Learning Forum

[Frederic Wu]

In Lumerical FDTD, it is possible to sweep multiple parameters by defining the values or range that the user wants to sweep. However, performing optimization is more challenging. In my case, I want to simulate NbN absorption, which requires the NbN thin film and the absorbed power (Pabs) to move together. Additionally, any movement of the NbN layer should also cause the underlying silicon layer to move accordingly. Is it possible to instruct the optimization algorithm to change these three parameters in a coordinated fashion, maintaining their relationship during the optimization process?

[Guilin Sun]

Once you set the parameters and the geometry build-up correctly, it should work. Suppose the frst layer begins at z0, and their thickness is d1,d2,d3:

setnamed("layer1","z min",z0);

setnamed("layer1","z max",z+d1);

setnamed("layer2","z min",z+d1);

setnamed("layer2","z max",z+d1+d2);

setnamed("layer3","z min",z+d1+d2);

setnamed("layer3","z max",z+d1+d2+d3);

then you can optimize d1,d2 and d3.