . But I have another problem which cannot let me see if this solution works.
I apply a Electromagnetic , and an electrostatic field and try to look the modes .
So I use the Mode Analysis , but the study about the mode analysis changes the value of the Electrostatic field to absurds values ( Even If I apply 0 V between my 2 electrods ) : I have a kind of noise but very important .
Do you know why this study change the Electrostatic field and how I can overcome this problem ?
Thank you !
I apply a Electromagnetic , and an electrostatic field and try to look the modes .
So I use the Mode Analysis , but the study about the mode analysis changes the value of the Electrostatic field to absurds values ( Even If I apply 0 V between my 2 electrods ) : I have a kind of noise but very important .
Do you know why this study change the Electrostatic field and how I can overcome this problem ?
Thank you !