Learning Forum

[notyourphoton]

I am new to Lumerical, and I have tried searching through different examples, but I couldn't get a direct answer. If yes, what Lumerical packages do we need to simulate such a structure? If someone can help with this, I would be grateful. Thanks in advance.

[Guilin Sun]

For nonlinear material, whether it is layered or not, as long as the nonlinear material can be well modeled, you can simulate it using FDTD or varFDTD.
Current nonlinear material models:
Advanced and custom optical material models in FDTD and MODE
Examples:
Nonlinear optics - list of examples

[notyourphoton]

Thank you for getting back to me on this, but can we use a broadband pulse to simulate such a structure? Or we can only use CW sources? Moreover, is there any other way to simulate such structures with broadband pulses if it can't be done using FDTD.

[Guilin Sun]

This will depend on your goal and type of nonlinear effects: for laser single wavelength is needed. For other cases, if your Chi coefficients are not dispersive the result ight not accurate, and there are many more "generated" wavelengths. For example, in SHG, you have one fundamental frequency then you will have the 2nd, and 3rd frequencies. If the fundamental frequency is broadband, then you will get a broadband 2nd and 3rd harmonics. I am not sure it this is desired. In addition, the other "generated" frequencies will depend on the intensity of the incident source. When a broadband source is used, you may not know exactly how strong the incident source at each fundamental frequency will be, and it will depend on the pulse shape and carrier frequency.
In principle there is nothing to forbid using broadband pulse though. Please try and see if the results are expected.