Learning Forum

[Guanhui Wang]

The waveguide most important dimension is its thickness, that supposed to be around 110nm-125nm, in order to insure a single mode propagation. I got that dimension size from analytical calculation (V-number method). Does Lumerical have a better (simulative) way to calculate it?nI need to know (or see) the number of mods propagating in order to compare it to the analytical calculation (single mode).nHow can I see the propagating mods inside the Silicon Nitride layer itselft, and not at the whole structure? How do I need to setup the Eigenmode solver parameters? I would appreciate if you could explain it in as much details as you can, I pretty new to the software and having trouble understanding how to setup the simulations specific to what I need…nI attached my preliminary design in a sketch, it has more dimension sizes so you could understand the “bigger picture”. Could you maybe help me build it or explain to me how to? also, in the design there is a binary grating, it is only an initial structure, and the main goal is that the grating will be more customized one, more like a cut sinus profile, or dome-like lines. Could it be design in Lumerical?nnThanks again for all your help.n

[Guanhui Wang]

Thanks for trying Lumerical and I hope you will have a good experience using our software.nAll you want is doable using FDE, and we can discuss it more as we progress on the specific application that you are interested. If you are new to the software, I recommend you watching this introductory webinar:nhttps://www.lumerical.com/support/courses/mode_introductory_webinar_video.html 115nA similar example as what you are trying to simulate is the arrow waveguides:nhttps://kb.lumerical.com/en/index.html?nanophotonic_applications_arrow_waveguide.html 81nTo begin with, I recommend you start building geometry and add FDE simulation region. Then you can run the simulations and extract the modes.nOf course this will be the first step to calculate the modes inside the waveguide, but later on we can develop it to simulate your case. You should be able to find many useful links, example of which can be found in the link below:n 2D FDE mode solver Eigenmode AnalysisnHi everyone I am constructing a waveguide in mode solution using 2D FDE solver to support 3 modes. The problem is when putting this in FDTD solution and adding a mode source to enter one mode, I do not get the modes I saw in mode solution to choose from them!! I got new modes with different refractive indices (the effective index is important for the whole design parameters, length, coupling,?). Any help will be appreciated.n