Getting started in Lumerical Mode solutions


Hi All

I just installed my Trial version in order to test the software if it suitable to our needs.
I need to simulate a Silicon Nitride waveguide that is attached to a SiO2 layer on top of Silicon substrate.
I need to see the mode that are propagating inside the waveguide, as the mods are results of diffractive orders coming from a grating (from another simulation at another software).
Did anyone do something similar to the above and can send me a detailed manual or instruction of how to do what I need?

Many thanks in advanced…


Hi @yaakobio
In Lumerical’s knowledge base you can find details about MODE Solutions and waveguide simulations. You can read the introductory webinar (here). Also, here you can find the information about the basic waveguide properties (here). Let me know if you need more help.

Best regards


Hi, Thanks for the reply.

Unfortunately, these links are more suitable to people who have some
experience with the software, Which I don’t.

The examples are a little bit far from what I need to build. Could you help
me understand if my design can be built in the software?

I need, for the first step, to build a Silicon Nitride Waveguide on top of
SiO2 and with a Silicon substrate. I need to know only the power of the
modes getting inside and outside of the waveguide, and only the number of
modes that are propagating inside, and nothing else.

At the second step, I need to check the coupling efficiency from a n=1.4
binary grating - do you know if it can be done in the software?

I would really appreciate if you could explain me how to build and simulate
the above structures, it will really help me.

Thanks in advanced,


2017-04-26 21:15 GMT+03:00 Konstantinos KXC Lekkas <>:


Hi @yaakobio
Sorry for the delay. All the materials that you referred exist in materials list of MODE and FDTD. Concerning Silicon Nitride you have two material options.You can choose either “Silicon nitride-Kischkat” or “Silicon nitride-Philipp”. The number of modes depend from the dimensions of the waveguide. Could you please tell me the waveguide dimensions and the kind of Silicon nitride material?Three layer waveguide.lms (272.0 KB)


Hi again, and thank you very much again for helping me !

  1. 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?

I need to know (or see) the number of mods propagating in order to compare
it to the analytical calculation (single mode).

  1. How 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…

  2. I 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?

Thanks again for all your help.


2017-05-16 21:42 GMT+03:00 Konstantinos KXC Lekkas <>:


Dear @yaakobio

Thanks for trying Lumerical and I hope you will have a good experience using our software.

All 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:

A similar example as what you are trying to simulate is the arrow waveguides:

To begin with, I recommend you start building geometry (as @konslekk started preparing some files) and add FDE simulation region. Then you can run the simulations and extract the modes.

Of 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:

Please keep me updated with your thoughts and simulation file, and I will be glad to be of a help.