plasmonic Directional Coupler

fdtd
waveguide
plasmonics
directional_coupler

#1

hi
is it possible to couple light between 2 waveguides in plasmonic structure ?!
just like this directional coupler:
https://kb.lumerical.com/en/pic_passive_waveguide_couplers_evanescent.html

here is my structure:
directional coupler plasmonic.fsp (1.2 MB)

if it is possible, what changes and info will I be needing?!


#2

It is possible but the gap should be much smaller than the skin depth of the silver; in range of 10 to 20 nm, to allow for coupling between the 2 MIM waveguides.


#3

How can I control the light that is being coupled into the waveguide?!
In simple directional couplers like the one in the example above, a LC is used as a controllable RI material.
To have a change in refractive indext in plasmonic material with the control of light, I have to use Kerr nonlinear material. But I don’t know where to use it! How do you think I can achieve that?!


#4

Sorry, what is the LC? Do you mean the coupling length? If so, then, I suppose you can fill the slot of the MIM waveguides with a non-linear material to control the coupling coefficient by the incident light intensity. Is this your question?


#5

LC refers to Liquid Crystal.

I know I should use kerr nonlinear material in one arm to control light, but what ever I do, still the waveguide which the input light is coupled to, gets the most share of the input light and the coupling light is not under my control!
where do you think I should use NL kerr material in my structure?