I am simulating slot waveguide using mode analysis in wave optics module performed in COMSOL multiphysics. I got the results and also the effective mode index for our mode. however, when I calculate the effective mode index analytically using Matlab, the result is different a bit with the result obtained by COMSOL. why? the effective mode index can be computed by a simple equation in which we divide propagation constant over the wave number.(Neff = B/k0, B= propagation constant and K0= wave number). is there any way except this formula to calculate effective mode index? can any one explain what should I do?
Any help will be appreciated.
#waveguides
#Sensors
#Plasmonics
#Comsol
Hello, Actually, I don't understand " however, when I calculate the effective mode index analytically using Matlab, the result is different a bit with the result obtained by COMSOL ",
In my view, for a slot waveguide, the mode can't be solved analytically. Only the fiber mode can be solved analytically using the Bessel functions as a basis. Other waveguide such as rectangle waveguide will use some approximations to describe the mode.
COMSOL will solve the eigenvalue problem numerically and get the propagation constant \beta, and the effective index Neef will also be calculated by using the relation you mentioned.
Solving the mode for the solt waveguide numerically is the only and correct way. To improve the results, maybe you can use finer mesh, bigger simulation domain etc.
Zhaohua Tian
Dear Tian,
Thanks for responding me.
I got your meaning.
Kind Regards,
Parviz
Therer are more method to anlysis EM modes:
One of theme Mode anlysis, which you can found it in mathwork web as package.
Another method is called Marcetili Method.
And high grad index, and low grad index.
Finally, Fdtd, FEM.
hello, sir
I am new to COMSOL multiphysics. what is an effective mode index? why I am getting imaginary and real values in it when I simulate in COMSOL multiphysics and at a certain value, I can see the electric field can you explain it sir
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